A meta-analysis of the association between adolescent pregnancy and the risk of gynecological cancers.

Objectives: Despite several investigations, the association between adolescent pregnancy and gynecological cancers has yet to be conclusively established. To further explore this association, we conducted a meta-analysis of observational studies.

Methods: We conducted a comprehensive search of databases such as PubMed, Web of Science, and Scopus to identify studies investigating the link between adolescent pregnancy and gynecologic cancers. This search continued until February 20, 2023. To assess the heterogeneity among the studies, we used the I2-statistics. We also explored the potential presence of publication bias using the Begg and Egger tests. The overall effect sizes were reported as either risk ratio or odds ratio, accompanied by a 95% confidence interval (CI), using a random-effects model.

Results: From an initial pool of 25,436 studies, a total of 76 studies involving 13,991,683 participants met the predefined eligibility criteria. The analysis indicated that the overall effect size for individuals having their first pregnancy at age 20 or older, compared to those having it before age 20, was 0.54 (95% CI, 0.50 to 0.59) for cervical cancer, 0.82 (95% CI, 0.77 to 0.88) for ovarian cancer, and 0.96 (95% CI, 0.89 to 1.04) for uterine cancer.

Conclusions: Our findings suggest that experiencing one's initial pregnancy at the age of 20 or above is associated with a significantly reduced risk of cervical and ovarian cancer. However, no significant association was found between first pregnancy at this age and uterine cancer.