P47.04: Diagnosis of major fetal malformations in type 1 and type 2 diabetic women in a large multi‐ethnic region in the UK

Abstract

Aims: To document the types of major fetal malformations present in pre-gestational diabetic women in pregnancy and the rate of antenatal diagnosis by second trimester ultrasound. Methods: Pre-gestational diabetes was defined as either type 1 or type 2 diabetes which had been diagnosed at least 1 year before the mothers estimated date of delivery (EDD). Data was collected any time from booking to delivery between 1 March 2002 and 28 February 2003, and followed through to include the outcome of the baby at 28 days postnatally. Major anomalies were coded according to the 10th revision of the International Classification of Diseases (ICD10). Results: The major congenital malformation rate is 82.1/1000 births. There were 29 major congenital anomalies in pregnancies beyond 16 weeks’ gestation and all of these had a second trimester fetal ultrasound scan. In 17 cases the anomalies were diagnosed antenatally (16 by ultrasound and 1 by amniocentesis) and in 12 cases the scan was reported as normal. Therefore the antenatal major congenital malformation detection rate is 59% in pregnancies beyond 16 weeks’ gestation. Congenital cardiac defects remain the most commonly occuring anomalies in diabetic pregnancies (11/29 malformations). Major central nervous system defects, as in the national dataset, are also over-represented. The nature of the anomalies undiagnosed was varied, ranging from hypoplastic left heart to hypospadias. However all of these cases with the exception of a case of facial dysmorphia, hypospadias and two cases of trisomy 21 might have been expected to have been detected by detailed fetal anomaly and cardiac scanning at 20–22 weeks’ gestation. Even allowing for these cases 40% of major malformations were undiagnosed antenatally. Conclusions: All women with pre-gestational diabetes should receive a detailed scan performed by a practitioner with at least UK RCR/RCOG Higher Level Obstetric scanning accreditation.