Abnormal labor and delivery

Labor and delivery can be complicated by multiple factors: prolonged stages of labor can lead to active-phase labor arrest, obstructed labor can occur due to mechanical reasons (e.g., fetal malpresentation), abnormal rupture of membranes can increase the risk of chorioamnionitis and neonatal sepsis, and umbilical cord complications can increase the risk of birth asphyxia and stillbirth. Management of these complications is typically tailored to the individual and can include induction of labor, prophylaxis for neonatal GBS infection, assisted delivery, special obstetrical maneuvers, antibiotics, intrauterine resuscitation measures, and emergency C-section.

See also “Normal labor and delivery,” “Preterm labor,” “Postpartum hemorrhage,” “Chorioamnionitis,” and “Birth traumas.”

Fetal malpresentation and fetal malposition are associated with increased perinatal risks and may require assisted delivery or C-section to prevent maternal and fetal complications (See “Obstructed labor”).

Fetal malpresentation

• Definition: Any fetal presentation or fetal lie that is not a cephalic presentation and can pose a risk or obstacle to safe spontaneous vaginal delivery
• Examples
  • Breech presentations
    • Frank breech
    • Complete breech
    • Single Footling breech
    • Double Footling breech
  • Compound presentation
  • Shoulder presentation
  • Transverse lie
  • Oblique lie

Fetal malposition

• Definition: A type of fetal position that can pose a risk or obstacle to safe spontaneous vaginal delivery
• Examples
  • Occiput posterior position
  • Occiput transverse position

Etiology

• Abnormalities of the 3 P's of labor
  • Pelvis: size and shape of the maternal pelvis (e.g., small bony pelvis)
  • Passenger: size and position of the infant (e.g., fetal macrosomia or abnormal orientation)
  • Power: strength and frequency of contractions (e.g., dysfunctional contractions )

Abnormal labor stages

Complications of a prolonged second stage are postpartum hemorrhage and a poor neonatal outcome.

If the placenta is incomplete or if an accessory placenta is suspected, manual palpation should be performed and any remaining tissue should be removed by curettage.

Definition ^[2]

• Arrest of vaginal delivery because of a mechanical obstruction (see “Arrested active phase” for comparison)

Predisposing factors

• Excessive fetal size (macrosomia may be physiological or pathological, e.g., due to hydrocephalus)
• Fetal malpresentation/malpositioning
• Uterine abnormalities, e.g., due to tumor (e.g., uterine leiomyoma), deformities of maternal pelvis, bicornuate uterus, multiparity
• Placenta previa
• Short umbilical cord
• Oligohydramnios, polyhydramnios

Clinical features

• Caput succedaneum
• High presenting part; not engaged; ruptured membranes
• Head molding (excessive during obstructed labor)
• Frequent uterine contractions
• Edematous vulva

Management ^[2]

