Antenatal ultrasound follows a schedule, and each scan on that schedule exists to answer a specific question at the only point in pregnancy where that question can be answered well.
Dating scan — 6 to 9 weeks
Confirms the pregnancy is inside the uterus, that there is a heartbeat, and how many embryos are present. Crown-rump length at this stage dates the pregnancy more accurately than at any later point — an accurate due date here improves the interpretation of every scan that follows.
NT scan — 11 to 13 weeks and 6 days
The nuchal translucency scan measures the fluid layer at the back of the fetal neck, assesses the nasal bone and ductus venosus flow, and combines these with maternal blood markers into a risk figure for chromosomal conditions. The window is strict: before eleven weeks the structures are too small, after fourteen the fluid reabsorbs. This scan is FMF-certified at Snap Diagnostics.
Anomaly scan — 18 to 22 weeks
The most detailed study of the pregnancy. Every major organ system is examined in a defined sequence — brain, face, spine, heart, lungs, abdominal wall, kidneys, bladder and limbs — along with placental position, cord vessels and amniotic fluid volume. Expect it to take thirty to forty-five minutes.
Growth and Doppler — 28 to 36 weeks
Measures whether the baby is growing along the expected curve and uses Doppler to assess blood flow in the umbilical and middle cerebral arteries. This is the study that identifies growth restriction early enough to act on it.
Fetal echocardiography
A dedicated study of the fetal heart, offered where there is a family history of congenital heart disease, maternal diabetes, an abnormal four-chamber view on the anomaly scan, or an increased nuchal measurement. It is performed between eighteen and twenty-four weeks.
Is it safe?
Diagnostic ultrasound uses sound waves, not ionising radiation, and has an unblemished safety record across five decades of obstetric use. We follow ALARA output settings as a matter of routine. What we do not offer is non-medical "keepsake" scanning outside a clinical indication.