Late Preterm Labour

Late preterm labour is labour between 34 weeks and 36 weeks and 6 days. It is the commonest group of preterm births. These babies usually survive but have more respiratory problems, hypoglycaemia, jaundice, poor feeding and temperature instability than term babies, and more neonatal admissions.

• Risk factors: previous preterm birth, twin pregnancy, preeclampsia, infection, membrane rupture, diabetes, polyhydramnios, short cervix.
• Tocolysis is not used after 34 weeks.
• Elective delivery before 39 weeks without a medical reason is avoided.

Women have regular contractions, backache, pelvic pressure, a bloody show or leaking fluid, with a progressively dilating cervix.

• Contractions with cervical change at 3 cm or more.
• Breech presentation is common.
• Differential diagnosis: false labour, urinary infection, abruption, chorioamnionitis, early term labour with wrong dates.
• Complications: transient tachypnoea, respiratory distress syndrome, hypoglycaemia, hypothermia, jaundice, feeding difficulty, sepsis, neonatal admission.

The approach is to confirm labour and gestation and to assess presentation and infection.

• Confirm gestation; sterile speculum examination for membrane rupture and bleeding; cardiotocography.
• Ultrasound for presentation, estimated fetal weight, liquor and placental site.
• Urine dipstick and culture, high vaginal and rectovaginal swab, full blood count, C-reactive protein, blood pressure, urine protein.
• Blood group and glucose in women with diabetes.

The principle is to allow labour to proceed, give group B streptococcus cover and prepare for newborn care.

• Supportive: admit; left lateral position; continuous or intermittent monitoring; delayed cord clamping for 60 seconds; skin to skin contact and early breastfeeding within 1 hour; warmth; neonatal glucose checks.
• Pharmacological: benzylpenicillin 5 million units IV then 2.5 million units 4-hourly until delivery for group B streptococcus carriage, unknown status or membrane rupture; ampicillin 2 g IV 6-hourly plus gentamicin 5 mg/kg IV once daily for chorioamnionitis; betamethasone 12 mg IM twice, 24 hours apart, may be offered between 34 weeks and 36 weeks and 6 days for a singleton with no earlier course, no diabetes and no chorioamnionitis, when delivery is not imminent; oxytocin 10 IU IM at birth; newborn dextrose 10 percent 2 mL/kg IV over 10 minutes then 80 mL/kg per day for glucose below 2.6 mmol/L.
• Procedures: vaginal birth for cephalic presentation; caesarean section for breech, transverse lie or obstetric indications; no routine episiotomy.
• Special groups: diabetic women have glucose checked hourly in labour with soluble insulin infusion of 1 to 2 units per hour for glucose above 7 mmol/L; penicillin allergy of low risk uses cefazolin 2 g IV then 1 g 8-hourly.
• Red flags: fever above 38 degrees Celsius, bleeding, cord prolapse, abnormal cardiotocography, maternal hypertension.
• Follow-up: newborn observation for 24 to 48 hours, with glucose, temperature, feeding and bilirubin checks; maternal review at 6 weeks.