Relationship Between Abortion at First Pregnancy and Live Births by Young Adulthood: A Population-Based Study Among Mexican Women

Study Objective: To identify factors associated with having an abortion (spontaneous or induced) at the time of first pregnancy, and to test the association between abortion in the first pregnancy and the number of live births among young women 20-24 years of age. Design: Cross-sectional study. Setting: We used a nationally representative survey of Mexican women 20-24 years of age with data at time of survey and retrospective measures of exposures in adolescence. We include 1913 women who reported ever having a pregnancy. Main Outcomes: Our outcomes were history of abortion (spontaneous or induced) and number of live births by 20-24 years of age. We used multivariable logistic regression models to estimate the association between sociodemographic factors at the time of pregnancy and abortion history, and between abortion history and number of live births. Results: Among women 20-24 years of age who ever had a pregnancy, 15.5% reported an abortion in the first pregnancy, and 84.4% never had an abortion. Among women who had an abortion in the first pregnancy, 62.3% did not report any live birth by age 20-24 years. Young women living with their parents (adjusted odds ratio [AOR] = 1.87; confidence interval [CI] = 1.16-3.02) or with a partner with a higher educational level (AOR = 4.64; CI = 1.05-20.44) had greater odds of having an abortion in the first pregnancy. Compared with women who never had an abortion, women who reported an abortion in the first pregnancy had lower odds (AOR = 0.02; CI = 0.01-0.03) of having 1 or more children by the age of 20-24 years. Conclusion: Young women who reported abortion in the first pregnancy had fewer live births at ages 20-24 years compared to women with no history of abortion.