Might a bout of hay fever prompt a pregnant woman to deliver prematurely? Maybe. Research by Robert E. Garfield, director of reproductive sciences, and Egle Bytautiene, UTMB research fellow, offers the first experimental evidence that some types of allergic reactions trigger what is known as preterm labor.
In the study, reported last February at the annual meeting of the Society for Maternal-Fetal Medicine, Garfield’s group sensitized pregnant guinea pigs to albumin—the white of an egg—then challenged them by re-injecting that protein toward the end of the animals’ gestation. One-third of the sensitized animals delivered prematurely. In contrast, no guinea pigs not previously sensitized to albumin delivered early after similar injections, nor did guinea pigs previously sensitized to albumin that were challenged only with saline solution. The researchers found that they could protect sensitized guinea pigs from the albumin challenge by administering antihistamines, which blocked the histamine reaction before it could stimulate the uterine muscle. This research stems from work Garfield began in the1990s, when he showed that human uterine muscle from patients with known allergy to ragweed contracted vigorously when challenged with that common allergen.
Premature labor has long left doctors and researchers scratching their heads—about 50 percent of cases were attributed to a uterine infection, while the other half defied explanation. Garfield says the current research falls short of conclusively solving the mystery. But with an estimated forty to sixty million Americans testing positive for allergic disorders, the study offers a possible explanation and prospect for an effective countermeasure—antihistamines—for women who experience allergies during pregnancy. Garfield speculates that antihistamines might also suppress painful uterine contractions, called dysmenorrhea, in women who aren’t pregnant.—Judie L. Kinonen