Greatest reduction in pregnancy occurs with any contraception

1. Adoption of any contraceptive method among non-users was associated with a greater reduction in unintended pregnancy rate than adoption of LARC among women using a less effective method.

2. Among current contraceptive users, adoption of long-acting reversible contraception (LARC) was associated with a decrease in unintended pregnancy rate.

Evidence Rating Level: 2 (Good)

Study Rundown: Unintended pregnancies comprise approximately half of all pregnancies in the United States. Women who are unmarried, less than 15 years old, and of lower socioeconomic status are more likely to experience unplanned pregnancy. While many unplanned pregnancies are also undesired and are terminated, continued pregnancies are associated with significant infant and maternal morbidity. As such, significant efforts have been made to increase the use of LARC, such as intrauterine devices (IUDs) and implants, to decrease the rate of undesired pregnancies. Previous research demonstrated that risk of pregnancy in women using a LARC method is significantly lower than in women using less effective methods, such as oral contraception (OCP) and condoms. However, the population-level effects of choices regarding contraception have been less well studied. In the present work, authors performed simulations to evaluate the impact of adoption of any contraceptive method among non-users and the impact of choice of method among current users. They found that adoption of any method of contraception among non-users was associated with a greater reduction in the incidence of unintended pregnancy than adoption of LARC among users of less effective methods.

Strengths of the study included model parameters based on national data and real-world behaviors. The study was limited by simulated model variables and lack of data regarding women’s pregnancy intentions. Population-based prospective studies are needed to evaluate the accuracy of the results of these simulations and better tailor family planning interventions.

Click to read the study in Contraception

Relevant Reading: Non-use of contraception among women at risk of unintended pregnancy in the United States

In-Depth [population-based study]: This population-based simulation evaluated the population-level effects of contraceptive adoption and method among 50,000 unmarried individuals. Model parameters included demographics, sexual activity, contraceptive behavior and fecundity. Contraceptive method was categorized into non-use; LARC, which included IUD, implants, and injectables; and OCP, patch or vaginal ring. The primary outcome of interest was probability of pregnancy within 12 sexually active months.

Models assuming adoption of a contraceptive method among 5% of those not currently using contraception predicted a 6.3%, 10.3%, and 12.7% decrease in pregnancy rate among those adopting condom; pill, patch or vaginal ring, and LARC use respectively. The rate reduction when 5% of condom users and pill, patch or ring users switched to LARC was only 3.6% and 1.7% respectively.

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