Introduction (400 words)
Large-for-gestational-age (LGA) is variously defined as weighing over 4000 grams, 4500 grams, or over the 90th customized weight for gestational age centile1, 2. It affects about 10% of all pregnancies.3 Birth of LGA foetuses has a greater risk of complications including birth trauma, to the foetus specifically, from shoulder dystocia which can lead to fractures, brachial plexus injury, perinatal asphyxia, and death, and to the mother of vaginal tears, haemorrhage, and caesarean section.2A Cochrane review shows that compared with expectant management, early induction reduces the risk of shoulder dystocia and fractures.4 A large clinical trial of LGA foetuses underway in the United Kingdom is also actively exploring whether early induction of labour starting at 38 weeks will provide perinatal benefits to the foetus and mother.5
However, there is emerging evidence showing that early-term birth (37+0-38+6 gestational weeks) may be associated with reduced cognitive abilities or increased learning problems in childhood.6-10 Sixteen to 31% of the population are delivered between 37 to 39 gestational weeks,11, 12 and a high number of special education needs (SEN) cases may be attributed to early-term birth. Even small decreases in cognitive scores can have a marked impact on a child’s ability to learn and perform academically at school,13and the effects can persist into adulthood,14, 15bringing with them issues of work status and income-earning capacity.16, 17 The latest UK NHS guidance (2019) warns of increasing amounts of SEN attributed to early-term births.18
Considering the adverse effects on cognitive abilities may be confined to children born with growth restriction, an established risk factor for cognitive impairment from childhood into adulthood19, in LGA babies, it is still unclear whether by avoiding one risk (e.g. shoulder dystocia) we may increase another risk for reduced cognitive or academic abilities. To date, there are no systematic reviews assessing the association between LGA babies born at early-term and cognitive or academic abilities. Existing systematic reviews exploring the effects of only early-term births on cognitive or academic outcomes do not provide estimation for each specific week of pregnancy, which is crucial to induction timing selection.6-10, 20
We aimed to systematically review the available evidence on the cognitive effects of early-term delivery in LGA babies. However, if we are unable to find enough existing studies, then instead we will review the effects of early-term birth and LGA on outcomes independently.