Drugs and Pregnancy: Growing Information

Pharmacy TimesJune 2017 Women's Health
Volume 83
Issue 6

Pharmacists should be prepared to answer these questions because they are qualified to help preconceptive, pregnant, and breast-feeding patients.

Women frequently have questions about appropriate medication use and management during pregnancy for which they usually consult physicians, product inserts, and pharmacists.1 Pharmacists, however, often unnecessarily advise patients to call their primary care providers rather than provide available, evidence-based information. Pharmacists should be prepared to answer these questions2 because they are qualified to help preconceptive, pregnant, and breast-feeding patients.


Regarding drug safety in pregnancy, there is sufficient information on fewer than 10% of medications.3 Preconception care, which identifies risks to a woman’s future pregnancy, is a growing area of emphasis in the health care field. Its goals are to improve maternal and infant outcomes. Clinicians help women modify or manage risks through health promotion, screenings, interventions, and family planning services.4,5 Table 16 describes some preconception interventions that pharmacists can promote.


Women need to understand teratogenic risk, especially if they have conditions that require medication as treatment throughout pregnancy (Online Table 28-12); the treatments’ benefits may outweigh the possible risks to the fetus.1,7 Medication adherence is often a concern during pregnancy, as failure to take medications as prescribed can increase emergency department visits and hospitalizations.8 Sometimes, patients discontinue their medications to reduce risk to their infants—a decision that may risk disease relapse. All clinicians should help expectant patients determine their individual risk—benefit profiles.

Table 2: Conditions That May Require Ongoing Treatment Throughout Pregnancy8-12


Basic Facts


  • Exacerbations during pregnancy elevate the risks of preeclampsia, gestational diabetes, placental abruption, and placenta previa.
  • Do not start allergen immunotherapy during pregnancy due to the risk of a systemic reaction.
  • Avoid systemic corticosteroids and 5-lipoxygenase inhibitors.


  • Depression is linked to low maternal weight gain; greater risk of preterm birth; low birth weight; smoking, alcohol, and other substance abuse; and poor overall health status.
  • Recent studies find no association between first trimester antidepressant exposure and cardiac malformations.


  • Maintain the best glucose control possible (HbA1C < 7).


  • Medication throughout gestation ensures maternal seizure control and decreases the risk of sudden unexpected death.
  • Pregnant women may have lower adherence to their antiepileptic drugs due to epilepsy’s sporadic nature, the lack of immediate consequences of missing doses, and seizure frequency.
  • Patients’ epilepsy-related cognitive and memory impairments may contribute to medication errors.

Thyroid disease

  • Treat as usual, and monitor thyroid parameters periodically.

In addition to knowing when the benefits of ongoing maternal treatment outweigh possible harm to the fetus, because some medications are risky only in certain trimesters, pharmacists need to consider timing. Embryos are most vulnerable during the first trimester, but fetal drug toxicity may occur in later trimesters depending on a drug’s mechanism of toxicity and the fetus’s organ development.13 Online Table 313-16 describes information sources specific to drugs and pregnancy.

Table 3: Information Sources for Questions About Drug Use During Pregnancy13-16

Information Sources


Drug labeling

  • Present labeling is good but incomplete.
  • Labels have classified drugs into categories A, B, C, D, or X based on available data and have addressed fetal risk information since 1979.
  • Labels have been criticized as oversimplified, and the system is being replaced with a narrative framework that includes (1) a risk summary section, (2) a clinical consideration section, and (3) a data section that supports the risk summary.

MotherToBaby website: mothertobaby.org

  • Offers fact sheets on drugs, herbal products, infections, vaccines, maternal conditions, and other issues in English and Spanish
  • Hosted by information specialists trained in critical appraisal of the teratology literature; these experts accept questions
  • Provides accurate and current clinical information to patients and health care professionals about drug exposures during pregnancy and lactation

The American College of Clinical Pharmacy’s book Drugs in Pregnancy and Lactation

  • Currently in its ninth edition
  • Available in hard copy and as a mobile app


During each pregnancy, all women should receive the inactivated influenza vaccine, at any time is acceptable, and a Tdap (tetanus, diphtheria, and pertussis [whooping cough]) booster, ideally between 27 and 36 weeks’ gestation, but up to 38 weeks if necessary.17 The World Allergy Organization recommends that pregnant and lactating women and their breastfed infants take probiotics, the use of which significantly reduces the infants’ likelihood of developing atopic dermatitis.18


Because approximately one-half of all pregnancies are unplanned, women may turn to a pharmacist for information when they discover the pregnancy.19,20 They may be concerned about their embryo’s exposure to medications or illegal drugs they took before they realized they were pregnant, so they need comfort and information. The CDC, acknowledging that pregnant women often need and take medications, has a Treating for Two website (cdc.gov/pregnancy/meds/treatingfortwo).3 Working with nongovernmental partners, the CDC is trying to improve the quality of available information and offers several free, engaging graphics that can encourage conversation.

Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy.


  • Nordeng H, Ystrøm E, Einarson A. Perception of risk regarding the use of medications and other exposures during pregnancy. Eur J Clin Pharmacol. 2010;66(2):207-214. doi: 10.1007/s00228-009-0744-2.
  • Lyszkiewicz DA, Koren G, Einarson A, Gerichhausen S, Björnsdóttir I, Einarson TR. Evidence based information on drug use during pregnancy: a survey of community pharmacists in three countries. Pharm World Sci. 2001;23(2):76-81. doi:10.1023/A:1011227718654.
  • Treating for two infographic. CDC website. cdc.gov/pregnancy/meds/treatingfortwo/infographic.html. Updated August 15, 2014. Accessed March 14, 2017.
  • CDC. Recommendations to improve preconception health and health care—United States: a report of the CDC/ATSDR Preconception Care Work Group and the Select Panel on Preconception Care. MMWR Surveill Summ. 2006;55:1-22.
  • Kent H, Johnson K, Curtis M, Hood JR, Atrash H; CDC National Center on Birth Defects and Developmental Disabilities. Proceedings of the preconception health and health care clinical, public health, and consumer workgroup meetings. CDC website. cdc.gov/preconception/documents/WorkgroupProceedingsJune06.pdf. Accessed March 14, 2017.
  • DiPietro Mager NA. Fulfilling an unmet need: roles for clinical pharmacists in preconception care. Pharmacotherapy. 2016;36(2):141-151. doi: 10.1002/phar.1691.
  • Cohen LS, Wang B, Nonacs R, Viguera AC, Lemon EL, Freeman MP. Treatment of mood disorders during pregnancy, postpartum. Psychiatr Clin North Am. 2010;33(2):273-293. doi: 10.1016/j.psc.2010.02.001.
  • Faught E, Duh MS, Weiner JR, Guerin A, Cunnington MC. Nonadherence to antiepileptic drugs and increased mortality: findings from the RANSOM study. Neurology. 2008;71(20):1572-1578. doi: 10.1212/01.wnl.0000319693.10338.b9.
  • Ali Z, Hansen AV, Ulrik CS. Exacerbations of asthma during pregnancy: impact on pregnancy complications and outcome. J Obstet Gynaecol. 2016;36(4):455-461. doi: 10.3109/01443615.2015.1065800.
  • Chisolm MS, Payne JL. Management of psychotropic drugs during pregnancy. BMJ. 2016;532:h5918. doi: https://doi.org/10.1136/bmj.h5918.
  • Pali-Schöll I, Namazy J, Jensen-Jarolim E. Allergic diseases and asthma in pregnancy, a secondary publication. World Allergy Organ J. 2017;10(1):10. doi: 10.1186/s40413-017-0141-8.
  • Einarson A. Antidepressants and pregnancy: complexities of producing evidence-based information. CMAJ. 2010;182(10):1017-1018. doi: 10.1503/cmaj.100507.
  • Briggs CG, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. 9th edition. Philadelphia, PA: Lippincott Williams & Wilkins; 2011.
  • Pregnancy labeling. FDA Drug Bull. 1979;9(4):23-24.
  • Feibus KB. FDA’s proposed rule for pregnancy and lactation labeling: improving maternal child health through well-informed medicine use. J Med Toxicol. 2008;4(4):284-288.
  • MotherToBaby website. mothertobaby.org/. Accessed March 15, 2017.
  • Johnson K. Probiotics in pregnancy, lactation reduce dermatitis. November 25, 2015. Medscape website. medscape.com/viewarticle/835445. Accessed March 15, 2017.
  • Maternal vaccines: part of a healthy pregnancy. CDC website. cdc.gov/vaccines/pregnancy/pregnant-women/index.html. Updated August 5, 2016. Accessed March 15, 2017.
  • Finer LB, Henshaw SK. Disparities in rates of unintended pregnancy in the United States, 1994 and 2001. Perspect Sex Reprod Health. 2006;38(2):90-96.
  • Bradley CP. The future role of pharmacists in primary care. Br J Gen Pract. 2009;59(569):891-892. doi: 10.3399/bjgp09X473105.

Recent Videos
Practice Pearl #1 Active Surveillance vs Treatment in Patients with NETs