Fetal growth restriction (Intrauterine growth restriction)

Fetal growth restriction (FGR) is a condition where a baby is smaller than expected or when a baby's growth slows or stops during pregnancy. It is also called intrauterine growth restriction (IUGR).

Babies are sometimes called small for gestational age (SGA) or small for dates (SFD). Most babies that are smaller than expected will be healthy. But up to 10% of pregnancies will be affected by FGR and will need close monitoring during pregnancy. In some cases, you may need to give birth earlier than expected.

What causes FGR?

FGR can happen when the placenta is not working well enough to provide the baby with the nutrients they need to grow normally. However, we don’t always know why FGR happens.

Sometimes it can be caused by other conditions, such as chromosomal problems or infections, such as cytomegalovirus or toxoplasmosis.

Is there anything that increases the risk of FGR?

There are several things that can increase the risk of FGR. The most common risks are:

If you have any bleeding during your pregnancy, with or without pain, it’s very important to get it checked out.

What does FGR mean for my baby?

If your baby has FGR, there is an increased risk of complications in pregnancy. Sadly, this can include stillbirth. But your healthcare team will monitor the baby’s growth and wellbeing closely to reduce the risk of this happening. They will also talk to you about the best time for you to give birth. This is likely to be earlier than your due date.

Being born early and small can also lead to complications after birth. This includes a higher risk of high blood pressure, coronary artery disease, type 2 diabetes and thyroid disease in later life. Some babies may need to spend time on a specialist baby unit (Neonatal Intensive Care Unit or NICU).

However, after your baby is born, their growth will not be typically different from other children. Having FGR does not mean they will be smaller than other children when they are school age.

Can I do anything to reduce the risk?

We don’t know why some pregnancies are affected by FGR and some are not. But it is unlikely to be related to anything you have done before or during pregnancy. It is important not to blame yourself.

“I was told by well-intentioned but not medically trained friends to eat more calories, sleep as much as I could and stop worrying, because the worry would be having an impact on my baby’s personality and growth! To my knowledge these comments offer no real help to anyone experiencing this. The best thing to do is to listen to the medical professionals in charge of your care.”

Laura

Some things that increase your risk of having a small baby can’t be changed. But there are some things you can do to reduce the risk, including:

If you are overweight, you are more likely to develop high blood pressure, which can cause complications leading to problems with the baby’s growth. It can help to maintain a healthy weight before and during pregnancy.

High levels of caffeine in pregnancy has been linked to low birthweight, as well as miscarriage. Try to limit your caffeine to 200 milligrams (mg) a day. This is about the same as 2 mugs of instant coffee. Use our caffeine calculator to check your caffeine intake.

If you are considered at risk of FGR

If you are considered at risk of being affected by FGR , your healthcare team may recommend that you take low-dose aspirin (150mg) at night from 12 weeks of pregnancy until 36 weeks.

How will I know if my baby isn’t growing well?

If you have no risk factors for FGR identified in early pregnancy, your midwife will start to measure your bump from 24 weeks, during your routine antenatal appointments, to check that your baby is growing well. This is a simple test using a tape measure. They will measure your bump from the top of the uterus (womb) to your pubic bone. The measurement should then be plotted on a growth chart in your personal maternity record. If your midwife has any concerns about the baby’s growth from this measurement, you will be referred for an ultrasound scan within 72 hours. This does not necessarily mean something is wrong. The scan is just a more accurate way of assessing the baby's growth.

If you have any risk factors for FGR, the growth of your baby will be monitored by ultrasound scans instead of using a tape measure.

Depending on your medical and pregnancy history, you may also be referred for an ultrasound scan to measure the blood flow to your placenta (this is known as the uterine artery Doppler). This measurement is done at 20–24 weeks of pregnancy. It will determine how often you will need to have ultrasound scans during your pregnancy.

What do I do if I’m worried that my bump isn’t getting bigger?

Baby bumps come in all different shapes and sizes. Although it can be difficult, try not to compare your baby bump to anyone else’s. No two women or two pregnancies are the same. If you are concerned, you can call your midwife at any time.

What happens if my baby is small or not growing?

If your midwife or doctor thinks your baby might have FGR, you will be referred for an ultrasound scan to assess the growth of your baby. During this scan, there will be other tests to check the wellbeing of your baby. These include an assessment of the blood flow through the umbilical cord between the placenta and the baby (umbilical artery Doppler) and an assessment of the fluid around the baby (liquor volume).

Following this assessment, you will be advised how your baby is growing. If it is confirmed that your baby has FGR, you will need further scans to monitor the pregnancy more closely until your baby is born. The frequency of these scans will depend on the size of your baby and blood flow measurements in the umbilical artery. You may also be asked to have a tracing of your baby’s heart rate, known as a cardiotocograph (CTG). Your healthcare team may also discuss the benefit of delivering your baby before your estimated due date (EDD).

If the umbilical artery Doppler test is abnormal, you may also be referred for a more detailed scan with a fetal medicine specialist.

Monitoring your baby’s movements

It’s very important to monitor your baby’s movements during pregnancy. Most women usually begin to feel their baby move between 16 and 24 weeks of pregnancy. A baby’s movement can be described as anything from a kick, flutter, swish or roll. There is no set number of normal movements. If you think that your baby’s movements have slowed down or stopped, it is important that you contact your maternity unit immediately. There is always a midwife available 24 hours a day. Do not wait until the next day to seek advice. This is particularly important if there are concerns about your baby’s growth during pregnancy.

