University of Adelaide researchers say women pregnant with twins should elect to give birth at 37 weeks to avoid serious complications.
The advice is based on the world's biggest study addressing the timing of birth for women who have an uncomplicated twin pregnancy, the results of which are published today in the British Journal of Obstetrics & Gynaecology.
Studying 235 women in Australia, New Zealand and Italy, researchers found that babies born to women in the early birth group (37 weeks) were significantly less likely to be small for their gestational age compared with babies born to women in the standard care group (38 weeks or later).
Lead researcher Professor Jodie Dodd from the University of Adelaide's Robinson Institute and the Women's & Children's Hospital says: "Infants of a twin pregnancy are recognized to be at risk of problems during pregnancy, particularly from a slowing of the rate of growth in one or both twins.
"This slowing of the growth rate can result in low birth weight, which is associated with an increased need for care in the neonatal nursery in the short term and increased risk of health problems in later life, including heart disease and diabetes. There is also the risk of one or both twins being stillborn.
"This is why we've taken such a great interest in the optimal time for twins' birth," Professor Dodd says.
"We found that at 37 weeks, elective birth is associated with a significant reduction in the risk of serious morbidity for infants, without increasing complications related to immaturity or induction of labor."
Professor Dodd says there has been a lot of uncertainty in clinical practice about the optimal time for twins' birth.
"We hope this study will help clinicians to make recommendations to women with healthy twin pregnancies that lead to less complications at birth, and therefore lead to happier, healthier lives for their babies.
"While this is the biggest study of its kind so far, our research supports the evidence shown in previous studies, and it also supports the guidelines of care released by the Royal College of Obstetricians & Gynaecologists in September 2011. These guidelines recommend that women who have uncomplicated twin pregnancies should elect to give birth at 37 weeks."