Presentation on theme: "ECGECG ANTENATAL AND INTRAPARTUM FETAL SURVEILLANCE USG Doppler CTG."— Presentation transcript:
ECGECG ANTENATAL AND INTRAPARTUM FETAL SURVEILLANCE USG Doppler CTG
MAJOR CAUSES OF PERINATAL LOSS Fetal abnormality Preterm delivery Chronic utero – placental insufficiency Acute Hypoxia Unexplained intrauterine death Others
MODALITIES OF ANTENATAL FETAL SURVEILLANCE Detection of fetal abnormalities Assessment of fetal growth Monitoring of fetal well-being Others
APPROACH TO ANTENATAL MONITORING OF FETAL GROWTH AND WELL-BEING Confirmation of gestational age Clinical methods of monitoring Investigations
DYNAMIC PARAMETERS To monitor fetal dynamic response to chronic utero-placental insufficiency AFI – renal perfusion Umbilical arterial flow (A/B ratio) – fetal peripheral and placental circulation Cerebral arterial flow (MCA) – head sparing effect
FETAL MONITORING Fetal distress is defined in terms of the manifestation of the fetal hypoxia (by changes in the fetal heart rate FHR or fetal blood pH) SIGNIFICANCES OF FETAL DISTRESS Hypoxic damage to the foetus is difficult to quantify, but the effect can be devastating. - neurological abnormalities - cerebral palsy and mental retardations - fetal death – results from severe intrapartum asphyxia
BASIC DEFINITIONS HYPOXAEMIA - decrease in the oxygen content of the arterial blood alone HYPOXIA - decrease in the oxygen content that affects the peripheral tissues ASPHYXIA - general oxygen deficiency that affects the high priority organs as well
PATHOPHYSIOLOGY OF FETAL HYPOXIA In the absence of stress, the fetus is neither acidotic nor hypoxic. An adequate delivery of oxygen to the tissues occurs despite the low fetal arterial partial pressure of oxygen (pO 2 ). The transfer of oxygen across the placenta to the fetus is enhanced by following mechanisms : - fetal cardiac output and systematic blood flow rates are higher than those of the adult. - the affinity of fetal blood for the oxygen and - the fetal oxygen – caring capacity, both of which are greater than those of an adult
PATHOPHYSIOLOGY OF CHRONIC FETAL COMPROMISE utero-placental insufficiency reduced pO2 to fetal CNS redistribution of fetal cardiac output perfusion to CNS & heartperfusion to peripheral & viscera renal perfusion visceral circulation OLIGOHYDRAMNIOS bowel distensionumbilical arterial resistance meconium peritonitis necrotising enterocolitis etc
A decreased amniotic fluid volume is frequently one of the first clues to an underlying fetal abnormality. The sonographer/sonologist should, therefore, have a basic understanding of the mechanisms responsible for normal amniotic fluid production. Once the derivation of amniotic fluid is understood, the potential mechanisms that can result in oligohydramnios can be better appreciated.
Etiology of Oligohydramnios 1. intrauterine growth restriction 2. post-term pregnancies 3. preterm rupture of the membranes 4. fetal anomalies and/or aneuploidy 5. iatrogenic
30 week gestation. A single deepest pocket of amniotic fluid (7 cm), indicating a normal amniotic fluid volume. Visually normal amniotic fluid volume at 18 weeks' gestation. Subjective assessment of amniotic fluid volume. 20 week fetus with a unilateral multicystic kidney and congenital absence of the other kidney, resulting in anhydramnios 1.8 cm pocket of amniotic fluid indicating oligohydramnios. The color box confirms that umbilical cord is not present in the pockets of amniotic
Oligohydramnios due to bilateral renal agenesis. Transabdominal ultrasound at 20 weeks' gestation.
An amniotic fluid index of 4.2 cm, indicating oligohydramnios there is an absence of amniotic fluid in the upper quadrants. The color box to the right of the image indicates the presence of umbilical cord.
19 week fetus with Turner's syndrome, cystic hygroma (arrows) and oligohydramnios. 15 week fetus with posterior urethral valves. The bladder (b) is massively distended. Enlarged "key-hole" bladder associated with posterior urethral valves.
Amniotic fluid has a number of important roles in embryo/fetal development: 1. Permitting fetal movement and the development of the musculoskeletal system. 2. Swallowing of amniotic fluid enhances the growth and development of the gastrointestinal tract. 3. The ingestion of amniotic fluid provides some fetal nutrition and essential nutrients.
Amniotic fluid has a number of important roles in embryo/fetal development: 4. Amniotic fluid volume maintains amniotic fluid pressure thereby reducing the loss of lung liquid an essential component to pulmonary development. 5. Protects the fetus from external trauma. 6. Protects the umbilical cord from compression. 7. It's constant temperature helps to maintain the embryo's body temperature. 8. It's bacteristatic properties reduces the potential for infection.
