News & Events
Jane E. Henney, M.D. - FDA/NICHD Conference
This text contains Dr. Henney's prepared remarks. It should be used with the understanding that some material may have been added or deleted during actual delivery.
Jane E. Henney, M.D.
Commissioner of Food and Drugs
U.S. Food and Drug Administration
Clinical Pharmacology during Pregnancy:
Addressing Clinical Needs through Science
December 4, 2000
Good morning. On behalf of the Food and Drug Administration, I'd like to thank each of you for taking the time to join us today--to hear our perspectives, and to share your views about the important subject of clinical pharmacology during pregnancy.
I'd also like to thank Dr. Kirschstein, Dr. Duane Alexander from NICHD, and Dr. Vivian Pinn from NIH's Office of Women's Health, for their support and partnership. It's with your help that we've been able to hold this conference, to raise awareness of this issue, and to facilitate the development of much needed research. It's a great privilege to jointly host this conference with NIH and NICHD.
The NICHD workshop held last September generated much enthusiasm and support for expanded research efforts in this area. Our goal for this two-day conference is to broaden the range of ideas and actions that can be taken to facilitate the research needed in this area, and to urge other organizations to participate in a matter of importance to the health of women and their unborn children.
Acquiring the data necessary to make good treatment decisions will take the cooperation of all interested parties, from clinical study patient volunteers, to academic investigators, to industry-supported R&D, to government agencies.
Interest and concern related to the pharmacology of drugs used by pregnant women is not new. This issue has traditionally been addressed through pregnancy labeling of medicines using a letter category system. This system assigns the letter A, B, C, D, or X to a drug based on its risk to the developing fetus, with drugs in category A presenting the least risk, and drugs in category X presenting the greatest risk.
The categories are applied to drugs depending on the human and animal data available, and for most drugs data are sparse. Fully two-thirds of approved drugs are in Category C, because data in pregnant women are lacking, and--animal studies have either revealed adverse effects or have not been done. Having this on the label doesn't give the prescribing physician the kind of information that would help to guide physicians in their decision-making.
Most recently, FDA's Pregnancy Labeling Taskforce has made great strides in developing a new model label that would distinguish clinical advice from risk information, providing different levels of information, with narrative text instead of letter categories.
Whether the old category or new narrative system is used, it's time--some would say long overdue--to assess our current understanding of the pharmacology in pregnant women and start acquiring the additional data necessary to allow health practitioners to appropriately prescribe drugs for women during pregnancy. Drug labeling in any form can only go so far without appropriate data to support it.
In spite of the current lack of information there would appear to be little reluctance to prescribe.
Prescription drug use by pregnant women is more common than you might think. In 1995, FDA conducted a study that examined an HMO database over two years in the 1990's, looking specifically at the numbers of prescriptions taken by women during pregnancy. This study excluded the commonly prescribed prenatal vitamins, iron supplements, and tocolytic drugs.
Surprisingly, the findings were that women under thirty-five years of age were taking, on average, three prescriptions during the course of their pregnancies. In women over thirty-five, this average rose to five prescriptions.
Some of the drugs used most extensively by pregnant women fall into the therapeutic categories of antibiotics, analgesics, and narcotics. Other commonly used drugs included antiepileptics, antihypertensives, antinauseants, psychotherapeutics, and respiratory therapies. For most of these drugs, no well-controlled studies have been conducted in pregnant women.
These therapies are used to treat conditions that affect not only the woman's health but also impact the health of the developing fetus. In most cases, stopping these treatments during pregnancy is not a reasonable option, even though the risks may be unknown or poorly characterized. Certainly the well-intended but misguided practice of prescribing lower doses of drugs to pregnant women to minimize exposure to the fetus is not the answer. What often happens when this is done is that the patient's illness doesn't respond to the lowered dose and thus requires a longer period of treatment, or even a different drug.
It has long been appreciated that the changes in a woman's physiology during pregnancy are dramatic, particularly during the second and third trimester, and can significantly influence the pharmacokinetic profiles of many drugs. Because the clinical pharmacology of many drugs has not been systematically studied, our understanding is limited. The lack of data impedes the careful selection of safe treatments, appropriate dosages, and what might be done when treatments fail. Simply put, this lack of knowledge puts women and their unborn children at risk.
It's very troubling that while pregnant women are a population of patients where we want to have the most certainty about the effects of drugs on both the patient and fetus, it's an area where we have the least data.
For what some may view as ethical and others as paternalistic reasons, pregnant women have generally been excluded from clinical trials. For many investigational products, this may well be a sound and reasonable course. However, once a drug is on the market, we know that there may be inadvertent exposures during pregnancy; for example, when a women learns that she is pregnant while taking a drug. In addition, pregnant women often require treatment for conditions or illnesses that occur during pregnancy, or that were preexisting.
These drug exposures provide opportunities to collect data on the pharmacology of specific drugs in pregnant women, and conceivably in every trimester of pregnancy.
These opportunities to collect data have often been missed, or ignored. We need to do a better job of gathering this information and making it available in a way that will help physicians and the women they care for make the best treatment decisions.
The need for research is apparent and must be undertaken in a way that is based on the deliberative process of science but encouraged and expedited by the support of both health professionals and women's health advocates.
As such an effort is undertaken, the studies need to be carefully designed, and the highest ethical standards met as all matters related to human subject protection are considered.
There is another concern that relates to unknowns. It is that many pregnant women are turning to herbal remedies and dietary supplements, believing they might be safer than synthetic drugs. But since there's often even less safety information about the effects of these remedies in general, and especially in pregnant women, this represents a risk of unknown magnitude. Combining drugs with these products complicates the picture even further.
Let me leave you with this message. It's time to commit to and undertake this work. It's encouraging to see that we're on the right track, but we need action, and it's going to take action on the part of each of us. Will Rogers once said, "Even if you're on the right track, you'll get run over if you just sit there." We've been sitting here long enough.
Thank you again for being here, and for your interest, your participation, and your willingness to engage in this important effort.