• General: cesarean delivery for any maternal etiologies or congenital anomalies
• Uncertain fetal presentation/position: Perform intrapartum transabdominal ultrasound if fetal head position is uncertain during delivery. ^[3]
  • Fetal head position is an important factor in determining the mode of delivery.
  • More accurate than digital cervical examination
• Compound presentation
  • If the head is engaged: forceps delivery with/without repositioning of the arm
  • If head is not engaged: cesarean delivery
• Transverse lie
  • No intervention is necessary before 37 weeks of gestation since the majority of fetuses will eventually rotate naturally to a cephalic or breech presentation before labor. ^[4]
  • Neglected transverse lie: additional impaction of the fetus (prolapsed arm, wedged-in shoulder) ^[5]
  • Cesarean delivery is recommended if fetus is still in transverse lie at the time of labor.
• Persistent occiput posterior position
  • Lateral positioning of the mother to achieve a 90° rotation of the fetal head, stimulate uterine contractions (e.g., with oxytocin)
  • In the case of arrested labor: cesarean delivery
• Deep transverse arrest
  • Conservative treatment
    • Lateral positioning of the mother to achieve 90° rotation of the fetal head
    • Stimulate uterine contractions (e.g., with oxytocin)
  • Use of forceps or a vacuum to rotate the fetal head if arrested labor ≥ 60 min
• Breech presentation
  • No intervention necessary before 37 weeks' gestation, as most fetuses spontaneously convert to cephalic presentation as they get closer to term
  • External cephalic version
    • Should be offered in all cases ≥ 37 weeks who would like to attempt a vaginal delivery, unless there are contraindications.
    • Involves manual adjustment of fetal position by applying pressure on the mother's abdomen
    • Contraindications for external cephalic version
      • Multiple pregnancy
      • Ruptured membranes
      • Fetal anatomical abnormalities
      • Hyperextension of fetal neck
      • Non-reassuring fetal status
      • Oligohydramnios
      • Antepartum hemorrhage
      • Placental abnormalities
      • Patient in active labor
  • Cesarean delivery: if external cephalic version is unsuccessful or contraindicated (e.g., in active labor, fetal distress)
  • Assisted vaginal delivery
    • In emergency cases where cesarean delivery was not possible
    • For a low-risk pregnancy, if the patient wishes to avoid surgery
• Shoulder dystocia: various obstetrical maneuvers may be tried (e.g., McRoberts, Zavanelli) to deliver the infant and avoid fetal demise from umbilical cord compression.

Complications

Neonatal ^[6][7]

• Birth asphyxia
• Infections (intrauterine and neonatal)
• Intracranial hemorrhage
• Birth injuries
• Perinatal death

Maternal ^[8]

• Vesicovaginal fistula and ureterovaginal fistula
• Uterine rupture
• Infections (e.g., puerperal sepsis)
• Postpartum hemorrhage
• Stress urinary incontinence
• Perinatal death

• Definition: an obstetric emergency in which the anterior shoulder of the fetus becomes impacted behind the maternal pubic symphysis during vaginal delivery
• Epidemiology: ∼ 0.2–3% of births
• Risk factors
  • History of shoulder dystocia
  • Fetal macrosomia
  • Prolonged second stage of labor
  • Maternal diabetes mellitus
  • Maternal obesity
• Clinical features
  • Features of arrested active phase of labor
  • Turtle sign: the fetal head is partially delivered but retracts against the perineum
  • Failed restitution of the head
• Diagnosis: clinical diagnosis
• Treatment
  • The patient should stop bearing down and lie supine with the buttocks on the edge of the bed.
  • Perform shoulder dystocia maneuvers:
    • First-line: McRoberts maneuver
    • Any of the internal maneuvers below may be attempted next.
    • Move to another maneuver if delivery is not accomplished within 20–30 seconds.
    • If all above maneuvers fail, attempt the all fours position.
  • Last-resort options:
    • Fracture of fetal clavicle
    • Zavanelli maneuver
    • Symphysiotomy

• Complications
  • Fetal
    • Brachial plexus injury; (Erb palsy; is more common than Klumpke palsy)
    • Clavicle or humerus fracture
    • Hypoxia over an extended period of time as a result of umbilical cord compression
  • Maternal
    • Perineal lacerations
    • Postpartum hemorrhage
• Prognosis ^[9]
  • Spontaneous remission occurs in over 90% of infants within the first 3 months of life
  • Infants in whom symptoms persist typically recover by one year of age.

Most cases of shoulder dystocia occur in the absence of identifiable risk factors.

Rupture of membranes (ROM) typically occurs spontaneously during the first stage of labor. The following are abnormal variants of ROM.

