Is it my imagination or are we hearing more and more about larger babies, in the news?
It is true that the average size of a newborn baby is increasing, but so is the average size of a person. Are the babies bigger in proportion to this?
According to The Lancet (a medical journal) there has been a 15-25% increase in babies weighing more than 4kg (8 pounds 13 ounces) in the last 20-30 years within the developed world. They also noted an increase within the developing world too.
The average newborn weighs 3.4Kg (7 pounds 8 ounces). In 2009, 1.7% of babies born were over 4.5Kg. Boys are often larger than girls.
Why are babies getting bigger?
This is thought to be due to our diets and the increase in obesity in the population as a whole, as well as the increase in gestational diabetes, which often goes hand in hand. Gestational diabetes, if not controlled, can cause the baby to grow excessively. This is because excess sugar in your blood travels into the baby’s blood. The constant over supply of glucose leads to excessive growth. Large babies can also be a result of genetics.
How will I know if I have a big baby?
Throughout your pregnancy you are being monitored. At 12 weeks you have the dating scan that measures your developing baby and estimates a due date according to size. At 20 weeks an anomaly scan takes place, where your baby’s head circumference, abdominal circumference and length are measured.
In addition, a midwife or doctor will measure your tummy during scheduled appointments, helping to estimate the size of your baby. If there is any concern, you will be sent for an ultra sound scan which will give the doctor more of an idea as to the size of your baby. Do bear in mind that the scans are not always accurate, but will provide a fairly good idea.
If you have one large baby then you are more likely to have another large baby.
If you are overdue, between 40 and 42 weeks, your baby is likely to be bigger.
What are the complications of having a big baby?
You may need to be induced early so you can have a vaginal delivery.
Shoulder dystocia- this is when your baby’s head is delivered but the shoulders get stuck behind your pelvic bone. The medical team then need to help your baby by using manoeuvres to free the shoulders and allow for delivery.
Shoulder dystocia may result in damage to the nerves in a baby’s arm or shoulder- this only occurs in 4-16% of cases and heals quickly and completely in most cases. The baby’s collar bone may have to be broken in order to free up the shoulder for delivery- this sounds brutal, but can be the only way to free the baby. It heals quickly and causes no problems later on.
You may need a caesarean section if the baby is felt to be too large to deliver vaginally.
Your risk of having a bad tear with a vaginal delivery is increased. 80% of women tear in delivery. The majority of these are minor and either heal on their own or need only a few stitches. With large babies the tears can be deeper. This will increase your risk of blood loss and the need for stitches.
Your baby’s blood sugar might be low as their body is producing too much insulin as a result of there being too much sugar in the blood during the pregnancy. This will mean that they will need careful monitoring in the first few hours of life with blood tests.
Yes, babies are getting bigger and our growing weight and gestational diabetes appear to be the main cause. So, maintaining a healthy weight before, during and after pregnancy is important. If you have diabetes or you get gestational diabetes it is really important that you keep your blood sugar under control with diet, medicine or insulin- follow your doctor’s advice.
About the Author
Dr. Anastasia Alcock
The Prenatal Classroom
Mother-of-two Anastasia Alcock holds a Diploma in Obstetrics and Gynaecology from Imperial College School of Medicine in London. She has worked as a paediatrician in hospitals including Guy’s and St Thomas’ Hospital, London, The Royal Brompton Hospital, London and the John Radcliffe Hospital, Oxford and has significant experience in delivery and newborn care.
Most expectant mums have a multitude of questions as they prepare for their new arrival. Who better to ask for advice and support than an experienced doctor who is also a mum and who above all has the time to listen to your concerns and worries?
Anastasia launched The Prenatal Classroom to offer group and private lessons for expectant parents to teach them the knowledge they need to approach parenthood with confidence.
The course was put together based on Anastasia’s medical knowledge, her own experiences as a mother the psychological wellbeing of pregnant women and with additional input from experts in nutrition, breastfeeding and baby care.
Classes are held in West London and Oxford. They are relaxed and informal but have a clear format and come with the guarantee that the same doctor will teach all your classes.