D1 At my Trust we use 2500g as our cut off for postnatal monitoring of growth restricted babies rather than below the 10th centile as we do not want to medicalise care for healthy babies. Is this appropriate?
Since gestational age is now routinely determined at the beginning of each pregnancy, the 2.5 kg cut off is no longer useful, as it mixes up smallness due to immaturity, constitutional factors, and growth restriction. The term ‘small for gestational age’ (SGA) gets around this problem by adjusting the fetal or neonatal size according to the gestational age, with the usual cut-off being the 10 centile, and this limit is further refined by using the customised GROW (gestation related optimal weight) standard. See GAP Guidance.
D2 How do we calculate a customised birth weight centile?
The customised birth weight centile is calculated using any of the GROW software options (GROW-App, GROW-Centile of GROW-API). The date of birth, gender and birth weight of the baby is entered. If your hospital is using the GROW-App or GROW-API it will also ask you some additional questions: Unit responsible for providing antenatal care Outcome (whether the baby was a live birth or stillbirth) Referral for suspected fetal growth restriction, based on fundal height measurement(s) Detection of small for gestational age or fetal growth restriction (based on ultrasound scan) This information is used to provide individual Trusts/hospitals with reports on FGR, referral and detection rates.
D3 We plot the birth weight onto the GROW chart to identify the birthweight centile- is this accurate?
The term optimal weight (TOW) when creating a chart is calculated without taking the sex of the baby into account. Once the baby is born and the sex confirmed the centile can be generated and used to populate Trusts referral and detection of SGA reports. Plotting the birth weight onto the gender neutral chart may not accurately represent the centile.
D4 How do I calculate birthweight centiles in a twin pregnancy?
Centiles can be created in GROW 2.0 for each twin by entering the relevant details when prompted for each baby in the birth weight centile section of the mother record.