Premature rupture of membranes (PROM)

• Definition: rupture of membranes occurring before onset of labor at term
• Epidemiology: between 5 and 10% of all deliveries
• Risk factors
  • Ascending infection (common)
  • Cigarette smoking
  • Multiple pregnancy
  • Previous preterm delivery
  • Previous PROM
• Complications ^[10]
  • Umbilical cord prolapse or injury
  • Placental abruption
  • Chorioamnionitis, possibly leading to:
    • Preterm labor and birth
    • Fetal distress
    • Stillbirth
    • Sepsis
  • Pulmonary hypertension, pulmonary hypoplasia, ARDS (newborn)
  • Postpartum infection
  • Endometritis

Preterm premature rupture of membranes (PPROM)

• Definition: : rupture of membranes before onset of uterine contractions AND before 37 weeks' gestation
• Epidemiology: occurs in 2–5 % of pregnancies
• Risk factors: previous PPROM, in addition to PROM risk factors
• Complications: Same as the complications of PROM.

Prolonged rupture of membranes

• Definition: Rupture of membranes that occurs > 18 hours before the onset of uterine contractions in term or preterm pregnancies
• Risk factors: young maternal age, smoking, STDs, low socioeconomic status

Diagnosis

• Clinical diagnosis: : history of a sudden “gush” of pale yellow or clear fluid from the vagina.
• Sterile speculum examination: : often required; clinical uncertainty is common in PROM; and PPROM
  • Positive pool: amniotic fluid exiting the cervix and pooling in the vaginal fornix
  • Detection of amniotic fluid
    • Litmus test or nitrazine test: test strips turn blue
    • Positive fern test: fern pattern on glass slide
    • Positive IGF1: IGF1, normally present in amniotic fluid, appears in the cervix if membranes rupture.
    • Positive placental α-microglobulin-1 (PAMG-1) in cervicovaginal fluid
• Ultrasound: oligohydramnios may be present

Management ^[11]

The management of PROM and PPROM depends on the gestational age and the presence of intraamniotic infection or nonreassuring fetal status.

• Monitor for signs of intraamniotic infection (body temperature, uterine tenderness, WBC count)
• Perform fetal heart rate monitoring to assess for nonreassuring fetal status
• Consider intrapartum risk factors and prophylaxis for neonatal GBS infection, depending on whether previous antenatal GBS screening has been performed (see also “GBS prophylaxis considerations in preterm labor”).

Unstable patients

• Prompt delivery in:
  • Patients with signs of intraamniotic infection, abruptio placentae, cord prolapse
  • Signs of fetal distress (nonreassuring fetal heart rate)
• Additionally, collect cervical cultures and commence empiric antibiotic therapy ampicillin and gentamicin.

Stable patients

• Gestational age: ≥ 37 0/7 weeks (term)
  • Delivery by induction of labor is generally recommended.
  • Expectant management for up to 12–24 hours is reasonable in otherwise uncomplicated pregnancies and in the absence of infection.
• Gestational age: 34 0/7–36 6/7 weeks (late-preterm)
  • Expectant management and induction of labor are both reasonable options.
  • Expectant management
    • Bed rest, pelvic rest
    • Induction of fetal lung maturity: single-course of antenatal corticosteroids if not previously given if there is no evidence of chorioamnionitis and delivery is anticipated in > 24 hours and < 7 days
• Gestational age: 24 0/7–33 6/7 weeks
  • Expectant management
    • Bed rest, pelvic rest
    • Prophylactic antibiotics to reduce the risk of infection and delay delivery
      • Ampicillin IV PLUS erythromycin IV followed by amoxicillin PO PLUS erythromycin PO
        OR
      • Ampicillin IV PLUS azithromycin IV followed by amoxicillin PO PLUS azithromycin PO
    • Single-course of antenatal corticosteroids (betamethasone or dexamethasone)
    • Tocolysis; can be used to delay delivery for up to 48 hours so that antenatal corticosteroids can be administered. ^[12]
    • Magnesium sulfate; if preterm delivery < 32 weeks gestation is anticipated ^[13]
• Gestational age < 23–24 weeks
  • Fetal outcome is generally poor in PPROM before or at the limit of viability.
  • The choice of management depends on patient-specific factors and preference.
  • Expectant management
    • Not recommended before viability
    • Same approach as for pregnant women at 24 0/7–33 6/7 weeks

Tocolysis is contraindicated in advanced labor (cervical dilation > 4 cm), chorioamnionitis, nonreassuring fetal signs, abruptio placentae, or risk of cord prolapse.

