Coitus and associated amniotic-fluid infections.

Data were analyzed from 26,886 pregnancies to determine whether coitus is involved in the genesis of amniotic-fluid infections. The frequency of infection was 156 per thousand births when mothers reported coitus once or more per week during the month before delivery, versus 117 per thousand when no coitus was reported (P less than 0.001). The percentage of infected infants who died was 11.0 when there was coitus versus 2.4 when there was no coitus (P less than 0.001). The frequencies of low Apgar scores, neonatal respiratory distress, and hyperbilirubinemia were about doubled when mothers reported coitus. The coitus-associated effects were greater in preterm than in fullterm infants. The pregnancies in the study took place between 1959 and 1966, when national perinatal mortality rates were higher than they are now. Deaths from coitus-associated infections may be less frequent today.