Oral contraceptives are used the world over. In fact, birth control pills are currently the most popular form of contraception in most developed European countries, including France, Germany and the United Kingdom. In America, an estimated 82% of sexually-active women have used oral contraceptives like Yaz and Ortho-Novum at least once, according to data from the US Centers for Disease Control. Little is known, however, about how the use of oral contraceptives can affect developing fetuses.
Do Oral Contraceptives Increase The Risk Of Birth Defects?
That might seem like an odd line of inquiry, since the point of any birth control is first to prevent pregnancy. But researchers at Harvard Medical School and the University of Copenhagen report that a surprising 9% of women taking birth control pills get pregnant during the first year of use. Oral contraceptives are still our most effective form of birth control, but that’s only true if they’re used perfectly.
The point, however, is that women can inadvertently expose their developing babies to drugs that alter hormone levels, many of which are crucial to early human development. But the effect of that exposure was almost completely unstudied until now.
No Link Between Birth Control Pills & Birth Defects, New Study Finds
Using more than 880,000 birth records logged in Denmark, the international team struck out to find an answer. They took Denmark’s remarkably thorough Prescription Register and figured out which pregnant women had been taking oral contraceptives at the onset of their pregnancies:
- 21% of the mothers never used birth control pills at all;
- 69% had used oral contraceptives, but stopped at least 3 months before getting pregnant;
- 8% had used oral contraceptives less than 3 months before becoming pregnant; and
- only 1% had taken birth control pills after the onset of pregnancy.
As for their children, 2.5% of the babies were diagnosed with major birth defects. But across all these groups, no matter when or if a woman took oral contraceptives, the rate of birth defects stayed the same. In this study at least, birth control pills had no effect on a baby’s health.
The researchers did learn some interesting things about the mothers who continued to take oral contraceptives within 3 months or less of becoming pregnant. Compared to mothers who stopped taking the drugs well before getting pregnant, these women were more likely to be young, less likely to have advanced educations and made less money. They also smoked more often during pregnancy. The study was just published in the British Medical Journal’s January 2016 edition, under the title Maternal use of oral contraceptives and risk of birth defects in Denmark: prospective, nationwide cohort study. You can find the full write-up here.
Why American Researchers Turn To Europe For Answers
Birth defect researchers often look to European databases to conduct their studies. Denmark and Sweden, in particular, maintain exhaustive records of pregnancy outcomes. But it’s the countries’ rigorous record-keeping on prescription drug use that’s captured the attention of international medical scientists.
In the US, officials only seem interested in tracking the use of controlled substances, like hydrocodone, and even those tracking efforts are administered by states, making a systematic review difficult. Denmark and Sweden, on the other hand, log every prescription, whether or not its for an addictive substance.
Those records aren’t anonymous, either. Digging into Denmark’s National Prescription Registry gives researchers an accurate view of who’s taking which drugs, and what happens afterward. That’s what Danish researchers were looking for in 2013, when they investigated the possible effects of the world’s most popular morning sickness drug on fetal development.
Danish Birth Records Call Zofran’s Pregnancy Safety Into Question
Zofran is the drug in question, a powerful anti-nausea medication manufactured by GlaxoSmithKline. While it’s never been approved for use during pregnancy, that hasn’t stopped doctors around the world from prescribing it to treat morning sickness. Zofran has dominated the pregnancy market for almost a decade, but its unstudied consequences for developing babies had scientists from Denmark’s Copenhagen University worried enough to look into their data.
Reviewing every Danish birth record filed between 1997 and 2010 (almost 1 million pregnancies), the team used the country’s comprehensive prescription records to find out which women had been prescribed Zofran during the first trimester. Then they looked for patterns. What they found should give any pregnant woman pause.
Zofran was associated with a major increase in the risk for congenital heart defects. Women who took the drug in early pregnancy were 60% more likely to have babies with heart defects of any kind, and more than twice as likely to give birth to children with cardiac septal defects. These abnormalities involve holes in the heart, which can have fatal effects.
In response to those results, hundreds of American families have filed Zofran lawsuits against GlaxoSmithKline. Public awareness, however, is still growing around this important issue, and the legal community believes that many parents have yet to come forward.