New immigrants to Western nations are believed to experience fewer chronic health problems (e.g., diabetes, high blood pressure and heart disease) than long-time residents of those countries. Dr. Joel Ray and coauthors tested whether this "healthy immigrant effect" extends to complications during pregnancy.

In the Recent Immigrant Pregnancy and Perinatal Long-term Evaluation Study (RIPPLES), Ray and colleagues examined the incidence of maternal placental syndrome — defined as a diagnosis of pre-eclampsia or eclampsia (also called toxemia of pregnancy), placental abruption (a premature separation of the placenta from the uterus) or placental infarction (sudden blockage of the blood supply to the placenta) — among more than 795 000 women who had a first documented delivery in Ontario between 1995 and 2005. They found that the risk of maternal placental syndrome was lowest among the most recent immigrants to Ontario (women who immigrated within 3 months before delivery) and highest among those who had been living in the province for 5 or more years before delivery. The more months which have passed since immigration, the higher the risk of placental complications. Health factors such as high blood pressure, obesity and tobacco dependence — all of which can affect the health of the placenta — were noted to increase in incidence with length of residence in Ontario.

Currently immigrants are screened carefully to ensure good health at the time of immigration. A reasonable public health recommendation based on the RIPPLES findings is that the apparent healthier state of new immigrant women should be preserved through policies designed to discourage the adoption of adverse lifestyle choices.

p. 1419 Results of teh Recent Immigrant Pregnancy and Perinatal Long-Term Evaluation Study (RIPPLES)
J.G. Ray et al

p. 1439 Healthier on arrival? Further insight into the "healthy immigrant effect"
B. Gushulak