9-management Of Normal And Abnormal Labor

MANAGEMENT OF LABOR JEHAD AL-HARMI DEPARTMENT OF OBS & GYN FACULTY OF MEDICINE/KUWAIT UNIVERSITY

You should know-1 • • • •

Obstetrical history & examination Definition of labor Mechanism of labor initiation Anatomical considerations: – The female pelvis – The fetal skull

• The stages of labor

You should know-2 • • • • • • •

The mechanism of labor (vertex, OA) Management of normal labor Pain relief during labor Drugs commonly used during labor Induction of labor (IOL) Abnormalities of labor Malpresentations (breech, brow, face & shoulder presentations)

You should know-3 • • • • •

Labor in multifetal gestation Preterm labor Vaginal birth after cesarean section (VBAC) Shoulder dystocia Complications of the third stage: – Retained placenta – Uterine inversion

Obstetrical History-1 • Biodata: – Name, age, nationality, occupation

• Marital status: – Duration of marital life, previous marriages & if any resulted in offspring, consanguinity

• Gravidity = pregnancy – Nulligarvida – Primigravida – Multigravida

Obstetrical History-2 • Parity = delivery of an infant (alive or dead) weighing 500 g or more which is approximately 20/52 • Nullipara, primipara, multipara, grandmultipara (5 or more) • G P (T + P + A + L) • Remember: – Multiple pregnancy – Ectopic pregnancy

Obstetrical History-3 Current pregnancy: – LNMP: • Accuracy • Regularity & length of menstrual cycle • Confounding factors: OCP, lactation, spotting, Hartman’s sign

– Nigel’s rule: • To calculate EDD from LMP. Assuming: – Duration of pregnancy = 266 days from conception – Ovulation occurs 14 days prior to onset of menstruation

Obstetrical History-4 • Nigel’s rule: – Add 7 days & subtract 3 months – 40% deliver within 5/7; 67% within 10/7 – What if cycle length 21 days? Or 35 days?

• Calculate & report gestational age (GA) in weeks not months • Exceptions: IVF. 2 dates (EC & ET) • Obstetrical calculator or calendar

Obstetrical calculator or calendar • Two concentric circles • Outer circle represents days & months of the year • Inner circles represents weeks of gestation • Arrows indicate current status

EXAMPLE – LMP – EDD

06/04/2008 13/01/2009

– Today 06/10/2008 – GA 26 weeks

Obstetrical History-5 Other methods to determine GA: – Date of first positive pregnancy test • Urine • Serum

4-5/52 after LMP 8-10/7 after conception

– Uterine size during first half of pregnancy Caution! – Time of quickening (16-20/52) – Time of detection of fetal heart beats (FHB) • Doptone • Pinard

10-12/52 18-20/52

Obstetrical History-6 Other methods of determining GA: – U/S: • CRL during T1 Error of 7/7 • BPD, FL, AC up to 22/52 Error of 10/7 • Endovaginal U/S can detect an IUGS at 5/52 gestation and βHCG=1000-1500 mIU/ml (discriminatory zone) • Transabdominal U/S can detect an IUGS one week later when βHCG=6500 mIU/ml

Obstetrical History-7 Past obstetrical history: – Date – Onset of labor & indication of IOL – Mode of delivery – Sex, BW, AS of baby – Complications: antepartum, intrapartum, postpartum, &/or puerperal – Breastfeeding

Obstetrical Examination-1 Abdomen: – Striae gravidarum (red or white) – Linea nigra – Organomegaly (HSM, hydronephrosis)

Obstetrical Examination-2 Uterine fundus: – Just above symphysis pubis: 12/52 – At umbilicus: 20-22/52 – At xiphisternum: 36/52 – What happens after 36/52? – Lightening

Obstetrical Examination-3 • Determination of fundal level using the ulnar side of the left hand • Symphysial-fundal height = SFH – SFH in cm correspond to GA in weeks after 24/52 – Can detect SFD babies in 75% of cases with maximal accuracy at 32-34/52 – Causes of SFD & LFD – Confirmation

Obstetrical Examination-4 Leopold maneuvers: • Clockwise from upper left corner – Determination of fundal level – Fundal grip – Lateral grips – First pelvic grip

Obstetrical Examination-5 Leopold maneuvers: – Second pelvic grip

• Determine: – – – – – –

SFH & EFW Lie Presentation Position Station FHR

Obstetrical Examination-6 • Palpation of fetal parts after 28/52 • Description of relationship of fetus to maternal trunk and pelvis: – Lie: relationship of long axis of fetus to long axis of uterus • Longitudinal • Oblique • Transverse

Obstetrical Examination-7 • Fetal poles: head, breech – Head: hard, round, discreet, ballotable – Breech: soft, more diffuse

• Ascertain position of fetal back and limbs. Why?

