Childbirth

Childbirth begins with the onset of labor, which consists of contractions that lead to progressive cervical dilation and effacement, eventually resulting in the birth of the infant and expulsion of the placenta. Complications of childbirth include arrest of or prolonged labor, premature rupture of membranes and preterm premature rupture of membranes, and nerve injuries. The clinical status of the mother and fetus should be consistently monitored during childbirth. While vaginal delivery is typically preferred, cesarean delivery may be indicated under certain circumstances.

Obstetric contractions (uterine muscle contractions)

False labor only requires reassurance!

Stages of labor

First stage of labor

• Definition: period from the onset of labor until complete dilation of the cervix has occurred
• Phases
  • Latent phase of labor
    • Occurs during onset of labor (regular contraction) → ends at 6 cm of cervical dilation
    • Characterized by mild, infrequent, irregular contractions with gradual change in cervical dilation (< 1 cm per hour).
    • Duration
      • Primipara: < 20 hours
      • Multipara: < 14 hours
  • Active phase
    • Occurs after the latent phase at ≥ 6 cm of cervical dilation → ends with complete (∼ 10 cm) cervical dilation
    • Characterized by an increase in the rate of cervical dilation (1–4 cm per hour)
    • Duration
      • Primipara: ≥ 1.2 cm/hour
      • Multipara: ≥ 1.5 cm/hour
• Clinical features
  • Cervix effaces and shortens → cervical dilation
  • Bloody show: A blood-tinged mucous plug may be discharged when the cervix shortens and dilates.
  • Spontaneous rupture of membranes: Watery discharge (caused by rupture of amniotic sac) usually occurs during the onset of labor.
• Management
  • Analgesia at request
  • Fetal heart rate monitoring
  • Determine fetal position with abdominal (see Leopold's maneuvers) and pelvic (palpation of fetal sutures/fontanelles) examination
    • If fetal position cannot be determined by examination, perform ultrasound
  • Regular assessment of cervical dilation and descent of the fetal head
  • Amniotomy may be performed during the active phase if the fetal head is well applied (lying against the cervix).

Second stage of labor

• Definition: a stage of labor that begins once the cervix is completely dilated and ends with the birth of the infant
• Duration
  • Primipara: < 3 hours
  • Multipara: < 2 hours
• Clinical features
  • Completely dilated cervix
  • Regular uterine contractions increasing in frequency and intensity
  • Crowning: the appearance of the fetus's head at the vaginal opening as contractions progress
• Management
  • Warm compresses and perineal massage
  • Assist the mother to find any comfortable and safe position.
  • Episiotomy: not routinely performed
    • Definition: usually a midline incision of the perineum to enlarge the vaginal opening during delivery
    • Indications: shoulder dystocia, forceps or vacuum-assisted delivery, or vaginal breech delivery
  • Delay cord clamping for ∼ 1 minute; alternatively milk the cord (to enhance blood transfusion to the newborn )

Third stage of labor

• Definition: stage of labor that begins with the birth of the infant and lasts until the complete expulsion of the placenta
• Duration: 30 minutes
• Clinical features
  • Uterine contractions (in order to expel the placenta)
  • Signs of placental separation:
    • Cord lengthening
    • Gush of vaginal blood (usually accompanied a blood loss of 300 mL)
    • Uterine fundal rebound (the uterus becomes less elongated and more spherical)
      • Fundal massage: massaging of the uterine fundus to induce its contraction and stop bleeding
      • Active management (reduces the risk of postpartum hemorrhage)
        • Oxytocin, administered after cutting the umbilical cord (reduces blood loss by inducing stronger uterine contractions)
        • Controlled traction while allowing the placenta to separate spontaneously (Brandt-Andrews maneuver)
      • Examine the placenta to confirm completeness (regular surface with complete cotyledons), which should also consist of the umbilical cord, complete amniotic membranes, and 3 blood vessels (one vein, two arteries).
      • Repair any obstetric lacerations.

