Worried your baby’s too big for your tiny body? Here’s what you need to know

Posted in Pregnancy Health.

Most first-time mums worry about how an entire human baby is going to come out of their tiny lady bits, but for those who are petite or carrying gigantic babies, the fear is REALLY real. Here are all the facts when it comes to birthing babies when you have a small pelvis and/or a big bub.

Pelvis too puny?

The term ‘cephalopelvic disproportion’ (also known as CPD) refers to when a woman’s pelvis is simply too small for their baby’s head to pass through.

While it is a real condition, it’s extremely rare and mostly occurred in previous centuries when poor nutrition and illnesses like polio caused women to have pelvic anomalies. Thankfully, almost all women these days have a pelvis that will adjust to allow the baby to move safely through the birth canal; the only exceptions might be if you have a pelvic injury or congenital abnormality.

Other true cases of CPD are very few and far between and can only be diagnosed once labour has started. However, misdiagnosis is common too (when labour is taking longer than expected), which is perhaps why people believe CPD occurs more often than it actually does.

Bare pregnant belly with hands - feature

Moving objects

While you might be bewildered about how your big baby is going to fit, you have to remember that the human body is incredible and both your pelvis and a baby’s head are designed to move in a way that makes the birthing process possible. For starters, your pelvis is made up of several different bones held in place by ligaments, and when pregnant, your body releases the hormone ‘relaxin’ which loosens your pelvic joints and ligaments in preparation for labour.

Unlike an adult’s skull, your baby’s head is also made up of several bones that aren’t yet fused, which means it’s malleable and can change shape to sufficiently fit through the birth canal. A baby’s skull bones don’t connect and strengthen until a little while after they’re born, which is why newborns have those soft spots called fontanelles (the membranous gaps between the bones). 

Where’s your baby at?

For a baby to descend and travel through the birth canal and into the world, they ideally needs to be in the right position to begin with, which is head down. When babies are facing the other way, it’s called a breech position. While most babies will turn around in the final weeks or days before labour starts, some don’t, which can make birth quite difficult. A vaginal breech delivery is not impossible, but it is considered riskier for a baby to be delivered feet first, and a lot harder for the mother.

If a baby is breech, often doctors will try methods to turn the baby, such as using their hands in a procedure called ‘external cephalic version’ (ECV). Otherwise, they may recommend a c-section delivery.

In all of these cases, the issue is the position of the baby, and NOT because the mother has a pelvis that’s too small.

Widening the gap

If your bub isn’t breech and you’re going for a vaginal delivery, you can help create more room for your baby during labour, depending on your birthing position. Lying flat on your back or even a bit reclined is the preferred norm for a lot of women and doctors. However, this can actually narrow your pelvis by 30 percent which is not what you want at all!

The best positions to help widen the gap (so to speak), and help your baby travel down the birth canal, are squatting, on all fours, or lying on your side.

Woman in labour

Bigger than they seem

You may think that your baby bump is huge, or perhaps your doctor has estimated you’re carrying a big one, but it’s important to remember two things. The first is that all women carry babies differently. Some look huge and have average-sized babies, some look tiny and have whoppers. The size of your bump doesn’t necessarily determine the size of your baby.

The second thing to know is that doctors can only estimate with ultrasound measurements, there isn’t an accurate way to predict the size and weight of a baby before birth, so often they may be smaller (or bigger) than what’s anticipated.

You can do this!

If your baby isn’t breech and you’re keen for a vaginal birth, but you’re terrified that your bub isn’t going to fit, relax and remember that your body is designed to make it happen. Your baby WILL fit! It can just take a bit longer for some babies than others.

And of course, in the event of an emergency, the doctors are on hand to assist with forceps or perform an emergency c-section if required, making sure you and your bub are safe.


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