If you are wondering what causes big babies or are worried about giving birth naturally to a large baby this will help educate you all things big babies.
I was born at a whopping 10lbs 13oz and I still wasn’t my mother’s biggest baby. She had two children before me who were both over 12lbs each.
No, I’m not lying.
And I have inherited my mother’s propensity to birth large babies and go over my due date.
My first pregnancy was with twins who weighed 6lbs 15oz and 6lbs 14oz at birth or nearly 7lbs each, making it almost 14lbs of baby, total. And that was 2 weeks and a day before my due date. Imagine if they had kept cooking in there instead of taken via planned C-section!
My third big baby was born via VBAC 13 days overdue and he was 9lbs 8oz at birth.
My fourth big baby was born two days past her due date at 9lbs 4oz also delivered vaginally.
My fifth big baby was born three days past her due date and weighed 11lbs 2oz born vaginally.
The last big baby surprised me by being so darn massive, but it also explains all the extra weight I gained and all the extra pain and discomforts this last time around!
What may surprise you is that I have never once failed the initial glucose test done during regular prenatal exams. I have never done the longer test with blood draws and I have never been diagnosed with gestational diabetes (though my mother did have it with me and some of my siblings). This is often surprising to people because diabetes and large babies often go together.
My body is just designed to conceive, carry, and birth large babies. My husband and my tall statures likely contribute to their size as well.
And while I think it’s kinda awesome that my babies are born huge, it seems the medical community isn’t as convinced that macrosomia babies, which are any babies weighing more than 8lbs 13oz. at birth, are so awesome.
And chances are you too may be worried about what having a big baby means for you, your baby, your delivery.
Let me help you out with those worries but educating on what’s the big deal about big babies.
What Causes Big Babies?
It’s not super clear why some women, like myself, my mother, and my sisters, have such large babies. For us, it seems to be more a genetic disposition thing. Other possible reasons people give birth to big babies are:
- Parents are taller and/or heavier
- Mom is obese before becoming pregnant (BMI of 30 or more)
- Mom experiences excessive weight gain during pregnancy
- Mom has a poor diet during pregnancy
- Mom had diabetes before conceiving
- Mom has/develops gestational diabetes or hyperglycemia
- Mom already had a large baby
- Mom is over the age of 35
- Mom has had multiple pregnancies
- Mom is Hispanic
- Mother took antibiotics during pregnancy
- Pregnancy goes beyond 40-42 weeks
- Baby is male
And genetic reasons the baby might be born large include:
- Baby has Sotos syndrome
- Baby has Beckwith-Wiedemann syndrome
- Baby has Perlman syndrome
- Baby has congenital abnormalities
How to Avoid Having a Big Baby
While there are some causes of big babies outside of our control, there are some things you can do to avoid having a big baby, or as much as you can.
Controlling your diet and diabetes (if you have it) will ultimately be your best in avoiding large babies.
My last pregnancy doctor told me that to avoid a big baby I needed to avoid things like processed sugar, refined sugars, cooked potatoes and even cooked carrots. I needed to avoid things like white bread and cereals.
Perhaps unsurprising, I didn’t listen to him and ate what I always eat which is all of those things.
Changing your diet while pregnant is hard! We all want our comfort foods when we feel ravenous or can finally keep something down. We also feel like treating yourself because we are growing another life inside of us!
But, if you really do want to avoid having a big baby, you need to eat better and get exercise during pregnancy. You need to go easy on the brownies and cookies, and say yes more to salads, fruits, and nuts. Oh and for going on more walks.
The fact is, women who gain more weight during pregnancy tend to deliver large babies. So, you need to do your part to limit the pregnancy weight gain (in healthy ways of course).
What If My Baby Is Too Big to Deliver?
Generally, it is believed that these macrosomia babies (or babies with “Big Baby Syndrome”) carry higher birth complications, though I’ve never had any.
The most common birth complication that can come from having big babies is shoulder dystocia, where the baby’s shoulders get stuck behind their mother’s pubic bone, causing the baby to get stuck in the birth canal during delivery. The possible outcomes of this are:
- Broken collarbone or upper arm bone
- Nerve damage or paralysis (brachial plexus injuries) to the arm of the shoulder that was trapped
The good news is that shoulder dystocia is a super rare complication (complicating 1.4 percent of all vaginal deliveries).
