Teratogenic Medications and Contraception Management

The use of prescription medications by pregnant women has increased over the past 30 years and with the usage comes an increased associated risk of exposing the fetus to the drugs. These medications can cause fetal abnormalities during a pregnancy. Often, for unique reasons, women are not concomitantly prescribed contraception or are not educated regarding the importance of using contraception while taking these high risk medications. Although, the use of teratogenic medications may be necessary for a woman’s health it is important to use birth control while on these drugs to prevent exposure during a pregnancy. 

What are teratogenic medications?

Teratogens are agents that interfere with fetal development when exposed during pregnancy and cause abnormalities. Examples of these teratogens include, but are not limited to alcohol, smoking, and various prescription medications. 

The thalidomide tragedy is an unfortunate example of what teratogenic drugs can do to the development of fetuses. In the late 1950s and early 1960s, thalidomide was widely used for the treatment of nausea in pregnant women soon after, it became apparent that the treatment caused malformations of the arms and legs. Currently, the drug is limited to use for the treatment for various conditions such as skin lesions caused by leprosy and multiple myeloma.

Why is it important to take contraception while on these medications?

Many women take potentially teratogenic medications for health conditions such as hypertension, diabetes, cholesterol, etc. and taking these medications while pregnant increases the risk of fetal malformations and spontaneous abortions. The use of contraception while taking these medications reduces the risk of having pregnancies with abnormalities. 

A study was conducted to evaluate teratogenic medications and associated prescription of contraception in the primary care setting. They found that 25% of the patients that participated in the study were prescribed at least 1 high risk medication from Table 1 and of those patients over half did not have contraceptive management. Ondansetron, often used for nausea in pregnancy, was excluded from the second analysis resulting in 10% of the patients on a high-risk medication and 61.9% of those patients were found to be without any use of contraception management.

The table below summarizes the medications that were used in a study and the teratogenic risks associated with them.

Table 1. Common teratogenic medications and related potential fetal effects

Who is at risk? 

Women who were less than 25 years of age had a low probability of receiving contraception when prescribed a teratogenic medication compared to patients who were of advanced maternal age (over 35 years old). Demographically, among all women who participated in the study, 60% belonged to a minority group compared to the 40% who were not in a minority group which suggests that minorities may be prescribed teratogenic medications more frequently compared to their non-minority counterparts.

Why is this a problem?

The study did not explore why this trend was seen. There are multiple challenges that family physicians face regarding contraception and teratogenic medication management. The first is that physicians may not be able to identify their patients’ family planning intentions, making appropriate counseling challenging. Second, they may experience difficulty finding clinically relevant information on the teratogenic medications. Additionally, while some medications are monitored strictly such as isotretinoin (Accutane), most are not, which makes it difficult for the provider to regularly re-evaluate reproductive plans when patients do not make frequent office visits. Lastly, specialists might prescribe these medications and fail to communicate with the primary care physician leaving the management of contraception up to the patient.

What can pharmacists do? 

It is important to practice interprofessional collaboration which results in safer prescribing practices. Pharmacists are now able to prescribe birth control in some states and can educate patients about contraception use while on teratogenic medications and directly provide contraception if needed and document it.

References

1. Panchal, BD, Cash, R, Moreno, C, et al. (2019). High-Risk Medication Prescriptions in Primary Care for Women Without Documented Contraception. The Journal of the American Board of Family Medicine 2019;32(4):474–480.
2. Kim, JH, Scialli, AR. “Thalidomide: The Tragedy of Birth Defects and the Effective Treatment of Disease.” Toxicological Sciences 2011;122(1):1–6.
3. “Thalidomide: Research Advances in Cancer and More.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 25 May 2019. Available at: https://www.mayoclinic.org/diseases-conditions/cancer/in-depth/thalidomide/art-20046534

About the Author

Sara Shaikh, PharmD Candidate is a pharmacy student at the University of California San Francisco School of Pharmacy in San Francisco, California.