The study used data from approximately one million births, but the babies born with defects were rare. When used properly, these are over 99 per cent effective, researchers wrote in The BMJ. Meaning, women who think they’re protected end up getting pregnant, and it may be a while before they realize it – so they keep taking the pill.
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In total, 68% of mothers used oral contraceptives, but stopped more than three months before pregnancy, and 21% never used oral contraceptives.
Recent oral contraceptive use less than three months before the pregnancy or use during early pregnancy was analysed based on prescription information from a national registry.
However, around 9% of women become pregnant in the first year of use because of missing a dose, taking the pill with other medications, or illnesses.
“This should reassure women as well as their doctors”, said Charlton, an instructor in the department of epidemiology at Harvard’s T.H. Chan School of Public Health in Boston.
“For women who have a breakthrough pregnancy during oral contraceptive use or even intentionally become pregnant within a few months of stopping oral contraceptive use, any exposure is unlikely to cause her fetus to develop a major birth defect.”
“Our findings were especially reassuring given that we were able to use a different approach”, Charlton added.
The final analyses included 880,694 live-born infants, 2.5 per cent of whom had a major birth defect – like an orofacial cleft or limb defect – within the first year of life. Eight percent had discontinued use within three months of becoming pregnant, and 1 percent, or well over 10,000 women, had used oral contraceptives after becoming pregnant. It showed that the overall rate of birth defects was consistent for women who had used the pill and those who have not.
Big news was just made recently when officials from OR announced that birth control pills will now be available to purchase over the counter in that state.
Medical Research: What is the background for this study? An estimated 16% of women aged 15-44 use the contraceptive pill regularly. They found that the prevalence of birth defects occurred consistently among all of these groups, showing that the birth control didn’t contribute at all to the risk.
Charlton’s team excluded any infants with defects caused by known factors, such as fetal alcohol syndrome or chromosomal abnormalities.
“We conservatively assumed that a woman was exposed up to the date of her most recently filled prescription”.
The study didn’t find any significantly increased risk associated with any subgroup of birth defects.
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A lot of studies have been done in the past to see the connection between birth defects and this method of contraception, and they concluded that they were linked.
