Being at the doctor’s office also gives you the added benefit of being able to immediately discuss the results of your fundal height test with your doctor, should anything out of the ordinary be found.
The reason for this is that starting at around the 17-week mark, a full bladder can cause the fundal height measurement to off by a matter of centimeters. [1] X Trustworthy Source Mayo Clinic Educational website from one of the world’s leading hospitals Go to source
Clothes, belts, and so on can cause small differences in your fundal height, so they are typically removed before measuring. Changing into a hospital gown minimizes the possibility of an inaccurate result and additionally offers your doctor the ability to easily access all areas needed for a good fundal height measurement.
The doctor, nurse, and/or midwife will also check the volume of amniotic fluid and also attempt to identify the uterine fundus - the point on your stomach where the “top” of the uterus can be felt.
This means that the doctor will measure from the highest point of your uterus to the top of your symphysis pubis (the area located below your belly button where your pubic bone begins). The doctor will record your fundal height measurement in centimeters and enter it on your chart. As a very general rule, a woman’s fundal height should be within 1 to 3 centimeters of the baby’s gestational age in weeks. For example, for a woman who’s been pregnant for 20 weeks, a fundal height of about 17-23 cm is expected.
This can be for a variety of reasons - some completely harmless, others that are cause for concern (but by no means catastrophic). Below are many of the causes for an abnormal fundal height:[2] X Trustworthy Source Mayo Clinic Educational website from one of the world’s leading hospitals Go to source Being especially tall and thin or short and heavy Having a full bladder Having twins, triplets, etc. Abnormally slow or rapid fetal growth Too little or too much amniotic fluid Uterine fibroids Having a child that has settled into breech or another unusual uterine position
Because most laypeople aren’t medically trained in the procedure of measuring fundal heights and because, as noted above, an abnormal fundal height can have a wide variety of causes, it’s important to remember not to make any medical decisions based on the results of a self-performed fundal height test. If you obtain an abnormal result, follow up with a trained doctor, nurse, or midwife for confirmation.
Generally, before the 20th week of pregnancy, the fundus will be below the belly button, while after the 20th week, it will be above it.
If you don’t have measuring tape or a ruler handy, use the old, traditional method of using your fingers. The width of one finger in the fundal height is roughly equivalent to one week of gestation time. Thus, for a 15 week-old pregnancy, you should expect roughly 15 finger-widths of fundal height.