Obstetrical Examination-8

• Attitude: relationship of various fetal body parts to one another – Flexion – Extension

Obstetrical Examination-9 Presentation: – The presenting part of the fetus is that part which is in or over the pelvic brim – Cephalic: • Well-flexed head • Completely extended • Deflexed

vertex face brow

Obstetrical Examination-10 Presentation: – Breech: • Flexed hips, extended knees • Flexed hips & knees • Extended hips & knees

– Shoulder – Cord

frank complete footling

Obstetrical Examination-11 • Position: relationship of a denominator (bony point) on the presenting part to the right or left side of the maternal pelvis – Vertex – Face – Breech

occiput mentum/chin sacrum

• 8 positions for each presentation

Obstetrical Examination-12

Obstetrical Examination-13 • Station: – The relationship between the presenting part & the pelvis

• Engagement: – When the widest diameter of the fetal head has passed through the pelvic brim

Obstetrical Examination-14 • P/A the station is described in fifths above the pelvic brim – 5/5 – 2/5

floating engaged

• P/V the station is described in cm above or below the ischial spines – Engaged = 0 station

Obstetrical Examination-15 Auscultation: – FHS: • Doptone 10-12/52 • Pinard 24/52 • Location: anterior shoulder

– Uterine and funic souffle

Definition of Labor • The process whereby the products of conception are expelled from the uterus after 20 weeks of gestation • It begins when uterine contractions of sufficient intensity, frequency & duration are attained to bring about progressive effacement & dilatation of the cervix as well as descent of the presenting part

Mechanism of Labor Initiation-1 • Braxton-Hicks contractions • Myometrial unresponsiveness  transitional phase  labor

initiation: the phases of parturition

Mechanism of Labor Initiation-2 • These mechanisms are not well defined in humans • In most mammalian species studied, progesterone withdrawal precedes the initiation of labor – This is not true in primates including humans – Progesterone levels decline only after delivery of the placenta

Mechanism of Labor Initiation-3 Retreat from pregnancy maintenance theory: – No substantial evidence of: • Increased progesterone metabolism • Progesterone compartmentalization or sequestration • Increased protein-binding (decreased free, active hormone) • Reduced number of receptors

Mechanism of Labor Initiation-4 The role of the placenta: – Human pregnancy is a hyperestrogenic state • The placenta is virtually the sole site of estrogen production during pregnancy • In the placenta, estrogen is NOT synthesized de novo from acetate or cholesterol

Mechanism of Labor Initiation-5 The role of the placenta: – Human pregnancy is a hyperestrogenic state • Fetal adrenal gland produces DHEA which is hydroxylated in the fetal liver (16 OH-DHEA) & then converted in the placenta to estriol (E3) by aromatization • Placental sulfatase deficiency may be associated with prolonged gestation because it is associated with decreased placental estrogen production

Mechanism of Labor Initiation-6 The role of the fetus: – The fetus has been implicated as the source of the initial signal for the commencement of labor – Little direct experimental support in humans – Some fetal anomalies are associated with prolonged pregnancy: • Anencephaly • Congenital adrenal hypoplasia

Mechanism of Labor Initiation-7 The role of the fetus: – These are associated with reduction in the supply of precursors for estrogen – Other fetal anomalies that prevent or severely reduce the entry of fetal urine (renal agenesis) or lung secretions (pulmonary hypoplasia) into amniotic fluid do not cause prolongation of pregnancy – This implies that a fetal role in initiation of labor by a paracrine mechanism is unlikely

The Female Pelvis

• True vs. false pelvis • True pelvis: – Pelvic brim – Pelvic cavity – Pelvic outlet

The Pelvic Inlet • Shape:

– Oval & in one plane

• Boundaries:

– Anteriorly: SP – Laterally: upper margin of pubic bone & iliopectineal line – Posteriorly: sacral promontory

• Dimensions:

– AP = 11 cm Transverse = 13.5 cm

The Pelvic Cavity • Shape: –Imaginary plane between inlet & outlet

• Boundaries: –Anteriorly: middle of SP –Laterally: pubic bone, obturator fascia & inner aspect of ischial bone. Ischial spine! –Posteriorly: junction between S2 & 3

• Dimensions: –AP = transverse = 12 cm

The Pelvic Outlet • Shape: – Diamond shaped in 2 planes

• Boundaries: – Anteriorly: lower margin of SP – Laterally: descending ramus of pubic bone, ischial tuberosity & sacrotuberous ligament – Posteriorly: last piece of sacrum (not coccyx)

