Jul 13, 2009 - News

Opportunity To Study Pregnant Women In Large National Study Must Not Be Missed, Experts Say


There’s no shortage of books out there to help a woman know what to expect when she’s expecting, but when it comes to knowing how medications she might need during her pregnancy will affect her, there is very little guidance.

A woman’s body goes through profound physiological changes during pregnancy that have potential ramifications for the efficacy of a variety of drugs.   But despite a 1994 recommendation by the Institute of Medicine, most clinical trials still do not include pregnant women.   This means that for most drugs, doctors faced with a pregnant patient who needs a prescription have no choice but to guess the right thing to do.

“Any medicine taken to treat a woman’s illness during pregnancy — from hypertension to cancer, thromboembolism to asthma — is used without data adequate to guide dosing, make decisions about safety, or inform differential decisions about which medicine to prescribe.   The cost of this ignorance is profound,” Dr. Anne Lyerly and colleagues write in a recent article in the American Journal of Public Health.

The best strategy would be a large systematic study of women already taking medications during their pregnancies, so that there would be no extra risk for the unborn children.   According to Lyerly et al., just such an opportunity has presented itself in the form of the National Children’s Study (NCS).

The NCS aims to study the effects of the environment on 100,000 children from before birth to age 21.

Researchers hope to enroll 25% of the children before they are conceived, with 90% of the total being enrolled by the end of the first trimester. Lyerly et al. argue that this important study of children’s health also offers an unprecedented opportunity to collect information about the mothers too. But action must be taken soon to make sure that researchers don’t miss out on the chance to collect a wealth of information. Recruitment for the pilot phase of the study has already begun, and the final study protocol will be finalized in May 2010.

“Although the NCS will provide important and much-needed information about the effects of maternal medication use on the health of the fetus, absent is the other side of the coin: whether the medication is safe for the woman herself, whether it is effective in treating her underlying or emergent illness, and whether decisions to forgo medication or substitute older medications compromise her health,” the authors write.

Every additional piece of information collected will add to the already $3.2 billion projected cost of the NCS, but Lyerly et al. advocate for the inclusion of at least two additional research components:

  • Add questions to the surveys and medical chart evaluations already planned during the pregnancies of the women involved.
  • Take advantage of the maternal blood tests already planned to identify medications that are metabolized differently in pregnant women.   These drugs could then be investigated in more depth in follow-up studies.

“These two efforts together–at very little additional cost–would result in a rich data set that could lead to critical improvement in the care of pregnant women. Failure to include them would be hard to justify.”

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