Fourth stage

• 2-hour postpartum period
• Requires monitoring to rule out hemorrhage or preeclampsia

References:^{[1][2][3][4][5][6][7][8][9][10][11]}

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 )

First stage of labor

Prolonged latent phase

• Diagnosis: poor acceleration phase with a cervical dilation ≤ 6 cm
  • > 20 hours in a primipara
  • > 14 hours in a multipara
• Management
  • Rest, hydration, and adequate analgesia
  • Oxytocin may be considered in well-rested mothers if the other measures have been implemented.

Prolonged active phase

• Etiology: abnormalities of the 3 P's of labor
• Diagnosis: ≥ 6 cm cervical dilation without adequate dilation (< 1 cm/2h)
• Management
  • Augmentation with oxytocin for hypotonic contractions
  • Analgesia for hypertonic contractions

Arrested active phase

• Etiology: abnormalities of the 3 P's of labor
• Diagnosis: ≥ 6 cm cervical dilation with ruptured membranes and no cervical change for ≥ 4 hours if adequate contractions (i.e., ≥ 200 Montevideo units) are present; or no cervical change for > 6 hours if only inadequate contractions are present
• Management: cesarean delivery

Prolonged second stage of labor

• Etiology: abnormalities of the 3 P's of labor
• Diagnosis: failed delivery of the baby after 3 hours in a primipara and after 2 hours in a multipara (an extra hour may be added if an epidural was administered)
• Management
  • Augmentation with oxytocin if uterine contractions are inadequate and progress is > 1 cm after 60–90 minutes of pushing
  • Trial of forceps or vacuum delivery if the fetal head is engaged AND maternal contractions are adequate
  • Cesarean delivery if the fetal head is not engaged

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

Prolonged third stage of labor

• Etiology: inadequate contractions or retained placenta (e.g., abnormal placental implantation such as placenta increta, placenta percreta, or placenta accreta)
• Diagnosis: failed delivery of the placenta after 30 minutes
• Management
  • Manual removal of the placenta
  • Hysterectomy if the above approach fails

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!

References:^[12][13][14]

Types

Premature rupture of membranes (PROM)

• Definition: rupture of membranes occurring before onset of labor at term
• Epidemiology: ∼ 15% of pregnancies
• Risk factors
  • Ascending infection (common)
  • Cigarette smoking
  • Multiple pregnancy
  • Previous preterm delivery
  • Previous PROM
• Complications
  • Umbilical cord prolapse
  • Placental abruption
  • Chorioamnionitis

Delayed rupture of membranes

• Definition: rupture of membranes occurs during fetal expulsion, after cervical dilation and effacement

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 % pregnancies
• Risk factors: previous PPROM, in addition to PROM risk factors
• Complications:
  • Preterm delivery
  • Pulmonary hypoplasia
  • Chorioamnionitis
  • PROM complications

Clinical features

• Sudden “gush” of pale yellow or clear fluid from the vagina (may also be a constant leaking sensation)

Diagnosis

• Sterile speculum examination
  • Positive pool: amniotic fluid exiting the cervix and pooling in the vaginal fornix
  • Detection of amniotic fluid: during sterile speculum examination
    • 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.
• Ultrasound: Oligohydramnios may be present.

Management

• Stable patients
  • < 23 weeks
    • Expectant management (intervention based on viability of fetus)
    • Bed rest, antenatal corticosteroids; (to avoid fetal lung hypoplasia or immaturity), antibiotic prophylaxis; (to reduce risk of infection with group B Streptococcus and preterm labor), and planned delivery ≥ 34 weeks
    • Outcome is usually poor (fetal pulmonary hypoplasia) and termination of pregnancy may be considered.
  • 23–33 weeks
    • Expectant management
    • Bed rest, antenatal corticosteroids; (to avoid fetal lung hypoplasia or immaturity), antibiotic prophylaxis; (to reduce the risk of infection with GBS and preterm labor), and planned delivery ≥ 34 weeks
    • Tocolysis (e.g., with indomethacin, magnesium sulfate ) may be used to delay delivery up to 48 hours.
  • ≥ 34 weeks
    • Delivery of the fetus is usually recommended.
    • The risks of prematurity are diminished compared to the risk of infection and other complications with expectant management.
• Unstable patients: require prompt delivery of the fetus
  • Chorioamnionitis (also collect cervical cultures and commence empiric antibiotic therapy prior to delivery)
  • Abruptio placentae
  • Cord prolapse
  • Nonreassuring fetal heart rate

