1. NORMAL AND ABNORMAL LABOR

2. Terminology Gravida - number of pregnancies
Para - number of pregnancies carried to viability and delivered
Primigravida - pregnant for first time
Multigravida - pregnant more than once
Nulliparous - never carried a pregnancy to viability
Multiparous - has had two or more deliveries that were carried to viability

3. Duration of Pregnancy Average 280 days or 40 weeks
Estimated Date of Confinement (EDC)
Nagele’s rule
Date of first day of LMP
Subtract 3 months
Add 7 days

4. DURATION OF PREGNANCY
TERM: a pregnancy from the beginning of week 38 of gestation to the end of week 42 of gestation.
PRETERM: a pregnancy that has reached 20 weeks of gestation but before completion of 37 weeks of gestation.
POSTDATE OR POSTTERM: a pregnancy that goes beyond 42 weeks gestation.
VIABILITY: capacity to live outside the uterus; about 22 to 24 weeks since last menstrual period, or fetal weight greater than 500 grams.

5. PUERPERIUM The time after childbirth Lasting approximately 6 weeks
The anatomic and physiologic changes brought about by pregnancy resolve and a woman adjusts to the new or expanded responsibilities of motherhood and nonpregnant life.

6. NORMAL LABOUR: Definitions
Onset of regular involuntary coordinated, painful uterine contractions associated with cervical effacement and dilatation
Delivery is the expulsion of the product of the conception after fetal viability.

7. TRUE LABOUR VS FALSE LABOUR
Regular contractions
Increase in frequency and intensity
Cervix dilate
No relieve with sedation
Abdominal and back pain
Irregular
Remain the same
Unchanged
relieve
Lower abdominal pain

8. STAGES OF LABOUR 4 First stage cervical dilatation and effacement
Second stage is the expulsion of the fetus
Third stage is the delivery of the placenta
Fourth stage is the early recovery

9. First Stage of Labor
Begins with onset of coordinated contractions leading to dilation of cervical os and ends with complete dilation (10 cm) of the cervical os.
Duration of first stage
Primigravida: 12 hours
Multiparous: 7 hours or less

10. Assessing Progress of Labor
Vaginal Exam
Cervix
Soft or Hard
Effaced or Thick
Dilatation
Presentation
Part (cephalic, breech, shoulder)
Flexion, Extension
Station

11. (A) Cervix is uneffaced and minimally dilated
(A) Cervix is uneffaced and minimally dilated. (B) Cervix is almost completely effaced and dilated.

13. Three factors: the power, the passage, and the passenger.
Labor Mechanics
For a successful vaginal delivery, the fetus must negotiate the maternal pelvis.
Three factors: the power, the passage, and the passenger.

14. Labor Mechanics The passenger
Fetal lie: Fetal position relative to the maternal spine: longitudinal, oblique, transverse
Presentation: refers to the fetal part that is above the pelvic inlet.
Attitude: refers to position of fetal head relative to the fetal spine
Position: referes to the relationship of a nominated site of the presenting part to a denomintating location in the internal pelvis. Eg. Occiput/sacrum ROA, RSA
Station: a measure of descent of the presenting part.
Abnormalilty of any of these variables can influence whether or not to proceed with a vaginal delivery.

15. Fetal presentation: Fetal part directly over the pelvic inlet; e
Fetal presentation: Fetal part directly over the pelvic inlet; e. g breech, cephalic, compound, funic

17. Labor Mechanics The passenger
Station: measure of descent of the presenting part through the birth canal relative to ischial spines
this is the relationship between the leading bony part of fetal presenting part ( skull bone NOT scalp) and the maternal ischial spines. Must take into account molding and caput succedaneum (not doing so is a common error)
Often described as -3 to + 3
Newer scale is -5 to +5

19. FRIEDMAN’S CURVE

21. ATTITUDE

24. FETAL HEAD POSITION

27. A: Right occiput anterior (ROA); B: Left occiput anterior (LOA); C: Occiput anterior (OA).

28. Occiput posterior

29. Labor Mechanics The passenger
Malpresentation is any presentation that is not cephalic with occiput leading. (about 5%)
Multifetal pregnancies increase the risk of malpresetnation

31. FACE PRESENTATION

32. TRANSVERSE LIE

34. LEOPOLD MANEVOEURS

35. Labor Mechanics The Passenger
The passenger is the fetus. Fetal size can influence labor
Can be assessed by Leopold’s, US or both. ( Mom’s opinion counts, too!)
ACOG definition of Macrosomia is defined as >4500 g

36. Labor Mechanics The passenger
Estimating fetal size: ultrasound, leopolds, what does mom think?
How big is too big? Definition of macrosomia is
diabetics: 4500g non-diabetics: 5000g

37. Labor Mechanics The Passage
The passage consists of the bony pelvis (sacrum, ilium, ischium, pubis) and the resistance provided by the soft tissues.
Bony pelvis is divided into the greater (false) and lesser(true) pelvis by the pelvic brim which is demarcated by the sacral promontory.
The diagonal conjugate is the distance from the sacral promontory to the inferior margin of the symphysis pubis as assessed on examination
Clinical pelvimetry is the only way to assess the dimensions of the pelvis in labor.