STRESSED FETUS When perfusions is decreased because of impaired uterine or umbilical blood flow, the transfer of oxygen to the fetus is diminished, and the results is an accumulations of carbon dioxide in the fetus. 1. Increased carbon dioxide causes an increase in the partial pressure of carbon dioxide (pCO 2 ) and a concomitant fall in pH, analogous to adult respiratory acidosis. 2. Continued hypoxia deprives the fetus of sufficient oxygen to perform the aerobic reactions, resulting in buildup of organic acids with the accumulation of pyruvic and lactic acids resulting in metabolic acidosis
STRESSED FETUS 3. Transient decreases in the fetal or uterine perfusions usually cause a short-lived respiratory acidosis, whereas more prolonged or profound decreases results in a combined respiratory and metabolic acidosis 4. fetal oxygen deprivation usually results in the FHR or fetal bradycardia
FETAL DEFENCE MECHANISMS Increased tissue oxygen extraction Reduced non-essential activity Increased sympathetic activity Redistribution of blood flow Anaerobic metabolism with the metabolism of blood sugar – glucolysis, and glycogen - glycogenolisis
Hipoxaemia More effective uptake of oxygen Reduced activity Decrease in growth rate Maintained energy balance FETAL RESPONSE TO HYPOXAEMIA sO 2 t days and weeks hoursminutes Hypoxia Asphyxia
Hipoxaemia Hypoxia Asphyxia Surge of stress hormones Redistribution of blood flow Peripheral tissue anaerobic metabolism Maintained energy balance FETAL RESPONSE TO HYPOXIA sO 2 t days and weeks hoursminutes
Hipoxaemia Hypoxia Asphyxia Alarm reaction Anaerobic metabolism in the central organs The heart fails to function FETAL RESPONSE TO ASPHYXIA sO 2 t days and weeks hoursminutes
Cardiotocography Contraction stress test Nonstress test Biophysical profile Fetal movement counts Umbilical artery Doppler velocimetry Fetal electrocardiography Fetal pulse oxymetry Fetal blood sampling ANTENATAL AND INTRAPARTUM FETAL SURVEILLANCE
Fetal Neurodevelopment and Sequence of Fetal Deterioration CST=contraction stress test; NST=nonstress test; BPP=biophysical profile.
BIOPHYSICAL PROFILE biophysical profile was first introduced in the late 1970s. It requires more expensive equipment and more highly trained personnel than the other testing modalities. The study is based on the concept that hypoxic fetuses lose certain behavioral parameters in the reverse order in which they were acquired in the course of fetal development It evaluates indicators of chronic fetal hypoxia and placental function, such as amniotic fluid volume, in addition to more acute indicators, such as fetal breathing, movements and tone.
PATHOPHYSIOLOGY OF BIOPHYSICAL VARIABLES The gradual hypoxia concept Fetal CNS centresembriogenesis FTcortex FMcortex-nuclei FBMventral surface of 4th ventricle FHRposterior hypothalamus medulla hypoxia
INTERNAL FETAL HEART MONITORING IS DONE TO: - help determine whether the stress of labor is threatening the health of the fetus. - measure the strength and duration of labor contractions.
CONTINUOUS ELECTRONIC FETAL MONITORING
CC = cord compression; FA = fetal anaemia; FS = fetal sepsis; Other = other mechanisms; RFR = reduced fetal nutritional reserves; RUPO = reduced uterine perfusion or oxygen delivery (no vascular disease); UPVD = uteroplacental vascular disease Indications for continuous electronic fetal monitoring
Maternal Chronic hypertension Collagen-vascular diseases Sickle cell anemia Current substance abuse Impaired renal function Asthma Pneumonia Significant cardiac disease Seizure disorders Diabetes Acute febrile illnesses Significant anemia (hematocrit <26%) Fetal Intrauterine growth restriction Congenital anomalies Fetal cardiac arrhythmias Isoimmunization Hydrops fetalis Fetal infections such as parvovirus, coxsackievirus B, syphilis, toxo Pregnancy-related Poorly controlled gestational diabetes Multiple gestations Pregnancy-induced hypertension Cholestasis of pregnancy Premature rupture of the membranes (preterm) Unexplained elevated maternal serum alpha-fetoprotein Polyhydramnios Oligohydramnios Placental abruption Abnormal placentation Postdates Unexplained stillbirth in a prior pregnancy CONDITIONS THAT PLACE FETUSES AT RISK FOR ADVERSE OUTCOMES
ANTENATAL RISK FACTORS
INTRAPARTUM RISK FACTORS
ELECTRONIC FETAL MONITORING
TermDefinition Baseline fetal heart rate The mean level of the FHR when this is stable, excluding accelerations and decelerations. It is determined over a time period of 5 or 10 minutes and expressed in bpm. Preterm fetuses tend to have values towards the upper end of this range. A trend to a progressive rise in the baseline is important as well as the absolute values Normal Baseline FHR bpm Moderate bradycardia bpm Moderate tachycardia bpm Abnormal bradycardia <100 bpm Abnormal tachycardia 180 bpm
Baseline variability The minor fluctuations in baseline FHR occuring at three to five cycles per minute. It is measured by estimating the difference in beats per minute between the highest peak and lowest trough of fluctuation in a one-minute segment of the trace Normal baseline variability Greater than 5 bpm between contractions Non-reassuring baseline variability Less than 5 bpm for 40 minutes but less than 90 minutes Abnormal baseline variability Less than 5 bpm for 90 minutes Accelerations Transient increases in FHR of 15 bpm or more and lasting 15 seconds or more. The significance of no accelerations on an otherwise normal CTG is unclear
Decelerations Transient episodes of slowing of FHR below the baseline level of more than 15 bpm and lasting 15 seconds or more Early decelerations Uniform, repetitive, periodic slowing of FHR with onset early in the contraction and return to baseline at the end of the contraction Variable decelerations Uniform, repetitive, periodic slowing of FHR with onset mid to end of the contraction and nadir more than 20 seconds after the peak of the contraction and ending after the contraction. In the presence of a non-accelerative trace with baseline variability < 5 bpm, the definition would include decelerations < 15 bpm Variable decelerations Variable, intermittent periodic slowing of FHR with rapid onset and recovery. Time relationships with contraction cycle are variable and they may occur in isolation. Sometimes they resemble other types of deceleration patterns in timing and shape
Atypical variable decelerations Variable decelerations with any of the following additional components: loss of primary or secondary rise in baseline rate slow return to baseline FHR after the end of the contraction prolonged secondary rise in baseline rate biphasic deceleration loss of variability during deceleration continuation of baseline rate at lower level Prolonged deceleration An abrupt decrease in FHR to levels below the baseline that lasts at least seconds. These decelerations become pathological if they cross two contractions, i.e. greater than 3 minutes Sinusoidal pattern a regular oscillation of the baseline long-term variability resembling a sine wave. This smooth, undulating pattern, lasting at least 10 minutes, has a relatively fixed period of 3--5 cycles per minute and an amplitude of bpm above and below the baseline. Baseline variability is absent
CATEGORISATION OF FETAL HEART RATE TRACES
CATEGORISATION OF FETAL HEART RATE FEATURES
ELEMENTS OF FHR PATTERN The baseline FHR – is the steady rate fetal that occurs during and between contractions in the absence of accelerations and decelerations. The normal baseline FHR is beats per minute. At 16 weeks, the average baseline is 160 BPM. The baseline FHR decreases approximately 24 BPM from 16weeks to term.
