Measuring Development During Pregnancy
Your outward sign of pregnancy is your growing abdomen, and everyone seems to have their own opinions about whether or not you’re measuring too large or too small. Perfect strangers might offer you opinions on how you are “showing” and what that means for you and your baby. However, the opinion and measurements that matter most will come from your doctor. Typically during the 16th to 20th weeks of gestation your healthcare provider will begin to measure what is called the fundal height.
Your fundal height is obtained when your doctor measures the distance from your pubic bone up and over to the top of your uterus (also known as the fundas) when you are lying down on your back. The size of this measurement in centimeters is roughly equal to the number of weeks along you are in your pregnancy. For example, if your fundal height measures 24 centimeters, it would be estimated that you are 24 weeks along in your pregnancy. This measurement is used to assess and monitor the growth and development, but can be influence by several things that don’t have any negative consequences on the health of your pregnancy.
- Your due date has been miscalculated.
- This is not your first pregnancy and your abdominal muscles have been stretched, allowing you to “show” earlier.
- The baby is positioned in such a way to create a larger or smaller measurement.
- Your baby’s body build is small, especially if you and your partner are small-framed.
- Your weight and/or body size is contributing to a misleading measurement.
Should I Worry About Measuring Small During Pregnancy?
Once your doctor has assessed and ruled out any of the above common and non-threatening reasons for measuring small during your pregnancy, he or she may want to further examine the potential cause of the small measurement. This is most often initially done by an ultrasound to check the overall health of your pregnancy. Some doctors will also use amniocentesis to investigate growth and development concerns.
Doctors usually take these steps when there is a discrepancy of 4 or more centimeters difference between your measurement and your predicted gestational stage. There are different reasons why your measurements could be small, but one that your doctor might be most concerned about is what is known as asymmetrical intrauterine growth restriction, or IUGR.
What is IUGR?
The condition of asymmetrical intrauterine growth restriction is typically characterized by a baby who has an accurate head measurement for that gestational age, but is accompanied by abdominal and leg measurements that are lagging. This can be the result of several factors that lead to inadequate nutrients provided to the baby. The baby’s body automatically feeds the brain first – using the limited resources as best as possible – which results in the asymmetrical development of the head when compared to the rest of the body. This nutritional deficiency can be caused by poor maternal nutrition or those who smoke, but it is also commonly found in women who have healthy diets but whose placentas are not functioning well enough to supply health blood flow and nutrition.
No matter what the cause is for your small gestational measurements, your doctor can monitor these with the use of several tests, including repeated ultrasounds, non-stress tests like kick counts, and amniocentesis. If your baby is found to be in danger of poor nutrition because of a placental breakdown, your doctor may decide to deliver your baby earlier than expected in order to provide adequate nutrients.
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