Use of different methods of detecting if a baby is large-for-gestational-age, to improve health outcomes

What is the issue?

A baby may sometimes grow to be bigger than expected and be born with a high birthweight. When overgrowth of the baby is suspected during a pregnancy the mother can have extra scheduled antenatal visits and tests to assess her health and the health of her developing baby.

Why is this important?

Tests can detect if there are signs of any deterioration in the baby’s condition, or development of complications in the mother. The specified frequency and combinations of tests vary with local protocols and policies. Tests may include fetal movement counting, fetal heart rate assessment (cardiotocography), checking the mother's blood sugars or the use of ultrasound for fetal growth scans, Doppler ultrasound examination of fetal blood vessels and assessing the volume of fluid around the baby.

Large babies are associated with increased risks to both the mother and baby, including increased risk of intra-uterine death and stillbirth. At birth the baby is at a higher risk of low oxygen levels, shoulder dystocia, nerve injuries, bone fracture, low blood sugar levels, and admission to the neonatal intensive care unit. Maternal complications include prolonged labour, operative births including caesarean section, perineal trauma, postpartum haemorrhage and uterine rupture.

Interventions that may slow growth acceleration and improve health outcomes for the mother and her baby include dietary advice, lifestyle modification, and in women with diabetes or gestational diabetes blood glucose monitoring and insulin therapy.

What evidence did we find?

We searched for studies on 10 August 2015 but did not find any randomised controlled trials looking at the effects of performing extra tests on health outcomes in pregnant women with overgrowth of the baby after 20 weeks gestation.

What does this mean?

There is a need for randomised controlled trials in this area in order to inform clinical practice when large babies are identified during a pregnancy, to assess if extra tests or surveillance can improve the health of these women and their babies. It is also important to identify any harms associated with extra tests and surveillance, as identifying women with suspected large babies may lead to unnecessary maternal anxiety with additional investigations and interventions, including induction of labour or caesarean section.

Authors' conclusions: 

We found no randomised controlled trials that assessed the effect of antenatal fetal surveillance regimens of a suspected LGA fetus on important health outcomes for the mother and baby.

There has been a rise in the prevalence of LGA babies over the past few decades in many countries. Research is therefore required on regimens of antenatal surveillance of suspected LGA infants, in order to guide practice and improve the health outcomes for the mother and infant. In particular, randomised control trials to investigate whether serial antenatal clinic and ultrasound assessments of suspected LGA infants (including liquor volume and markers of fetal adiposity) would be useful, to assess whether surveillance methods improve health outcomes. In addition, as there are concerns that identifying suspected LGA fetuses may lead to unnecessary maternal anxiety, investigations and interventions, any such trial would need to assess the risks as well as benefits of regimens of fetal surveillance for suspected LGA fetuses.

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Background: 

Policies and protocols vary widely for fetal surveillance in a pregnancy where the fetus is suspected to be large-for-gestational-age (LGA). All ultimately culminate in decisions about the mode and timing of birth. LGA is known to be associated with increased risks to both the mother and baby. Interventions based on surveillance regimen findings may be associated with risks to the mother and baby.

Objectives: 

To assess the effectiveness or efficacy of different antenatal surveillance methods for the suspected LGA fetus on important health outcomes for the mother and baby.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 August 2015), ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) (21 August 2015).

Selection criteria: 

Published and unpublished randomised, quasi-randomised and cluster-randomised trials comparing the effects of described antenatal fetal surveillance regimens for women with suspected LGA infants.

Data collection and analysis: 

We identified no studies that met the inclusion criteria for this review.

Main results: 

There are no included trials.

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