Why does the doctor measure my stomach during prenatal appointments?

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 baby inside. 

Belly MeasureWhat is abdomen measurement?
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. That measurement, in centimeters, should be about the same as your current week of pregnancy. For instance, if you are 24 weeks pregnant you will 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 will be slightly off. In my case, the measurement in my 34th week was 62 centimeters, but I was carrying twins. In that case the measurement was about right for two singlets. 

If you consistently measure much larger than expected and you are of normal weight your doctor may suggest an ultrasound to rule out multiples and measure amniotic fluid. If nothing out of the ordinary is found there are no medical concerns to worry about - you are just measuring larger than normal. 

I always loved the abdominal measurement part of my prenatal visits, especially with my twins. None of my children were born on the estimated due date based on my last menstrual cycle, but that measurement was always within one week.