Pregnancy
Detailed Test & Procedure Guides See All First Trimester Screening in Detailed Test & Procedure Guides First trimester screening combines fetal ultrasound and blood tests for the mother. It’s done during the first trimester of pregnancy, during weeks 1 to 12 or 13. It can help find out the risk of the fetus having certain birth defects. ...more Second Trimester Prenatal Screening Tests in Detailed Test & Procedure Guides Screening is usually performed by taking a sample of the mother's blood between the 15th and 20th weeks of pregnancy (16th to 18th is ideal).