How to have a smaller baby

Having a large baby | Pregnancy Birth and Baby

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When you have a baby, one of the first things people like to know — besides the baby's name — is their birth weight. Even before the baby's born, parents can start to worry about its growth and development in the womb, particularly if they've been told they're having a big baby. But does size really matter?

Babies come in all shapes and sizes

More than 9 out of 10 babies born at term (37 to 40 weeks) weigh between 2.5kg and 4.5kg.

If your baby weighs 4.5kg or more at birth, they are considered larger than normal. This is also known as 'fetal macrosomia' and large for gestational age (LGA). (If they weigh less than 2.5kg, they may be considered smaller than normal. )

How is a baby's size measured?

During routine antenatal check-ups, your doctor or midwife may estimate the growth and size of your baby by measuring the 'fundal height'. That is the measurement from your pubic bone to the top of your uterus.

An ultrasound can also give health professionals an idea of how big your baby is likely to be, but it's not very accurate.

Your doctor may also check the level of amniotic fluid. Excessive amniotic fluid, which surrounds the baby in the womb, can indicate the baby is larger than average, since larger babies can produce more urine.

However, there's no way of reliably measuring your baby's weight until after they are born. In many cases, women who are told they're going to have a large baby actually give birth to a baby within the normal range.

Why is my baby big?

A baby may be large at birth due to genetic factors, the mother's health or, in rare cases, a medical condition that causes the fetus to grow too quickly.

Several factors can contribute to large birth weight. For example:

the baby's parents' height and stature
if the baby is a boy (baby boys tend to be larger than baby girls)
having older siblings (the chance of fetal macrosomia increases with each pregnancy)
a previous pregnancy in which the baby was large
being overdue by more than 2 weeks
if the mother has diabetes during pregnancy
if the mother gains a lot of weight during pregnancy or is obese
if the mother is aged 30 or older

In some cases, larger-than-normal birth weight doesn't have a clear cause and can't be explained.

Giving birth to a large baby

Most large babies who weigh more than 4.5kg do not have a difficult birth. But there are still some risks associated with having a big baby.

Labour may take longer and be more likely to involve complications. There's an increased risk of having a forceps or vacuum-assisted delivery or a caesarean, and of birth injury to the mother or baby.

There is a link between fetal macrosomia and shoulder dystocia. Shoulder dystocia occurs during a vaginal birth when the baby's head has been born, but one of the shoulders becomes stuck behind the mother's pelvic bone. The baby's shoulders need to be released quickly so the baby's body can also be born, and they can start breathing.

Shoulder dystocia can happen during any birth. At least half of all babies who experience shoulder dystocia at birth weigh less than 4kg.

Large babies can be born via a normal, vaginal delivery — but it's best to give birth where you can access specialist medical services, just in case things don't go according to plan. Every pregnancy and birth is unique, so talk to your doctor or midwife about the best place for you to give birth.

After the birth of a large baby

Since many large babies are born to mothers with diabetes, some babies will need help regulating their blood sugar after they're born. Later in life, the risk of childhood obesity or being overweight may increase and the baby may develop other problems with their metabolism.

A larger than average baby may need help breathing following the birth, so they may be admitted to the neonatal intensive care unit (NICU) or special care nursery (SCN).

There is also an increased risk of jaundice (yellowing of the skin) among large babies.

Regardless of their size at birth, a baby's weight is always monitored closely after they are born to make sure they are healthy and growing properly. But their weight isn't the only thing that's important. How well they are feeding and the number of wet nappies and poos they produce daily can also indicate that your baby is doing well.

Can you avoid having a large baby?

Often there's nothing you can do to avoid having a large or small baby. But looking after yourself during pregnancy is important for all women. You should consider:

giving up smoking (if you currently smoke)
eating a balanced, healthy diet
maintaining your weight or, if overweight, losing weight before conception if possible
if you have diabetes, trying to manage it properly
avoiding alcohol and illegal drugs

Where to seek help

Always talk to your doctor, obstetrician or midwife first if you are concerned about your pregnancy, your own health or the health of your baby.

If you are worried about your baby's growth — or how fetal macrosomia might affect you as a mum — call Pregnancy, Birth and Baby on 1800 882 436 to speak to a maternal child health nurse.

Sources:

Australian Institute of Health and Welfare (Australia's mothers and babies data visualisations), South Australian Perinatal Practice Guidelines (Fetal growth – accelerated), Department of Health (Clinical practice guidelines: Pregnancy care), health.vic (Gestational diabetes), The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (Shoulder dystocia)

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: September 2020

Labour complications
Guide to a healthy pregnancy
Pre-existing diabetes and pregnancy
Gestational diabetes
Weight gain in pregnancy
Check-ups, tests and scans available during your pregnancy
Routine antenatal tests
Having a small baby

This information is for your general information and use only and is not intended to be used as medical advice and should not be used to diagnose, treat, cure or prevent any medical condition, nor should it be used for therapeutic purposes.

