Preterm birth, birth before 37 weeks gestation, is the most common cause of infant mortality, and among other medical problems, it is strongly associated with neurological disorders in children. Advances in care have improved survival rates for preterm babies, but this sort of care is not often available in low- to middle-income countries. Preventing premature births is a better option.

Aspirin has been shown to reduce the risk of preterm birth and preeclampsia among pregnant women, and the low cost and relative safety of aspirin could make it appropriate for widespread use.

Women who took low-dose aspirin were less likely to lose their babies.

The largest study yet of low-dose aspirin therapy was recently published by the Global Network for Women’s and Children’s Health Research. The study looks at what happens when aspirin therapy is begun early in pregnancy to prevent preterm birth.

Women in six low- to middle-income countries — India, Pakistan, the Democratic Republic of the Congo, Guatemala, Kenya and Zambia — were enrolled in a randomized trial of low-dose aspirin (81 mg per day). The Aspirin Supplementation for Pregnancy-Indicated risk Reduction In Nulliparas (ASPIRIN) study was begun when women were between six weeks and almost 14 weeks pregnant. Participants were all first-time mothers with singleton pregnancies.

The researchers assigned nearly 6000 women to receive low-dose aspirin and another 6000 women to receive an identical placebo in a randomized controlled study. Nearly 5800 women in the aspirin group and 5800 in the placebo group were followed to check for birth before 37 weeks’ gestation.

Fewer Preterm Births, No Side Effects

Fewer women taking aspirin developed pregnancy-related hypertension. They also had lower rates of early preterm delivery, compared to controls. Preterm birth occurred in 668 (11.6 percent) of women in the aspirin group and 754 (13.1 percent) of controls. Women who took low-dose aspirin were less likely to lose their babies. They also had significantly lower rates of infant death after 16 weeks’ gestation and within seven days post partum.

There was no difference found in terms of side effects from aspirin among the mothers.

Complications like asthma, heart disease, stroke and learning disabilities are much more common in babies who were born early.

Aspirin reduced rates of perinatal mortality, stillbirth or death within the first seven days, by 14 percent, and early preterm delivery by 25 percent. “Very few things have been able to have that sort of impact,” Matthew Hoffman, lead author on the study, told TheDoctor.

“Our results are probably fully applicable to high-income countries,” Hoffman said, adding that, at the moment, the incidence of infant mortality is much higher and more complex in lower-income countries. Complications like asthma, heart disease, stroke and learning disabilities are much more common in babies who were born early, and when the long-term care of premature infants is taken into account, “The best place for babies to be is in the mother, and it seems taking low-dose aspirin helps support that,” Hoffman said.

The U.S. Preventive Services Task Force recommends the use of low-dose aspirin to prevent preeclampsia, and the American Academy of Obstetricians and Gynecologists has endorsed these recommendations.

Decisions about taking low-dose aspirin during pregnancy should be made with your doctor. You need to understand your risks for preterm birth, which in the U.S. is about 10 percent, according to Hoffman, director of the Center for Women’s and Children’s Health Research at Christiana Care in Newark, Delaware, and have a conversation with your provider based on that risk. Going forward, the team hopes to determine which women are best served by low-dose aspirin.

The study and a related editorial are published in The Lancet.