Find out more about your baby’s movements in pregnancy.

Will FGR affect how I give birth?

The majority of women who want one will be able to try for a vaginal birth, if there are no other complications. But it is likely that you will be advised to give birth early. This may just be a week earlier than your expected date of delivery or it may be several weeks before, depending on how your baby is. Some babies may be too small to go through labour and a vaginal delivery, so you may be advised to have a caesarean section. Your healthcare professional will talk to you about what they think is best.

You may be advised to have your baby in a hospital where there is a specialist baby unit (Neonatal Intensive Care Unit or NICU). This is because your baby may need extra care, especially if they are very small and born early (prematurely). Not all small babies will need to go to NICU.

Depending on when and how you are going to have your baby, you may be offered steroids to help your baby’s lung development and reduce the chance of breathing problems after birth. You may also be offered magnesium sulphate, which is a medicine given before delivery to reduce the risk of cerebral palsy.

Will FGR affect my next pregnancy?

If you get pregnant again, the risk of having a small baby again is slightly higher. But you may be able to reduce your risk by trying to live a healthy lifestyle.[SS28]  It can help to:

In your next pregnancy, your doctor may recommend that you take low-dose aspirin (150mg) at night from 12 weeks of pregnancy.

Try not to worry too much if you want to get pregnant again. Your care will likely depend on what risk factors you have, but if you’ve had a small baby before, your healthcare team will monitor you closely during your next pregnancy.

If you need someone to talk to, call our midwives pregnancy line on 0800 014 7800 (Monday to Friday, 9am to 5pm), or email [email protected].

Stories about fetal growth restriction

Sources

Nardozza, L.M.M., Caetano, A.C.R., Zamarian, A.C.P. et al. Fetal growth restriction: current knowledge. Arch Gynecology and Obstetrics 295, 1061–1077 (2017). https://doi.org/10.1007/s00404-017-4341-9 https://link.springer.com/article/10.1007/s00404-017-4341-9

Royal College of Obstetricians & Gynaecologists (2013) The Investigation and Management of the Small-For-Gestational-Age Fetus https://www.rcog.org.uk/globalassets/documents/guidelines/gtg_31.pdf

The Shrewsbury and Telford Hospital NHS Trust. If your baby is not growing as well as expected. (Last reviewed December 2014 Next review due December 2017)

NHS Choices. Should I limit caffeine in pregnancy? https://www.nhs.uk/common-health-questions/pregnancy/should-i-limit-caffeine-during-pregnancy/ (Last reviewed 02/05/2018 Next review due 02/05/2021)

NICE (2015). Antenatal care for uncomplicated pregnancy. National Institute for health and care excellence https://www.nice.org.uk/guidance/cg62

Southend University Hospital NHS Foundation Trust. Small baby and intrauterine growth restriction (Last reviewed October 2015 Next review due October 2017)

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    Last reviewed on May 29th, 2020. Next review date May 29th, 2023.

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    Comments

    Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.
    • By Emma (not verified) on 26 Mar 2017 - 00:46

      Hi, my son was born via emergency c-section due to my severe preeclampsia at 31+4 on 1/1/17. He weighed 2lbs 13oz at birth and I was told the placenta was 1/3 of the size it should be.

      After the 20week scan of pregancy I had to go for regular growth scans- 2 to 3 weekly as he was measuring small, My question is..
      No one has ever mentioned IUGR to me but it seems to be exactly what me and my son went through. Would this affect him in his life outside the womb? and is it something I should bring up with the GP? Thanks

    • By Midwife @Tommys on 27 Mar 2017 - 10:13

      Hi Emma,
      This is outside our remit as midwives so I don't really know the full answer to your question I am afraid.
      I would certainly tell your GP and Health Visitor about the IUGR you and your son experienced during pregnancy so that they can keep a closer eye on his progress as he grows and develops.
      Take good care of yourself and your little man, Emma!

    • By themba (not verified) on 19 Mar 2017 - 10:52

      hello there...my name is Themba and I'm worried since me and my girlfriend are expecting a baby.She is 9 months pregnant now and the baby is too small so she cant deliver since the child is small.So id like to know what is it that oftenly happens when the baby isn't growing and what can we do in order for our baby to grow because at hospital they give her medication and injection to help the baby to grow but my concern is its now the 9th month

    • By Midwife @Tommys on 20 Mar 2017 - 09:41

      Hi Themba.
      Without knowing your girlfriends full medical history it is a little difficult to fully understand your case. Your baby needs to be closely monitored by the midwife and obstetric dr's caring for your girlfriend. It would be sensible to visit your doctor/midwife as soon as possible if you are concerned about either of their health. Please take care of yourself.

    • By Midwife @Tommys on 22 Sep 2016 - 10:21

      We are very sorry to hear about William and hope our information can give you some understanding of what happened. Thank you for your feedback. Best wishes from all at Tommy's.

    • By Anonymous (not verified) on 21 Sep 2016 - 17:06

      I found this page informative and easy to follow. I wish I had known about it when I was diagnosed with placenta problems which
      led to William being growth restricted and eventually stillborn. I feel it was never fully explained to me at the time and I was told all it meant was I needed more monitoring and that I would not be going to term.

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