• Dimensions: – AP = 13.5 cm

Transverse = 11 cm

Clinical Pelvimetry • Pelvic inlet: – Sacral promontory • True conjugate (TC)= AP of inlet • Diagonal conjugate (DC) measured clinically • TC = DC − 1.5 cm

• Pelvic cavity: – Anterior surface of sacrum & ischial spine

• Pelvic outlet: – Subpubic arch & intertuberous diameter

Types of Female Pelvis-1 Gynecoid: – Rounded brim with widest transverse diameter slightly behind its center – Rounded subpubic arch

Types of Female Pelvis-2 Platypelloid: – Flat pelvis – Elliptical brim with a wide transverse diameter – Wide subpubic arch

Types of Female Pelvis-3 Android: Heart-shaped brim Convergent side walls Prominent ischial spines Straight sacrum Narrow subpubic arch Both AP & transverse diameters of outlet reduced – Funnel-shaped cavity – – – – – –

Types of Female Pelvis-4 Anthropoid: – AP diameter of pelvis > transverse diameter – Deep pelvis; sacrum often has 6 segments – Narrow subpubic arch but wide sacrosciatic notches – Large AP diameter of outlet

Fetal Skull-1 • Vault • Face • Base

Fetal Skull-2 Vault: – Parietal & parts of occipital, frontal & temporal bones – Bones not well ossified by birth – Joined by membranes at the sutures – Moulding: alteration of the shape of the skull by overriding of the cranial bones with reduction of some of its diameters – Caput & chignon

Fetal Skull-3 Sutures: – Sagittal: between the superior borders of parietal bones – Frontal: the forward continuation of the sagittal suture; between the two parts of the frontal bone – Coronal: between the parietal & frontal bones

Fetal Skull-4 • Fontanelles: – Anterior (bregma): kite-shaped; where the sagittal, frontal & coronal sutures meet – Posterior: triangular; where the two parietal & coronal bones meet

• Vertex: – Area bounded by the two parietal eminences & the two fontanelles

Fetal Skull-5 Presentation Transverse

Diameter Biparietal

Value (cm) 9.5

Vx, well-flexed Suboccipitobregmatic

9.5

Vx, deflexed Persistent OP Brow

Suboccipitofrontal Occipitofrontal Mentovertical

10 11 13.5

Face

Submentobregmatic

9.5

Symptoms & Signs of Labor • • • • •

Contractions “Show” ROM Abdominal examination Pelvic examination: – Manual or digital – Speculum

• CTG

Stages of Labor • First stage: average 4-7 hours – Latent phase – Active phase: at 3-5 cm dilatation

• Second stage: – Phase A – Phase B (active pushing)

• Third stage • Fourth stage

Mechanism of Labor-1

Mechanism of Labor-2 Vertex presentation, OA position: – The cardinal movements of labor: • Occur simultaneously • Descent & engagement: in the transverse position • Flexion: occurs as the head reaches the pelvic floor to present the smallest possible diameter • Internal rotation: from OT position towards SP to OA position or towards sacrum to OP position

Mechanism of Labor-3 Vertex presentation, OA position: – The cardinal movements of labor: • Extension: occurs as the base of the occiput comes into contact with the subpubic arch “Crowning” • Restitution • External rotation: shoulders rotate into AP diameter as they reach the pelvic floor, head follows • Delivery of the shoulders & trunk with next 1-2 contractions

Management of Normal Labor-1 • Health education during ANC • History taking & physical examination • Preparation: – Shaving the pubic hair – Enema

Management of Normal Labor-2 First stage of labor: – Observation: – Partogram: • Visual representation of events during labor against time • Maternal VS • Cervical dilatation • Station of presenting part, moulding & caput formation

Management of Normal Labor-3 First stage of labor: – Observation: – CTG: •

•

FHR: baseline rate, variability & periodic events (accelerations or decelerations) Uterine activity

– Other methods of intrapartum fetal surveillance?

Management of Normal Labor-4 First stage of labor: – Pain relief & emotional support – Hydration

Management of Normal Labor-5 Second stage of labor: – Position – Preparation – Maternal pushing & perineal support – Ritgen’s maneuver – Episiotomy – Cleaning the upper airways – Clamping the cord

Management of Normal Labor-6 Third stage of labor: – Normal duration: < 30 minutes – Signs of separation of the placenta – Delivery of the placenta: • Spontaneous • Maternal effort • Controlled cord traction or Brandt-Andrews technique

– Repair perineal tears

Drugs Commonly Used During Labor • • • • • • • •

Phosphate enema Syntocinon, oxytocin or pitocin PGE2, prostin E2 or dinoprostone Methergine or methylergotamine maleate Pethidine (HCl) Naloxone HCl or narcan Phenergan or promethazine HCl Entonox

