Expectant mothers who resort to popping anti-depressants during their pregnancy are at a slight risk of giving birth to children with high blood pressure.

The condition, clinically known as pulmonary hypertension, is a rare one, in which the right side of the heart needs to work harder than normal. This is because of abnormally high blood pressure levels in the arteries of the lungs, leading to respiratory problems.

According to a study published in the online edition of the British Medical Journal Jan. 12, a total of 11,014 pregnant women, who used an anti-depressant called - selective serotonin reuptake inhibitors - late in their pregnancies. The study also worked with 17,053 mothers who used anti-depressant drugs early in their pregnancies.

According to the results, of the children born to women from the first batch (11,014 women), 33 (0.2 percent) were diagnosed with persistent pulmonary hypertension. The number of children born to mothers who took anti-depressants early in their pregnancies and were diagnosed with the same condition dropped very marginally; 32 (0.2 percent) were reported to have been born with the condition.

The study was carried out in five Nordic countries and reviewed 1.6 million births between 1996 and 2007.

Researchers studied the use of the following drugs - fluoxetine (Prozac), fluvoxamine (Luvox), citalopram (Celexa), paroxetine (Paxil), sertraline (Zoloft) and escitalopram (Lexapro). It was found that fluvoxamine was rarely used and none of the children with persistent pulmonary hypertension were exposed to this drug.

Although the risk of developing pulmonary persistent hypertension in such cases was found to be low, the study's authors advised caution while treating expectant mothers under prescribed anti-depressants.

According to the American Congress of Obstetricians and Gynecologists (ACOG), depression is a mood disorder that affects 1 in 4 women at some point during their lifetime and between 14 and 23 percent of women struggle with some symptoms of depression during their pregnancy.