The information is not a substitute for independent professional advice and should not be used as an alternative to professional health care. If you have a particular medical problem, please consult a healthcare professional.

Except as permitted under the Copyright Act 1968, this publication or any part of it may not be reproduced, altered, adapted, stored and/or distributed in any form or by any means without the prior written permission of Healthdirect Australia.

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Exercise During Pregnancy for Smaller Baby

Moderate Exercise During Pregnancy Lowers Baby's Birth Weight, May Reduce Baby's Risk of Obesity

Written by Kathleen Doheny

April 5, 2010 -- Women who exercise moderately during pregnancy give birth to somewhat smaller babies, which may reduce the infants' obesity risk later, according to a new study.

The average birth weight of babies born to exercising mothers was lower but still very healthy.

The average birth weight of babies born to mothers who exercised was 7.5 pounds, compared to 7.8 pounds for mothers who did not exercise, says a team of researchers from New Zealand and the U.S. Babies born weighing 8.8 pounds or more are defined as high birth weight.

At the two-week checkup, the babies of exercising moms averaged 8.1 pounds; the babies of sedentary moms averaged 8.6 pounds.

"We would suggest this study support the recommendations of at least 30 minutes of moderate exercise daily and probably more," says study co-author Paul Hofman, MD, a researcher at the University of Auckland in New Zealand. The study is published in the Journal of Clinical Endocrinology & Metabolism.

The new research follows a recent study finding that three out of four pregnant women in the U.S. do not get enough exercise.

Exercise During Pregnancy: The Study

Hofman and his colleagues assigned 84 women pregnant with their first child to an exercise group or a control group. Women in the exercise group rode stationary bikes at home at a moderate intensity for 40 minutes, 5 times a week maximum, beginning at 20 weeks into the pregnancy and continuing until about week 36.

Women in the control group were instructed to continue their normal daily activities during the same time periods.

Women in both groups had, on average, a healthy body weight before pregnancy and were similar in other regards such as age and ethnicity.

Exercise During Pregnancy: Results

The babies born to the exercisers had a lower body weight and a lower body mass index or BMI.

There were no differences in the length of the babies, on average, between exercisers and non-exercisers. The exercise didn't affect the length of the pregnancy, either, or the mothers’ weight.

Exactly why the exercising mothers produced smaller babies isn't known, says study co-author Chris Baldi, PhD, an assistant professor of biological sciences at Northern Arizona University, Flagstaff.

Researchers initially believed the exercising mothers would become less insulin-resistant. Typically, Baldi says, a woman becomes more insulin-resistant during pregnancy, a normal occurrence within certain boundaries. "It has a lot to do with hormonal changes," he says. If a woman becomes too insulin-resistant, gestational diabetes can occur.

"It did not come out as we suspected," Baldi tells WebMD, with no substantial differences found in insulin resistance between the two groups.

The difference, says Baldi and Hofman, may be because of other factors, such as differences found in certain growth factors. Another possible explanation, Hofman says, is slightly reduced blood flow that occurs to the placenta during exercise and for several hours afterward.

Exercise During Pregnancy: Other Input

The finding of lower birth weights of infants of exercising mothers is not surprising to Linda May, PhD, an associate professor of anatomy at the Kansas City University of Medicine and Biosciences in Kansas City, Mo., who has also researched the topic.

The finding that there was no change in insulin sensitivity between groups was surprising, she tells WebMD.

Her research has found that during pregnancy, more exercise [within recommended amounts for an individual] yields more benefits.

More study is needed on high-risk pregnant women, Hofman and May say. The women in the study, exercisers and non-exercisers, were not high risk.

For most healthy pregnant women, Hofman says, the research seems to support exercising at least 30 minutes a day moderately, and probably more. Some studies, he says, have demonstrated up to 60 minutes daily is generally safe.

the less the better?

9 months Mother and child

You can often hear from pregnant women that they are afraid to "feed" the baby and it is desirable that the weight of the baby be less before childbirth - so, they say, it will be easier to give birth, and there will be more chances not to break. But is it so unequivocally good if the baby weighs a little at the time of birth and what are the criteria for the normal weight of the child at birth?

“If I were a queen,” the third girl said, “I would give birth to a hero for the father-king,” these lines of the classic are still relevant today. The first question asked by happy dads and grandparents after giving birth: “What is the weight and height?” Moreover, “heroic” parameters are always perceived as an indisputable merit of the mother and a sign of the baby’s health, and the modest size of the newborn disappoints the male half of the family. Newly-made grandmothers and aunts also ask about the baby’s weight, but their reaction to the heroic data of a new family member is usually the opposite: they express sympathy for the mother and clarify whether everything is fine with her and the baby’s health after such “heroic” childbirth. If the newborn turns out to be miniature, the female half of the family sincerely rejoices for him and for his mother and congratulates him on an easy birth!