38. To figure out the true conjugate, measure the diagonal conjugate and subtract 1.5 – 2cm. The limiting factor is the interspinous diameter.

40. MIDPELVIS

41. PELVIC OUTLET

42. Size and shape of female pelvis differs widely due to morphological factors (developmental, sexual, racial, etc.)

43. CALDWELL-MOLOY CLASSIFICATION
On the basis of the shape of the inlet, female pelvis is divided into four parent types:
Gynecoid
Android
Anthropoid
Platypelloid

45. ANATOMICAL FEATURES OF PARENT PELVIC TYPES

46. GYNECOID (50%) ANTHROPOID (25%) ANDROID (20%) PLATYPELLOID (5%)
Apart from these parent forms, intermediate forms with combination of features are also found.

47. INLET GYNECOID ANTHROPOID ANDROID PLATYPELLOID Shape Round
Antero-posteriorly oval
Triangular
Transversely oval
Anterior & posterior segments
Almost equal & spacious
Both increased with slight anterior narrowing
Posterior segment short & anterior segment narrow.
Both reduced- flat
Sacrum
Sacral angle >90⁰
Inclined backwards.
Well curved from above down and side to side
Inclined posteriorly.
Long and narrow
Sacral angle <90⁰
Inclined forwards and straight.

48. CAVITY AND OUTLET Gynecoid Anthropoid Android Platypelloid
Sacrosciatic notch
Wide & shallow
More wide & shallow
Narrow & deep
Slightly narrow & small
Sidewalls
Straight or slightly divergent
Straight or divergent
Convergent
Divergent
Pubic arch
Curved
Long & curved
Long & straight
Short & curved
Subpubic angle
Wide (85⁰)
Slightly narrow
narrow
Very wide (>90⁰)
Bituberous diameter
Normal
Normal or short
Short
Wide

49. OBSTETRIC OUTCOME IN PARENT PELVIC TYPE

50. INLET GYNECOID ATHROPOID ANDROID PLATYPELLOID Position
Occipito-lateral or oblique Occipito-anterior
Direct Occipito-anterior or posterior
Occipito-lateral or oblique Occipito-posterior
Occipito-lateral
Diameter of engagement
Transverse or oblique
Antero-posterior
Transverse
Engagement
No difficulty
Usual mechanism
No difficulty except flexion is delayed
Delayed and difficult
Difficult by exaggerated parietal presentation

51. CAVITY AND OUTLET GYNECOID ATHROPOID ANDROID PLATYPELLOID
Internal rotation
Easy anterior rotation
Non-rotation common
Difficult anterior rotation. Not occurs early above the ischial spine, chances of arrest
Anterior rotation occurs late in the perineum
Delivery
No difficulty
More incidence of face to pubis delivery.
Difficult delivery with increased chances of perineal injuries

52. INTERMEDIATE OR MIXED TYPE OF PELVIS
Apart from these parent forms, intermediate forms with combination of features are found more commonly.
Based on the type of posterior & anterior segments of inlet.
Posterior segment determines the type of pelvis.

54. CLINICAL SIGNIFICANCE
SMALL GYNECOID PELVIS:
Shape is normal
Diameters are proportionately reduced. Hence, there is delay at every stage of labour due to lack of space.
Powerful uterine contractions are required to push the presenting part downwards.

55. Clinical significance (cont.)
ANDROID PELVIS:
Occipito-posterior position is common
Due to the funnel shape of the pelvis
Progressive difficulty is faced.
Rotation fails to occur.
Transverse arrest is common.
PLATYPELLOID PELVIS:
Difficulty in engagement of foetal head.

56. Bony pelvis—most favorable is gynecoid and antropoid

57. Labor Mechanics
The most precise way of determining uterine contractions are adequate is with internal monitoring by IUPC
External monitoring measures the change in shape of the abdominal wall relative to contractions thus is qualitative rather than quantitative. Does allow for accurate correlation between fetal heart rate and contraction pattern .