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

References:^{[2][15][16][17][18][19][20][21][22]}

Electronic fetal heart rate monitoring

• Widely used diagnostic tool during 3^rd trimester and labour to detect signs of fetal distress
• Procedure
  • Determination of the fetal heart rate (FHR), presence of acceleration or deceleration by Doppler ultrasound, recording beats per minute in the upper curve (cardiogram)
  • During birth, the FHR may be monitored internally via an electrode that is attached to the fetal head (fetal scalp electrode); rupture of the membranes must have occurred or an amniotomy performed.
  • Mechanoelectrical measurement of uterine contractions via a pressure transducer, recording in the lower curve in kPa (tocodynagraph)
• Indications
  • During labor
  • Admission in the labor ward
  • In every case of complication during pregnancy or delivery, such as impending preterm birth, abnormalities of the fetal heart, multiple pregnancy, suspected placental insufficiency, uterine bleeding, tocolysis

Fetal heart rate ^[23][24][25]

• In CTG, the FHR is designated as the baseline or basal heart rate and is normally 110–160 bpm.
• Tachycardia
  • Mild tachycardia: FHR of 160–180 bpm for > 10 minutes
  • Severe tachycardia: FHR of ≥180 bpm for > 10 minutes
  • Causes: stress, hypotension, maternal fever, medication (e.g., betamimetics for the treatment of tocolysis), chorioamnionitis, fetal arrhythmias, hypoxia
• Bradycardia
  • Mild bradycardia: FHR of < 120 bpm for > 3 minutes
  • Severe bradycardia: FHR of < 100 bpm for > 3 minutes
  • Causes: supine hypotensive syndrome, fetal heart defects, central nervous system anomalies, hypoxia
• Methods to assess FHR: e.g., nonstress test (NST) and contraction stress test (CST) performed during the third trimester of pregnancy to measure FHR reactivity to fetal movements and FHR reactivity in response to uterine contractions respectively.
  • See nonstress test and contraction stress test in “Prenatal care” for details.

Acceleration (CTG)

• A normal temporal increase in the FHR from the baseline by > 15 bpm for more than 15 seconds but less than 10 minutes.

Decelerations (CTG)

• A temporary decline in the FHR of > 15 bpm for a maximum duration of 3 minutes
• Early deceleration
  • The beginning and end of deceleration correspond with the progression of a contraction; deceleration reaches its minimum, known as the nadir, when the contraction curve attains its peak.
  • Onset to nadir is gradual (≥ 30 sec)
  • Typically occur during active labor when the cervix is dilated ≥ 5 cm and the head is engaged within the pelvic cavity
  • Usually a normal reading (no fetal distress)
  • Causes: compression of the head during contraction triggers a vagal response
• Late deceleration
  • Decrease in the FHR following the maximum contraction curve
  • Onset to nadir is gradual (≥ 30 sec)
  • Causes: uteroplacental insufficiency (leads to fetal hypoxia and acidosis)
  • Measures
    • Intrauterine resuscitation
    • If FHR pattern does not improve despite intrauterine resuscitation → emergency c-section
• Variable deceleration
  • Rather variable presentation and temporal relation to the contractions changes
  • Onset to nadir is abrupt (< 30 sec) and lasts at least 15 sec
  • Causes
    • Umbilical cord compression/prolapse (see umbilical cord complications below)
  • Measures
    • If intermittent variable decelerations (< 50% of contractions): usually no interventions are needed
    • If recurrent variable decelerations (≥ 50% of contractions)
      • Intrauterine resuscitation
      • If FHR pattern does not improve despite intrauterine resuscitation → emergency c-section
• Prolonged deceleration
  • A decrease in FHR by ≥ 15 bpm from the baseline, lasting ≥ 2 min but < 10 min
  • Causes
    • Same as those for late and variable deceleration, but more prolonged and severe
    • Continued uterine contraction, inferior vena cava syndrome (see below), peridural anesthetic, rapid decrease in the mother's blood pressure
  • Measures
    • Intrauterine resuscitation
    • If FHR pattern does not improve despite intrauterine resuscitation → emergency c-section
• Management with intrauterine resuscitation measures ^[26]
  • 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
  • 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

