Is 35 Weeks and 6 Days Gestation with PROM Considered Preterm?
Yes, a pregnancy at 35 weeks and 6 days gestation is definitively preterm, as preterm is defined as delivery occurring before 37 weeks and 0 days of gestation. 1
Definition of Preterm Gestation
- Preterm delivery is explicitly defined as occurring at less than 37 weeks and 0 days of gestation 1
- At 35 weeks and 6 days, this pregnancy falls into the late preterm category (34-36 6/7 weeks) 1
- The CDC guidelines consistently use the threshold of <37 weeks and 0 days to define preterm status across multiple iterations 1
Clinical Implications for This Specific Case
Since this patient has premature rupture of membranes (PROM) at a preterm gestational age, the following management is indicated:
Immediate GBS Management
- Obtain a vaginal-rectal culture for Group B Streptococcus immediately upon admission if no screening was performed within the preceding 5 weeks 2, 3, 4
- Initiate GBS prophylaxis immediately without waiting for culture results 2, 3, 4
- Use Penicillin G 5 million units IV initially, then 2.5-3 million units IV every 4 hours until delivery 3, 4
- Continue GBS prophylaxis until delivery if the patient enters true labor 3, 4
Antenatal Corticosteroids
- Administer antenatal corticosteroids if delivery is anticipated and no prior course has been given, as this remains beneficial even in the late preterm period 3, 4
Delivery Timing Considerations
- At 35 weeks and 6 days with PROM, delivery is generally recommended rather than expectant management 5
- The risks of maternal complications (hemorrhage and infection) with expectant management outweigh potential neonatal benefits at this gestational age 5
- Expectant management carries infection rates up to 58.1% and maternal sepsis rates of 6.8% 2, 4
Critical Pitfalls to Avoid
- Do not rely on oral antepartum antibiotic treatment for GBS, as it is ineffective and does not prevent neonatal disease 3
- Do not delay diagnosis or intervention for intra-amniotic infection, as clinical deterioration can occur rapidly with a median time to death of only 18 hours once infection is identified 2, 4
- Monitor closely for fever ≥38.0°C, maternal tachycardia, uterine tenderness, fetal tachycardia, and purulent cervical discharge as signs of chorioamnionitis 4