59. Cardiocotography
Cardiotocography (CTG) is a continuous electronic record of the fetal’s heart rate obtained via an ultrasound transducer placed on the mother’s abdomen
It is sometimes referred to as ‘electronic fetal monitoring’ (EFM)

61. CTG
The machine used to perform the monitoring is called a cardiotocograph, more commonly known as an electronic fetal monitor (EFM)

63. Purpose To record FHS continuously To check uterine activity
To detect any fetal distress
To gain information about rate, rhythm of the fetal heart rate and fetal movement

64. Continuous EFM should be offered and recommended for high-risk
pregnancies where there is an increased risk of perinatal death,
cerebral palsy or neonatal encephalopathy.
Continuous EFM should be used where oxytocin is being used for
induction or augmentation of labour.
Indication

65. ADMISSION CTG
Current evidence does not support the use of the admission CTG in low-risk pregnancy and it is therefore not recommended
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66. High-Risk Indications
Maternal medical illness Gestational diabetes Hypertension Asthma
Obstetric complications Multiple gestation Post-date gestation Previous cesarean section Intrauterine growth restriction
Oligohydramnios Premature rupture of the membranes Congenital malformations Third-trimester bleeding Oxytocin induction/augmentation of labor Preeclampsia
Meconium stained liquor
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67. A Continuous EFM should be
A Continuous EFM should be offered and recommended in pregnancies previously monitored with intermittent auscultation:
if there is evidence on auscultation of a baseline less than 110 bpm or greater 160 bpm
• if there is evidence on auscultation of any decelerations
• if any intrapartum risk factors develop.

68. Methods
External Cardiotocography-
For continuous or intermittent monitoring of
The fetal heart rate and
The activity of the uterine muscle
Placed two transducers on the mother's abdomen(one above the fetal heart and the other at the fundus).

69. External (Indirect) Monitoring
The tocodynamometer (“toco”) is placed over the uterine fundus. The toco provides information that can be used to monitor uterine contractions.
The ultrasound device is placed over the area of the fetal back. This device transmits information about the FHR.

70. Toco sensor The pressure transducer transmits the pressure generated
by uterine contractions in mm Hg.
Each small vertical square is 5 mm Hg
Each small horizontal square is 10 seconds .
Each large horizontal square is 1 minute .
Toco sensor
Pressure Transducer

71. Ultrasound transducer
The ultrasound probe transmits the
fetal heart rate in beats per minute.
Each small vertical square is 10 beats.
Each small horizontal square is 10 seconds .
Each large horizontal square is 1 minute .
Ultrasound Probe

72. Information from both the toco and the ultrasound device is transmitted to the electronic fetal monitor.
The FHR is displayed in a digital display (as a blinking light), on the special monitor paper, and audibly (by adjusting a button on the monitor). The uterine contractions are displayed on the special monitor paper as well.

73. Internal Cardiotocography-
Uses an electronic transducer connected directly to the fetal scalp through the cervical opening and is connected to the monitor.
Internal monitoring provides a more accurate.
Internal monitoring may be used when external monitoring of the fetal heart rate is inadequate.
It need some degree of cervical dilatation.

74. Internal Monitoring Criteria for Internal Monitoring:
Amniotic membranes must be ruptured
Cervix dilated 2 cm.
Presentation must be cephalic
Presenting part down against the cervix

75. Spiral Electrode is placed on the fetal occiput which allows for more accurate continuous data than external monitoring.
Also is not affected by mom or fetal movement as with external monitoring.
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76. The spiral electrode is attached to the
Internal Monitoring
The spiral electrode is attached to the
fetal scalp
Wires that extend from attached spiral electrode are attached to a leg plate and then attached to electronic fetal monitor.

77. Procedure Equipments Cardiotocograph Transducer(2):Toco and cardio
Conduction gel or paste
Abdominal binder (two belts)
Monitor paper
Tissue paper
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79. – Moderate bradycardia 100–109 bpm – Moderate tachycardia 161–180 bpm
– Normal Baseline FHR 110–160 bpm
– Moderate bradycardia 100–109 bpm
– Moderate tachycardia 161–180 bpm
– Abnormal bradycardia < 100 bpm
– Abnormal tachycardia > 180 bpm
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81. Baseline Fetal Heart rate Normal Pattern
Baseline FHR = 110 – 160 bpm

82. Baseline variability
Variability refers to the normal beat to beat changes in FHR.
Normal variability is between 5-15 bpm.
Variability can be measured by analysing a one-minute portion of the CTG 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

83. Baseline variability
The fluctuations are visually quantities as the amplitude of the peak-to-trough in bpm. Using this definition, the baseline FHR variability is categorized by the quantitated amplitude as:
Absent- undetectable
Minimal- greater than undetectable, but less than or equal to 5 bpm
Moderate- 6-25 bpm
Marked- greater than 25 bpm
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88. FHR Variability
Absent variability =
Amplitude range undetectable
Minimal = < 5 BPM
Moderate = 6 to 25 BPM
Marked = > 25 BPM

89. Accelerations
To be called an acceleration, the peak must be greater than or equal to 15 bpm, and the acceleration must last greater than or equal to 15 seconds from the onset to return to baseline.
Prolonged acceleration: is greater than or equal to 2 minutes but less than 10 minutes in duration.
Before 32 weeks of gestation, accelerations are defined as having a peak greater than or equal to 10 bpm and a duration of greater than or equal to 10 seconds.

