Your Developing Baby: Week 33

What's going on with your baby in pregnancy week 33? Find out all about important pregnancy milestones and exciting fetal development specific to this week of pregnancy!

Week 33 American Institute of Ultrasound in Medicine -

An ultrasound can offer your health care provider -- and you -- a thorough look inside the womb in the weeks leading up to your delivery. If your provider has any concerns about your baby's health or your pregnancy, she might request that you have a biophysical profile (BPP). A BPP is an evaluation of your unborn baby's well-being, using an ultrasound examination and a non-stress test.

The ultrasound portion of a BPP includes four parts. Over a period of 30 minutes, the sonographer looks for:

    1. Fetal breathing movements. Looking closely at your unborn baby's lungs, the sonographer will confirm breathing motions by watching lung movements.
    2. Body movements. The sonographer will watch for your unborn baby to move his body, head, arms, and legs.
    3. Fetal tone. At this stage in development, your unborn baby should be able to extend or flex his arms, legs, and fingers. Your sonographer will look for your baby to make these movements.
    4. Amniotic fluid. By taking various measurements of the dark spaces on the ultrasound image, the sonographer can determine how much amniotic fluid volume is within the uterus. These fluid levels need to be within a certain range; decreased fluid levels could indicate a problem with the pregnancy.

      Terms to Know

      Biophysical profile (BPP): An in-depth evaluation of a fetus' well-being using ultrasound imaging and a non-stress test to look for indications of fetal distress or difficulties in a woman's pregnancy.

      Important Information About Your Pregnancy

      Copyright © 2010 Meredith Corporation.

      Images courtesy of the American Institute of Ultrasound in Medicine (


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