Prospective assessment of pregnancy outcome following first trimester exposure to benzodiazepines
Benzodiazepines (BDZs) are used for diverse clinical indications because oftheir anxiolytic, anticonvulsant, muscle relaxant and sedative-hypnotic properties. Thousands of pregnant women may need them to reduce anxiety, induce sedation or muscular relaxation, or treat eclampsia or preeclampsia. Moreover, since half of the pregnancies in North America are unplanned, a large number of women will expose their fetuses to BDZ before they realize they have conceived. It has been estimated that 11% of American adults use some anti-anxiety medication annually and up to 35% of pregnant women take some type of psychoactive drug during fetal development. Maternal use near term may cause decreased neonatal respiratory rate and withdrawal, hypo-to nia and de tect able phar ma col ogi cal ac tiv ity in the newborn for up to 10 days. Nihas and Goujard have postulated that BDZs cause cleft lip, cleft palate or both; however, prospective studies are needed to confirm or refute the teratogenicity of BDZ. buy ortho tri-cyclen online
Retrospective analyses using birth defect registry data have suggested that infants exposed in utero to diazepam are more likely to be born with both a cleft lip and palate but less likely to be born with cleft palate alone. However, in a subsequent retrospective case control analysis, which controlled for potential confounding factors, others were unable to corroborate such findings. Laegreid et al reported that eight infants of mothers who regularly ingested high doses ofeither diazepam or oxazepam throughout pregnancy had a common pattern of dysmorphic features and abnormal neurology in the neonatal period, whereas in a survey based on four different epidemiological approaches, Czeizel reported no association between first trimester BDZ exposure and abnormal fetal outcome.
Collectively the above data are confusing in that lack of a consensus in the medical literature may cause a woman to terminate her pregnancy unnecessarily following first trimester BDZ exposure. Obtaining maternal information regarding the timing of BDZ exposure after delivery may introduce recall bias, and retrospective studies have limitations. It is probable that clinicians are more likely to report abnormal outcomes since they have less motivation to report a pregnancy with a normal outcome. Unless one prospectively ascertains first trimester BDZ exposure and compares pregnancy outcome in this group with outcome in a control group, patient selection or referral and recall bias may result.
We prospectively collected and compared pregnancy outcome and rate of major birth defects in BDZ-exposed women and a conlrol group. Both groups had voluntarily sought counselling at the Motherisk Program in Toronto, Ontario .
Tags: Benzodiazepines, Fetus, Pregnancy