Second trimester diagnosis of imperforate anus

Imperforate anus or anorectal atresia is often associated with major fetal structural defects but it may also be an isolated abnormality. Prenatal diagnosis is difficult but may be assisted by ultrasound detection of enterolithiasis in dilated bowel and confirmed by MRI study. We report a case of imperforate anus in which enterolithiasis with dilated bowel was detected by ultrasound examination at 25 weeks of gestation and confirmed by MRI examination. At birth, the newborn was diagnosed to have a low type of imperforate anus