Duration of rupture of membranes and microbiome transmission to the newborn: A prospective study

Objective: To assess whether labour variables (i.e. individuals characteristics, labour characteristics and medical interventions) impact maternal and newborn microbiomes. Design: Prospective monocentric study. Setting: Saint-Joseph Hospital tertiary maternity unit, in Paris, France. Population: All consecutive primiparous women with a physiological pregnancy and term labour from 15 April to 1 June 2017. Methods: 16S ribosomal RNA gene sequencing of the maternal vaginal, newborn skin and newborn oral microbiomes from 58 mother-baby dyads. Main outcome measures: Analysis of the effects of 19 labour variables on the composition and diversity of these microbiomes. Results: The 19 labour variables explained a significant part of the variability in the vaginal, newborn oral and skin microbiomes (44%-67%). Strikingly, duration of rupture of membranes was the single factor that explained the greatest variability (adjusted R-2: 7.7%-8.4%, p <= 0.002) and conditioned, by itself, the compositions of the three microbiomes under study. Long duration of rupture of membranes was specifically associated with a lower relative abundance of the Lactobacillus genus (1.7-fold to 68-fold reduction, p < 0.0001) as well as an increase in microbiome diversity, including genera implicated in nosocomial infections. The effects of duration of rupture of membranes were also present in newborns delivered by non-elective caesarean section. Conclusions: Maternal and newborn microbiomes were greatly affected by labour variables. Duration of rupture of membranes, even in non-elective caesarean sections, should be considered in epidemiological and microbiological studies, as well as in vaginal seeding practices.