Causes

• Most common: Umbilical cord prolapse
• Uterine contractions during childbirth
• Nuchal cord (wrapping of the umbilical cord)
• Knotting of the umbilical cord
• Entanglement of the umbilical cord

Umbilical cord prolapse

There are 3 types:

• Overt umbilical cord prolapse
• Occult umbilical cord prolapse
• Cord presentation

Overt umbilical cord prolapse

• Definition: Condition in which a part of the umbilical cord lies between the antecedent part of the fetus (mostly head) and the pelvic wall, causing rupture of membranes and acute, life-threatening hypoxia for the fetus.
• Epidemiology: Most common form of cord prolapse (0.5% births)
• Etiology: often seen in presentation anomalies (e.g., breech presentation, transverse fetal position), multiple pregnancy, long umbilical cord, or abnormal fetal movement (polyhydramnios, premature birth)
• Clinical features: an abrupt change from a previously normal CTG to one with fetal bradycardia or recurrent, severe decelerations, occuring after the rupture of membranes
• Diagnostics: thick, pulsating cord is palpable on vaginal examination
• Management: intrauterine resuscitation measures

Occult umbilical cord prolapse

• Similar to overt umbilical cord prolapse, but the umbilical cord has not advanced past the presenting fetal part.

Cord presentation

• Definition: part of the umbilical cord lies between the antecedent part of the fetus (mostly head) and the pelvic wall; the amniotic sac is intact
• Etiology: oligohydramnios, presentation abnormalities
• Clinical features: recurrent variable decelerations on cardiotocography ; may progress to umbilical cord prolapses if membranes rupture
• Diagnostics: clinical diagnosis
• Treatment
  • See “Treatment with intrauterine resuscitation measures” in “Intrapartum fetal monitoring”.
  • Often, spontaneous reduction of the umbilical cord into the uterus if the mother is placed in a different position (e.g., Trendelenburg position ) enables vaginal birth.

Nuchal cord ^[2]

• Most often caused by activity/turning of the fetus
• Single cord around the neck: observed in ∼ 20% births
• Multiple cord loops around the neck: < 1% births

Knotting of the umbilical cord

• Most often caused by activity/turning of the fetus
• Cord knot: 1–2% births

Indications for induction of labor

• Post-term pregnancy (≥ 42 weeks of pregnancy or gestation)
• PPROM after 34 weeks
• PROM at term
• Hypertension during pregnancy, preeclampsia, eclampsia, HELLP syndrome
• Maternal diabetes to avoid post-term pregnancy (risk of macrosomia)
• Maternal request at term
• Intrauterine fetal demise

Contraindications for induction of labor ^[14]

• History of uterine rupture; previous classical cesarean section
• Complete placenta previa
• Vasa previa
• Transverse fetal lie
• Cord prolapse
• Active maternal genital herpes
• Nonreassuring fetal heart rate

Modified Bishop score

• Used to assess the cervix and the likelihood of a successful induction
• Interpretation
  • Bishop score ≥ 8: favorable cervix for vaginal delivery
  • Bishop score ≤ 6: unripe or unfavorable cervix; not ready for vaginal delivery
  • Simplified Bishop score
    • Considers only fetal station, cervical dilation, and cervical effacement
    • A score ≥ 5 indicates a favorable cervix for vaginal delivery.

Approach

• Membrane sweeping (shortens time to onset of labor)
• If the cervix is still unfavorable: cervical ripening with prostaglandin E1 or E2 (e.g., misoprostol)
• Maternal oxytocin infusion
• Consider amniotomy (only if the cervix is partially dilated and completely effaced, and the fetal head is well applied)
• Administer under fetal heart rate monitoring.