• Indications
  • Post-term pregnancy (≥ 42 weeks of pregnancy or gestation)
  • Preterm premature rupture of membranes after 34 weeks
  • Premature rupture of membranes at term
  • Hypertension during pregnancy, preeclampsia, eclampsia, HELLP syndrome
  • Maternal diabetes to avoid post-term pregnancy (risk of macrosomia)
  • Maternal request at term
  • Intrauterine death
• Contraindications
  • History of uterine rupture; previous high-risk cesarean delivery
  • 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.

References:^[27]

Obstetric forceps delivery

• 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
• 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)
  • Fetal: head or soft-tissue trauma (e.g., scalp lacerations, injured ears), facial nerve palsy

Vacuum extractor delivery

• 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!

References:^[5][28]

Overview

• Definition: the delivery of a newborn through a vertical or horizontal incision in the lower abdominal and uterine wall
• Advantages
  • Safest method of birth if maternal and/or fetal health is compromised by a vaginal delivery
  • Fetal birth trauma is rare.
• Disadvantages
  • Postoperative complications
  • Long recovery period

Indications

Types of incisions

Procedure

• Cesarean delivery is usually performed through a lateral incision.
  • Skin incision above the pubic symphysis.
  • Largely blunt penetration through the abdominal muscles, fascia, and peritoneum
  • Hysterotomy
  • Fetal extraction, cord clamping, and manual placental removal
  • Wound closure
• Procedural time: fetal extraction within ∼ 3–10 min

Complications

• Maternal
  • Hemorrhage
  • Thromboembolic events
  • Surgical injury (i.e., to the bowel, bladder)
  • Infections (i.e., of the endometrium, pelvis, lungs, urinary tract)
  • Impaired uterine regression
  • Higher risk of complications in subsequent pregnancies (e.g., abnormal placental attachment, uterine rupture)
• Fetal: risk of postnatal transient tachypnea of the newborn and respiratory distress syndrome

There are guidelines detailing indications for cesarean delivery that are based on scientific findings. However, each hospital can individually determine how these indications are interpreted. The well-being of the mother and child should be of the utmost priority!

References:^{[29][30][31][32][33]}

Obstetric lacerations

• Definition: tear of the perineal body due to significant or rapid stretching forces during labor and delivery; most common obstetric injury of the pelvic floor
• Risk factors
  • Macrosomia
  • Forceps delivery
  • Occiput posterior delivery
  • Rapid delivery of head in breech presentation
  • Head extension before crowning
  • Lack of perineal elasticity (e.g., perineal edema)
• Classification

• Treatment
  • Surgical repair within 24 hours
  • Depending on the degree of severity, local, regional, or general anesthesia can be used.
  • Suturing the torn structures with subsequent digital-rectal examination to assess wound care
• Complications
  • Hemorrhage
  • Fistulae
  • Pain and dyspareunia
  • Infection
• Prevention: application of warm compress to perineum during delivery and avoidance of risk factors

Complications of fourth degree tears include rectovaginal fistulae!

Obstetric nerve injuries

Acute nerve injury can occur during childbirth due to compression, transection, traction, or vascular injury to the nerve.

References:^[15][34][35]

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: vaginal palpation → thick, pulsating cord is palpable
• Treatment: Trendelenburg position; fetus is pushed back into the uterus; immediate tocolysis using β₂-mimetics (e.g., fenoterol) → emergency cesarean delivery

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” above
  • Often spontaneous reduction of the umbilical cord into the uterus if the mother is placed in a different position (e.g., Trendelenburg position ) → vaginal birth possible

Nuchal cord

• 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

References:^[5][36][37]