PROM at term: when might be the best time to induce labour? A retrospective analysis.

Purpose: PROM after 37 weeks of gestation occurs in approximately 10% of pregnancies. When spontaneous onset of labour does not follow, induction is recommended to decrease the risk of infection for both mother and child. However, there is no clear consensus on whether induction before 24 h after PROM results in fewer complications compared to induction after > 24 h.

Material and methods: This retrospective observational study analysed the outcomes of 3174 women with PROM admitted to the delivery room of LMU Women's Hospital between 10/2015 and 09/2020. We evaluated whether timing of labour induction was associated with maternal or newborn postpartum infection rates.

Results: Comparing women with spontaneous onset of labour to those who underwent induction, no significant differences were found in maternal CRP or leukocyte levels, fever, endometritis, or Group B streptococcus colonization. However, intrapartum antibiotic therapy was significantly higher in the induction group. When the induction group was subdivided based on the interval from PROM to induction, no significant differences were observed in maternal infection parameters, need for antibiotics, postpartum length of hospital stay, or endometritis. For newborn infections, a significant difference in CRP levels was found, with higher levels in the groups with "induction < 12 h" and "> 24 h".

Conclusion: The presented data suggests that waiting for spontaneous contractions within the first 24 h after PROM was not associated with the risk of infection if no initial signs for infection are present. However, beyond 24 h, the risk of infection increased. These findings support current recommendations regarding the timing of induction after PROM.