NORMAL & ABNORMAL LABOR Assoc. Prof. Olus API, DEPARTMENT OF OBSTETRICS AND GYNECOLOGY, YEDITEPE UNIVERSITY HOSPITAL

NORMAL LABOR  Normal labour: regular, frequent uterine contractions with cervical changes and descent of the presenting part  At least 3 contractions coming with at least 3 minutes intervals in 10 minutes  The amplitude of contractions should reach at lesat mmHg on cardiotocogram.  The contractions should cause cervical changes:  Dilatation: Cervical canal dilates from 0 to 10 cm.  Effacement: The distance between internal cervical ostium and external ostium shortens (thinning of the cervix)

Stages of labour  I – Latent: up to 3-4 cm dilation and effacement (false labour, pre-labour) Active: 4cm to full dilation → abnormal if 4hours  II – Full dilation to delivery → abnormal if no descent over >1hour pushing  III – Delivery of placenta  IV – 2 hours postpartum

Latent phase Active phase 2nd stage 1st stage max slope acceleration dec Time (hours) Cervical dilatation (cm) Friedman labor curve in nulliparous

Labor duration (Friedman,1978) Variable Nulliparas (h) Multiparas(h) Latent phase mean upper limit Active phase mean dilatation rate(cm/h) Second stage mean upper limit

Dysfunctional labor Definition Any deviation in normal progress of labor, either in cervical dilatation or in descent of the presenting part

Etiology 1. Malfunction in the myogenic, neurogenic, or hormonal mechanisms of uterine activity. 2. Malpresentation, fetal anomalies, uterine malformation, pelvic tumors, overdistension of the uterus, CPD 3. Extrinsic factors : sedation, anxiety, anesthesia, supine position, unripe cervix, chorioamnionitis

Classification Freidman (1989) : 1. Prolonged latent phase 2. Protraction disorders:1.Protracted active phase 2. Protracted descent 3. Arrest disorders:1.2ndry arrest of cervical dilatation 2. Prolonged deceleration phase 3. Arrest of descent 4. Failure of descent

1.Hypotonic dysfunction a.Prolonged latent phase b.Prolonged active phase c. Prolonged deceleration phase d. Prolonged 2 nd stage 2.Hypertonic dysfunction

Assess the the 5 P’s:  Power: –Strength of contractions (not on monitor, must feel) –Must have rest in between ( beware of tachysystole, coupling) –May be augmented with oxytocin

PASSENGER –Size –Lie: longitudinal/transverse –Presentation: face (mentum – anterior can deliver vaginally), brown (frontum), vertex (occiput), transverse (shoulder), breech (sacrum) –Position: OA 8.5cm diameter, OP 9cm, brow 13cm –Attitude: asynclitism

Passage  Is the pelvis suitable for delivery?  Is there any cephalopelvic disproportion?

Lie, presentation &position FETAL LIE  The relation of the long axis of the fetus to that of the mother  Longitudinal lie is found in 99% of labours at term  Predisposing factors for transverse lie/oblique lie  multiparity, placenta previa, hydramnious, & uterine anomalies FETAL PRESENTATION  The presenting part is the portion of the body of the fetus that is foremost in the birth canal  The presenting part can be felt through the cerviks on vaginal examination  Longitudinal lie  cephalic presentation  breech presentation  breech presentation  Transverse lie  shoulder presentation

Lie, presentation & position CEPHALIC PRESENTATION  Head is flexed sharply  vertex / occiput presentation  Head is extended sharply  face presentation  Partially flexed  bregma presenting (sinciput presentation)  Partially extended  brow presentation BREECH PRESENTATION  Frank breech  Complete breech  Footling breech

.'" '.'" ' I !1\!1\ 1 A B i iiFiiF c D Longitudinal lie. Cephalic presentation. Differences in attitude of fetal body, Note changes in fetal attitude in relation to fetal vertex as the fetal head becomes less flexed. (A) vertex(B) sinciput(C) brow (D) face

Longitudinal lie. Frank breech presentation. I Longitudinal lie. Complete breech presentation.

Longitudinal lie. Incomplete, or footling, breech presentation.

