Pregnancy and Childbirth Current Topics in Pregnancy

Mom's Pill Use Increases Boys' Allergy Risk

(iVillage Total Health) - Women who use certain oral contraceptive pills prior to their pregnancies may increase their children's risk of developing allergic rhinitis later in life, according to a new study.

Also known as hay fever, allergic rhinitis is triggered by pollen, dust and animal dander and affects an estimated 20 percent of the American population. Researchers noted that the risk associated with birth control pills appeared to increase for boys and children whose parents also had allergies.

Past studies have found strong evidence that the pill elevated the risk of allergic disease in children. The latest study sought to take the research a step further by examining the role that different types of birth control pills—with different concentrations of synthetic estrogen and progesterone—might have on the likelihood of offspring later developing allergic diseases.

Researchers in Finland selected children between the ages of 5 and 6 for the study. About half were taken from a group who had been reimbursed for asthma medication and the remaining subjects were randomly selected from the same age group. More than half of the children (52 percent) had asthma , 35 percent had allergic rhinitis and 48 percent had atopic eczema . Their mothers were asked a series of questions, including whether they had taken oral contraception within 1 year of becoming pregnant and the type of pill they used. More than a third (36.5 percent) had used the pill and their children's histories of allergic episodes were compared to children of women who did not take the pill prior to their pregnancies.

Women in the study took oral contraceptives that were combined pills (with synthetic estrogen and progesterone) and progesterone-only pills. Progesterones are female sex hormones produced by the ovaries each month to prepare the lining of the uterus to support a fertilized egg. Some synthetic progesterones also contain androgens, which are sex hormones responsible for development of male characteristics.

Researchers evaluated the effect of the pills based on the type of synthetic progesterone, called progestin. contained in them. The two groups of pills were those containing androgenic types of progestin (levonorgestrel, nortestosterone or lynestrol)and those with antiandrogenic progestins (desogestrel, gestodene and cyproterone acetate).

Researchers concluded that the birth control pills in the second group—those with lower androgen effects—appeared to increase the risk of allergic rhinitis in male preschool aged children. The risk was highest if there was also a parental allergy. Researchers noted that the biological interactions that led to allergic disease were unknown and further studies were needed.

The study was published in the December 2006 issue of the journal Allergy.

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