Can My Baby Lose Weight In The Womb

What does low birth weight mean?During pregnancy, your midwife will assess how much your baby is growing by estimating their size and weight. If your baby measures less than other babies of the same sex, at the same stage of development, your midwife may describe them as having a low birth weight. This means your baby is likely to be smaller than other babies at birth.

Your baby has a low birth weight if they’re born after 37 weeks and weigh less than 2.5kg (5.5lb) (Cleary-Goldman & Robinson 2019, RCOG 2013). About seven in every 100 babies born in the UK have a low birth weight (ISD Scotland 2019, NISRA 2018, ONS 2017, 2019). Some, but not all, low birth weights are due to being born early or because the baby’s growth was restricted in the womb for some reason.

Traditionally, your baby was classed as small for gestational age if they were smaller than 90 per cent of other babies in the population at the same stage (RCOG 2013). It didn’t take into account your own size or your family history. That’s why midwives are now advised to use customised growth charts, which take into account your height and weight, your ethnic background, your baby’s sex and how many babies you’ve had before (RCOG 2013, 2014).

How To Lose Weight During Pregnancy

It’s not always easy for doctors and midwives to estimate the size of a baby in the womb (uterus). Your midwife will get an idea of your baby’s size in later pregnancy by measuring your bump and working out your fundal height. This is the measurement in centimetres from your pubic bone to the top of your womb. Fundal height usually equals the number of weeks that you’re pregnant, give or take 2cm (0.78in) either way (Divon 2019). So when you’re 32 weeks pregnant, your measurement should be somewhere between 30cm and 34cm (12 in and 13 in).

If this is your first baby, your midwife will do this from around 25 weeks. If you’ve had a baby before, it’ll happen at around 28 weeks.

Your fundal height will only give a rough idea of your baby's size and growth (Divon 2019, RCOG 2013). If your midwife is concerned, you’ll be referred on for an ultrasound scan, to check whether your baby really is on the small side or growing more slowly than they should (RCOG 2013).

Is My Baby's Weight Normal?

You’ll also be referred for a scan if your midwife can't get an accurate fundal height measurement. This may happen if you have a large fibroid or if you’re obese (RCOG 2013).What causes low birth weight?Some babies are just smaller than others. Your family background is really important here. Up to 70 per cent of babies who are classed as small for gestational age are growing appropriately, considering their ethnicity and mum’s size (Divon 2019, RCOG 2013). These babies are called constitutionally small.

Parents who are shorter and weigh less than the European average, or who were small at birth, may have smaller children (RCOG 2013).

In the UK, babies born to parents who are of Indian, Asian or black ethnic origin, are more likely to have a low birth weight than babies born to white or Chinese parents (NHS Digital 2019, RCOG 2013).

Baby Weight Chart Singapore: Guide To Newborn Weight Loss & Gain

At your booking appointment, your midwife will ask you lots of questions about you and your family’s medical history. This will help them to work out whether you’re at increased risk of having a baby with a low birth weight.

If your midwife is concerned, they’ll suggest you have extra monitoring and scans throughout your pregnancy, particularly between week 28 and week 36 (RCOG 2013).

There are many other health and lifestyle factors that can increase your risk of having a low-birth-weight baby, although not by as much as the factors listed above. These include: high caffeine consumption (more than 300mg a day in the third trimester), alcohol consumption, and heart disease (RCOG 2013). What tests or treatment will my baby and I have?What tests you are offered will depend on what your midwife or doctor knows so far. If your baby's growth appears to be severely restricted, you may be offered:

Newborn Weight Gains And Losses

If you’re thought to be carrying a baby who is small for gestational age and your labour starts naturally, your doctor may recommend that you go into the maternity unit when you’re in the early stages so your baby can be continuously monitored (Mandy 2019, RCOG 2013).What’s the outlook for my low-birth-weight baby?It depends on the cause of your baby’s size. If your baby is small but healthy, they’re not at increased risk of any complications (Mandy 2019, RCOG 2013, 2014).

If your baby’s growth has been restricted, there are increased risks depending on what’s caused the problem. That doesn't mean that your baby will have health problems. However, complications are more likely the earlier in pregnancy growth restriction starts, and the more severe it is (RCOG 2013, 2014). Babies who have growth problems later in pregnancy are likely to have fewer problems (RCOG 2014).

