Fetal growth restriction (FGR)
Fetal growth restriction (FGR) is a common pregnancy complication where an unborn baby fails to thrive.
FGR can put babies at risk of cardiovascular disease, lung and brain injury and life-long problems like cerebral palsy, autism, learning and other behavioural dysfunctions.
What is FGR?
FGR, sometimes called intrauterine growth restriction (IUGR), is a condition where an unborn baby, or fetus, is smaller than expected according to the stage of the mother’s pregnancy. There are two types of IUGR
- Symmetrical FGR – all parts of the body are a similar small size.
- Asymmetrical IUGR – the head and brain are a normal size, but the rest of the body is small.
FGR can begin at any time during pregnancy, and puts babies at risk of lung, cardiovascular and brain damage which can cause the child long-term problems in later life such as cerebral palsy, autism, learning and other behavioural challenges.
What causes FGR?
FGR is predominantly caused by a problem with the placenta – the organ that delivers nutrients and oxygen to the developing baby during pregnancy.
In FGR, the placenta fails to deliver the required oxygen and nutrients to a baby in the womb, resulting in poor growth of the baby. The reduced oxygen supply to the unborn baby also causes oxidative stress and inflammation which can injure a developing brain in the weeks prior to birth.
What are FGR risk factors?
The biggest risk factor for FGR, which a mother cannot influence, is placental insufficiency. If a woman has had a previous FGR pregnancy, she is at increased risk of a future FGR pregnancy.
Other maternal factors that increase the likelihood of FGR include
- Maternal obesity
- Smoking, drinking alcohol or using illegal drugs
- Some medicines
- Having an existing medical condition eg; high blood pressure, heart disease, diabetes
- Carrying multiples eg; twins, triplets
- Conceiving within 18 months of a previous birth
- Having previously had a small baby or stillbirth
- Being under 17 or over 35 years of age
- Having pregnancy complications eg; preeclampsia, heavy bleeding.
While some of these factors can’t be changed, pregnant women can reduce the risk of FGR by stopping smoking, eating a healthy and balanced diet, not drinking alcohol, not using illegal drugs and maintaining a healthy weight.
Uterine/placental FGR risk factors include
- Decreased blood flow in the uterus and placenta
- Detachment of the placenta from the uterus
- The placenta attaching too low in the uterus
- Infection in tissues around the fetus.
More than one in seven or 20,000 Australian babies are born with FGR each year and up to 20 per cent of babies born globally are affected by FGR.
In addition, FGR increases the risk of stillbirth 20-fold and is a principal cause of perinatal death or preterm birth in survivors.
Our fetal growth restriction (FGR) research
The period from conception through to neonatal life is critical in determining the health of a baby and subsequent life-long health.
Our FGR researchers aim to improve health outcomes for women and babies by investigating how maternal and fetal treatments including nutrition and the intrauterine environment affect growth, development and long-term health.
Hudson Institute scientists work in close collaboration with Monash Health clinicians who treat women and babies affected by FGR.
Improving the transition at birth in newborns with growth restriction.
Clinical practice. Professor Graeme Polglase’s project aims to determine the cardiovascular adaptations that a growth restricted fetus takes to survive chronic hypoxia, and how this alters the cardiovascular transition at birth, making the newborn prone to cardiovascular disease and brain injury. The team also aim to identify strategies to improve cardiovascular function in growth restricted newborns.
Improving functional deficits associated with fetal growth restriction
New treatment. Professor Suzanne Miller’s project is examining treatment strategies that will help improve the structure and function of the developing brain.
Several different neuroprotective strategies are under investigation that could be used during pregnancy (antenatally) or after birth (postnatally) that aim to optimise a developing baby’s brain development. The treatments include antioxidants, anti-inflammatory compounds and cord blood stem cells.
Investigating the effect of birth asphyxia in growth restricted newborns.
Clinical practice. The aim of this project is to develop strategies to protect the growth restricted newborn from the consequences of perinatal asphyxia – a common comorbidity.
Professor Graeme Polglase is investigating the unique physiological response to perinatal asphyxia and developing potential treatments, including beta blockers and physiological-based cord clamping, to reduce morbidities associated with perinatal asphyxia in growth restricted newborns.
Early diagnosis of brain injury associated with FGR
Early detection. Imaging. Professor Suzanne Miller and A/Professor Atul Malhotra are using advanced imaging techniques such as magnetic resonance imaging (MRI) scans to detect subtle brain injury associated with FGR. A/Prof Malhotra is a consultant neonatologist at Monash Children’s Hospital and an Honorary Clinical Associate at Hudson Institute’s Ritchie Centre.
In preclinical research, Prof Miller and A/Prof Malhotra have shown that advanced MRI techniques can detect altered brain organisation in the FGR brain. The team are now translating this into early detection of subtle brain changes in human infants.
Assessing antenatal maternal melatonin supplementation for fetal neuroprotection in early-onset FGR
Clinical trial protocol. Melatonin is a powerful antioxidant that can reduce oxidative stress. In a clinical trial pregnant women with a growth restricted fetus are taking melatonin to determine if it can protect at-risk babies’ developing brains.
Professor Suzanne Miller is working with collaborators in the trial including Dr Kirsten Palmer, Monash Health along with hospitals across Australia and New Zealand.
The effects of FGR on the developing preterm lung and cardiovascular system
Structure and function. Dr Beth Allison and Professor Suzanne Miller are investigating the effect of FGR on development of the preterm lung, heart and cardiovascular system.
The project goal is to identify the mechanisms that alter organ development in utero and how growth restricted babies respond to various treatments after birth.
Dr Allison and the team are working to understand whether newborn growth restrictions respond similarly to ‘well-grown’ babies, to ensure that those particularly vulnerable receive the most suitable treatments.
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