A Queen's-led study shows that giving nitroglycerin to women who enter labour early results in significant improvement to their babies' health. The improvement is most marked in babies who are born very prematurely (at 24 to 28 weeks). The study is funded by the Canadian Institutes of Health Research (CIHR).
Until now, no drug to stop pre-term labour has demonstrated an improved outcome from a baby's point of view.
Led by Dr. Graeme Smith (Obstetrics and Gynaecology), the five-year, randomized controlled trial involved 153 women who were recruited at the time they went into pre-term labour. The study was organized by the Queen's Perinatal Research Unit at Kingston General Hospital, with data management by the Ottawa Maternal Neonatal Investigators at the Ottawa Health Research Institute.
The study shows that using nitroglycerin patches for pregnant women helps to prolong pregnancy and - most importantly - improves babies' outcome, with fewer side effects than experienced through the use of other drugs.
"Our team is very excited about these findings," says Dr. Smith, an expert in high-risk obstetrics. "It is estimated that it costs the Canadian health system almost $2 billion a year to take care of premature babies and their medical complications. Given the immeasurable societal and family costs associated with pre-term birth and having a sick baby or child, treatment with nitroglycerin may result in major cost saving and longer-term health benefits for these babies."
The incidence of pre-term birth - the leading cause of death and disability of newborn babies worldwide - continues to rise, he notes. Approximately 7.5 per cent of all babies born in Canada are born prematurely (before 37 weeks) and 1 to 2 per cent are born before 34 weeks. "It is this later group that is most concerning as these babies are at the highest risk of immediate and long-term medical complications," says Dr. Smith.
Funded through a $1.7-million Randomized Control Trial grant from CIHR, the Pre-term Labour Nitroglycerin Trial team also includes: Drs. Mark Walker from the University of Ottawa, and Arne Ohlsson, Karel O'Brien and Rory Windrim from the University of Toronto.
"Dr. Smith's trial results have provided us new information on one possible solution to reduce the adverse effects of pre-term labour," said Dr. Michael Kramer, Scientific Director of the CIHR Institute of Human Development, Child and Youth Health. "This result is very promising and it provides reassurance for expecting mothers and their families."
The team's findings are highlighted as an "Editor's Choice" in the January issue of the American Journal of Obstetrics and Gynecology. An editorial in the journal commends "the excellence of their clinical research" and "the study design, execution and report."