Chlamydia, gonorrhea tied to higher risk of pregnancy complications

Women with Chlamydia Infection or gonorrhea infections before or during pregnancy are at increased risk for pregnancy complications such as stillbirth and premature birth, a new study suggests.

Researchers analyzed data from more than 350,000 Australian women who had their first child between 1999 and 2008. Of those women, 1 percent had at least one chlamydia infection before they gave birth, and 81 percent of those women were diagnosed before they became pregnant.

The study also found that 0.6 percent of the women had a gonorrhea infection before they gave birth, and nearly 85 percent of those women were diagnosed before they became pregnant. Half of the women diagnosed with gonorrhea had also previously been infected with chlamydia, found researchers Dr. Bette Liu, at the University of New South Wales, and colleagues.

Among all the women in the study, 4 percent had an unplanned premature birth, 12 percent had babies who were small for their gestational age, and 0.6 percent had stillborn babies.

After taking into account factors known to increase the risk of birth complications -- including age, poverty, smoking and health conditions such as diabetes and high blood pressure -- the researchers found that a prior infection with either chlamydia or gonorrhea also increased the risk.

Women who'd had chlamydia transmission were 17 percent more likely to have an unplanned premature birth and 40 percent more likely to have a stillborn baby. There was no increased risk of having a baby that was small for its gestational age.

For women who'd had chlamydia, the risk of an unplanned premature birth did not differ between those diagnosed with an infection more than a year before conception, within a year of conception, or during the pregnancy.

Women who had had gonorrhea were more than twice as likely to have an unplanned premature birth, but they were not at increased risk of having a baby that was small for its gestational age, according to the study published online Sept. 4 in the journal Sexually Transmitted Infections.

Not enough data existed to determine the impact that gonorrhea infection had on the risk of stillbirth.

These findings don't prove that chlamydia and gonorrhea infections actually cause pregnancy complications, but do suggest that such infections may be important in predicting pregnancy complications, the study authors concluded.