Rehbinder EM, et al. - In the Preventing Atopic Dermatitis and Allergies in children (PreventADALL) study cohort, researchers investigated the presence of a microbiota in sterilely collected amniotic fluid in uncomplicated pregnancies at term. Amniotic fluid was randomly sampled at cesarean sections in pregnant women and was analyzed by culture-independent and culture-dependent techniques. Researchers selected 10 elective (planned, without ongoing labour) cesarean sections with intact amniotic membranes (non-ROM group) and all 14 pregnancies with prior rupture of membranes (ROM group). Findings suggest that in uncomplicated pregnancies, fetal development occurs in the absence of an amniotic fluid microbiota and that the offspring microbial colonization starts after uterine contractions and rupture of amniotic membrane.