Study Says "The Pill" Doesn't Cause Birth Defects
In a study evaluating nearly 900,000 births, a team of Danish and American researchers found no link between birth defects and the use of oral contraceptives around the time of conception and early pregnancy.
The oral contraceptive pill is the most commonly used form of contraception in America, used regularly by an estimated 16 percent of women aged 15 to 44. The pills are simple to take and 99 percent effective when used properly.
Still, about 9 percent of users become pregnant -- generally through missed doses, illness or drug interactions. And when a woman decides to become pregnant and stops taking the pill, she may become pregnant within just a few menstrual cycles. In both of these cases, the fetus may have some exposure to the sex hormones in the pill.
Sex hormones can increase levels of vitamin A and decrease the levels of folate in the mother. Both of these changes have the potential to affect the development of the embryo.
The current study, published in The BMJ, is the largest and most wide-ranging study to delve into the details of this topic. The team poured over the records of live births in Denmark between 1997 and 2011. In total, after discounting children born with birth defects caused by a known factor, for instance, fetal alcohol syndrome, the team was left with 880,694 births.
Of this huge sample of births, 2.5 percent had birth defects within the first year of life. Of the mothers, 68 percent used the contraceptive pill but stopped using it more than 3 months before becoming pregnant.
The findings were clear-cut across all four groups: Never used oral contraceptives: 25.1 birth defects per 1,000 births; Used oral contraceptives more than 3 months before pregnancy: 25.0 birth defects; Oral contraceptive use 0-3 months before pregnancy: 24.9 birth defects; Oral contraceptive use during early pregnancy: 24.8 birth defects.
The study authors say the numbers offer compelling evidence for the safety of oral contraceptives.
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