Obesity during pregnancy may account for the higher risk of giving birth to an atypically large infant independent of its health consequences such as diabetes according to a study published November 13 2017 in JAMA Pediatrics. Beginning in the 21st week of pregnancy ultrasound scans revealed that for fetuses of obese women the femur and humerus were longer than those of the fetuses of non obese women. The differences persisted through the 38th week of pregnancy.