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Safety of Medications During Pregnancy


Ravindu Gunatilake

, MD, Valley Perinatal Services;

Avinash S. Patil

, MD, University of Arizona College of Medicine

Reviewed/Revised Nov 2023
Topic Resources

During pregnancy, women may need to take medications to treat new or existing health conditions. Also, certain vitamins are recommended during pregnancy. Before taking any medication (including over-the-counter medications) or dietary supplement Overview of Dietary Supplements Dietary supplements are used by about 75% of Americans. They are the most common therapies included among integrative medicine and health (IMH) and complementary and alternative medicine (CAM)... read more (including medicinal herbs), a pregnant woman should consult a doctor. Women currently taking medications and planning to become pregnant should consult a doctor before pregnancy, if possible, to see if those medications need to be stopped or changed. (See also the Centers for Disease Control and Prevention: Medicine and Pregnancy.)

Medications or other substances taken by a pregnant woman may reach the fetus by crossing the placenta, the same route taken by oxygen and nutrients, which are needed for the fetus's growth and development. However, those that do not cross the placenta may still harm the fetus by affecting the uterus or the placenta.

Medications or other substances that a pregnant woman takes during pregnancy can affect the fetus in several ways:

Some medications stay in the body and can have effects after they are stopped. For example, isotretinoin, a medication used to treat skin disorders, is stored in fat beneath the skin and is released slowly over weeks. Isotretinoin can cause birth defects if a woman becomes pregnant within 2 weeks after the medication is stopped. Therefore, women are advised to wait at least 3 to 4 weeks after the medication is stopped before they become pregnant.

How Medications Cross the Placenta

Some of the fetus's blood vessels are contained in tiny hairlike projections (villi) of the placenta that extend into the wall of the uterus. The mother's blood passes through the space surrounding the villi (intervillous space). Only a thin membrane (placental membrane) separates the mother's blood in the intervillous space from the fetus's blood in the villi. Medications in the mother's blood can cross this membrane into blood vessels in the villi and pass through the umbilical cord to the fetus.

How Medications Cross the Placenta

How a medication affects a fetus depends on the


Government agencies that oversee drug safety may classify medications based on current knowledge about safety during pregnancy. In the United States, the US Food and Drug Administration (FDA) provides information about drug safety in pregnancy (see FDA: Medicine and Pregnancy). Knowledge about drug safety in pregnancy is based on research in humans and animals and on side effects that are reported by people who have taken the medication. In general, doctors advise pregnant women about taking a medication based on available research, importance of the medication to the health of the pregnant woman, and whether there are other treatments that have less risk to the pregnant woman or fetus. Medications are given in pregnancy if the benefits outweigh the risks.


Vaccines During Pregnancy

Some vaccines that are considered safe in pregnant women and are recommended during pregnancy include

Evidence about the safety and effectiveness of COVID-19 vaccination during pregnancy has been growing. These data suggest that the benefits of receiving a COVID-19 vaccine outweigh any known or potential risks of vaccination during pregnancy. (See also CDC: COVID-19 Vaccines While Pregnant or Breastfeeding.)

Medications Used to Treat Heart and Blood Vessel Disorders During Pregnancy

Several types of antihypertensives, such as angiotensin-converting enzyme (ACE) inhibitors and thiazide diuretics, are usually not given to pregnant women. These medications can cause serious problems in the fetus, such as kidney damage, inadequate growth before birth (growth restriction Small-for-Gestational-Age (SGA) Newborns A newborn who weighs less than 90% of newborns of the same gestational age at birth (below the 10th percentile) is considered small for gestational age. Newborns may be small because their parents... read more ), and birth defects. Spironolactone is also not given to pregnant women. This medication may cause the development of feminine characteristics (feminization) in a male fetus.

Antidepressants During Pregnancy

Clinical depression is common during pregnancy and, therefore, antidepressants Medications for depression Depression is a feeling of sadness and/or a decreased interest or pleasure in activities that becomes a disorder when it is intense enough to interfere with functioning. It may follow a recent... read more , particularly certain selective serotonin reuptake inhibitors (SSRIs) such as sertraline, are commonly used during pregnancy. For pregnant women, the benefits of treating depression usually outweigh the risks.

Paroxetine appears to increase the risk of heart birth defects Overview of Heart Defects About one in 100 babies is born with a heart defect. Some are severe, but many are not. Defects may involve abnormal formation of the heart's walls or valves or of the blood vessels that enter... read more . So if a pregnant woman takes paroxetine, echocardiography should be done to evaluate the fetus's heart. However, other SSRIs do not increase this risk.

If a pregnant woman takes antidepressants, the newborn may have withdrawal symptoms (such as irritability and shaking) after delivery. To prevent these symptoms, doctors may gradually reduce the dose of the antidepressant during the third trimester and stop the medication before the baby is born. However, if a woman has significant signs of depression or if symptoms worsen as the dose is reduced, antidepressants should be continued. Depression during pregnancy can lead to postpartum depression Postpartum Depression Postpartum depression is a feeling of extreme sadness and loss of interest in usual activities during the first few weeks or months after delivery. Women who have had depression previously are... read more , which involves a serious change in mood and requires treatment.

Antiviral Medications During Pregnancy

Some antiviral medications (such as zidovudine and ritonavir for HIV infection) have been safely used during pregnancy for many years. However, certain antiviral medications may cause problems in the fetus. For example, some evidence suggests that when some HIV regimens with a combination of antiviral medications are given during the first trimester, the risk of cleft lip and palate Cleft Lip and Cleft Palate A cleft is an opening that can form in the lip (cleft lip), roof of the mouth (cleft palate), or both if the tissue does not join together completely during pregnancy. Cleft lip and cleft palate... read more Cleft Lip and Cleft Palate may be increased.

For a pregnant woman with early mild to moderate COVID-19, her treatment team may discuss the risks and benefits and decide whether either nirmatrelvir-ritonavir or remdesivir is appropriate. For pregnant patients hospitalized for COVID-19, use of baricitinib or tocilizumab, may also be considered. Generally, experts recommend that theoretical concerns about the safety of the antiviral medications during pregnancy should not prevent their use in pregnant women.

If a pregnant woman gets influenza, she should seek treatment as soon as possible because treating influenza within 48 hours of when symptoms begin is most effective. However, treatment at any point during the infection reduces the risk of severe complications. No well-designed studies of zanamivir and oseltamivir have been done in pregnant women. However, many studies based on observation indicate that treating pregnant women with zanamivir or oseltamivir does not increase the risk of harmful effects. There is little or no information about the use of other influenza medications during pregnancy.

Acyclovir taken by mouth or applied to the skin, usually to treat herpes simplex virus, appears to be safe during pregnancy.

Medications Used During Labor and Delivery

Medications used to relieve pain during pregnancy Pain relief Labor is a series of rhythmic, progressive contractions of the uterus that gradually move the fetus through the lower part of the uterus (cervix) and birth canal (vagina) to the outside world... read more (such as local anesthetics and opioids) usually cross the placenta and can affect the newborn. For example, they can weaken the newborn's urge to breathe. Therefore, if these medications are needed during labor, they are given in the smallest effective doses.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Absorica, Absorica LD, Accutane, Amnesteem , Claravis , MYORISAN, Sotret, ZENATANE
Aldactone, CAROSPIR
Digitek , Lanoxicaps, Lanoxin, Lanoxin Pediatric
Zoloft, Zoloft Concentrate, Zoloft Solution
Sitavig, Zovirax, Zovirax Cream, Zovirax Ointment, Zovirax Powder, Zovirax Suspension
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