BEAT TO BEAT VARIABILITY represents the continuous interaction of the sympathetic and parasympathetic nervous system in adjusting the FHR to fetal metabolic or hemodynamic conditions. -decreased variability may signify loss of fine autonomic control of FHR - good variability usual predict a good fetal outcome
DECELERATIONS Periodic changes in the FHR assume importance in defining the mechanism and intensity of asphyxia insults. There are 3 patterns of periodic decelerations based on the configuration of the waveform and the timing of the deceleration in relation to the uterine contraction. 1.EARLY DECELERATIONS 2.LATE DECELERATIONS 3.VARIABLE DECELERATION
EARLY DECELERATIONS -are not caused by systemic hypoxia -do not appear to be associated with poor fetal outcome -occur with fetal head compressions -begin with the onset of uterine contractions -reach their lowest point at the peak of the contraction -Return to baseline as the contraction ends
LATE DECELERATIONS Occur in situations : - ablation of placentae - maternal acute hypotension - hyper stimulation during oxitocin infusion - acute decrease in the intervillous space flow Are found with increased frequency : - preeclampsia - hypertension - diabetes mellitus - intrauterine growth retardation - other disorders associated with chronic placental insufficiency.
LATE DECELERATIONS -usually are associated with acute/chronic fetoplacental insufficiency -occur after the peak of the uterine contraction -are precipitated by hypoxemia (which slows the FHR as results of CNS asphyxia) or direct myocardial depression and associated with mixed respiratory and metabolic acidosis
VARIABLE DECELERATIONS - are inconsistent in configurations - have no uniform temporal relationship to the onset of the contraction - usually are the results of compressions of the umbilical cord between fetal parts and surrounding maternal tissues - often are associated with oligohydramnions (ex. PROM) - may be associated with profound combined acidosis
In the presence of abnormal FHR patterns and uterine hypercontractility (not secondary to oxytocin infusion) tocolysis should be considered. A suggested regimen is subcutaneous terbutaline 0.25 mg. In cases of suspected or confirmed acute fetal compromise, delivery should be accomplished as soon as possible, accounting for the severity of the FHR abnormality and relevant maternal factors. The accepted standard has been that, ideally, this should be accomplished within 30 minutes.
FETAL BLOOD SAMPLING
CLASSIFICATION OF FETAL BLOOD SAMPLE RESULTS
FETAL MOVEMENT COUNTS Perception of fetal movement is an inexpensive, noninvasive method of assessing fetal well-being. Generally, the patient is asked to relax on her left side 30 minutes after eating and to concentrate on fetal movement. The patient should record the time that she starts the test and note each time the baby kicks or moves. A healthy fetus should move approximately three to five times within one hour in this setting.
An alternative method is the Cardiff Count-to-Ten chart, whereby the patient records fetal movements during the course of usual daily activity. A period of 12 hours without at least 10 perceived movements is considered a warning signal. If the test result is not reassuring, the patient should be evaluated and should undergo further testing, such as evaluation with a nonstress test. FETAL MOVEMENT COUNTS
Studies have shown that fetal movement counts are an effective screening measure, with reported reductions in fetal mortality from 8.7 deaths per 1,000 live births to 2.1 deaths per 1,000 live births. Although the ideal method for performing the test, including how often it should be repeated, has not been defined, it is clear that complaints of decreased fetal movement are significant and warrant further evaluation.
NONSTRESS TEST Nonstress test is an indirect measurement of uteroplacental function. The patient is usually seated in a reclining chair, slightly tilted to the left to avoid supine hypotension. A Doppler ultrasound transducer and a tokodynamometer are used to monitor the fetal heart rate and uterine activity simultaneously. Fetal movements can also be recorded during the test. A reassuring, or reactive, nonstress test exhibits at least two accelerations in the fetal heart rate in a 20-minute period that are at least 15 beats per minute above the baseline and last at least 15 seconds. A nonreactive test does not meet these criteria.
NONSTRESS TEST Fetal heart rate reactivity is a reflection of the balance between the fetus's sympathetic and parasympathetic tone. It is an acquired neurologic reflex and is therefore dependent on gestational age: about 65 % of healthy fetuses will have a reactive nonstress test at 28 weeks of gestation, 85 %t at 32 weeks of gestation and 95 % at 34 weeks of gestation. Fetal heart rate accelerations are coupled to fetal movement as the fetus matures; consequently, they will be seen more frequently when the fetus is awake or in an active sleep state. Since fetuses can have normal sleep cycles lasting up to 40 minutes, a nonstress test might require over an hour to complete if it is initially nonreactive. It is important to differentiate whether a nonreactive tracing truly represents a compromised fetus or merely reflects a temporary behavioral state.
CONTRACTION STRESS TEST
Doppler ultrasound in high risk pregnancies (Protocol for a Cochrane Systematic Review) Department of Obstetrics and Gynaecology of the Center for Integral Attention to Women’s Health (CAISM) State University of Campinas (UNICAMP), Brazil
The first Doppler ultrasound report using continuous wave assessment of umbilical artery flow was published in 1977 (Fitzgerald 1977). With the use of colour Doppler, in 1987, it was possible to study the middle cerebral artery in fetuses and compare to umbilical artery pulsatility index (PI) ratio to demonstrate centralization of the fetal circulation (Wladimiroff 1987). Waveforms in the ductus venosus, was recognized as a key examination to predict right heart failure in the hypoxic fetus and an important indicator of imminent fetal demise (Kiserud 1991). The relationship between abnormal uterine artery Doppler velocimetry and pre-eclampsia, intra-uterine growth retardation and adverse pregnancy outcome is well established (Aquilina 1996).
When the fetus is hypoxic, the cerebral arteries tend to become dilated in order to preserve the blood flow to the brain. In the middle cerebral artery, the systolic to diastolic (A/B) ratio will decrease (due to an increase in diastolic flow) in the presence of chronic hypoxic insult to the fetus. This increase in blood flow can be evidenced by Doppler ultrasound of the middle cerebral artery. This effect has been called "brain sparing effect" and is demonstrated by a lower value of the pulsatility index.
UMBILICAL ARTERY DOPPLER VELOCIMETRY... is based on the observation that flow velocity waveforms in the umbilical artery of normally growing fetuses differ from those of growth-restricted fetuses. Specifically, the umbilical flow velocity waveform of normally growing fetuses is characterized by high- velocity diastolic flow, whereas with intrauterine growth restriction, there is diminution of umbilical artery diastolic flow. In some cases of extreme intrauterine growth restriction, flow is absent or even reversed.
Normal Doppler waveform of umbilical artery
Normal Doppler waveform of umbilical artery
Abnormal Doppler waveform of umbilical artery showing absent end diastolic flow (AEDF)
Abnormal Doppler waveform of umbilical artery showing reversed end diastolic flow (REDF)
Normal Doppler waveform of uterine artery
Abnormal Doppler waveform of uterine artery “Notch”
Normal Power-Doppler waveform of middle cerebral artery
Normal Doppler waveform of middle cerebral artery
Abnormal Doppler waveform of middle cerebral artery Normal high diastolic velocities
Normal ductus venosus waveform at 25 weeks of gestation
Normal flow velocity waveforms of the ductus venosus
Normal Ductus venosus sonogram. Positive A wave. Abnormal Ductus venosus sonogram. Reverse A wave S= systole; D= diastole; A= atrial contraction
Abnormal waveform with reversal of flow during atrial contraction
T/QRS riseBiphasic ST type 1 Biphasic ST type 2 Biphasic ST type 3
Suspicious CTG Pathological CTG Inadequate quality CTG poor contact from external tranducer? FSE not working or detached? Check: maternal pulse, position of transducer, consider applying FSE. Uterine hypercontactility Is the mather receiving oxytocin? Has the mother recently received vaginal prostaglandins? Stop oxytocin infusion consider tocolysis Maternal tachycardia/pyrexia maternal infection? Tocolytic infusion? Dehydrated? Other maternal factors what is the maternal position ? Is the mother hypotensive? Has she just had a vaginal examination? Has she had a vasovagal episode? Has she just had an epidural? Fetal blood sampling indicated Fetal blood sampling inappropriate Encourage mother to adopt left lateral position Check blood pressure give crystalloid if appropriate Encourage mother to adopt left lateral position Check blood pressure give crystalloid if appropriate Expedite delivery Urgency of delivery should take into account the severity of the FHR abnormality and relevant internal factors IF T>38 consider screening and treatement If pulse >140/min. reduce Tocolytic infusion Check blood pressure give crystalloid if appropriate Encourage mother to adopt left lateral position Check blood pressure give crystalloid if appropriate >7,25 FBS should be repeated if the FHR abnormality persists 7,21-7,24 repeat FBS within 30 min. or consider delivery if rapid fall since last sample <7,20 Delivery indicated (all scalp pH estimations should be interpreted taking into the previous pH measurment, the rate of progress in labour, clinical features of the mother and baby)
