Best timing for 3D ultrasound in pregnancy

1. Timing breakdown

• Before 22 weeks: Fetus is too small with underdeveloped organs; many abnormalities cannot be visualized clearly.

• 22–26 weeks (prime window): Moderate fetal size + adequate amniotic fluid. Organs, facial features and limbs are fully developed for screening structural defects (neural tube, heart, face, limbs and visceral malformations).

• After 28 weeks: Fetus grows larger, limited uterine space and curled limbs lead to poor visibility and missed diagnosis.

Note: Most hospitals require booking 1–2 months in advance; reserve your appointment early once pregnancy is confirmed.

2. Other key prenatal scans

• NT scan (first-trimester screening): 11 ~ 13⁺⁶ weeks (for nuchal translucency, early chromosome risk screening, not 3D)

• 3D/4D anatomy scan: 22～26 weeks

• Second-trimester follow-up scan: 28～32 weeks (recheck fetal growth, fetal position and amniotic fluid volume)

3. Exam preparation tips

• No fasting or full bladder required.

• If the baby’s position blocks viewing: walk around or eat sweets for a repeat check.