No birth defect risk seen with malaria drug

NEW YORK (Reuters Health) - Pregnant women who take the anti-malarial drug Malarone during their first trimester might not be increasing their baby's risk of birth defects, a new study suggests.

Most anti-malaria drugs -- including this one -- are not approved for use in pregnancy. So when pregnant women want to travel to malaria-ridden regions, they face a huge problem: should they take preventive medicines that haven't been proven safe for the fetus?

In general, experts advise all pregnant women to avoid traveling to countries where malaria is common, since the infection itself may be dangerous to the mother and fetus.

The new study, published in the Archives of Internal Medicine, is the first to look at pregnant women's use of Malarone -- known generically as atovaquone-proguanil -- and the risk of birth defects.

So the researchers say it is too soon to declare the drug safe for the small number of pregnant women who might need to take it.

The cheapest and mostly widely used anti-malaria drug, called chloroquine, is considered safe during pregnancy. But resistance to that drug has become common worldwide.

Another anti-malaria drug, the antibiotic doxycycline, is known to have adverse effects on the fetus.

In the new study, researchers looked at data on nearly 571,000 births in Denmark between 2000 and 2008. Overall, 2 to 3 out of every 100 newborns had a birth defect.

Among the 149 women who used Malarone at some point during the first trimester, roughly one of every hundred had a baby with a birth defect.

The findings offer some reassurance that the drug is not linked to any large risk of birth defects, said lead researcher Dr. Bjorn Pasternak, of Statens Serum Institute in Copenhagen.

Still, since only a small number of women in the study took Malarone during early pregnancy, the findings cannot rule out the possibility of some risk, Pasternak said.

"We believe it is far too soon to declare this drug to be safe for use in pregnancy," he told Reuters Health in an email.

Malarone is not inexpensive -- it costs close to $200 for 24 pills. The number of pills a woman would have to take depends on how long she stays in the malaria region.

Caused by a mosquito-borne parasite, malaria is widespread (the technical term is "endemic") in large areas of Africa, Asia and South and Central America, where it kills about 1 million people a year.

An estimated 10,000 to 30,000 travelers develop malaria every year, and about 150 die.

Pasternak said pregnant women traveling to malaria-endemic countries should consult a doctor experienced in travel medicine. That way, they can learn about the pros and cons of traveling altogether, the details of malaria in the region they are visiting, and their options for anti-malaria medication.

If chloroquine is not an option, a second choice might be mefloquine, according to Pasternak. For that drug, he said, there is data on more than 1,000 infants exposed during the first trimester, with no evidence of an increased birth defect risk.

However, he added, the World Health Organization still recommends avoiding mefloquine during the first trimester.

SOURCE: bit.ly/hshlAV Archives of Internal Medicine, February 14, 2011.