Elective Delivery of Twins at Week 37 May Be Safer

Ricki Lewis, PhD

June 17, 2012

June 17, 2012 — Elective delivery of uncomplicated twin pregnancies appears to lower the risk for adverse outcomes for the infants compared with standard care (allowing the pregnancy to continue), according to a study published online June 13 in BJOG.

Twin pregnancies extending beyond 37 weeks are associated with elevated risk for perinatal morbidity and mortality. Studies place the safest time for delivery at 36 to 38 weeks. To assess whether elective delivery at 37 weeks lowers risk, Jodie Dodd, MBBS, PhD, from the Australian Research Centre for Health of Women and Babies, Robinson Institute, University of Adelaide, Australia, and colleagues conducted the Twins Timing of Birth Randomised Trial.

The researchers recruited 235 women with uncomplicated twin pregnancies from Australia, Italy, and New Zealand and randomly assigned them to either the elective birth group at 37 weeks (n = 116) or the standard care group (continuing the pregnancy; n = 119). The investigators excluded women with fetal demise of 1 or both twins, women who were in active labor at the time of enrollment, women who had abnormal fetal heart rates, and women with other fetal or maternal anomalies.

Outcomes included fetal or infant death and measures of serious morbidity. These included birth trauma, low birth weight, poor Apgar scores, low cord blood pH, seizures during the first day or requiring 2 or more medications, neonatal intensive care unit admission, severe respiratory distress syndrome, chronic lung disease, necrotizing enterocolitis, and systemic infection within 48 hours of birth.

Elective birth was significantly associated with risk reduction (elective birth, 11/232 [4.7%] vs standard care, 29/238 [12.2%]; risk ratio [RR], 0.39; 95% confidence interval [CI], 0.20 - 0.75; P = .005). Reduction in birth weight resulting from earlier delivery was less than the third centile compared with singletons. The trend toward reduction in serious adverse infant events emerged from a post hoc analysis using twin gestational age–specific charts (elective birth, 4/232 [1.7%] vs standard care, 12/238 [5.0%]; RR, 0.34; 95% CI, 0.11 - 1.05; P = .06).

Elective birth was more likely to require induction of labor, but this did not adversely affect maternal health or the ability to deliver vaginally. "Infants in the Elective Birth Group were at significantly lower risk of serious adverse infant outcome when compared with infants in the Standard Care Group," the authors conclude.

Limitations include premature cessation of the study because of lack of funds, keeping the sample size too low to power assessment of serious adverse outcomes. A second limitation was that 45% of the women assigned to the standard care group gave birth between 37 and 38 weeks. Because of these limitations, the observed reduction in birth weight of the elective group, the researchers write, could have been a result of chance.

The study was funded by the Women’s and Children’s Hospital Foundation, Adelaide, South Australia, and by the Australian Research Centre for Health of Women and Babies, the Robinson Institute, University of Adelaide. Dr. Dodd was supported through an Australian National Health and Medical Research Council Neil Hamilton Fairley Clinical Fellowship and an Australian National Health and Medical Research Council Clinical Practitioner. The authors have disclosed no relevant financial relationships.

BJOG. Published online June 13, 2012.


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