Sept. 30, 2002 -- A popular arthritis drug safely stops preterm labor. In a study, Celebrex was found to work just as well as the most common preterm labor drug, but was much safer for mother and baby.
Indomethacin has been used for more than 25 years to stop preterm labor. It slows uterine contractions, delaying delivery. But it can cause serious side effects, including the constriction of a major blood vessel -- the ductus arteriosus -- in the fetus.
Indomethacin prevents production of two proteins -- Cox-1 and Cox-2. But only Cox-2 is elevated in women in preterm labor, and Celebrex is known to affect that protein only.
Researchers tested Celebrex and indomethacin in 24 women experiencing preterm labor at 24-34 weeks of pregnancy. Half received Celebrex and half received indomethacin, for 48 hours.
According to the American college of obstetrics and gynecology, one in every 10 births is preterm and about 75% of newborn deaths not related to birth defects are caused by preterm delivery.
Preterm labor was stopped in both groups and didn't recur during the 48 hours except in one woman on indomethacin. She developed an amniotic infection and had to be delivered.
The researchers found after receiving indomethacin, but not Celebrex, fetuses had significantly increased pressure of the ductus arteriosus artery. The increase in pressure makes it harder for blood to get through the artery.
They also found that while both groups experienced a drop in amniotic fluid volume, it was more severe in the indomethacin group. Less amniotic fluid can mean a more hazardous environment for the fetus.
Blood tests confirmed that Celebrex worked only on the Cox-2 protein while indomethacin affected both Cox-1 and Cox-2.
"[Celebrex] appears to be safer, particularly for the fetus," says lead researcher Yoel Sadovsky, MD, of Washington University. In a news release, Sadovsky says he and colleagues are planning a larger study to focus on long-term safety and effectiveness of the drug before they recommend widespread use of Celebrex to treat preterm labor.
The study is published in the September issue of the American Journal of Obstetrics and Gynecology.