Dr. Christina D. Chambers
Over the last 50 years, we have also seen an important evolution in our ability to conduct pregnancy exposure safety studies. Though we still have limited ability to conduct clinical trials in pregnant women, the need for good quality observational studies has become more widely accepted. The Centers for Disease Control and Prevention’s National Birth Defects Prevention Study (now in its most recent iteration known as BD STEPS) has been one very important source of data on the safety of a wide variety of medications. Using a case-control study design, women who have delivered infants with specific birth defects and comparison women who have delivered non-malformed infants are interviewed about their exposures in pregnancy. These data have been extremely helpful in generating new hypotheses, confirming or refuting findings from other studies, and in testing hypotheses regarding the safety of medications widely used in women of reproductive age. These analyses, for example, have contributed to the large body of literature now available on the safety of antidepressant medications in pregnancy.
At the same time, in the last 30 years, we have seen a tremendous increase in the number of pregnancy registries required or recommended upon approval of a new drug in the United States. These registry studies, while challenging to complete in a timely manner, have steadily improved in terms of rigor, and several disease-based pregnancy exposure studies have been implemented, which have allowed us to better understand the comparative risks or safety of anticonvulsants and antiretroviral drugs, to name a few.
It is important to note that with all these advances in the last 50 years, we still have a huge gap in knowledge about medication safety in pregnancy and lactation. Recent reviews suggest that more than 80% of drugs currently marketed have insufficient or no data available. If we include over-the-counter medications, the knowledge gap grows larger. With the 2014 approval of the long-awaited Pregnancy and Lactation Labeling Rule, clinicians are now beginning to experience the elimination of the old A-B-C-D-X category system for pregnancy safety. In its place, data-driven product labels are required. These are expected to provide the clinician with a clear summary of the relevant studies for a given medication, and to place these in the context of the background risks for the underlying maternal disease being treated, as well as the population risks. However, it is painfully clear that we have a long way to go to generate the needed, high-quality data, to populate those labels.
Dr. Chambers is a professor of pediatrics and director of clinical research at Rady Children’s Hospital, San Diego, and associate director of the Clinical and Translational Research Institute at the University of California, San Diego. She is director of MotherToBaby California, a past president of the Organization of Teratology Information Specialists, and past president of the Teratology Society. She has no relevant financial disclosures.
Moving toward personalized medicine
Nowhere is a lack of actionable data more pronounced than in the impact of mental health drugs in pregnancy.
As Dr. Briggs and Dr. Chambers have outlined, the quality of data regarding the reproductive safety of medications across the therapeutic spectrum has historically been fair at best. The methodology and the rigor has been sparse and to a large extent, in psychiatry, we were only able to look for signals of concern. Prior to the late 1980s and early 1990s, there was little to guide clinicians on the safety of even very commonly used psychiatric medications during pregnancy. The health implications for women of reproductive age are extraordinary and yet that urgency was not matched by the level of investigation until more recently.
Dr. Lee S. Cohen
In psychiatry, we have rapidly improving data informing women about the risk for major congenital malformations. The clinical dilemma of weighing the necessity to stay on a medication to prevent relapse of a psychiatric disorder with the potential risk of malformation in the fetus is a wrenching one for the mother-to-be. Only good information can help patients, together with their physician, make collaborative decisions that make sense for them. Given the same information and the same severity of illness, women will make different decisions, and that’s a good thing. The calculus couples use to make these private decisions is unique to those involved. But they are able to move through the process because they have a platform of high-quality information.
So where do we go in the future? We need to get beyond the question of risk of major malformations and move toward understanding the long-term neurodevelopmental implications of prenatal exposures – whether such exposures confer risk or are even potentially salutary. One needs only look at the vast body of literature regarding fetal exposure to selective serotonin reuptake inhibitors (SSRIs) to observe the realization of this trend. When it comes to SSRIs, a fairly clear picture has emerged that they pose little absolute risk in terms of congenital malformations. What is missing is how SSRIs impact a child’s learning and development at age 3, 5, and 10. There have been a few studies in this area, but not a single, large prospective study that accurately quantifies both exposure to SSRIs and maternal psychiatric illness during pregnancy.
I expect that the future will also bring a greater understanding of the impact of untreated mental illness on the risk for obstetrical, neonatal, and longer-term neurodevelopmental outcomes. Most of the safety concerns have centered around the effect of fetal exposure to medications, but we also need to better understand how untreated psychiatric disorders impact the spectrum of relevant outcomes.
Getting back to the dilemma faced by pregnant women who really need medication to sustain emotional well-being, there simply is no perfect answer. No decision is perfect or risk free. What we can hope is that we’ll have personalized approaches that take into account the best available data and the patient’s individual situation and wishes. We’ve already come a long way toward meeting that goal, and I’m optimistic about where we’re going.