Late Pregnancy Ultrasound

37W4D
This applies to ultrasound after 28 weeks, commonly much later.  Some examples of reasons a third trimester ultrasound is:

  • The fetus, or the mother’s abdomen, feels too big or small for the stage of pregnancy.
  • The mother has a medical condition that can affect fetal growth and well-being, such as high blood pressure or gestational diabetes.
  • The placenta was low-lying on the midtrimester ultrasound.
  • The position of the fetus could be unusual eg breech.
  • Abnormal symptoms such as pain or bleeding.
  • Movements decrease.
  • A fetal abnormality noted at an earlier ultrasound requires follow-up.

Third trimester ultrasound (late ultrasound) includes:

  • Fetal position.
  • Fetal size. An estimated fetal weight is calculated from measuring the fetal head, abdomen and femur.  The weight ‘estimate’ is truly that, with one standard deviation being 15% either side of the true weight.
  • Some assessment of fetal anatomy, bearing in mind that late pregnancy limits the views and the check will not generally be a universal check like the 19-week ultrasound.
  • Placental position and maturity.
  • Amniotic fluid volume.
  • The Doppler blood flow in the umbilical cord, which gives an idea of placental function and reserve.
  • Fetal movements.
  • Other factors as requested by the referring doctor.

Late Pregnancy Ultrasound Images

Further late pregnancy images are seen under 3D-4D Ultrasound