Association between maternal age at conception and risk of idiopathic clubfoot

Background and purpose - Results from case-control studies of maternal age at conception and risk of idiopathic clubfoot have been inconsistent. We conducted a meta-analysis to determine whether there is any association between maternal age at conception and the morbidity of idiopathic clubfoot. Methods - We searched PubMed-MEDLINE, EMBASE, and the Cochrane Library up to June 2015 and supplemented the search with manual searches of the reference lists of the articles identified. 11 studies published between 1990 and 2015 were pooled. We investigated heterogeneity in maternal age and whether publication bias might have affected the results. Results - Compared to a control group, maternal age at conception of between 20 and 24 years old was associated with an increased risk of occurrence of clubfoot (OR = 1.2, 95% CI: 1.1-1.4). No such association was found for the age groups of ≥ 35, 30-34, 25-29, and < 20 years. There was no heterogeneity in the age groups of ≥ 35, 30-34, and 20-24 years, moderate heterogeneity in the 25- to 29-year age group, and a large degree of heterogeneity in the group that was < 20 years of age. The prediction intervals for the age groups of 25-29 and < 20 years were 0.56 to 1.3 and -0.39 to 2.4, respectively. We found no evidence of significant publication bias. Interpretation - From the results of this meta-analysis of 11 studies, maternal age at conception between 20 to 24 years of age appears to be associated with an increased risk of occurrence of clubfoot.