Yes Intremittent ausculation for full minute after a contraction Abnormal FHR on ausculation Baseline 160bpm Any decelerations Yes CONTINUOUS ELECTRONIC FETAL MONITORING Are any of the following risk factors present? Maternal problems: previous cesarean section Pre-eclampsia Post-term pregnancy (>42weeks) Prolonged membrane rupture (>24hs) Induced labour Diabetes Antepartum haemorrhage Other maternal medical disease Fetal problems: Fetal growth restriction Prematurity Oligohydramnios Abnormal Doppler artery velocimetry Multiple pregnancy Meconium-stained liquor Breech presentation Cardiotocograph classification NORMALA CTG where all four features fall into the reassuring category SUSPICIOUSA CTG where features fall into one of the non-reassuring categories and the remainder of the features are reassuring PATHOLOGICAL A CTG where features fall into two or more of the abnormal categories Fetal heart rate feature classification Baseline(bpm)variability(bpm)DecelerationAcceleration Reassuring 5nonepresent Non-reassuring <5 for 40early <90minutesvariable single prolonged up to 3 minutes Abnormal<100<5 for 90Atypical variable >180minuteslate sinusoidal single prolonged pattern for 10min.greater than 3 min. The absence of accelerations with an otherwise normal CTG is of uncertain significance Offer and recommend continuous EFM Intrapartum risk factors oxytocin augmentation epidural analgesia vaginal bleeding in labour maternal pyrexia fresh meconium-stained liquor Yes No
„ There are still those who think that the delivery of a woman is easy. ” François Mauriceau, 1694
PELVIMETRY SHOULD BE DONE AS A MATTER OF ROUTINE IN ALL PRIMIPARAE Following pelvic measurements, should be taken : The intercristal The interspinous The intertrochanteric The external conjugate
28 cm 25 cm 31 cm EXTERNAL DIMENSIONS OF THE BONY PELVIS The intercristal The interspinous The intertrochanteric
THE BONY PELVIS
Iliac crest – provides attachments to the iliac fascia, abdominal muscles,and fascia lata. Anterior superior and inferior spine – superior spine provides the point of fixation of the inguinal ligament Posterior superior and inferior spine – superior spine is the point of attachment for the sacrotuberous ligament and the posterior sacral iliac ligament. Arcuate line – marks the pelvic brim and lies between the first two segments of the sacrum Iliopectineal eminence (linea terminalis) – the line of junction of the ilium and the pubis. Iliac fossa – the smooth anterior concavity of the ilium, covered by the iliacus muscle. ILIUM
Ischial spine – delineates the greater and lesser sciatic notch above and below it. It is the point of fixation for the sacrospinous ligament. The ischial spine represents an important landmark in the performance of pudental nerve block and sacrospinous ligament vaginal suspension; vaginal palpation during labor allows detection of progressive fetal descent. Ischial ramus – joins that of the pubis to encircle the obturator foramen; provides the attachment for the inferior fascia of the urogenital diaphragm and the perineal musculofascial attachments. ISCHIUM
Body – formed by the midline fusion of the superior and inferior pubic rami. Symphysis pubis – a fibrocartilaginous symphyseal joint where the bodies of the pubis meet in the midline ; allows for some resilience and flexibility, which is critical during parturition. Superior and inferior pubis rami – join the ischial rami to encircle the obturator foramen. Provide the origin for the muscles of the thigh and leg. Provide the attachment for the inferior layer of the urogenital diaphragm. Pubic tubercle – a lateral projection from the superior pubic ramus, to which the inguinal ligament, rectus abdominis, and pyramidalis attach. PUBIS
1- TRUE CONJUGATE DIAMETER ( 10,5 - 11,5 cm ) 2- OBSTETRIC CONJUGATE ( cm ) 3- DIAGONAL CONJUGATE DIAMETER ( 12,5 cm ) PELVIC DIAMETERS 1 2 3
For obstetrical purposes, the pelvis is described as having 3 imaginary planes Plane of the inlet: Four diameters have been described. Anteroposterior diameter: This is the distance between the sacral promontory and the symphysis pubis; it is designated the obstetrical conjugate. This conjugate normally measures approximately 10 cm or more, but it may be shortened considerably in an abnormal pelvis. Transverse diameter: This is the greatest distance between the linea terminalis on either side of the pelvis. This imaginary line usually intersects the obstetrical conjugate at a point approximately 4 cm in front of the promontory. Two oblique diameters: Each of these diameters extends from one of the sacroiliac joints to the iliopectineal eminence on the opposite side of the pelvis. These diameters normally average less than 13 cm each.
Plane of the mid pelvis: This is the plane of the smallest dimensions. This plane is extremely important following engagement of the head in obstructed labor. The interspinous diameter (approximately >10 cm) usually is the smallest diameter of the pelvis.
Plane of the pelvic outlet: This consists of 2 triangular areas created from the connection of an imaginary line between the 2 ischial tuberosities. The apex of the posterior triangle is at the tip of the sacrum, and the apex of the anterior triangle is under the pubic arch. The following 3 diameters of the outlet are of importance: Anteroposterior diameter: This normally is cm and extends from the lower margin of the symphysis pubis to the tip of the sacrum. Transverse diameter: This commonly is 11 cm and is the distance between the inner edges of the ischial tuberosities. Posterior sagittal diameter: This usually exceeds 7 cm and extends from the tip of the sacrum to a right-angle intersection with the line between the ischial tuberosities.
Pelvis of Mrs H extremely distorted by Mollities Ossium, a disease of adult life, which leads to softening of the bones of the body. Brim triangular - nearly closed on the left side. Successful Caesarean section performed, May 1849.
Transversely Contracted Pelvis. "Robert" pelvis. Note the faulty development of the sacral alae. The patient from whom this pelvis was removed was admitted to St. Mary's Hospital in June 1867 and delivered by Caesarean Section. Mother –died Child- lived
Small Round Pelvis. The pelvis of Mrs B, aged 27 years who died of rupture of the uterus as a result of dystocia, 1st October, 1853.