IOL-1 • Definition: – Induction vs. augmentation

• Indications: – Maternal – Fetal

• Contraindications: – Absolute – Relative

IOL-2 • Methods: – Stripping or sweeping the membranes – ARM or amniotomy – Mechanical dilatation: 24-Fr Foley or laminaria – PGE2 – Pitocin, oxytocin or syntocinon

• Patient preparation including informed consent

IOL-3 • Bishop’s score:

– Total = 0 – 13; favorable ≥ 7

cm

%

Station

Consistency Position

0

Closed

0-30

−3

Firm

Post

1

1-2

40-50

−2

Medium

Central

2

3-4

60-70

-1 or 0

Soft

Ant

3

≥5

80≤

+1 or +2

---

---

Abnormalities of Labor-1 Prolonged latent phase: – Definition: • > 20 hours in primipara • > 14 hours in multipara

– Treatment: • Maternal sedation (therapeutic morphine test) • Oxytocin stimulation

– Outcome of sedation: • 85% progress into the active phase • 5% wake up without contractions

Abnormalities of Labor-2 Protracted active phase: – Definition: • Dilatation < 1.2 cm/h in primipara • Dilatation < 1.5 cm/h in multipara

– Causes – Management: • Observation • Augmentation

Abnormalities of Labor-3 Arrest of active phase: – Definition: • Cessation of previously normal dilatation after uterine contractions of 200 montevideo units has been present for ≥ 2 hours

– Causes: • CPD • Malpresentation or malposition

– Management: • Augmentation • CS

Abnormalities of Labor-4 • Protraction of descent: – Definition: • Descent < 1 cm/h in primipara • Descent < 2 cm/h in multipara

– Causes & management

• Arrest of descent: – Definition: no descent for 2 hours – Causes & management: • Operative vaginal delivery • CS

Malpresentations-1 Breech: – Incidence: 2-3% at term – Risk factors: fetal, maternal & placental – Options for delivery: • External cephalic version (ECV) • Elective CS • Trial of vaginal delivery, assisted breech delivery (ABD)

Malpresentations-2 ABD: – Pre-requisites: • • • • • •

Not footling No neck flexion (star-gazing) EFW < 3800 grams No previous scar Experienced operator & assistant No other medical complications

Malpresentations-3 ABD: – Maneuvers: • • • • • •

Allow spontaneous delivery until umbilicus Abduct thighs to deliver legs Rotate back anteriorly Gently pull until scapulae are visible Rotate trunk to deliver arms Maintain held flexion: – “Mauriceau-Smellie-Veit maneuver – “Piper forceps” – Assistant

Malpresentations-4 Face: – Incidence: • Approximately 1 in 2000 at term

– Management: • Expectant in early labor • Mento-anterior  allow trial of vaginal delivery • Mento-posterior  CS

Malpresentations-5 • Brow: – No mechanism of labor

• Shoulder: – Transverse lie – Delivery by CS

VBAC-1 • • • • •

Incidence: CS rate ~ 20% Indications for CS Types of uterine incisions Pre-operative preparation for CS Complications of CS: – Intra-operative – Post-operative: • Short-term • Long-term

VBAC-2 • VBAC or trial of labor • Management: – Elective repeat CS – Trial of vaginal delivery

• Complications: – Uterine rupture vs. dehiscence 1% • Prior transverse incision 1-7% • Prior low vertical incision 4-7% • Prior classic or inverted T incision

VBAC-3 • Counseling: – Chances for success – Risks – Pre-requisites

60-70%

Shoulder Dystocia-1 • Definition: – Impaction of fetal shoulders against maternal pelvis (usually: anterior shoulder above or behind SP)

• Incidence: – In general 0.6 – 1.4% – 4000-45000 grams 3 – 5% – > 4500 grams 8 – 20%

Shoulder Dystocia-2 • Risk factors: – Macrosomia – Diabetes – Dysfunctional labor – Operative vaginal delivery

• Complications: – Maternal – Fetal: asphyxia & trauma

Shoulder Dystocia-3 • Management: – HELP!!! HELP!!! HELP!!! – Episiotomy – McRobert’s maneuver: • Sharp flexion of maternal legs upon abdomen

– Suprapubic pressure – Woods corkscrew maneuver: • Rotating posterior shoulder 180º

– Delivery of the posterior shoulder

Shoulder Dystocia-4 • Management: – Rubin maneuver: • Displacing anterior shoulder towards chest

– Deliberate fracture of the clavicle(s) – Zavanelli maneuver: • Flexion of fetal head & replacement into uterus followed by CS – Symphysiotomy or deliberate fracture of SP

THE END