Underdiagnosis of Mild Congenital Anorectal Malformations.

OBJECTIVE: To determine whether the frequency and severity of congenital anorectal malformations (CARMs) differs by sex.

STUDY DESIGN: We included 129 patients (0-319 weeks old) diagnosed with CARMs, who had been referred to our Department of Pediatric Surgery between 2004 and 2013. Rectoperineal and rectovestibular fistulas were classified as mild CARMs, all others as severe. If a patient was diagnosed with CARM within 48 hours after birth, this was considered an early diagnosis, all others as late.

RESULTS: Seventy-five (58%) girls and 54 (42%) boys were diagnosed with different forms of CARM. More patients had mild rather than severe forms of CARM (67% and 33%, respectively, P <.001). We found that 89% of girls had a mild form of CARM, whereas 65% of boys had severe forms (P <.001). All severe forms were diagnosed early, whereas 54% mild forms were diagnosed early and 46% were diagnosed late.

CONCLUSIONS: Girls more often have mild forms of CARM, whereas boys more often have severe forms. Overall, the distribution across the sexes is equal. Because chronic constipation can be the only symptom of mild CARMs, it often requires more time to diagnose than severe forms. Many women are, therefore, diagnosed with CARMs at an older age, or they may go undiagnosed altogether. Subsequently, these women have a greater risk of full rupture during vaginal delivery.