Kyphotic or Funnel shaped Pelvis. The transverse diameters diminish from above downwards, being most contracted at the outlet. The conjugate of the outlet is also affected owing to the tilting forwards of thelower end of the sacrum.
Model of female pelvis of Mrs M. distorted by a large exostosis springing from and intimately connected with the sarum. This large bony tumour occupied the cavity of this bone and also that of the coccyx. Caesarean section was performed Sept 1829, Woman's age at time of birth 26. Duration of Labour –about 30 hours Mother - Died Child - Dead before operation.
Kyphotic or Funnel shaped Pelvis
„ The pelvis of Elizabeth Thompson is in the museum of St Mary's Hospital, Manchester, and was presented by me. There is a block of oak carved on the model which, with others, I have given to the aforesaid hospital. I have endeavoured to bring a mutilated infant through it, but I have never succeeded. However, it is one thing to operate on an inanimate machine, a block of wood, let it be ever so accurately formed, and another topo erate on the pelvis of a living woman. I deny the possibility of bringing a mutilated full-grown child through such a pelvis, whatever appliances are used." Thomas Radford
The passage of a baby through a normal pelvis during birth. The attempted passage of a baby through an abnormal pelvis during birth. Note how natural birth would have been impossible.
DIAMETERS OF THE FOETAL SKULL MENTO-OCCIPITAL (13.5cm) SUBOCCIPITO-BREGMATIC (9.5 cm) FRONTO-OCCIPITAL (12.0 cm)
POSTERIOR FONTANEL ANTERIOR FONTANEL SAGITAL S. LAMBOID S. CORONAL S.
STAGES IN THE MECHANISM OF LABOUR IN THE VERTEX PRESENTATION : Descent with engagement of the head and increased flexion Internal rotation Extension, resulting in the birth of the head Restitution, or the untwisting of the neck External rotation of the head, accompanied with internal rotation of the shoulders Delivery of the shoulders Expulsion of the rest of the body of the foetus
DESCENT The movement of descent is brought about by two factors : General contents pressure of the uterus before rupture of the membranes Foetal axis pressure which comes into effect after the rupture of the membranes
DESCENT In normal cases the head engages in what is known as a synclitic manner : the sagittal suture of the head lies in one or other of the oblique diameters of the pelvic brim, so that the parietal bones on either side are at the same level.
DESCENT where abnormalities of mechanism occur, the sagittal suture may be pushed towards the symphysis pubis (posterior asynclitism = Litzmann’s obliquity) or the sacral promontory (anterior asynclitism = Naegeli’s obliquity)
The fetal head descending through the pelvis in labour
The concept of the fetal head descending through the pelvis in labour is checked by vaginal examination when the level of the presenting part is assessed against the level of the ischial spines (in centimetres) vertically
ENGAGEMENT OF FETAL HEAD A- maximum diameter of head is above inlet of pelvis and head is not engaged; B- engagement has taken place (maximum diameter of head is below inlet of pelvis); C- head is not engaged; D- when mother sits up on her elbows,the head sinks in, an indication that the head will engage when labour starts
INTERNAL ROTATION The shape of the pelvis : the forward incline of the walls of the pelvic cavity helps to rotate forwards the most dependent part of the presenting pole. The tendency to forward rotation is helped by the contour of the musculo-fascial forming the pelvic floor.
INTERNAL ROTATION The impetus given by the spine of the ischium is another dominant causative factor in this phenomenon. The effective contractions of the uterus are essential to promote internal rotation.
EXTENTION is the resultant of forces : the effect of the uterine contractions from above and the elastic resistance of the pelvic floor from below
EXTENTION The occiput hitches against the symphysis pubis, the face sweeps over the perineum, and the successive parts of the foetal head to be born are the sinciput.
RESTITUTION As soon as the head is free outside the vulval outlet it rotates through 1/8 of a circle, and thus the neck is untwisted and the chin rotates towards the right (left occipito-ant. position) or the left (right occipito-ant. position)
EXTERNAL ROTATION After the untwisting of the neck has occurred, the next movement is one of internal rotation of the shoulders. This brings the anterior shoulder underneath the symphysis pubis, and with this movement occurs external rotation of the head: the bisacromial diameter is brought into the antero-posterior diameter of the pelvic outlet.
Once the shoulders have rotated into the antero-posterior diameter of the outlet, descent continues with the uterine contractions, until the anterior shoulder hitches underneath the symphysis pubis and the posterior shoulder sweeps over the perineum by a process of latero- flexion of the spine and is delivered first. EXTERNAL ROTATION
VAGINAL EXAMINATION IN LABOUR 1. Condition of the vulva, the vagina: the extent to which they are dilatable and the pressure of any lubricating mucus. 2. The condition of the cervix: whether the cervical canal is dilated and the extend to which the external os is dilated or dilatable. 3. The condition of the bladder and rectum
VAGINAL EXAMINATION IN LABOUR 4. Whether the membranes are entire or ruptured. If present, the nature of the bag and whether the membranes are tough. 5. The presenting part - whether it is the head or any other part of foetus, and the particular details concerning the presenting part. 6. The presence of a caput and the degree of moulding in cephalic presentations.
VAGINAL EXAMINATION IN LABOUR 7. The exact position of the presenting part with reference to the maternal pelvis is whether the head is at the brim, or through the inlet in the cavity, or at the outlet. 8. Whether in cases of cephalic presentation the occiput has rotated, and if so, to what extent.
VAGINAL EXAMINATION IN LABOUR 9. Whether the sacral promontory can be palpated or not. 10. The presence of abnormalities, such a prolapsed cord, or placenta praevia.
