Can you take antidepressants while pregnant?

Many women who become pregnant while taking antidepressants face a difficult decision: 

Should they continue taking their medication to protect themselves against severe depression? Or should they stop to avoid possible risks to the baby?

“We know that untreated severe mental illness can be dangerous for both the baby and the mother. Lack of appropriate treatment can increase the risk of relapse, suicidal thoughts, poor engagement with antenatal care, and complications in pregnancy,” says Soili Marianne Lehto.

She is a professor at the University of Oslo and Akershus University Hospital (Ahus).

"For many, this choice feels like an ethical and medical dilemma,” she adds.

Standard doses appear safe

In a new study, Lehto and colleagues examined the use of antidepressants during pregnancy and whether it can have any effect on the child in the womb.

The results indicate that it is safe for women to use antidepressants up to the standard doses.

“Using a standard dose does not seem to be harmful to the baby based on the factors we have assessed after birth,” says researcher Guro Pauck Bernhardsen at Ahus.

The researchers looked at several birth outcomes, such as birth weight, placental weight, the length of the umbilical cord, and whether the baby was born preterm.

They also looked at the Apgar score, which is a rapid assessment of a newborn's health, and whether the newborn was admitted to the neonatal intensive care unit (NICU).

Important that pregnant women who take antidepressants are followed up by a doctor

The study shows that it is the size of the dose that affects how the baby does.

“We see that persistently high doses of antidepressants are associated with changes in the placenta. Sustained high doses are also linked to an increased risk that the baby will need treatment in a NICU,” says Bernhardsen.

For women who are on medication for severe mental illness and are worried about whether they can continue it during pregnancy, this is good news.

“Our findings support the view that use of standard doses of SSRIs during pregnancy may be safe. However, persistently high doses may carry extra risk. These women should be closely followed up by a doctor during pregnancy,” she says.

The study looked at SSRIs: dose, duration, and patterns of use

The researchers focused on one common group of antidepressants called SSRIs. They are widely used to treat depression and anxiety.

“SSRIs are the most commonly used antidepressants in the Nordic countries, also among pregnant women,” says Bernhardsen.

In the study, the researchers looked at different doses of antidepressants throughout pregnancy. They also looked at how the women used antidepressants during pregnancy, meaning different patterns of use.

"Unlike many earlier studies that categorised use simply as ‘yes’ or ‘no’, this study examined dose, duration, and usage patterns across pregnancy," the researcher says.

Compared data on mothers who used antidepressants

The research team used registry data from Kuopio University Hospital in Finland. 

They compared 553 mothers who used antidepressants during pregnancy with 2,765 mothers who did not use antidepressants. The groups were matched on depression, other psychiatric diagnoses, and age.

Women who used antidepressants were divided into four categories based on how they took the medication: 

1. Standard dose throughout the entire pregnancy 
2. Low dose that increased during pregnancy 
3. High dose throughout pregnancy 
4. Tapering down from a standard dose early in pregnancy to a lower dose later

The researchers then examined how both mother and baby were doing after birth.

Why the placenta matters

For mothers who needed high doses of antidepressants throughout pregnancy, the researchers found several notable results. 

Researchers already know that there is a correlation between the weight of the placenta and the baby's birth weight. If the placenta is too large relative to the baby, it may indicate that the placenta has not been able to efficiently provide nutrients to the foetus.

In this study, women who took high doses had larger placentas and a higher placenta-to-birthweight ratio.

“Measuring placental size relative to the baby’s weight can provide important information about whether the baby achieved optimal growth in the womb. Poor growth can indicate a need for extra follow-up after birth and may have implications for long-term health,” Bernhardsen explains.

These same infants had roughly double the risk of being admitted to the NICU compared with infants of women who did not use antidepressants during pregnancy.

Balancing medication changes against mental health risks

In Norway, just under two per cent of pregnant women use SSRIs.

“The lower proportion of SSRI use among pregnant women compared with non-pregnant women may indicate that many choose to stop treatment for depression during pregnancy. This is likely due to uncertainty about possible consequences for the foetus,” Lehto says.

She stresses the importance of individual evaluation of antidepressant dosing in pregnant women. Newborns of women on high doses should also be observed more closely after birth.

“The risks of changing or reducing treatment should always be taken into account when making decisions on antidepressant dosage in pregnant women,” Lehto says.

Reference:

Bernhardsen et al. 'Trajectories of selective serotonin reuptake inhibitor use in pregnancy and perinatal outcomes: A longitudinal register study', BJOG: An International Journal of Obstetrics & Gynaecology, 2025. DOI: 10.1111/1471-0528.18337 (Abstract)

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Read the Norwegian version of this article on forskning.no

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