MARINE N-3 FATTY-ACID AND CALCIUM INTAKE IN RELATION TO PREGNANCY-INDUCED HYPERTENSION, INTRAUTERINE GROWTH-RETARDATION, AND PRETERM DELIVERY - A CASE-CONTROL STUDY

Objective. To evaluate whether low intakes in pregnancy of marine n-3 fatty acids or calcium increase the risk of preeclampsia, pregnancy in duced hypertension, intrauterine growth retardation, or preterm delive ry and whether high intakes of the above nutrients increase the risk o f postterm delivery. Design. A case-control nested in cohort study. Su bjects and methods. Between 1989 and 1991 a cohort of 9,434 pregnant w omen was established. Forty-three preeclamptics, 179 women with pregna ncy induced hypertension, 182 with intrauterine growth retardation, 15 3 delivering preterm, and 189 delivering postterm together with 256 co ntrols were sampled for this study. Dietary information was obtained r etrospectively between six months and 3 1/2 years after delivery using a semiquantitative food frequency questionnaire, whilst information o n potential confounders was obtained from the cohort data base and ana lyzed by multiple logistic regression. Questions regarding marine n-3 fatty acids and calcium intake provided the basis for categorization i nto three and five intake groups respectively. Results. For ail five p regnancy outcomes and both nutritional factors, none of the confounder -adjusted odds ratios comparing higher intake levels with the lowest i ntake level were significant. Neither were chi(2)-tests for trend calc ulated for each pregnancy outcome statistically significant (p>0.20). Odds ratios for highest Versus lowest intake levels were for n-3 fatty acids 0.79 ((0.27 to 2.34 (95% CT)) for pregnancy induced hypertensio n, 1.00 (0.34 to 2.95) for intrauterine growth retardation, and 0.99 ( 0.35 to 2.74) for preterm delivery; for calcium they were 0.92 (0.33 t o 2.60) for pregnancy induced hypertension, 0.77 (0.25 to 2.42) for in trauterine growth retardation, and 1.05 (0.36 to 3.10) for preterm del ivery. Conclusions. No associations could be detected in these data be tween calcium or fish intake and adverse pregnancy outcome.