POSITION The relation of an arbitrary chosen point of the fetal presenting part to the Rt or Lt side of the maternal birth canal The chosen point  Vertex presentation  occiput  Face presentation  mentum  Breech presentation  Sacrum Each presentation has two positions Rt or Lt Each position has 3 varieties : Ant, transverse, post OA OP LOTROT LOAROA LOP ROP

~ 'tJ'tJ LONGITUDINAL LIE VERTEX PRESENTATION LOA LOP

FREQUENCY OF VARIOUS PRESENTATIONS & POSITIONS AT TERM  Vertex  96% 2/3  Lt 2/3  Lt 1/3  Rt 1/3  Rt  Breech  3.5%  Face  0.3%  Shoulder  0.4%

Longitudinal lie. Face presentation. Left and right anterior and ri posterior positions. Rt mento-postRt mento-antLt mento-ant

~ Longitudinal lie Breech presentation LSP

Transverse lie. Right acromiodorsoposterior position (RADP). The shoulder of the fetus is to the mother's right, and the back is posterior.

MECHANISM OF LABOUR WITH OCCIPUT PRESENTATIONS THE CARDINAL MOVEMENTS OF LABOUR 1-ENGAGEMENT The greatest transverse diameter BPD passes through the pelvic inlet It may occur in the last few weeks of pregnancy or only in labour especially in multipara The fetus enters the pelvis in transverse or oblique diameter  LOT  40%  ROT  20%  OP  20% ROP >LOP  ROA / LOA  20%

THE CARDINAL MOVEMENTS OF LABOUR 2-DESCENT  In nullipara engagement takes place before the onset of labour & further descent may not occur till the 2 nd stage  In multipara descent begins with engagement  It is gradually progressive till the fetus is delivered  It is affected by the uterine contractions & thinning of the lower segment

3-FLEXION  The descending head meets resistance of pelvic floor, Cx & walls of the pelvis   flexion  The shorter suboccipito-begmatic is substituted for the longer occipito-frontal

Lever action producing ftexion of the head; conversion from occipitofrontal to suboccipitobregmatic diameter typically reduces the anteroposterior diameter from nearly 12- to 9.5 cm.

4-INTERNAL ROTATION  Turning of the head from the OT position  anteriorly towards the symphysis pubis ie. Occiput moves from transverse to ant 45º  Less commonly OT  posteriorly towards the sacrum 135º  It is not accomplished till the head has reached the spines The levator ani muscles form a V shaped sling that tend to rotate the vertex anteriorly  It is completed by the time the head reaches the pelvic floor 2/3 or shortly after ¼

EXTENSION  When the flexed head reaches the vulva it undergoes extension  the base of the occiput will be in direct contact with the inferior margin of the symphysis pubis  Crowning  the largest diameter of the fetal head is encircled by the vulvar ring  The head is born by further extension as the occiput, bregma, forehead, nose, mouth & chin pass successively over the perineum

EXTERNAL ROTATION  After delivery of the head it returns to the position it occupied at engagement, the natural position relative to the shoulders (oblique position)Restitution  Then the fetal body will rotate to bring one shoulder anterior behind the symphysis pubis ( biacromial diameter into the APD of the pelvic outlet)  Restitution is followed by complete external rotation to transverse position (occiput lies to next to Lt maternal thigh)  The ant shoulder slips under the pubis  By lateral flexion of the fetal body the post shoulder will be delivered & the rest of the body will follow

Engagement;descent, flexion 6. Restitution (external rotation) 3. Further descent, internal rotation 4. Complete rotation, beginning extension Cardinal movements in the mechanism of labor and delivery, left occiput anterior position.

 Psyche

PAIN –Reduce stimuli –Activate peripheral sensory receptors (water, TENS) –Enhance descending inhibitory pathway (hypnosis, music) –Narcotics (with antiemetic) –Entanox (inhaled N2O) –Do not use sedatives/hypnotics –Epidural: most effective, does not lengthen 1st stage –Pudendal: use in 2nd stage (10cc local under ischial spines) –Perineal infiltration

Prolonged latent phase Define > 20 h in PG, > 14 h in MG from onset of labor (difficult to determine) Incidence PG: 4% MG: 1%

Etiology 1. Wrong diagnosis of labor 2.Excess sedation 3. An abnormal or high presenting par t 5.Idiopathic. Risks are created by aggressive intervention. If membranes are intact, no risk, only maternal anxiety.

Primary dysfunctional labor Define Cx. Dil. < 1cm/h before normal active phase has been established Incidence PG: 20% MG: 8% Etiology 1. Inefficient C.: the commonest 2. CPD: 1/ 3 3. Malpresentation or malposition

Risks 1. F. distress 2. Maternal fear & anxiety, dehydration & acidosis 3. Incordinate u. activity.

2ndry arrest of labor Define Active phase started normally( cervical dilatation reached 5-7 cm ) then cervical dilatation stop or slows significantly within 2 h Incidence PG: 6% MG: 2%

Risks F. distress: rare

Cervical dilatation (cm) Time (hours) Types of dysfunctional