Magnesium intake and status and pregnancy outcome in a Danish population

Abstract

Objective— To investigate the relation between pregnancy outcome and magnesium intake and status. Design— A prospective observational study in which the estimate of nutrient intake and serum samples were obtained before the final outcome of pregnancy was known. A second part of the investigation was a cross‐sectional comparison of magncsium status of normal pregnant women and women with certain pathological pregnancies. Setting— Antenatal clinic associated to the University Clinic of Obstetrics and Gynaecology, University of Aarhus, Denmark. Subjects— 1203 consecutive women in the 30th week gestation were invited to participate in the study, 991 (82.4%) accepted and records for 965 (80.2%) were available for analysis. Data— Food intake data were collected by a combination of a self administered questionnaire and a structured interview of a dietary history type. Serum samples were obtained from blood withdrawn in the 30th and 37th week gestation. Obstetric data were collected from the midwifery and hospital records. For a second part of the investigation, biopsies from the uterus and the abdominal rectus musclc were obtained from women delivered by caesarean section. Results— In the women with normal pregnancies and in the three groups of pathological pregnancies (pre‐eclampsia, SGA‐infants and preterm labour) the average magnesium intake was with in the range of 200 to 208 mg per 1000 kcal perday (SD 32)and there were no differences between the groups. Neither were differences in serum magnesium observed. Birthweight for gestational age was not influenced by determinationm intake. No differences in magnesium status as assessed by determination of magnesium content in muscle biopsies were found between the normal pregnancies and women with pre‐eclampsia, SGA‐infants or preterm labour. Conclusion— The intake of magnesium seemed adequate, and pre‐eclampsia, SGA‐infants, or preterm labour did not seem associated with a low dietary intake of magnesium or magnesium deficiency. Routine magnesium supplementation during pregnancy is not recommended for populations of relative good socio‐economic status.