Elective birth at 37 weeks of gestation versus standard care for women with an uncomplicated twin pregnancy at term: the Twins Timing of Birth Randomised Trial

Objective: To evaluate whether for women with an uncomplicated twin pregnancy, elective birth at 37 weeks of gestation was associated with reduced risk of death or serious outcomes for babies, without increasing harm.

Design: Randomised controlled trial.

Setting: Maternity hospitals across Australia, New Zealand and Italy.

Population: A total of 235 women with an uncomplicated twin pregnancy at 36(+6) weeks of gestation, with no contraindication to continuing their pregnancy.

Methods: Using a computer-generated, central telephone randomisation service, 235 women were randomised to Elective Birth (birth at 37 weeks; n=116) or Standard Care (continued expectant management, with birth planned from 38 weeks; n=119). Outcome assessors were masked to treatment allocation.

Main outcome measure: A composite of serious adverse outcome for the infant.

Results: For women with an uncomplicated twin pregnancy, elective birth at 37 weeks of gestation was associated with a significant reduction in risk of serious adverse outcome for the infant (Elective Birth 11/232 [4.7%] versus Standard Care 29/238 [12.2%]; risk ratio [RR] 0.39; 95% CI 0.20-0.75; P=0.005), reflecting a reduction in birthweight less than the third centile using singleton gestational age-specific charts (Elective Birth 7/232 [3.0%] versus Standard Care 24/238 [10.1%]; RR 0.30; 95% CI 0.13-0.67; P=0.004). In a post hoc analysis using twin gestational age-specific charts, there was evidence of a trend towards a reduction in the primary composite of serious adverse infant outcome (Elective Birth Group 4/232 [1.7%] versus Standard Care Group 12/238 [5.0%]; RR 0.34; 95% CI 0.11 to 1.05; P=0.06).

Conclusion: The findings of our study support recommendations for women with an uncomplicated twin pregnancy to birth at 37 weeks of gestation.