The Value of Mid-Trimester Routine Ultrasonographic Screening in Antenatal Detection of Congenital Malformations
Somsri Pitukkijronnakorn MD*, Apichart Chittacharoen MD*, Thavat Jetsawangsri MD*, Panyu Panburana MD*, Adithep Jaovisidha MD*, Rasig Roungsipragarn MD*, Nopadol Saropala MB, BS, MRCOG*, Yongyuth Herabutya MB, BS, FRCOG*
Affiliation : * Maternal Fetal Medicine Unit, Department of Obstetrics and Gynaecology, Ramathibodi Hospital, Faculty of Medicine, Mahidol University, Bangkok, Thailand
Objective : To evaluate the detection rate of major fetal anomalies by mid-trimester routine ultrasound
screening in a single center with low-risk population.
Material and Method: The present study was a cross sectional study. All pregnant women attending the
antenatal clinic between January 1996 and December 2002 had routine ultrasound screening between 18-22
weeks’gestation. The ultrasonographic results were compared with the pregnancy outcome in aspects of
prediction of major fetal anomalies.
Results : Three hundred and sixteen fetuses out of 29,839 (1.06%) had major anomaly. One hundred and
forty four fetuses (45.57%) were diagnosed as having major anomaly by routine ultrasound screening. One
hundred and seventy two fetuses (54.43%) were undiagnosed. The sensitivity, specificity, positive predictive
value, and negative predictive value were 45.57%, 99.97%, 94.74% and 99.42% respectively.
Conclusion : Although the rate of the detection of major congenital fetal anomaly was low, almost all lethal
and life threatening anomalies could be diagnosed antenatally thus allowing the option of counseling,
pregnancy termination, or selective referral.
Keywords : Congenital abnormalities, Second trimester pregnancy, Prenatal ultrasonography
