Prenatal visits, in the beginning, are rather uninteresting. There is no heartbeat for the first 10 weeks or so and you don't have an ultrasound to look forward to until much later in the pregnancy. All you have to do is show up once a month, pee in a cup, and step on the scale of horror. But, starting in the 20th week of the pregnancy things start getting a little more interesting. The size of your belly starts telling you secrets about the baby inside. Your growing stomach will be measured and this is known as tracking the fundal height.
What is the fundal height?
Each visit starting around 20 weeks, you will get an abdomen measurement which will be logged into your medical file. The doctor will place a measuring tape at the top of your pubic bone and run the tape to the top of your growing belly (where your uterus ends that week). That measurement is the fundal height. in centimeters, it should measure about the same as your current week of pregnancy. For instance, if you are 24 weeks pregnant, you should measure about 24 centimeters.
What causes the measurement to be off?
Babies can grow larger or smaller than expected and the amount of amniotic fluid also comes into play. If mom is overweight or underweight, measurements may be slightly off. However, if you consistently measure much larger than expected and you are of normal weight your doctor may suggest an ultrasound to rule out multiples. If you have twins or multiples, the measurement may be significantly increased.
Your doctor may also want to measure the amniotic fluid. Too much amniotic fluid is known as polyhydramnios. Sometimes there is no cause found for having too much amniotic fluid, but other times it can be linked to diabetes in the mother, a neural tube defect or congenital condition in the baby, or other medical reasons.
If nothing out of the ordinary is found, you may just be measuring larger than normal. It may not be of any concern but your doctor or midwife will likely monitor it.