Obstetric forceps delivery ^[2]

• Definition: a forcep is a metal device that enables gentle rotation and/or traction of the fetal head during vaginal delivery
• Types
  • Kielland: enables rotation and traction of the fetal head
  • Simpson: only enables traction of the fetal head
  • Barton: used for occiput transverse position of the fetal head
  • Piper: used to deliver the fetal head during breech delivery
• Classification (See “Station” in “Mechanics of childbirth”)
  • Outlet: fetal head lies on the pelvic floor
  • Low: fetal head is below +2 station (not on the pelvic floor)
  • Mid: fetal head is below 0 station (not at +2 station)
  • High: fetal head is not engaged
• Indications
  • Prolonged second stage of labor
  • Breech presentation
  • Nonreassuring fetal heart rate
  • To avoid/assist maternal pushing efforts (.g., maternal fatigue or cardiopulmonary conditions)
• Prerequisites
  • Skilled clinician
  • Clinically adequate pelvic dimensions (see “Mechanics of childbirth”)
  • Full cervical dilation
  • Engagement of the fetal head
  • Knowledge of exact position and attitude of the fetal head
  • Emptied maternal bladder
  • No suspicion of fetal bleeding or bone mineralization disorders
• Advantages (compared to vacuum delivery)
  • Scalp injuries are less common
  • Cannot undergo decompression and “pop off”
• Complications
  • Maternal: obstetric lacerations (cervix, vagina, uterus), perineal hematomas, urinary tract injury, anal sphincter injury
  • Fetal: head or soft tissue trauma (e.g., scalp lacerations, injured ears), facial nerve palsy, intracranial hemorrhage, retinal hemorrhage, skull fractures, fetal death (rare)

Vacuum extractor delivery ^[2]

• Definition: a vacuum extractor is a metal or plastic cup, attached to the fetal head with a suction device, that enables traction of the fetal head during vaginal delivery
• Indications
  • Prolonged second stage of labor
  • Nonreassuring fetal heart rate
  • To avoid/assist maternal pushing efforts
• Prerequisites
  • Skilled clinician
  • Clinically adequate pelvic dimensions
  • Gestation ≥ 34 weeks
  • Engagement of the fetal head
  • Full cervical dilation
  • Emptied maternal bladder
  • Vertex position
  • No suspicion of fetal bleeding or bone mineralization disorders
• Advantages (compared to forceps delivery)
  • Requires minimum space
  • ↓ incidence of third- and fourth-degree perineal tears
  • Less knowledge about exact position and attitude of the fetal head is acceptable
• Complications
  • Maternal: suction of maternal soft tissue → hematomas or lacerations
  • Fetal: cephalohematoma , scalp lacerations, life-threatening head injury (e.g., intracranial hemorrhage or subgaleal hematoma)

A routine episiotomy is not recommended with assisted vaginal delivery because of the risk of poor healing and anal sphincter injury!

An advantage of assisted vaginal delivery is avoiding cesarean delivery.

Indications ^{[15][16][17][18][19]}

• Late decelerations
• Recurrent variable decelerations
• Prolonged decelerations
• Nonreassuring fetal status
• Category III FHR tracing
• See “Fetal heart monitoring” for details.

Management ^[20][21][22]

• Repositioning of the mother, administer O2 and possibly fluids
  • Positions that reduce cord compression: lying on the right or left side, on hands and knees, Trendelenburg position, lateral semi-Fowler's position
  • Manual elevation of the fetal head (fetus is pushed back into the uterus)
  • Consider filling the bladder with saline
• If initial steps unsuccessful, consider:
  • Amnioinfusion: instillation of saline into the amniotic cavity after artificial rupture of membranes
  • If uterine tachysystole is present (> 5 contractions in a period of 10 minutes): reduce uterine activity by giving tocolytics
  • Emergency cesarean delivery
• Delay active pushing during the 2^nd phase of labor

• Consists of an incision of the perineum (usually in the midline) to enlarge the vaginal opening during delivery
• No longer routinely recommended.
• Can be considered if vaginal delivery needs to be expedited and maternal perineal tissue is thought to pose a significant obstacle, e.g.:
  • Shoulder dystocia
  • Inability to insert instruments required for assisted vaginal delivery
  • Vaginal breech delivery