Imagine finding out you were pregnant — and realizing you had already taken a medicine that wasn't recommended for expectant mothers. That happens more often than you might think, especially in the early weeks before a woman knows she is expecting. Now, a major new study offers reassuring news about one of those medicines.
Researchers at ISGlobal, a health institute in Barcelona, Spain, found that women who accidentally took ivermectin (ih-ver-MEK-tin) during the earliest stage of pregnancy did not face a higher risk of losing the pregnancy, having a stillborn baby, or having a baby born with major birth defects. The findings were published in the medical journal eClinicalMedicine.
Ivermectin is a drug used to fight parasites — tiny organisms that cause diseases like river blindness and scabies. Each year, health workers give it to millions of people in Africa and other parts of the world through programs designed to wipe out these neglected tropical diseases. It has also shown promise against malaria by killing the mosquitoes that spread it. But because there has been so little research on its effects in pregnant women, doctors have traditionally told pregnant women to avoid it.
The problem is that many women don't know they are pregnant during the first few weeks — the exact window when these drug programs are often running. "This happens all the time in real life," said Patricia Nicolas, the study's lead author and a researcher at ISGlobal.
To build better evidence, Nicolas and her team studied 238 women in Mozambique and Kenya who became pregnant around the time they received ivermectin or another parasite drug called albendazole (al-BEN-dah-zole). The women were tracked monthly until they gave birth. Of the 238 women, 129 had taken ivermectin and 109 had taken albendazole.
The results were encouraging. About 22.9 percent of women who took ivermectin had an adverse outcome — meaning miscarriage, stillbirth, or a baby with a major birth defect. For women who took albendazole, that number was 19.5 percent. The difference between the two groups was small enough that scientists could not say ivermectin was the cause. In other words, the two drugs looked equally safe.
According to Nicolas, this study is the largest of its kind ever done on this question. Previous research covered fewer than 100 documented cases of first-trimester ivermectin exposure.
The study also pointed to something broader: women who experienced pregnancy complications were less likely to have received antenatal care, including iron supplements, folic acid, mosquito nets, and malaria prevention treatment. While the researchers note this may partly reflect that women who miscarry early have fewer chances to attend checkups, it underscores the importance of prenatal support.
Still, the team is clear-eyed. "The number of documented pregnancies remains too small to support changes to clinical or regulatory recommendations," said Carlos Chaccour, a co-lead investigator on the study. More research will be needed before official guidelines can be updated.
For now, though, the findings offer real comfort to the many women around the world who unknowingly took ivermectin before learning they were pregnant.