Medicines and your baby
New drugs are being developed at a rapid pace, and many medications are available for use by pregnant and nursing mothers. Most women take at least one medication during pregnancy, and the use of multiple drugs during pregnancy is increasing. Approximately 2% to 3% of birth defects are related to a drug taken to manage a chronic condition or symptom during pregnancy. Thorough assessments of the risks of benefits of all drugs used during pregnancy and breastfeeding are crucial to making the best decision for yourself and your baby.
During pregnancy, most drugs cross the placenta—the same route that oxygen and other nutrients take to reach a developing fetus. Drugs may affect the fetus in several ways: they may cause direct damage or death; they can change the function of the placenta; or they can cause the uterus to contract, which can trigger preterm labor. Drugs can also indirectly impact the fetus by affecting the mother’s health: for example, drugs that lower a mother’s blood pressure can reduce blood flow to the placenta and reduce the amount of oxygen and nutrients that are delivered to the unborn baby. The affect that a drug has on the placenta and the fetus depends on the gestational age and stage of the fetus and the strength and dose of the drug, as well as the mother’s genetics and her overall health status.
The ABC’s of drugs and pregnancy
In the 1970’s, the United States Food and Drug Administration (FDA) implemented a letter-based system to describe drugs’ risks to pregnant women and their fetuses. The categories—A, B, C, D, and X—offered a simple, one-letter explanation of whether a drug was safe or not during pregnancy. For example, a Category A designation indicated that studies did not find any risk to a fetus if a drug was taken during pregnancy; on the other end of the spectrum, Category X drugs had evidence of fetal harm and the risks of using the drug outweighed any benefit. Much of the data used to assign the categories were based on animal studies, which may or may not always be clinically relevant to human use.
New and improved information
Unfortunately, the FDA’s drug categories did not provide much useful information and were often misunderstood and/or misinterpreted. In 2015, the FDA implemented a new system of communicating pregnancy-related drug safety information that replaced the letter-based system for prescription drugs. (Over-the-counter drugs—those available without a prescription—are not affected by the new requirements.)
The Pregnancy and Lactation Labeling Rule (PLLR) standardized how information about drugs used during pregnancy and lactation is presented. More human data is presented, which supports the clinical relevance of the information. Now, the package insert (the information provided with a prescription drug that lists risks and benefits of the product) contains a “Pregnancy” section that summarizes risks of negative side effects from all available sources and studies. The narrative text replaces the single-letter descriptor.
The PLLR also requires a separate “Lactation” section of the package insert that lists information that is known about the use of the drug during breastfeeding. If it is available, information on reducing exposure risks for breastfed infants is provided. The section entitled “Females and Males of Reproductive Potential” lists requirements related to contraception and fertility for a drug. The labeling also provides contact information for pregnancy exposure registries that collect data about medication use during pregnancy. Enrolling in such a registry helps support the gathering of real-world information about drug use, and the data compiled is used to update drug labeling when new information is learned.
The PLLR went into effect on June 30, 2015. Any drug submitted to the FDA for approval after that date must provide pregnancy and lactation information in the new format. Manufacturers of older products had 3 to 5 years to update package inserts to comply with the new rules of the PLLR. While some drug makers converted the labeling information sooner than required, you may still see the letter categories listed on the package inserts of older drugs until 2020.
Find out more
In addition to the package inserts, several resources are available to help inform healthcare providers and patients about drug use during pregnancy. Pregistry publishes hundreds of Expert Reports, which provide up-to-date drug, disease and common exposure information for pregnant and breastfeeding women for free. These reports can be downloaded and shared with friends and family. Go here to view, for example, Pregistry’s Expert Reports on Depression and Mental Health.
The Centers for Disease Control and Prevention, the FDA, and March of Dimes also offer reliable resources (in multiple languages) for understanding the risks and benefits of medications before, during, and after pregnancy. Overall, pregnant women are advised to ask questions before taking any prescription or OTC medicine, vitamins, or dietary supplements; read drug labels and other information provided about the safety of medications; be careful about information learned online or from friends and family members—what’s right for some people may not be right for you; and report problems with medications to your healthcare provider and, possibly, the FDA.
The FDA designed the PLLR to provide healthcare providers and patients with useful and clear information related to prescription medication use and expects the new information to be more easily interpreted than the previous system. But, if you have any questions about the risks or benefits to yourself or your unborn baby of any drug, ask your doctor or pharmacist.
Watch Pregistry’s video Understanding the Pregnancy and Lactation Sections of My Medication Label:
