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About SickKids

April 23, 2009

Morning sickness may lead to brighter kids

(Toronto) - For many expectant mothers, that queasy feeling is one of the hardest parts of pregnancy. But new research reveals that mom’s nausea and vomiting of pregnancy (NVP), commonly known as morning sickness, may actually result in a smarter baby.

Researchers at The Hospital for Sick Children’s (SickKids) Motherisk Program have found that morning sickness, which impacts up to 80 per cent of pregnancies, enhances children’s long-term neurodevelopment. The study will appear in the April 23 advance online edition of The Journal of Pediatrics.

This is the first study to assess the direct impact of morning sickness on children’s neurodevelopment. While previous studies suggested an early protective benefit of morning sickness, the long-term effects, including intelligence and specific cognitive skills, had not been directly investigated.

“Our findings suggest an association between NVP and improved neurodevelopment in the offspring,” says Dr. Irena Nulman, lead author of the study. “NVP is a widespread and puzzling physiological phenomenon that has yet to be sufficiently studied,” adds Nulman, Associate Director of the Motherisk Program, SickKids Associate Scientist and staff physician in SickKids Division of Clinical Pharmacology and Toxicology, and Associate Professor of Paediatrics at the University of Toronto.

Morning sickness may result from an altered secretion of hormones (HCG and thyroxine) during pregnancy. The change in hormone levels happens to ensure adequate placental growth.

For this study, participants were recruited through Motherisk’s NVP hotline database. The research included 121 women who called the hotline from 1998 to 2003. Participants were split into three groups of mother-child pairs: mothers who experienced morning sickness and were treated with diclectin (a drug used to treat nausea and vomiting during pregnancy); those who experienced morning sickness and did not take diclectin; and those who did not experience morning sickness.

Children aged three to seven years were assessed with standardized age-appropriate psychological tests, including measures of intelligence and behaviour. Other factors such as mother’s IQ, number of cigarettes smoked per day, alcohol consumption and socioeconomic status were also taken into account.

The study showed all children across the three groups scored within the normal ranges for neurodevelopmental outcome. It indicated children of women with morning sickness scored higher on performance IQ, verbal fluency, phonological processing and numerical memory. It also suggested diclectin does not appear to adversely affect fetal brain development. Severity of morning sickness was a significant predictor of higher scores, and maternal IQ also played a role in the outcome.

“The results from this study emphasize the need for further scientific investigation into the physiological basis of NVP, in order to provide safer management and more successful pregnancy outcomes in the future,” says Dr. Gideon Koren, principal investigator of the study, Director of the Motherisk Program, Senior Scientist at SickKids and Professor of Paediatrics, Pharmacology, Pharmacy and Medical Genetics at the University of Toronto.

The study was supported by Duchesnay, Canadian Institutes of Health Research, and the SickKids Foundation.

The SickKids Motherisk Program is a clinical research and teaching program that provides evidence-based information and guidance about the safety or risk to the developing fetus or infant, as a result of maternal exposure to drugs, chemicals, diseases, radiation or environmental agents.

The Hospital for Sick Children (SickKids), affiliated with the University of Toronto, is Canada’s most research-intensive hospital and the largest centre dedicated to improving children’s health in the country. As innovators in child health, SickKids improves the health of children by integrating care, research and teaching. Our mission is to provide the best in complex and specialized care by creating scientific and clinical advancements, sharing our knowledge and expertise and championing the development of an accessible, comprehensive and sustainable child health system. For more information, please visit www.sickkids.ca. SickKids is committed to healthier children for a better world.

For more information, please contact:

Matet Nebres
The Hospital for Sick Children
Phone: 416-813-6380
email: matet.nebres@sickkids.ca

Suzanne Gold
The Hospital for Sick Children
Phone: 416-813-7654 ext. 2059
email: suzanne.gold@sickkids.ca