Placenta praevia and male sex at birth: results from a population-based study

This study examined the relationship between male sex at birth and placenta praevia in 433 031 mother/infant dyads (linked by a common institutional c ode and hospital admission number) in the Canadian province of Quebec, duri ng the fiscal years of 1991/92-1995/96. The male-to-female ratio among preg nancies with and without placenta praevia was calculated and compared. The male-to-female ratio at birth was higher in pregnancies complicated by a pl acenta praevia (1.19) than in those without it (1.04; P < 0.02). This incre ased ratio persisted after accounting separately for the potential confound ing and/or modifying Effects of maternal age, infant birthweight and gestat ional age by stratified and multiple logistic regression analyses. We concl ude that pregnant women with male babies carry a higher risk of placenta pr aevia.