If you’re pregnant, you will probably wonder how big your baby will be. After all, how does an 8lb baby fit through the birth canal and out of your body?! Sometimes it seems like Mother Nature didn’t think through her method of birthing babies very well!
The average size of a baby girl is 7lbs, and 8 lbs for a boy, but a healthy baby can be anything from 5lbs 8oz to 10lbs. Less than 5 lbs 8oz is considered a low birth weight, and babies this weight may have some health problems
Over 9lbs 8 oz is considered much larger than average (the technical term is macrosomic). Approximately 5-10% of babies are considered macrosomic.
How can you tell how big your baby is going to be?
It’s hard to tell accurately how big a baby is going to be while it’s still in the womb, as even scans are only 90% reliable and can be up to 2 lbs out either way. Your midwife will measure your stomach at every antenatal appointment, to check the size of your baby (this is called a fundal measurement). If you measure large for your dates, you could be carrying a big baby.
However, some women who measure large for their dates actually have average sized babies, but measure large because the baby is surrounded by a lot of amniotic fluid (this is nothing to worry about). If your midwife thinks your baby is either larger or smaller than average, she will send you for a scan, which is more accurate than a fundal measurement. Overweight women are more likely to have inaccurate fundal measurements because of the extra weight they themselves are carrying.
Factors to Consider
There are certain factors that make it more likely that you will have a large baby. Boy babies are normally bigger than girls, and the height of the mother and father affect how large a baby will be. How much weight a woman puts on during pregnancy also affects how big her baby will be, especially during the last trimester.
Certain medical conditions make it more likely a woman will have a big baby, such as anemia during pregnancy, having diabetes mellitus, developing gestational diabetes during pregnancy, and if you are more than two weeks over your due date when you deliver. If you have previously had a big baby, you are more likely to have another big baby. Women who are overweight have a higher chance of giving birth to a baby who is macrosomic.
Babies born to parents who are smaller than average are more likely to have smaller babies, as are people who were small themselves at birth. Babies born to parents with white European origin are generally bigger than babies born to parents of Indian, Pakistani, black African, and African-Caribbean descent, while Hispanic women are more at risk of having a macrosomic baby. Studies have shown that people who live in high altitude areas, such as mountains, have smaller babies (the top floor of a block of flats probably doesn’t count).
Even if you have all these risk factors for having a big baby, try not to worry. It doesn’t necessarily mean you will have a big baby, and big babies are born to women who don’t fall into at risk categories for a macrosomic baby. If you are worried about the size of your baby, talk to your midwife or GP about your concerns.
Macrosomic babies are normally only a concern if the mother is very small. Having a big baby doesn’t mean you will need to give birth by caesarean or have an early induction, but if you are carrying a big baby talk to your health care provider about your birth options.
About the author: This article was written by Alice on behalf of www.pregnancy.co.uk, a website dedicated to helping parents understand how their baby could develop to be big or small!
Photo credit: Justyna Furmanczyk