OTTAWA (September 1, 2005) – An international randomized trial, funded by the Canadian Institutes of Health Research (CIHR), has revealed that amnioinfusion, the infusion of saline into the uterus, does not reduce the risk of meconium aspiration syndrome (MAS), as previously believed. The study, which is led by Dr. William Fraser from the Department of Obstetrics and Gynaecolgy of the Université de Montréal and the Maternal-Child Health Centre associated with Ste-Justine's Hospital, is published in today's issue of The New England Journal of Medicine.
"Dr. Fraser and his colleagues have made an extremely important contribution to our knowledge about the possible prevention of MAS, a rare but very serious neonatal lung condition," said Dr. Michael Kramer, Scientific Director of the CIHR Institute of Human Development, Child and Youth Health. "The rigorous study methods and international scope of this randomized trial (56 study sites in 13 countries) provides very strong evidence against the use of amnioinfusion, and the results are likely to have a major impact on childbirth practices around the world."
Meconium aspiration syndrome (also referred to as meconium aspiration) occurs when a newborn inhales a mixture of meconium and amniotic fluid during labor and delivery. Meconium is the material that fills the fetal intestinal tract during pregnancy and is formed from ingested amniotic fluid and dead intestinal cells. Although it is sterile, inhaled meconium is highly irritating to the lung when the infant takes its first breaths. It can cause a partial or complete blockage of the baby's airways when exhaling, making it difficult to breathe.
Meconium alters the amniotic fluid, reducing antibacterial activity and subsequently increasing the risk of perinatal bacterial infection. Aspiration induces 3 major pulmonary effects, which are airway obstruction, surfactant dysfunction, and chemical pneumonitis. Meconium-stained amniotic fluid occurs in 7 to 22% of term deliveries. In anywhere from 2% to more than a third of these deliveries, MAS can occur.
One of the techniques used to reduce its risk is amnioinfusion. This technique involves infusing saline, via insertion of a catheter in the uterine cervix, into the amniotic cavity of women in labour who show heavy meconium. Amnioinfusion is intended to reduce the risk of MAS by diluting the meconium.
Women were eligible for this randomized trial, after the fetal membranes ruptured and thick, opaque, meconium-stained (greenish colour) amniotic fluid was identified. In this trial, amnioinfusion was not effective in reducing the risk of meconium aspiration syndrome.
"Amnioinfusion has been used in the prevention of meconium aspiration syndrome, or MAS, for the past 15 years. Prior to our study, information about the effectiveness of the intervention was based on small studies carried out in single centers," said Dr. Fraser. "Our research is the first large study that has a sufficient sample size to answer the question as to whether the technique is effective to prevent MAS. We showed that it is not effective in this context. This trial did not examine amniofusion in other contexts. Thorough, large scale studies are needed before drawing conclusions on the potential role of amnioinfusion for other indications."
Dr. Fraser worked with collaborators in Canada, France (Dr. François Goffinet, from INSERM Unité149 and Maternité de Port-Royal), as well as with researchers from Argentina, Belgium, Brazil, Ireland, Mexico, Portugal, South Africa, Switzerland, Tunisia, the United Kingdom and Uruguay.
This study, led by Dr. Fraser and funded by the CIHR, was also supported by the Institut National de la Santé et de la Recherche Médicale (INSERM) in Paris, France. Utah Medical Products provided the amnioinfusion catheters for the study.
About CIHR
The Canadian Institutes of Health Research is the Government of Canada's agency for health research. Its objective is to excel, according to internationally accepted standards of scientific excellence, in the creation of new knowledge and its translation into improved health for Canadians, more effective health services and products and a strengthened Canadian health care system. Composed of 13 Institutes, CIHR provides leadership and support to close to 10,000 health researchers and trainees in every province of Canada. www.cihr-irsc.gc.ca
One of CIHR's thirteen Institutes, the Institute of Human Development, Child and Youth Health supports research that ensures the best start in life for all Canadians and the achievement of their potential for optimal growth and development.
About the Université de Montréal
Founded in 1878, the Université de Montréal today has 13 faculties. Together with its two affiliated schools, HEC Montréal and the École Polytechnique, it represents the leading higher education and research hub in Quebec, number two in Canada and one of the biggest in North America. It brings together 2,400 professors and researchers, welcomes over 55,000 students, offers more than 650 programs for every degree and awards some 3,000 Master's degrees and doctorates each year.
For further information
Marie-France Poirier
CIHR Media Relations
Tel.: (613) 941-4563
mediarelations@cihr-irsc.gc.ca
Marc Tulin
Media Relations, Université de Montréal
Tel.: (514) 343-7593
marc.tulin@umontreal.ca
Séverine Ciancia
Media Relations
Inserm
Tel.: +01 44 23 60 86
severine.ciancia@tolbiac.inserm.fr
Journal
New England Journal of Medicine