Patterns of pregnancy termination according to contraceptive use

Sánchez-Páez, David Antonio [UCL] Ortega, José Antonio [Universidad de Salamanca]

Background: The outcome of pregnancy is either a live birth or a pregnancy termination. The probability of a pregnancy ending in a live birth is a fundamental element in demographic models of reproduction, such as the proximate determinants framework, implicitly assuming the likelihood of pregnancy termination is independent of contraceptive use. Contraception signals if a pregnancy is unintended at the time; hence, failures in its use lead to unwanted pregnancies and induced abortion. Methods: We use individual-level calendar data of 1,316,885 women aged 15-49 from 94 DHS for 49 low- and middle-income countries to estimate non-parametric probabilities of pregnancy termination by age, marital status, and contraceptive use before pregnancy at the survey, region, and sample level. Also, we provide estimates for the probability of pregnancy loss and induced abortion. Results: On average, 11.7% of pregnancies end before birth. The odds of termination are higher for unmarried women by 1.2 percentage points. By contraception, users are 11.3 percentage points more likely to have terminations. The probability increases with age from 9.9% for adolescents to 27.4% at ages 45-49. The likelihood of biological loss follows a U-shaped pattern by age. The odds of induced abortion are 9.8% for users and 2.3% for non-users. Conclusions: Patterns differ by regions and are consistent with demographic risk factors as age and marital status. There is an association between contraceptive use at the time of pregnancy and terminations. Contraceptive failure leads to unintended pregnancies and increases the probability of pregnancy termination, thus, induced abortion. Unmarried women, adolescents, older women, and contraceptive users are the groups of higher risk. Users and non-users should be treated separately from the perspective of demographic modeling of fertility.