Other complications of giving birth to a big baby are:
- Difficult and/or long labor
- Perineal tears (or more severe tearing)
- Higher chance of getting an episiotomy
- Cesarean section
- Postpartum hemorrhage
- Bruised or broken tailbone
- Birth trauma to the baby, including cerebral palsy
Also, babies may experience the following if they are born large, especially if over 9lbs 15oz:
- Impaired glucose tolerance and higher blood sugar levels
- Childhood Obesity
- Metabolic syndrome
- Low blood sugar levels
- Hematological disturbances
- Electrolyte disturbances
- Childhood cancer
I know many women have fears of a “baby too large to deliver” or having a baby that won’t fit through the pelvis or birth canal, especially if they are on the petite side.
Having a baby too large to deliver vaginally through the birth canal is called cephalopelvic disproportion (or CPD) but in the modern era, this is extremely rare and nearly impossible to diagnose before labor begins. True CPD is most often a result of a congenital abnormality or severe injury in the pelvic region. A woman’s hips naturally widen during childbirth. Nearly all women’s bodies are indeed capable of fitting even a large baby through their pelvis.
In the case of assumed macrosomia (as ultrasounds are notoriously not reliable at guessing weight accurately at the end of pregnancy) many doctors strongly recommend induction or C-sections for large babies, especially if you have had a C-section before, as large babies can put extra strain on your uterus and any scars on it, putting you at risk of uterine rupture.
However, in 2001 the American Congress of Obstetricians and Gynecologists warned moms against getting a C-section or induction if their only concern is that their baby will be big saying that:
- Suspected fetal macrosomia is not an indication for induction of labor, because induction does not improve maternal or fetal outcomes.
- Labor and vaginal delivery are not advised against for women with estimated fetal weights up to 11lbs (in the absence of maternal diabetes).
A big part of this is because early-term infants have higher rates of respiratory distress, respiratory failure, pneumonia, and admission to neonatal intensive care units compared with infants born at 39 to 40 weeks gestation. Infants born at 37 to 38 weeks also have a higher mortality rate than those born later.
You will have to decide with your doctor if induction or a C-section is truly the right choice for you for giving birth to a large baby. All situations bring their own set of potential risks and complications as well.
Giving Birth to Large Babies
In many ways, I’m glad that my last OB never estimated the size of my daughter. He may have started to get antsy and worried about her size, pushing me to consider having a C-section or being induced early.
My previous doctor kept worrying about the size of my baby and it was very annoying to me, as I had already given birth to a large baby without complications, other than his sunny-side presentation, and it felt dumb that I had to reassure my doctor! He should be the one reassuring me that everything would go well!
While I have given birth naturally to a large baby three times now, without complications, it’s not always the case for all women who find themselves giving birth to a big baby.
Plus, there is something I want other moms to know and come to expect about giving birth to large babies in the hospital.
Big Babies Are at Risk of Hypoglycemia
Did you know that both babies born prematurely (or which are small for their size) and large babies at birth are at risk of developing hypoglycemia, or low blood sugar?
I didn’t until I had my first large baby birth!
When you have big babies, the medical community worries about your child’s glucose levels. A lot.
Because your big baby is no longer supplied with nutrients from the placenta, the worry is he or she will not have enough glucose stored to maintain their large body size until your breastmilk comes in (usually on day 3).
Hypoglycemia in newborns is worrisome because low blood glucose levels can make a baby unwell and sick. If their glucose levels are low in the first 24 hours of life and stay low, it can lead to major long-term neurologic damage like mental retardation, recurrent seizure activity, developmental delay, and personality disorders.
No wants that.
So every hospital I have birthed at has checked my big baby’s blood sugar levels starting shortly after birth and continuing on through most of the first 24 hours and sometimes into the next day.
How Baby’s Blood Sugar is Measured
To take a newborn’s blood sugar levels, a nurse will come in before you feed your baby and prick their heel with a small needle and suck up the blood into a little handheld machine which reads glucose levels.