If your baby’s growth restriction was caused by infection or by developmental or genetic problems, it’s likely to have been picked up earlier in your pregnancy (Mandy 2019, RCOG 2014).

Baby Weight Chart: What's The Average Weight For A Newborn?

It's hard to predict how severely a baby may be affected. Some growth restricted babies will be born with disabilities or have developmental problems. Some babies do better than others in the long term, despite their difficult start to life (Mandy 2019). Sadly, however, some growth-restricted babies are at greater risk of serious illness after birth or even being stillborn (RCOG 2014). How can I help my low-birth-weight baby during pregnancy?There are positive steps you can take to help your baby have a healthy start, and you can begin straight away:

Healthy lifestyle changes will benefit your growing baby’s health. If you smoke, quitting during pregnancy will reduce the risk of your baby having a low birth weight (RCOG 2013, 2014, Sonerji and Beltran-Sanchez 2019). It’s best for your baby’s health to give up in the first trimester, but it’s never too late to stop smoking. If you can give up by 15 weeks, you reduce your risk of having a low-birth-weight baby to the same as a non-smoker (RCOG 2013).

Your midwife or GP can help you to stop smoking, and can give you information about local support groups. You can also call the free NHS Smokefree support service, which offers help via an app, email programme, text messages and more.

Postpartum Weight Loss: Tips For Losing The Baby Weight And Staying Healthy

Try not to overcook starchy foods, such as potatoes and bread. When starchy food is fried, baked, roasted or grilled at high temperatures, a natural chemical called acrylamide forms (FSA nd). Evidence suggests that eating a lot of acrylamide-rich food in pregnancy is associated with low birth weight (Zhan et al 2020). See how to reduce the levels of acrylamides in your diet.

Make sure you attend all your antenatal appointments with your midwife, so any potential problems can be picked up.Where can I get more help for my baby and me?Talk to your midwife, health visitor or doctor about any concerns you have about your pregnancy. And read our articles on:

The charity, Bliss, supports parents-to-be whose babies are likely to be born with a low birth weight. You can email them for support at hello@bliss.org.uk    

Understanding Baby Growth Charts

NISRA. 2018. PfG 2016-21 measurement annex - % babies born at a low birth weight. Northern Ireland Statistics and Research Agency. www.nisra.gov.uk [Accessed May 2020]

ONS. 2017. Birth characteristics in England and Wales 2016: percentage of babies remains unchanged since 2011. Office for National Statistics. www.ons.gov.uk [Accessed May 2020]

RCOG. 2013. The investigation and management of the small-for-gestational-age fetus. Minor revisions January 2014. Royal College of Obstetricians and Gynaecologists, Green-top guideline, 31. www.rcog.org.uk [Accessed May 2020]

Childhood Obesity Starts In The Womb?

Zhan Y, Xiao Y, Guan T, et al. 2020. Relationship between gestational acrylamide exposure and offspring's growth: a systematic review and meta-analysis of cohort studies. Public Health Nutr Online first: 30 ApAlthough I am a doctor, I am not your doctor. This information is for informational purposes only and should not substitute the advice from your healthcare professional. All kinds of exercise and dietary changes are potentially dangerous, and those who do not seek counsel from the appropriate health care authority assume the liability of any injury which may occur. Please read my full Disclaimer for more information. Also, this post may contain affiliate links: meaning I may receive a commission if you use them.

A 2015 systematic review and meta-analysis shows that women who lost weight during pregnancy have a 76% higher likelihood of having a small for gestational age baby (<10th percentile).

In general, an appropriate amount of weight gain is necessary to support your growing baby, regardless of your body mass index (BMI).

Rapid Weight Gain In Babies

With that said, if you were overweight prior to pregnancy, you may be able to gain less weight than recommended as long as your baby is growing appropriately.

Studies of overweight and obese women who experience gestational weight loss or inadequate weight gain (<11 lbs) demonstrate that the risks do not outweigh the benefits.

So all in all: The official recommendation from the American College of Obstetricians and Gynecologists (ACOG) is against intentional weight loss during

Is It Normal To Lose Weight During Pregnancy?