Prior pregnancy outcome and the risk of intraamniotic infection in the following pregnancy

Objective: Our purpose was to determine whether the outcome of a prior pregnancy influenced the risk of intraamniotic infection in the following pregnancy. Study Design: A case-control study was conducted at five King County, Washington, hospitals from 1990 through 1994. Cases (n=585) of intraamniotic infection were identified by a medical record review for clinical signs of infection during labor and compared with controls (n=575). Women were classified as having a spontaneous abortion or elective termination if the pregnancy had been diagnosed by a health care professional before 20 weeks and was verified by medical record review. Adjusted odds ratios and 95% confidence intervals were estimated using logistic regression. Results: Women with spontaneous abortion (odds ratio=4.3; 95% confidence interval 2.9 to 6.4) or elective termination (odds ratio=4.0; 95% confidence interval 2.7 to 5.8) had an increased risk of intraamniotic infection. The increased risk was similar for women who did and did not have an earlier pregnancy carried beyond 20 weeks. Conclusions: Women who have had a spontaneous abortion or an elective termination have an increased risk of intraamniotic infection regardless of previous successful pregnancy outcome.