Fetal Growth & Wellbeing
A third trimester ultrasound is an ultrasound scan performed during the final stage of pregnancy, typically after 28 weeks. It is usually recommended when there is a medical reason to assess the baby’s wellbeing, growth, or position. Unlike the routine scans performed earlier in pregnancy, not everyone will need a third trimester ultrasound unless advised by their healthcare provider
What are looking for on this scan
The main purpose of a third trimester ultrasound is to check how your baby is growing and developing. It allows the sonographer to measure your baby’s size, monitor growth over time, and assess the amount of amniotic fluid around the baby.
The position of the baby (whether head-down, breech, or transverse) and the location and appearance of the placenta are also checked.
Blood flow in the umbilical cord and other vessels may be assessed using Doppler ultrasound if there are concerns about the baby’s growth or overall health.
A third trimester ultrasound may be recommended if there are concerns such as reduced fetal movements, high or low levels of amniotic fluid, abnormal fundal height (the size of your belly), maternal medical conditions (like high blood pressure or diabetes), previous pregnancy complications, or if the baby is suspected to be too small or too large for gestational age.
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You do not usually need a full bladder for this scan, and no special preparation is required. The scan usually takes around 20 to 30 minutes, but this may vary depending on the baby’s position and the specific reason for the ultrasound. You can typically bring a partner or support person with you