WHEN SHOULD THE MEMBRANES BE RUPTURED ARTFICIALLY? When the cervix is fully dilated and the bag of waters remains entire owing to tough membranes. In some cases of antepartum haemorrhage, rupturing the membranes controls bleeding.
WHEN SHOULD THE MEMBRANES BE RUPTURED ARTFICIALLY? As a method of induction of labour As a preliminary to operative delivery
STAGES OF LABOUR I - the stage of dilatation II - the stage of expulsion III - the stage of placental delivery and uterine contraction and retraction
THE FIRST STAGE True uterine contractions, or labour pains A muco-sanguinous discharge or the „show” The dilatation of the cervical canal, so that both the internal and the external os become completely dilated The fixation of the head at the brim of the pelvis and its progressive descent Rupture of membranes
Latent (a) and active (b) phase of labour in a multiparous and a primiparous woman, as shown on partogram
Information conveyed on a partogram Fetal heart rate by intermittent auscultation or continuous fetal heart rate monitoring Cervicogram a record of cervical dilatation and fetal head descent Uterine contractions quantification of frequency, strength, and duration Amniotic fluid (if the membranes are ruptured) state of fluid, any meconium Maternal urine production checked for ketones and protein Drugs given analgesics, oxytocics Maternal blood pressure, pulse, and temperature
THE SECOND STAGE The occurrence of the characteristic uterine contractions The coming into action of the accessory muscles of labour The progressive descent of the presenting part The dilatation of the vagina and vulva with stretching of the pelvic floor The expulsion of the foetus
When the cervix has dilated to 10 cm, the mother has an uncontrollable urge to push
STEPS OF NORMAL DELIVERY
THE EPISIOTOMY ISSUE
THE CAUSES OF PERINEAL LACERATIONS ARE : Relative disproportion in size between the presenting part and the vaginal outlet. Too rapid expulsion of the presenting part, so that enough time is not allowed for gradual stretching of the perineum Faulty mechanism, whereby a larger diameter of the presenting part emerges through the outlet
THE THIRD STAGE The separation of the placenta after the formation of a retroplacental haematoma The expulsion of the placenta The control of the haemorrhage The permanent contraction and retraction of the uterus
The Apgar test is a scoring system designed by Dr. Virginia Apgar, to evaluate the condition of the newborn at one minute and five minutes after birth. A Activity; muscle tone P Pulse rate G Grimace; reflex irritability A Appearance; skin color R Respiration
THE CAESAREAN SECTION Horizontal incision Vertical incision
The surgeon reaches into the abdominal incision and lifts the baby’s head as an assistant pushes down on the upper uterus.
C-section The surgeon will clamp and cut the umbilical
C-section 1 day after 1 year after
Forceps delivery – Simpson forceps
9 cm 1 cm 9,5 cm 40,5cm 4 cm FORCEPS Naegele type 15cm Franz Karl Naegele
Indications for operative vaginal deliveries are identical for forceps and vacuum extractors. The following indications apply when no contraindications exist: Prolonged second stage: (1) This includes nulliparous woman with failure to descend for 2 hours without, and 3 hours with, conduction anesthesia. (2) multiparous woman with failure to descend for 1 hour without, and 2 hours with, conduction anesthesia. Suspicion of immediate or potential fetal compromise is an indication. Shortening of the second stage for maternal benefits: Maternal indications include, but are not limited to, exhaustion, bleeding, cardiac or pulmonary disease, and history of spontaneous pneumothorax. In expert hands, fetal malpositions, including the after-coming head in breech vaginal delivery, can be indications for forceps delivery.
Prerequisites for forceps delivery include the following: The head must be engaged. The cervix must be fully dilated and retracted. The position of the head must be known. The type of pelvis should be known. The membranes must be ruptured. No disproportion should be suspected between the size of the head and the size of the pelvic inlet and mid pelvis. The patient must have adequate anesthesia. Adequate facilities and supportive elements should be available. The operator should be fully competent in the use of the instruments and the recognition and management of potential complications. An operator should be present who knows when to stop, to not force the issue, and to not aggressively use both forceps and vacuum in combination because this has been shown to increase morbidity for both the mother and fetus.
Forceps delivery technique
Forceps delivery The left handle held in the left hand (Simpson forceps)
Forceps delivery Introduction of the left blade into the left side of the pelvis
Forceps delivery Left blade in place; introduction of the right blade by the right hand
Forceps delivery A median or mediolateral episiotomy may be performed at this point. A left mediolateral episiotomy is shown here.
Forceps delivery The forceps have been locked. The inset shows a left occipitoanterior fetal position
Forceps delivery Horizontal traction with the operator seated
Forceps delivery Upward traction
Forceps delivery Disarticulation of the branches of the forceps; beginning modified Ritgen maneuver
Contraindications to forceps-assisted vaginal deliveries: Any contraindication to vaginal delivery. Refusal of the patient to consent to the procedure Cervix not fully dilated or retracted Inability to determine the presentation and fetal head position or pelvic adequacy Suspected cephalopelvic disproportion Unsuccessful trial of vacuum extraction Absence of adequate anesthesia Inadequate facilities and support staff Inexperienced operator
Maternal complications associated with forceps-assisted vaginal deliveries: Early (ie, acute) complications include (1) lacerations to the cervix, vagina, perineum, or bladder; (2) extension of episiotomies; (3) increase in blood loss; (4) hematomas; and (5) intrapartum rupture of the unscarred uterus. Late complications mainly are related to injury to the pelvic support tissues and organs and include (1) urinary stress incontinence, (2) fecal incontinence, (3), anal sphincter injuries, and (4) pelvic organ prolapse.
