January 6, 2014 — Women who used intrauterine devices or other long-acting, reversible contraceptives after pregnancy were four times less likely than women who used condoms or other barrier methods to become pregnant within 18 months, according to a study in the American Journal of Obstetrics and Gynecology, Reuters reports.
Despite evidence that close birth spacing increases the risk of early delivery or low birth weight, about one-third of repeat pregnancies in the U.S. occur within 18 months of the prior pregnancy, Reuters reports. The World Health Organization endorses spacing births by at least two years.
For the study, researchers from the University of California-San Francisco analyzed pregnancy spacing and contraceptive use among 117,644 women in California who had had at least two children. The researchers compared the state's birth registry with the women's health insurance claims for contraceptives through California's Medicaid program, called Medi-Cal, or through health providers offering state-funded services.
On average, the women in the study had claims for four months of contraceptives, although one-third of the women did not have any contraceptive claims. The researchers found that 64% of the women's pregnancies were spaced by at least 18 months, while the rest were not.
The study also found that about half of the women started to use birth control pills, the ring or the patch after pregnancy. Those women were twice as likely to have pregnancies at least 18 months apart.
In addition, researchers found that women who were counseled by a certified family planning service provider were 67% more likely to wait at least 18 months between pregnancies, compared with women who used only Medi-Cal services (Raven, Reuters, 1/3).