The study looked at the medical records of nearly 39,000 Norwegian children through the first year of life. It found that rates of congenital heart defects and physical therapy - a potential sign of movement-related problems - were elevated among babies whose mothers used antidepressants throughout pregnancy.
These children also tended to have more doctor visits and higher rates of certain other health problems, like respiratory and digestive symptoms. However, those rates were also elevated among children whose mothers had stopped using antidepressants before pregnancy.
This raises the possibility that the risks were related to the mother's depression itself, rather than antidepressant use, according to the researchers, led by Dr. Tessa Ververs of the University Medical Center Utrecht in the Netherlands.
The bottom line for women on the medications is that the decision to continue or stop during pregnancy is an individual one. Women should talk with their doctor about what is best for them, Ververs told Reuters Health in an email.
The question of whether to continue on antidepressants during pregnancy is not simple.
Initial studies on the drugs' safety were "reassuring," Ververs and her colleagues note, but some recent reports have linked the medications to problems in newborns - including cases of congenital heart defects.
Antidepressant use in the third trimester has also been connected to higher risks of respiratory distress, feeding problems and irritability in newborns, the researchers note in their report published in the British obstetrics journal BJOG.
On the other hand, there are concerns about leaving depression untreated in expectant mothers, at a time when stress can be high.
Of the 38,602 babies in the current study, 197 were born to mothers who used antidepressant throughout pregnancy. Another 820 mothers had stopped using the medications before pregnancy, while 543 used them only at certain points during pregnancy. Most women on medication during pregnancy - 71% - used a selective serotonin reuptake inhibitor (SSRI) such as paroxetine (Paxil) or fluoxetine (Prozac).
Ververs and her colleagues found that of the children whose mothers had used antidepressants throughout pregnancy, three had to have a major heart procedure performed in their first year of life. That made them six times more likely than children whose mothers had never used antidepressants to need a heart procedure.
The risk was not elevated among children whose mothers had stopped taking antidepressants.
When it came to doctor visits during the first year of life, both children whose mothers had continued to use antidepressants and those whose mothers had stopped tended to see the doctor more often than children whose mothers had never taken antidepressants. Similarly, both groups of children had higher rates of antibiotic use and respiratory or intestinal symptoms.
It's possible that mothers' depression itself was a factor here, according to Ververs' team. Past studies have found that depressed mothers tend to take their children to the doctor more often than other mothers do.
Compared with other mothers, Ververs and her colleagues note, depressed moms may find it more difficult to cope with problems like respiratory ills and digestive symptoms.
More studies, the researchers write, are needed to tease apart the relationships between mothers' mental health, medication use and specific health problems in infants.
For now, they say, the evidence does support foetal screening for heart defects when mothers continue to use antidepressants during pregnancy.