Blood pressure during pregnancy in Canadian Inuit: community differences related to diet.

OBJECTIVE: To assess a possible relation between the incidence of hypertension during pregnancy and the consumption of fatty acids found in fish and sea mammals. DESIGN: Retrospective survey of pregnancy-induced hypertension; prospective diet survey. SETTING: Inuit women from seven communities in the Keewatin region of the Northwest Territories. PATIENTS: All women from Arviat (formerly Eskimo Point), Baker Lake, Chesterfield Inlet, Coral Harbour, Repulse Bay, Sanikiluaq and Whale Cove who gave birth between Sept. 1, 1984, and Aug. 31, 1987. MAIN OUTCOME MEASURES: All blood pressure measurements recorded during the pregnancy, incidence of pregnancy-induced hypertension in the seven communities, harvest of country food (food obtained from the land or sea rather than bought in a store) for six of the communities, self-reported consumption of fish, sea mammals and terrestrial mammals by a subgroup of the subjects and levels of phospholipid fatty acids in cord serum samples from a subgroup of the infants. MAIN RESULTS: Significantly lower mean diastolic blood pressure values during the last 6 hours of pregnancy were noted for the women from the three communities with a higher consumption of fish and sea mammals (78.2 [95% confidence limits (CL) 76.6 and 79.9] mm Hg) than for those from the four communities with a lower consumption of such food (81.5 [95% CL 80.1 and 82.9] mm Hg) (p less than 0.005). The relation between community diet type and blood pressure was independent of other factors. Correspondingly, the women from communities with a lower consumption of marine food were 2.6 times more likely to be hypertensive during the pregnancy than those from communities with a higher consumption of marine food (p less than 0.007). Parity (p less than 0.05) and prepregnancy weight (p less than 0.005) were also significantly associated with pregnancy-induced hypertension; however, the relation between hypertension and community diet type remained significant in logistic regression analysis (odds ratio 2.56, p = 0.03). The differences between the community groups were substantiated by the results of the diet survey, the levels of eicosapentaenoic acid (EPA) in the cord serum phospholipids and the harvest data. CONCLUSIONS: Increased consumption of fish may be beneficial for women at risk for hypertension during pregnancy. A prospective randomized trial of fish or EPA supplementation during pregnancy is warranted.