Chlamydial and gonococcal infections and risk of unwanted obstetric results

The aim of a retrospective cohort study at the University of New South Wales (University of New South Wales, Sydney, Australia) was to examine the relationship between chlamydial and gonococcal infections and the risk of obstetric outcomes undesirable.

During the work, data were analyzed on women who had their first delivery between 1999 and 2008, and a probable relationship was established between chlamydia and gonococcal infections and the outcome of pregnancy. Obstetric outcomes and potential interference factors were clarified on the basis of labor history records. To establish a possible relationship between the above infectious diseases diagnosed before childbirth and the undesirable obstetric results, a logistic regression method was used taking into account the potential interference factors. Unwanted obstetric outcomes included spontaneous preterm labor, low fetal weight by gestational age, and stillbirths.

Among the data analyzed from 354,217 women, 1% (n = 368) were diagnosed with chlamydia infection before delivery and 0.06% (n = 196) had gonorrhea. Most (more than 80%) diagnoses of these STIs were made before the estimated date of conception. In 4.1% of women, a spontaneous premature delivery occurred, in 12.1% of cases, the children were light according to gestational age and in 0.6% of cases, the baby was born dead.

In women who had previously had chlamydia, there was an increased risk of spontaneous preterm labor and stillbirth (a correlated odds ratio of 1.17 (95% confidence interval 1.01-1.37) and 1.40 (95% CI 1.00-1.96), respectively), however, no association with low birth weight was found based on gestational age (a correlated odds ratio of 0 , 99, 95% CI 0.89-1.09).

Women with gonococcal infection had an increased risk of experiencing the same undesirable obstetric outcomes, namely, spontaneous preterm delivery (adjusted odds ratio 2.5, 95% CI 1.39-4.5) and stillbirths (adjusted odds ratio 2.35, 95% CI 0.58–9.56), and the effect of STIs on low birth weight by gestational age has not been established (the adjusted odds ratio is 0.98, 95% CI 0.58–1.68).

In women with chlamydia, the risk of spontaneous preterm delivery does not differ in cases where the diagnosis was made more than one year before conception, in the year before conception, or during pregnancy (p = 0.9).

Thus, this large-scale study has shown that STIs in women, not only during pregnancy, but even before conception, can play an important role in the development of adverse pregnancy outcomes.