Parity and gestational age are associated with vaginal microbiota composition in term and late term pregnancies

Abstract

Vaginal microbiota and its potential contribution to preterm birth has been under intense research in recent years. However, only few studies have studied vaginal microbiota in later stages of pregnancy or at the onset of labor. We analyzed vaginal swab samples collected between 37- and 42-weeks of gestation from 324 Finnish women before elective cesarean section, at the onset of spontaneous labor, and in pregnancies continuing beyond 41 weeks of gestation. Vaginal microbiota composition associated strongly with parity, i.e. previous deliveries, and advancing gestational age. Absence of previous deliveries was a strong predictor of L. crispatus dominated vaginal microbiota, and the relative abundance of L. crispatus was higher in late term pregnancies, especially among nulliparous women. The results underscore the importance of the vaginal microbiota for improving the currently limited understanding on how the duration of gestation and timing of birth is regulated, with potentially vast clinical utilities.

The vaginal microbiota of pregnant women varies with gestational age, maternal age, and parity

“…At an ASV-level, higher maternal parity was significantly associated with an increase in 58 ASVs classified as typical vaginal CST IV bacteria (e.g., Gardnerella, Megasphaera, Prevotella, and Sneathia), while lower maternal parity was exclusively correlated with 7 Lactobacillus ASVs, 6 of which were classified as L. crispatus (q<0.1) (Supplemental Table 1). This finding is consistent with a recent report of increased vaginal microbiota diversity with higher parity during subsequent gestations (109). The ecological and clinical implications of the correlation between increased parity and vaginal microbiota diversity warrant further investigation.…”

The early life microbiota mediates maternal effects on offspring growth in a nonhuman primate

“…More broadly, the maternal environment may program the infant gut microbiota for enhanced milk utilization via vertical microbial transmission. Thus far, parity effects on maternal microbiota have been demonstrated in agricultural species ( Berry et al., 2021 ; Bogado Pascottini et al., 2021 ), and more recently in humans ( Kervinen et al., 2021 ; Lopez Leyva et al., 2021 ). However, in pigs, parity effects extend to the infant gut microbiota, suggesting that such effects may be vertically transmitted from maternal reservoirs ( Berry et al., 2021 ).…”

The interrelation between microbial immunoglobulin coating, vaginal microbiota, ethnicity, and preterm birth

“…Parity harbors associations with microbiota composition and sPTB. Vaginal L. iners and Gardnerella dominance is associated with previous birth and the risk for recurrent sPTB is 30% [50][51][52]. Therefore, associations between vaginal microbiota and sPTB might be different for nulliparous and multiparous women.…”