Prevalence and detection of fetal anomalies by sonography in pregnancies complicated by pre-gestational diabetes mellitus

Rashmi Chathura

Abstract

Diabetes mellitus is being diagnosed in 0.3% of women at the reproductive stage of their life. Prevalence is around 10% in the urban Sri-lankan population. Objective were: 1. to analyze the prevalence of fetal malformations in pre-gestational diabetic pregnancies compared to uncomplicated non diabetic pregnancies. 2. to evaluate the clinical utility of a comprehensive program inclusive of clinical features, glycemic assessment and prenatal detailed ultrasound with fetal echocardiography for congenital anomalies in pregnancies complicated by diabetes mellitus. Prospective cohort study carried out in a maternity hospital- Colombo, Sri Lanka between August 2006 to August 2008 .A 789pre-gestational diabetic women who were registered in hospital clinics during Aug 2006 to Aug 2008 and their newborns were compared with age and parity matched low risk non diabetic population of 780 antenatal mothers for the development of fetal malformations. Interviewer administered questionnaire included detailed history, examination checking glycemic assessment and comprehensive fetal ultrasonography inclusive of a standard four-chamber view of the heart and detailed power Doppler fetal echocardiography according to ISUOG standards. Glycemic control was set at 90-130mg/dl at pre and postprandial values and target HbAiC was set at below 6.2%. Anomalies were identified in 49 of 789(6%) fetuses and neonates: 12 central nervous system, 03 abdomincal wall defects, 03 diaphragmatic hernias, 08 renal tract defects , 03 cystic hygromas, 02 isolated hydrothorax ,04 hydrops with multiple congenital abnormalities, 04 gastro intestinal malformations, 02 limb defects and 04 cardiac abnormalities were detected prenatally. 03 cardiac lesions 02 limb defect (VACTERAL) and down syndrome fetus detected postnatally. The results were compared with age and parity matched non diabetic control group of 780 routine visits mothers and antenatal admissions having 21/780 (2.7%) with only 1 cardiac abnormality this was significant p< 008 at (95% CI 0.77 – 5.03). This study demonstrates and confirms the view that pre-gestational diabetic pregnancy, despite the improved metabolic control, is still a strong risk factor for alterations in fetal development leading to fetal malformations. This study also demonstrate the advantage of a comprehensive program to detect fetal anomalies in pregnancies complicated by pre-gestational diabetes mellitus focusing further attention towards detecting fetal cardiac abnormalities.