90. ACCELERATIONS

91. Deceleration
Decreases in fetal heart rate from the base line by at least 15b/m, lasting for at least 15 seconds.

92. DECELERATIONS EARLY : Head compression LATE : U-P Insufficiency
VARIABLE : Cord compression
Primary CNS dysfn

93. Early Deceleration
Early Deceleration: Early begin at start of uterine contraction and end with conclusion of contraction. Early decelerations are not a sign of fetal problems.
In most cases the onset, nadir(lowest point), and recovery of the deceleration are coincident with the beginning, peak, and ending of the contraction, respectively

94. EARLY

95. Early Decelerations Related to Head Compression Intervention
No intervention necessary. Just continue to watch for any changes.

96. Early decelerations contd…
Early decelerations are a benign( kind/ gentle) finding caused by a vasovagal response as a result of fetal head compression by the contraction.
Pressure on the fetal skull alters the cerebral blood flow and this in turn stimulates the vagus nerve

97. Early Decelerations

99. Variable Deceleration

100. Variable Deceleration
Variable decelerations are variable in duration, intensity, and timing

101. Variable decelerations
Abrupt(sudden) decrease in FHR of > 15 beats per minute measured from the most recently determined baseline rate. The onset of deceleration to nadir is less than 30 seconds. The deceleration lasts > 15 seconds and less than 2 minutes.

102. VARIABLE
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103. Variable Decelerations
Related to cord compression
Intervention
Reposition
Amnioinfusion

105. variable deceleration contd…
The umbilical vein is often occluded first causing an acceleration in response
Then the umbilical artery is occluded causing a subsequent rapid deceleration
When pressure on the cord is reduced another acceleration occurs & then the baseline rate returns
Accelerations before & after a variable deceleration are known as the “shoulders of deceleration”
There presence indicates the foetus is not yet hypoxic & is adapting to the reduced blood flow.

107. Late Deceleration

108. Late Deceleration
Gradual decrease in FHR with onset of deceleration to nadir >30 seconds. Onset of the decleration occurs after the beginning of the contraction, and the nadir of the deceleration occurs after the peak of the contraction.

109. Late Decelerations
Related to decreased uteroplacental perfusion

111. LATE
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113. Late Deceleration
The fetal heart tones return to the baseline AFTER end of contraction

114. Two varieties of late decelerations reflex and nonreflex.
Reflex late decelerations: are those which occur in the presence of normal FHR variability
Non-reflex late decelerations occur in association with diminished or absent FHR variability.   

115. Reflex late decelerations are thought to be due to vagal stimulation by chemoreceptors in the head in response to low oxygen tension.
The hypoxemia increased sympathetic stimulation increased systemic vascular resistance. The response to this increased pressure is a vagally mediated decrease in heart rate.
This dual reflexive response may explain the delay in the heart rate following a contraction.
Reflex late decelerations are associated with normal FHR variability because CNS system is intact.

116. Nonreflex late decelerations are associated with a greater degree of relative hypoxemia and result in hypoxic depression of the myocardium coupled with the previously described vagal response.
In reflex late decelerations, variability was maintained because the fetus was able to compensate, shifting oxygenated blood to vital organs (e.g., the heart),

117. But in nonreflex late decelerations, the fetus is unable to compensate
But in nonreflex late decelerations, the fetus is unable to compensate. It is these late decelerations which are more typically associated with fetal acidosis, and they are more commonly associated with placental dysfunction rather than uterine hypoperfusion or hyperactivity.
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118. Prolonged Deceleration
A prolonged deceleration is present when there is a visually apparent decrease in FHR from the baseline that is greater than or equal to 15 bpm, lasting greater than or equal to 2 minutes, but less than 10 minutes.
If it lasts between 2-3 minutes it is classed as Non-Reasurring
If it lasts longer than 3 minutes it is immediately classed as Abnormal
Action must be taken quickly – e.g. Foetal blood sampling / emergency C-section

119. Prolonged Deceleration:
A deceleration that lasts greater than or equal to 10 minutes is a baseline change.

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123. Categorisation of fetal heart rate traces
Category
Definition
Normal
All four reassuring
Suspicious
1 non-reassuring
Rest reassuring
Pathological
2 or more non-reassuring
1 or more abnormal
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124. SPECIAL PATTERNS
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125. 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 5–15 bpm above and below the baseline. Baseline variability is absent
Associated with -
Severe chronic fetal anaemia
Severe hypoxia & acidosis
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126. SINUSOIDAL
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