Written By: Prerna Mittra | Published : July 19, 2025 10:50 AM IST
Medically Verified By: Dr Varsha Patil, director and head of IVF, Mother & Child Care, and program director and head for artificial reproductive training centres, Jananee IVF Centre and Mother Baby Care, Siddhagiri Hospital & Research Center
Ultrasound During Routine Prenatal Care: What To Expect During Different Scans (Photo: Freepik)
Ultrasound is a very important process throughout pregnancy. According to doctors, ultrasonography imaging plays a crucial role in prenatal management by providing clinicians with a 'non-invasive, safe, and accurate way' to assess fetal growth, maternal conditions, and potential complications that may arise during pregnancy. High-frequency sound wave-generated ultrasound allows the doctor to see the fetus, placenta, amniotic fluid, and the uterus in real time through images that form basic diagnostic information at different stages of the gestation period.
Dr Varsha Patil, director and head of IVF, Mother & Child Care, and program director and head for artificial reproductive training centres, Jananee IVF Centre and Mother Baby Care, Siddhagiri Hospital & Research Center explains the role of routine ultrasound during different stages of prenatal care; read on.
Dr Patil says this scan is generally performed between 6 and 9 weeks of gestation. This is the first ultrasound that ensures the pregnancy is 'viable', and has been implanted intrauterine. Clinicians also check for fetal heartbeat. This scan determines the number of fetuses and approximates the due date by measuring the 'crown-rump length' (CRL). Early scans can rule out ectopic pregnancy, molar pregnancy, and missed miscarriage, the doctor says.
According to the doctor, the NT scan is combined with maternal blood tests to assess the risk of chromosomal abnormalities like Down syndrome, Edwards syndrome, and Patau syndrome. This scan measures the fluid-filled space at the back of the fetus's neck. A thicker space may necessitate further genetic testing.
This is a detailed anatomy scan to evaluate fetal structure and organ systems for development and growth. During this scan, doctors look for congenital anomalies of the heart, spine, brain, kidney, limbs, and abdominal wall. The position of the placenta, cervical length, and amniotic fluid index are also analysed. It is done to detect early stages of fetal development, neural tube defects, congenital diaphragmatic hernia, and cardiac anomalies.
In the later stages of pregnancy, ultrasound is done to assess fetal growth parameters (biparietal diameter, head, and abdominal circumference, femur length), estimated fetal weight, and placental maturity. Doppler ultrasound can assess blood flow in the umbilical artery, uterine artery, and fetal middle cerebral artery, thereby helping with the detection of IUGR, risk for preeclampsia, or fetal distress, the doctor explains.
Dr Patil concludes by saying ultrasound provides critical obstetric insight during every stage of the pregnancy. "Besides reassuring the patient, ultrasound also works as a diagnostic tool for obstetricians, ensuring both maternal and fetal health," she says.
