Routine ultrasound examination at 12 or 18 gestational weeks for prenatal detection of major congenital heart malformations? A randomised controlled trial comprising 36 299 fetuses.
Objective To compare the rate of prenatal diagnosis of heart malformations between two policies of screening for heart malformations. Design Randomised controlled trial. Setting Six university hospitals, two district general hospitals. Sample A total of 39 572 unselected pregnancies randomised to either policy. Methods The 12-week policy implied one routine scan at 12 weeks including measurement o