So, among mothers - both experienced and future - there is a strong opinion that the lower the weight of the child, the better for childbirth. Let's try to figure out how true this is, whether low weight is always a sign of the baby's health and a guarantee of easy childbirth, what determines the weight of the fetus at the time of the onset of labor and whether it can be influenced, how the weight of the baby affects the various stages of childbirth and what is more important in assessing the size fetus - weight or other factors?

Does “less” always mean “better”?

In fact, low birth weight - just like a large newborn - is not in itself a criterion for a baby's health. And it does not necessarily guarantee an easy birth.

►Often, low weight is the result of a lack of nutrition of the fetus during fetal development. If the mother is healthy, lives in normal conditions and eats normally, there can be only one reason for malnutrition of the child: reduced transport of nutrients in the blood due to impaired blood circulation between mother and baby at the level of placental vessels. And then, in addition to low weight, the crumbs may have another problem - chronic hypoxia , a long-standing and prolonged lack of oxygen: after all, the baby receives both oxygen and nutrients in the same way - they come to him from the mother's body through the placental blood flow. That is why doctors monitor the baby's weight gain and assess the compliance of its size with the norms for the gestational age at each ultrasound examination: a lag in growth and weight may be the first indication of a deterioration in placental circulation and the development of fetal hypoxia.

►Another problem of low birth weight is related directly to the process of childbirth itself: births with small fetuses are often quick and even rapid, since a small child encounters less resistance from the walls of the birth canal. And this, oddly enough, is the problem: fast, and especially rapid, births are often accompanied by significant ruptures of the soft tissues of the birth canal, since they simply do not have time to stretch with its rapid progress. It's dangerous for a baby0015 birth injuries , and for the mother - bleeding from tears and severe pain of contractions : when the intensity of contractions necessary for the birth of a child increases in three hours instead of twelve, the nervous system of the woman in labor simply does not have time to adapt to increased pain.

At the end of the last - the beginning of this century, when imported multivitamin complexes first appeared in Russian pharmacies, the number of newborns weighing more than four kilograms increased by 30%.

Is it possible to feed the baby?

►How often the mother of a “hero” has to hear from those around her: “Well, mommy, apparently she ate well - she fed the baby so much!” The essence of this popular statement boils down to the fact that the abundant nutrition of the mother directly affects the large weight of the child (large fetus) at the time of birth. It turns out that the mother herself is “to blame” for the heroic size of her child and the reason for the large weight of the newborn is malnutrition during pregnancy. In this sense, the statement is incorrect: there is no direct digestive tube between the body of the mother and the baby. The food consumed by a pregnant woman decomposes in the digestive tract to proteins, fats and carbohydrates, and even from these end products only what the body needs for energy metabolism is absorbed, because our body must spend a lot of energy on processing and assimilation of nutrients, and it extremely economical and will not waste energy in vain! Those micro- and macro-elements from the food received by the mother, which the baby really needs, are absorbed into the mother's bloodstream and delivered to the baby through the vessels of the placenta and umbilical cord. Surplus food is ejected from the mother's body through the intestines, some is deposited in the form of "rainy day reserves" in adipose tissue.

Every seventh child in the world is born weighing less than 2.5 kg - new study |

May 16, 2019 Health

Every seventh child in the world is born with low birth weight. So, in 2015, according to a study conducted by the United Nations Children's Fund (UNICEF), the World Health Organization (WHO) and the London School of Hygiene and Tropical Medicine, more than 20 million babies weighing less than 2.5 kilograms were born.

Two thirds of these children were born in South Asia and Africa. However, according to experts, the problem of low birth weight exists in Europe, North America, Australia and New Zealand. Between 2000 and 2015, these states failed to make progress in reducing this rate.

“Over 15 years, we have seen almost no change, even in high-income countries where low birth weight is commonly associated with preterm birth, age of mothers, smoking, unmedicated caesarean section, and infertility treatment programs that lead to multiple pregnancies,” says Hannah Blencowie of the London School of Hygiene.

In poor countries, the study reports, the main reason for the birth of children with low birth weight is the developmental delay of the fetus in the womb. The weight of the unborn child is also affected by infectious diseases during pregnancy, chronic diseases of the mother, diet and ecology.

The study was conducted in 148 countries of the world among tens of millions of newborns. At the same time, in 47 countries, the experts were not able to access all the necessary data - some of them were missing. The authors of the study remind that the collection of information is the first step towards solving the problem of low weight in infants.

“In theory, every newborn should be weighed. In the meantime, we have no data on the weight of almost a third of babies. We will not be able to help them if we do not have accurate data on their condition,” said UNICEF representative Julia Krasevets.

According to the study, 2.5 million babies die every year worldwide, 80 percent of them are low birth weight babies.