Preterm labor

• Regular uterine contractions and cervix changes before 37wks

• ↑↑ risk: Previous preterm birth, short cervical length (<2.5cm), multiparity

  • Cerclage short cervix at 12-14wks and avoid coitus

• Other causes include infection, stress, placenta previa/abruption, smoking, bimodal age, low BMI

  • Stress ➔ HPA axis activation ➔ ↑ ACTH ➔ ↑ cortisol ➔ ↑ CRH ➔ prostaglandin activation ➔ cervical ripening and ROM

• DX

  • Fetal fibronectin ↑ in labor (not in false labor)

  • Dilated >3cm

  • Cervical length <2cm (or <3cm with fetal fibronectin)

Induction of fetal lung maturity (24 to 33wks 6/7)

• Antenatal steroids (IM betamethasone or IM dexamethasone) if at risk of delivery within 7d

  • 48hrs is ideal

  • Another dose if given >2wks ago

Tocolytics ⊣ uterus contractions (delays labor)

• • To prolong labor for up to 48hrs so steroids can work

  • 24-32wks ➔ indomethacin (NSAID) OR nifedipine (CBB) OR terbutaline (β-2 agonist)

    • MgSO4 can be used to reduce risk of cerebral palsy(neuroprotective) but is a less effective tocolytic

  • 32-34wks ➔ nifedipine OR terbutaline

• Tocolysis contraindications: cervical dilation > 4 cm, chorioamnionitis, fetal distress, placental abruption, prolapsed cord

  • MgSO4 CI in myasthenia gravis

  • CBB CI in aortic regurg

GBS infection PPX

• IV penicillin OR ampicillin OR cefazolin for at least 4hrs prior to delivery

Vaginal progesterone supplementation

• Previous spontaneous preterm birth OR short cervical length (<2.5cm)

  • Unclear if benefit in twin pregnancies

Premature rupture of membranes (PROM)

• Preterm PROM (PPROM): PROM before 37wks gestation

• Rupture of membrane (amniotic sac) before onset of labor

• Smoking, multiparity, hx of preterm delivery of PROM ➔ ↑ risk

• Can ➔ Chorioamnionitis (infection of amniotic fluid), cord prolapse, placental abruption, premature labor/fetal distress/ARDS ➔ death

• DX

  • Clinical and confirm with sterile speculum exam (avoid digital cervical exam out of concern for inoculation)

    • Fluid leaving cervix and pooling in vaginal fornix

    • Litmus/nitrazine (turns blue) amniotic fluid is more basic pH than vaginal fluid ➔ neutral/basic pH

• TX

  • Prompt delivery if cord prolapse, placental abruption, chorioamnionitis

  • 24-31wks: Expectant management

    • Admit with fetal HR monitor, assess mom for infection (GBS screening)

      • PPX ABX: IV Ampicillin AND IV erythromycin, then PO amoxicillin and PO erythromycin

      • Betamethasone or dexamethasone for fetal lung development

      • Magnesium sulfate for fetal neuroprotection

  • 32-36wks:

    • PPX ABX: IV Ampicillin AND IV erythromycin, then PO amoxicillin and PO erythromycin

    • Betamethasone or dexamethasone for fetal lung development

    • Monitor and deliver by 37wks

Vasa previa

• Fetal vessels in membranes near internal cervical os ➔ bleeding when ROM occurs

  • Velamentous umbilical cord insertion (abnormal insertion of umbilical cord in chorioamniotic membrane)

• Risk factors: Placenta previa, low-lying placenta, multiparity, IVF

• SSX

  • Painless vaginal bleeding (from fetus) suddenly after ROM

  • Fetal distress (exsanguination can occur quickly)

• DX

  • Transvag US with doppler shows fetal vessels overlying internal os and ↓ fetal vessel flow

• TX

  • Emergency cesarean delivery

  • BOLO retained placental tissue

Dystocia

• Anterior shoulder (MC) impacted behind maternal pubic symphysis

• Risk factors: Hx of dystocia, macrosomia/maternal obesity

• Complications

  • Hypoxia - baby can die if not delivered within 5mins

  • Brachial plexus injury ➔ Erb palsy (C5-6) later in life (adducted, extended, pronated, medially rotated arm)

    • Klumpke palsy (C8-T1) ➔ weakness of hand ➔ claw hand

  • Clavicle/humerus fracture

  • Mom at ↑ risk of PPH and lacerations

• SSX

  • Arrested active phase of labor

  • Head partially delivered but retracts til chin catches perineum ➔ turtle sign

• TX

  • Never apply pressure to fundus or pull fetal head

  • McRoberts maneuver first line : Mom stops bearing down, move butt to edge of bed and go supine

    • Then abduct, externally rotate, and hyperflex maternal hips (grab behind your knees and bring them to your ears)

  • OR Woods screw maneuver

  • Last resort: Fracture clavicle or symphysiotomy (divide the symphysis pubis)

Breech Presentation

• Oligoanhydroamniosis (MC RF)

• Butt or feet are presenting first

  • Frank breech (MC): Butt first (feet near head)

  • Complete breech: Cannonball - knees and hips flexed (feet and butt first)

  • Single Footling breech: One foot

  • Double Footling breech: Both feet

• Cesarean delivery is preferred route of delivery

Birth Trauma (fetal)

• Mechanical factors ➔ injury of newborn

• Risk factors: Forceps/vacuum, rapid/prolonged labor, abnormal presentation (breech, dystocia) macrosomiaHead

• Head

  • Caput succedaneum: Pitting edema that extends across suture lines and resolves in days

  • Molding: Elongation that resolves in days

  • Cephalohematoma: Hemorrhage between skull and periosteum limited to sutures, resolves in wks-mos

  • Subgaleal hematoma: Hemorrhage between periosteum and epicranial aponeurosis (↑ risk of shock)

• Peripheral facial nerve palsy

  • MCC forceps

  • Peripheral facial nerve ➔ forehead involvement (can't get baby to lift eyebrows)

    • Incomplete eye closure (one), absent nasolabial fold

    • Usually self resolves

Episiotomy: Incision of perineum to enlarge vaginal opening during delivery

• Indications: breech, shoulder dystocia, assisted delivery (forceps/vacuum)