What are the drug categories in pregnancy?

From the Guidelines

Medications during pregnancy are categorized into five main categories based on their safety profiles: A, B, C, D, and X, with the FDA transitioning to the Pregnancy and Lactation Labeling Rule (PLLR) for more descriptive information. The categorization of medications during pregnancy is crucial for healthcare providers to make informed decisions about treatment.

Medication Categories

• Category A medications have shown no risk to the fetus in human studies,
• Category B drugs show no risk in animal studies but lack adequate human studies,
• Category C medications have shown adverse effects in animal studies with insufficient human data,
• Category D drugs have demonstrated fetal risks in humans, but benefits may outweigh risks in certain situations,
• Category X medications are contraindicated during pregnancy due to proven fetal risks that outweigh any potential benefits.

Common Medications in Each Category

• Common Category B medications include acetaminophen, as reported in a study published in the American Journal of Obstetrics and Gynecology 1, penicillins, and certain antihistamines.
• Category C includes many antidepressants and some anticonvulsants,
• Category D includes certain antiepileptics like valproate and some antihypertensives, such as those discussed in the context of diabetes management in pregnancy 1,
• Category X includes isotretinoin, warfarin, and statins.

Key Considerations for Prescribing Medications During Pregnancy

When prescribing medications during pregnancy, healthcare providers should always consider the risk-benefit ratio, use the lowest effective dose for the shortest duration, and avoid medications in the first trimester when possible as this is the critical period for organ development, as emphasized in guidelines for managing cardiovascular disease and risk in pregnant women with diabetes 1. Additionally, certain medications like MPA products are contraindicated in pregnancy due to a high risk of congenital malformations and spontaneous abortions, highlighting the importance of careful medication selection and monitoring in pregnant women 1.

From the FDA Drug Label

Pregnancy Category C Teratogenic studies were performed with labetalol in rats and rabbits at oral doses up to approximately six and four times the maximum recommended human dose (MRHD), respectively. Pregnancy Teratogenic Effects Pregnancy Category C Albuterol has been shown to be teratogenic in mice when given subcutaneously in doses corresponding to 1.25 times the human nebulization dose (based on a 50 kg human).

The drug categories in pregnancy are:

• Pregnancy Category C: This category indicates that there are no adequate and well-controlled studies in pregnant women, and the drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Examples of drugs in this category include:
  • Albuterol 2
  • Labetalol 3

From the Research

Drug Categories in Pregnancy

The following are some drug categories in pregnancy:

• Biologic agents, which can be divided into 4 risk categories: minimal, uncertain, moderate, and high 4
• Medications that are considered safe, such as hydroxychloroquine, sulfasalazine, azathioprine, cyclosporine A, and low-dose aspirin 4
• Medications that may increase the risk of gestational diabetes and gestational hypertension/preeclampsia, such as glucocorticoids 4
• Nonsteroidal medications, which should only be used during the first trimester and for a short period during the second trimester 4
• Tumor necrosis factor-α inhibitor medications, which have limited experience but suggest minimal risk 4
• Contraindicated medications, such as methotrexate, mycophenolate, and leflunomide 4
• Antihypertensive drugs, such as methyldopa, labetalol, and nifedipine, which are perceived as safe to use during pregnancy 5
• Antineoplastic agents, angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists, and anticonvulsants, which are classified as high risk 6

Medication Safety During Pregnancy

Medication exposures during pregnancy can result in adverse pregnancy and neonatal outcomes, including birth defects, fetal loss, intrauterine growth restriction, prematurity, and longer-term neurodevelopmental outcomes 7 Health care providers need to be able to quickly locate the most up-to-date information to counsel pregnant women concerned about medication exposure 7 Pregnancy registries are initiated to obtain more data about the safety of specific medication exposures during pregnancy, but these studies are slow to produce meaningful information 7 The US Food and Drug Administration is committed to protecting and advancing the public health of pregnant women by guiding the development and ensuring the availability of effective and safe therapeutics for obstetrical indications and for medical conditions during pregnancy 8