Loratadine, a second-generation antihistamine, is commonly used to treat seasonal allergies. Some studies have suggested that use of loratadine by pregnant women increases the risk of hypospadias in male offspring. This meta-analysis was designed to assess the strength of the association between loratadine and hypospadias. To locate pertinent articles published in any language from January 1989 until August 2007, we searched electronic databases (MEDLINE, OVID, EMBASE, SCOPUS, TOXLINE Special, ReproTox, TERIS, CINAHL and others), conference proceedings and bibliographies. Studies were eligible for this analysis if they were cohort, case-control or case series studies that reported the incidence of hypospadias in the offspring of women who were or were not exposed to loratadine during pregnancy. Two authors independently extracted information on study design, participant characteristics, measures of outcome, control for potential confounding factors and risk estimates using a standardized data collection form. The Newcastle-Ottawa Scale was then used to assess the quality of each study. We used a random-effects meta-analysis model to combine the risk data. In 1402 potentially relevant titles, we found three case-control studies and seven cohort studies that reported the incidence of hypospadias or other congenital malformations in offspring of women who did or did not use loratadine during pregnancy. Together the studies in our meta-analysis provided information about 453 053 male births in Brazil, Canada, Denmark, Israel, Italy, Sweden, the UK and the US.Of 2694 male infants born to women using loratadine, 39 (1.4%) had hypospadias. Of 450 413 male infants born to women not using loratadine, 4231 (0.9%) had hypospadias. Women who used loratadine during pregnancy were not significantly more likely to have a son with hypospadias (unadjusted odds ratio [OR] 1.27, 95% CI 0.73, 2.23; adjusted OR 1.28, 95% CI 0.69, 2.39). The results of our systematic review and meta-analysis of controlled observational studies indicate that the use of loratadine during pregnancy does not significantly increase the risk of hypospadias in male offspring.