Transient facial forceps marks, bruising, lacerations, and cephalohematomas are possible. Skull fractures, intracranial hemorrhage with falx, or tentorial lacerations also have been reported. Cerebral palsy, mental retardation, and behavioral problems tend to be more related to hypoxic episodes or other intrapartum, environmental, or congenital factors. Fetal complications associated with forceps-assisted vaginal deliveries:
FORCEPS AND VACUUM EXTRACTION CONDITIONS : – Cervix - fully dilated – Membranes - ruptured – Position and station of fetal head – known and engaged – Fetus - alive – Maternal pelvis - evaluated and found appropriate
FORCEPS AND VACUUM EXTRACTION INDICATIONS : – Delay in the second stage of labour – Prophylaxis (to shorten the second stage of labour) – Fetal distress – Maternal distress
FORCEPS INJURIES BABY : Intracranial haemorrhage Shoulder dystocia Fractures of the skull Paresis of the facial nerve MOTHER : Tears of the cervix and vagina Uterine rupture Damage of the bladder and rectum Infection
VACUUM INJURIES BABY : Abrasion to the scalp Cephalhaematoma Retinal haemorrhage MOTHER : Local injuries are significantly less common then with forceps
The fetal malpresentations include: Breech presentation. Face presentation. Brow presentation. Occipito posterior position.(Back labour) Transverse lie. Shoulder presentation.
VARIETIES OF BREECH PRESENTATION - Breech with extended legs - Complete breech - Footling
BREECH PRESENTATION- DIAGNOSIS PRESENTING PART- the head is round, hard and regular. The breech is small, softer and irregular. EXTERNAL EXAMINATION- the head in the fundus is ballotable (first Leopold maneuver). FETAL HEART is detected higher in the abdomen (above the umbilicus).
BREECH PRESENTATION- PROGNOSIS Perinatal mortality is 5 times that of the cephalic presentation ! REASONS : Hypoxia Difficulty with delivery of the aftercoming head Birth trauma
BREECH PRESENTATION- MANAGEMENT What is the correct treatment ? Caesarean section External version Elective breech delivery
EXTERNAL (CEPHALIC) VERSION PROFITS Reduction of caesarean sections RISK Placental separation Premature rupture of the membranes Premature labour Entanglement of the cord Fetomaternal red cell transfer Fetal trauma
EXTERNAL (CEPHALIC) VERSION CONDITIONS Relax uterus and abdominal wall Breech mobile above brim Complete breech Multiparity The fetal heart should be monitored CONTRAINDICATIONS Caesarean section is to be carried out (the breech is easier then the head to deliver via a uterine incision) Antepartum bleeding Multiple pregnancy Ruptured membranes Oligo- and ahydramnion Fetal death
THE SUGGESTED CRITERIA FOR A VAGINAL BREECH DELIVERY Normal labour curve Estimated fetal weight between g Complete breech presentation A reassuring fetal heart tracking An adequate maternal pelvis by clinical pelvimetry Normally flexed fetal head
TRANSVERSE LIE AETIOLOGY Uterine malformations (bicornuate, subseptate uterus) Polyhydramnion Praevial attachment of the placenta Multiparity Tumours of the uterus Multiple pregnancy
TRANSVERSE LIE DIAGNOSIS Ultrasound ! Contour of the abdomen - lateral expansion No fetal pole in the fundus or lower uterus Vaginal examination- very carefully ! Possibility of placenta praevia and possibility of rupturing of membranes accidentally.
TRANSVERSE LIE - MANAGEMENT OF LABOUR AND DELIVERY Caesarean section - the procedure of choice Internal version followed by breech extraction - associated with a high fetal mortality rate and the risk of uterine rupture There is no normal mechanism of labour. Only small babies may occasionally be delivered by spontaneous evolution
DEFLEXION ATTITUDES OF THE FETUS BREGMA PRESENTATION (military attitude, “Eyes front” attitude) DIAGNOSIS anterior frontanelle (bregma) will be felt first, the smaller posterior frontanelle will be difficult to reach or out of touch Diameter of the fetal skull - Occipitofrontal (11-12 cm) Leading point - vertex (bregma) The prognosis for vaginal delivery is poor. Nowadays, caesarean section would be preferred to manual flexion followed by forceps delivery
DEFLEXION ATTITUDES OF THE FETUS BROW PRESENTATION DIAGNOSIS Palpation of the fetal trunk - the chest is pushed forward and may be on the opposite side to the breech. The fetal heart is often heard easily over the prominent chest Vaginal examination - central forehead will be felt, with the frontal suture running across it. Diameter of the fetal skull - mentovertical (14 cm) Leading point - brow (sinciput) Vaginal delivery is very difficult. Nowadays Caesarean section is the preferred manoeuvre (procedure of choice)
FACE PRESENTATION is the most extreme form of deflexion DIAGNOSIS External examination - the deep groove between fetal beck and occiput The fetal heart is heart easily over the prominent chest Vaginal examination - partly soft, partly firm, irregular contour will be noted (compare with breech, anencephalus) Diameter of the fetal skull - submentobregmatic (9,5 cm - the same as the most favourable when the head is fully flexed – suboccipito-bregmatic) Leading point - face (root of the nose) DEFLEXION ATTITUDES OF THE FETUS