Asthma Drug Not Tied To Anomalies.

CHICAGO -- The rate of congenital anomalies associated with montelukast use during pregnancy does not differ from the background rate, according to pregnancy registry data.

In the 3 years through May 2001 since montelukast (Singulair) was approved for use in asthma, the registry has recorded prospective data on 57 pregnancies that have resulted in live births. Of those live births, only one congenital anomaly--a missing left hand--has been reported. The child's pediatrician attributed the defect to an amniotic band deformity, a fibrous band that forms in response to a rupture of the amniotic membrane and restricts fetal growth, said Kris E. Shields, a research associate with Merck & Co., West Point, Pa., which manufactures the drug.

To be prospectively enrolled in the registry, an exposure needed to be reported while the woman was still pregnant, she said at the Third Triennial World Asthma Meeting.

The congenital anomaly rate for the prospective registry data is 1.8%, which compares with an overall background rate for U.S. births of 3.2%.

One spontaneous fetal death was also reported. In addition, one woman underwent an elective abortion of a fetus with triploidy, which usually is the result of two sperm fertilizing one egg, she said.

The registry has had a fairly large number of patients enrolled but some have been lost to follow-up, Ms. Shields said. Of the 142 total patients enrolled prospectively so far--including the 57 who have given birth and the 2 with terminated pregnancies--52 are still pregnant, and 31 have been lost. Ms. Shields attributed the high rate of lost patients partly to the fact that reports tend to come from allergy and asthma ...