If the results are close to, but below, what they consider a healthy glucose level range, they may take another sample again immediately to see if it the next sample will read just a little higher. Occasionally, they’ll need to test again too if the machine didn’t work for some reason or there wasn’t enough blood in the sample.
Then an hour after you feed your baby, your nurse will come in again, unwrap your baby, and prick their heel, again, and test their glucose again.
They will continue testing your baby’s blood sugar levels before and after feedings until the readings stay in the healthy range for at least two feedings. But, every hospital will have slightly different rules about testing and acceptable glucose levels.
If you have a good nurse, they will warm up your baby’s foot using a small little heating pack first, before pricking their heel, so the blood will flow easier and faster and will be less annoying and painful for the baby. Which you will appreciate!
My poor big babies come home with a dozen or so little red marks on the soles of their feet because of these in-hospital glucose test readings.
Breastfeeding Big Babies
I breastfeed. I have breastfed all of my babies at least 13 months, including the twins. And while I semi-regularly supplemented with formula and pumped milk for my twins, the rest of my children exclusively breastfed.
But, nothing puts pressure, stress, and worry on a new breastfeeding mom in the hospital like constant glucose tests!
Like most moms, my milk doesn’t fully come in until day three or later, so my big baby isn’t getting everything he or she needs to keep his or her glucose levels where they need to be due to his or her large size.
Newborn Glucose Levels and Breastfeeding a Large Baby
This means I have a few options for what to do:
- Nurse for as long as possible on both sides every 2 hours, or even more frequently
- Nurse and then pump afterward and then feed that to the baby after the next nursing session
- Nurse and then supplement with donated breastmilk afterward (if available)
- Nurse and then supplement with formula afterward
- Nurse and then give the baby glucose water or glucose paste
Having gone through three different hospitals testing my large babies’ glucose levels, I have done all of the above.
Honestly, by this last delivery, I knew to expect these newborn glucose tests and I knew exactly what I would do ahead of time: I would supplement with the Similac Ready-to-Eat formula after each nursing session.
While some women who are breastfeeding advocates may be aghast at my choice to do this, I assure you that it was the best decision.
Giving my daughter formula in the hospital was the right choice because:
- It allowed someone else to feed my baby and for me to sleep, rest, shower, and recover.
- It meant her glucose levels stayed higher as she could take in more food.
- It prevented me from having to pump, saving my nipples and my time.
Supplementing with formula, especially in the hospital, does not mean your baby will never successfully breastfeed or will get nipple confusion, or any of that. Supplementing with formula ensures that your large baby will have the nutrients needed to sustain their glucose levels while you wait for your milk to come in.
I am a believer that fed is best!
I, of course, still put the baby to the breast in order to encourage my milk to come in, and come in it did, in its own time. And I strongly encourage you to do the same if you intend to breastfeed.
But, I will not risk the health of my newborn so I chose to supplement with formula while in the hospital and a few days after coming home. You should never risk the health of your baby.
Supplementing with Similac helped calm my concerns about glucose levels and the health of my newborn in the hospital because I knew I was giving my baby something almost just as great as my own milk, and I still had the time to hold her and bond with her as I fed her a bottle or my husband fed her a bottle.
Her glucose levels finally stabilized and the heel pricks eventually stopped and she was able to go home just fine. Breastfeeding a large baby has been very successful for me and hopefully for you too if you choose that route.
Benefits of Having a Big Baby
While most of this has been rather depressing to read and think about, I have personally loved having a big baby! There are actually some serious benefits of having a big baby!
Big babies are:
- Better at regulating their body temperature
- Sturdier, better able to hold up head sooner
- Cuter with all the fat rolls
- Sleep better at night (or at least have bigger tummies so they can potentially be better sleepers)
- Heavier babies do better in school and are smarter
- Better protected from later diseases
Big babies also generally avoid the NICU as well! That’s always a great thing.
While it’s helpful to know what causes big babies, it’s also helpful to be educated about the risks associated with giving birth to big babies and what that means for your time in the hospital too so that you can make the best decisions for yourself and your new baby! Congrats and best of luck!