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Big Baby 2 Up

24-month infant follow-up, as part of the ‘Induction of labour for predicted macrosomia - ‘The Big Baby Trial’.

The Big Baby Trial was designed to investigate if early induction of labour reduces the incidence of shoulder dystocia in cases of suspected fetal macrosomia (a baby over the 90th centile on the fetal growth chart). As The Big Baby Trial was getting underway, evidence emerged linking some cognitive deficits (for example, the development of reading and language skills) in babies born one or two-weeks from full term , but it is not known whether this effects bigger babies in the same way. In this sub-study we will assess cognitive and language function of babies born to women participating in The Big Baby Trial when they reach 24-months of age. This will be assessed via the PARCA-R (Parent Report of Children’s Abilities-Revised) questionnaire (

It is important that pregnant women, their partners, midwives and obstetricians have evidence-based information to be able to discuss and make informed decisions about the timing of birth if their baby is predicted to be above the 90th centile on fetal growth chart and balance the risk of stillbirth, shoulder dystocia, maternal and neonatal morbidity, and babies longer-term cognitive function.

Women who participated in The Big Baby Trial and gave their consent to be contacted about participation in further research will be approached.

Research Questions

Primary research question

  • In babies with suspected macrosomia antenatally, does near-term delivery effect non-verbal cognition and language development, as measured by the Parent Report of Children’s Ability-Revised (PARCA-R), at 24 months?

Secondary research questions

  • In infants with suspected macrosomia does induction at 38+0 - 38+4 weeks, when compared to expectant management, affect cognitive function (non-verbal cognition; language development) at 24 months?
  • In babies with suspected macrosomia does gestational age at the time of birth, weight centile, mode of delivery (normal vaginal delivery, assisted delivery, caesarean section (elective / emergency)) and exclusive breast feeding predict cognitive function at 24 months?
  • What are the costs and health consequences of near-term delivery in macrosomic babies?

Sample Size

1500 participants.

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