Mothers who change male partners between the births of their first two children are at higher risk for pregnancy complications during the second birth. According to a study of some 450,000 Norwegian women who had the same partner for both births and nearly 32,000 women who were with two different men, the risk for premature birth doubled among the women who were with new partners. Low birth weight and infant mortality were also higher.
Researchers from the Norwegian University of Science and Technology in Trondheim speculate that the correlation may stem from higher rates of risky behavior among the second group of women, such as heavier smoking, alcohol consumption and poorer nutrition. Among the women who had changed partners, smoking was nearly three times as likely. The study was published in the British Medical Journal.
