Study links use of painkillers to miscarriage
Researchers caution against taking aspirin, ibuprofen, naproxen
August 16, 2003

Ulysses Torassa, Chronicle Health Writer
San Fransisco Gate

Women who take ibuprofen, aspirin and other similar painkillers around the time of conception may have an increased risk of miscarriage, according to a new study.

Researchers at Kaiser Permanente in San Francisco and South San Francisco interviewed 1,055 women who had recently gotten a positive pregnancy test, 75 of whom reported taking aspirin, ibuprofen (such as Advil or Motrin) or naproxen (such as Naprosyn) since their last menstrual cycle. Of those, 24 percent miscarried by their 20th week, versus a miscarriage rate of 15 percent in the women who didn't take the drugs. The study was published in Friday's edition of the British Medical Journal.

The Kaiser study adds support to an earlier Danish study that also found a link between the drugs and pregnancy loss. The March of Dimes already advises against aspirin and related drugs during pregnancy except when suggested by a doctor.

The theory is that the drugs cut down on the production of prostaglandins, hormone-like substances involved in pain signaling that are also needed for an embryo to successfully take hold in the uterus, according to Dr. De-Kun Li, a Kaiser epidemiologist in Oakland and the study's lead author.

While raising a caution flag over painkillers with ibuprofen and aspirin, Li said there appears to be no association between the use of Tylenol and other acetaminophen-based painkillers and subsequent miscarriages. Acetaminophen-based painkillers only block prostaglandins in the central nervous system, not in the uterus, Li said.

In 2001, Danish researchers also reported finding an association between prescriptions for aspirin, naproxen and ibuprofen and a greater risk of pregnancy loss in a group of women who had been hospitalized for miscarriage.

Dr. Alan Decherney, a professor of obstetrics and gynecology at UCLA, said he was surprised by the latest findings, because many doctors now prescribe aspirin to protect against miscarriage in women who have a specific clotting abnormality that interferes with embryo development.

Decherney said the results suggest patients who don't have that condition may want to be cautious about using aspirin or ibuprofen in the early part of their first trimester. But he also said that more research is needed before a firm recommendation could be made.

Dr. Victor Fujimoto, director of the in vitro fertilization program at UCSF,

prescribes low-dose aspirin for women who have miscarried in the past or who are taking part in IVF because studies have shown it actually increases the rate of successful conception. He said the small number of women in the study who took aspirin makes it hard to draw firm conclusions, but that the 81- milligram tablets he recommends aren't likely to trigger problems.