Third trimester ultrasound scan for detection of congenital abnormalities and associated factors, at Abebech Gobena MCH hospital, a cross-sectional study

Abstract

Congenital anomaly is a structural or functional anomaly that occurs during intrauterine life. Growing number of evidences suggest that systematic evaluation of the fetal anatomy during third trimester routine scan increases detection of congenital abnormalities that have been missed in earlier scans, occurred late in gestation or progressed from previous findings. To determine prevalence and associated factors of congenital malformations diagnosed during third trimester ultrasound. This was a facility based cross-sectional study. Data was collected for a sample size of 490 pregnant mothers at Abebech Gobena MCH using pre-tested structured questionnaire containing the following variables: age, parity, chronic illness, folic acid use, medication use, herbal medication use, pesticide exposure, alcohol consumption, khat chewing, passive smoking, surface water use, history of abortion and stillbirth. Ultrasound examinations were done by Maternal Fetal Medicine (MFM) Fellows at third trimester and suspected abnormality cases were confirmed by MFM Consultants. Data entered in to Epi Data version 4.6 & Statistical analysis made through SPSS version 29. Descriptive statistics and tables used to describe the study finding. Analysis was made using cochran mantel haenszel chi square test to detect association between third trimester congenital anomaly and the variables mentioned above. P value < 0.05 was used to show presence of statistically significant association. During the study period 490 third trimester ultrasound scans were enrolled. Thirty congenital anomalies detected, making the prevalence 6.1%. Of these 30 anomalies 6 of them were diagnosed in the second trimester anatomic scan; hence, the prevalence of first-time detected anomalies during the third trimester scan was 4.9%. The commonest organ affected by congenital anomaly detected during third trimester scan was Central nervous system (CNS) 9 (30%). The single most common type of congenital anomaly was Urinary Tract Dilation (UTD) 6 (20%). Congenital Pulmonary Airway Malformation (CPAM), skeletal dysplasia, diaphragmatic hernia, multi cystic dysplastic kidney disease, abdominal cyst and cleft lip and palate each contributed for two cases. Ventricular septal defect (VSD), left ventricular hypoplasia, omphalocele, dandy walker malformation and encephalocele each contributed for one anomaly. Not taking folic acid periconception (OR = 44.02; 95% CI:10.32–187.72) P < 0.001, medication use during early pregnancy (OR = 12.67; 95% CI:2.7–59.47) P < 0.001 and advanced maternal age (OR = 2.43; 95% CI: 1.13- 5.22) P 0.034 were associated with congenital malformation. High prevalence of third trimester congenital anomaly detected in this study; CNS was the commonest organ affected by third trimester congenital anomaly. Not using folic acid, medication use early during pregnancy and advanced maternal age were associated with congenital malformations.

The authors' abstract, as published at the source. BMC Pregnancy and Childbirth, 2026 · DOI ↗