Does maternal exposure during pregnancy to higher ambient temperature increase the risk of hypospadias?

SummaryIntroductionThe association between ambient temperature that the mother is exposed to during pregnancy and hypospadias has not been investigated by the studies, although the recent studies showed the correlation between some congenital malformations (congenital heart disease, neural tube defect, etc.) and ambient temperature.ObjectiveThe aim was to investigate the relation between hypospadias and the ambient temperatures that the mother is exposed to during her pregnancy.MethodsThe data of patients with hypospadias that had their gestational periods in Ankara and Istanbul regions, and had other urological treatments (circumcision, urinary tract infection, pyeloplasty, nephrolithotomy, etc.) between January 2000 and November 2015 were analyzed retrospectively. The ambient temperature at 8-14 weeks of gestation was investigated for each patient by reviewing the data of the General Directorate of Meteorology, since this period was risky for development of hypospadias. The data including ambient temperature that the pregnant mother was exposed to, maternal age, parity, economical status, gestational age at birth, and birth weight were compared between two groups. The retrospective nature of the study may be a potential source for selection bias.ResultsThe data of 1,709 children that had hypospadias repair and 4,946 children that had other urological treatments between 2000 and 2015 were retrospectively analyzed. There were no differences between the groups for maternal age, parity, economical status, gestational age at birth, and birth weight (Table). Analysis of exposed maximum and average ambient temperatures at 8-14 weeks of gestation revealed that July and August, hot periods in summer time, were more prevalent in the hypospadias group (p = 0.01). The average and maximum monthly ambient temperatures during summer increased the risk for hypospadias (OR, 1.32; 95% CI, 1.08-1.52; and OR, 1.22; 95% CI, 0.99-1.54, respectively.ConclusionsIn this paper, we evaluated the relation between hypospadias and the ambient temperatures that the mother is exposed during her pregnancy. The results of this study indicated that the high ambient temperatures the mother and fetus are exposed to at 8-14 weeks of gestation increased the risk of hypospadias in the offspring.Table. The characteristics of the patients included in the study.HypospadiasReferent population with no hypospadiaspNo. of patients1,7094,946Maximum monthly temperature, °C36.367 ± 10.826.008 ± 9.60.01Average monthly temperature, °C22.502 ± 13.918.742 ± 11.30.018-14 weeks of pregnancy Winter348 (20.3%)1099 (22.2%)0.14 Spring401 (23.4%)1328 (26.8%)0.21 Summer551 (32.2%)1361 (27.5%)0.01 Fall409 (23.9%)1158 (23.4%)0.19