Very Preterm Labour

Very preterm labour is labour between 28 weeks and 31 weeks and 6 days. Survival is high with neonatal intensive care, and in settings without it survival is much lower, so antenatal steroids, magnesium sulphate for neuroprotection and transfer matter most.

• Risk factors: infection, short cervix, previous preterm birth, twin pregnancy, preeclampsia, abruption, polyhydramnios, uterine anomaly.
• Magnesium sulphate lowers the risk of cerebral palsy before 32 weeks.
• Babies are managed by CPAP and feeding support.

Women have regular painful contractions, backache, pelvic pressure, bloody show or leaking fluid. The cervix is effaced and dilating on examination.

• Contractions every 5 minutes or less with a dilating cervix.
• Bleeding with a hard tender uterus suggests abruption.
• Differential diagnosis: threatened preterm labour, abruption, chorioamnionitis, urinary infection, ruptured membranes, uterine rupture.
• Complications: respiratory distress syndrome, intraventricular haemorrhage, necrotising enterocolitis, sepsis, retinopathy of prematurity, cerebral palsy, neonatal death, maternal infection.

The approach is to confirm labour and gestation and to look for infection, rupture and fetal condition.

• Confirm gestation; sterile speculum examination for liquor, bleeding and dilatation; cardiotocography with tocography.
• Ultrasound for presentation, estimated fetal weight, liquor, placental site and cervical length.
• Full blood count, C-reactive protein, urine culture, high vaginal and rectovaginal swab, malaria test, blood pressure, urine protein, group and cross-match.
• Fetal fibronectin or placental alpha microglobulin 1 test only if the cervix is less than 3 cm dilated.

The principle is steroids, magnesium sulphate, short term tocolysis to allow them and delivery in a unit with neonatal intensive care.

• Supportive: transfer in utero; left lateral position; two cannulae; delayed cord clamping for 60 seconds; warm delivery room and plastic bag for the baby; kangaroo mother care; fluids not restricted unless pulmonary oedema develops.
• Pharmacological: betamethasone 12 mg IM twice, 24 hours apart (or dexamethasone 6 mg IM 12-hourly for 4 doses); magnesium sulphate 4 g IV over 20 minutes then 1 g per hour until delivery for 24 hours at most (stop for absent patellar reflexes, respiratory rate below 12 per minute or urine below 30 mL per hour, with calcium gluconate 1 g IV over 10 minutes for toxicity); nifedipine 20 mg oral once then 10 to 20 mg oral every 6 to 8 hours for up to 48 hours (maximum 120 mg daily); ampicillin 2 g IV 6-hourly plus erythromycin 250 mg oral 6-hourly for 7 days if membranes are ruptured; benzylpenicillin 5 million units IV then 2.5 million units 4-hourly until delivery for group B streptococcus; oxytocin 10 IU IM at birth; neonatal surfactant (poractant alfa 200 mg/kg endotracheal, then 100 mg/kg) for respiratory distress, caffeine citrate 20 mg/kg oral or IV loading then 5 to 10 mg/kg once daily, and CPAP at 5 to 6 cm water pressure.
• Procedures: vaginal birth for a cephalic baby; caesarean section for breech presentation, transverse lie, abruption or fetal compromise; remove any cerclage at once.
• Special groups: twin pregnancy uses nifedipine with restricted fluids and avoids beta agonists; diabetes needs insulin increased by 25 to 40 percent for 72 hours after steroids; preeclampsia or chorioamnionitis stops tocolysis and requires delivery.
• Red flags: fever above 38 degrees Celsius, bleeding, cord prolapse, fetal heart rate above 160 or below 110 beats per minute, maternal breathlessness, severe hypertension.
• Follow-up: neonatal intensive care; maternal temperature 4-hourly for 24 hours after birth; review at 6 weeks; plan for the next pregnancy with cervical length scans and progesterone.