Most women who dream of being pregnant also dream of seeing their stomach grow proud and round as the baby develops. Did you know that the uterus also grows during this time and can actually be used as a guide for your doctor to determine fetal development and growth?
Why measure uterine height?
The height of the uterus, also known as fundal height, is used to assess the growth and development of the baby. Doctors measure from the pelvic floor to the top of the uterus. This height in centimeters should correspond with the number of weeks of gestation. For example:
- 25 weeks of gestation = 25cm
- 30 weeks of gestation = 30cm
When do doctors start measuring?
The first time your gynecologist measures your fundal height will be around the 16 week mark because this is when the uterus should be reaching about the level of your belly button. From this point on, your doctor will likely take this measurement at every appointment.
There are some cases where the uterine height actually diverges from the gestation period. Most of the time, a 2cm difference either higher or shorter is acceptable. There are many reasons why this could be happening and your gynecologist should be able to pick up a diagnosis from the ultrasound.
When your uterine height is shorter than expected
In most cases where the uterine height is less than it should be for the gestational age of the fetus it means that there is some kind of growth restriction. This could come from an aging placenta or you could be experiencing a problem like hypertension.
Your gynecologist will first confirm the gestational age of your baby through an ultrasound. Then they will check to see what the problem could be. Often, your biology and physical stature could lead to a smaller baby. When the parents are small or lean people, the baby you create will often follow suit and not grow to the expected size.
Another factor is the condition of the mother’s body. If you exercise regularly and have strong abdominal muscles, you could be restricting the baby’s growth slightly. However, this is not a cause for concern and the doctor will always check to confirm that both the baby and the placenta are healthy regardless of size.
Parameters for acceptable and expected uterine growth during pregnancy
When your uterine height is bigger than expected
Again, there are many, quite normal reasons for this to happen. If you are expecting twins, for example, your fundal height will be bigger than expected. Additionally, if you and your partner a larger people, it stands to reason that your baby will also be tall and big. Alternatively, you could have a medical condition such as uterine fibroids, gestational diabetes or polyhydramnios – too much amniotic fluid in the uterus.
The position of the baby within the uterus can also influence the fundal height. Alternatively, it could be the placenta interfering with getting an accurate reading. If the placenta is underneath the baby, it could push everything up and give you a much higher measurement than expected.
In some cases, if this isn’t your first pregnancy, your uterine height could well be higher than expected. Your doctor will know about this from your medical history and take it into account.
As with smaller than expected measurements, your gynecologist will always use the ultrasound examination to detect and diagnose the reason for the larger measurement.
What does it mean when the uterine height decreases?
Once you are only a few weeks away from giving birth, the uterine height will start to decrease. This is because the baby starts to descend towards the birth canal.
Remember, uterine height is merely a guide for gestational development. Your doctor will always do a full examination to discover the cause of any changes and know how to remedy any actual problems.