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Low glycaemic index diet in pregnancy to prevent macrosomia (ROLO study): randomised control trial

BMJ 2012; 345 doi: (Published 30 August 2012) Cite this as: BMJ 2012;345:e5605
  1. Jennifer M Walsh, clinical research fellow, specialist registrar in obstetrics and gynaecology,
  2. Ciara A McGowan, research dietician,
  3. Rhona Mahony, consultant obstetrician and gynaecologist,
  4. Michael E Foley, consultant obstetrician and gynaecologist,
  5. Fionnuala M McAuliffe, professor of obstetrics and gynaecology
  1. 1UCD Obstetrics and Gynaecology, School of Medicine and Medical Science, University College Dublin, National Maternity Hospital, Dublin, Ireland.
  1. Correspondence to: F McAuliffe fionnuala.mcauliffe{at}
  • Accepted 1 August 2012


Objective To determine if a low glycaemic index diet in pregnancy could reduce the incidence of macrosomia in an at risk group.

Design Randomised controlled trial.

Setting Maternity hospital in Dublin, Ireland.

Participants 800 women without diabetes, all in their second pregnancy between January 2007 to January 2011, having previously delivered an infant weighing greater than 4 kg.

Intervention Women were randomised to receive no dietary intervention or start on a low glycaemic index diet from early pregnancy.

Main outcomes The primary outcome measure was difference in birth weight. The secondary outcome measure was difference in gestational weight gain.

Results No significant difference was seen between the two groups in absolute birth weight, birthweight centile, or ponderal index. Significantly less gestational weight gain occurred in women in the intervention arm (12.2 v 13.7 kg; mean difference −1.3, 95% confidence interval −2.4 to −0.2; P=0.01). The rate of glucose intolerance was also lower in the intervention arm: 21% (67/320) compared with 28% (100/352) of controls had a fasting glucose of 5.1 mmol/L or greater or a 1 hour glucose challenge test result of greater than 7.8 mmol/L (P=0.02).

Conclusion A low glycaemic index diet in pregnancy did not reduce the incidence of large for gestational age infants in a group at risk of fetal macrosomia. It did, however, have a significant positive effect on gestational weight gain and maternal glucose intolerance.

Trial registration Current Controlled Trials ISRCTN54392969.


  • We thank the staff at the National Maternity Hospital; Jacinta Byrne, research midwife; Helen Colhoun, epidemiologist; Tim Grant, biostatistical consultant at C-Star, University College Dublin; and the mothers who participated in the study.

  • Contributors: FMMcA conceived and designed the study. RM and MEF contributed to the study design and manuscript preparation. CAMcG carried out the intervention and contributed to manuscript preparation. JMW did the analysis and wrote the manuscript. All of the authors reviewed and revised the final version of the manuscript. FMMcA is the guarantor.

  • Funding: This trial was funded by the Health Research Board of Ireland, with additional financial support from the National Maternity Hospital Medical Fund. None of the funding sources had a role in the trial design or manuscript preparation.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare: no support from any organisation for the submitted work (apart from the Health Research Board of Ireland and the National Maternity Hospital Medical Fund); no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: This study received approval from the Ethics Committee of the National Maternity Hospital in June 2006; all participants gave written consent.

  • Data sharing: No additional data available.

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