High prevalence of magnesium supplementation during pregnancy: results from the LIFE Child study.

PURPOSE: We examined the prevalence of magnesium supplementation among pregnant women in Germany and assessed whether risk factors for preterm birth might be associated with magnesium use. We explored the association between magnesium supplementation and pregnancy duration . METHODS: The LIFE Child Study (Leipzig, Germany) recruited pregnant women and collected data in the 24th and 36th week of pregnancy from 2011 to 2019. In this prospective observational cohort study (n = 1078 participants), we analysed potential associations for magnesium supplementation with health-related factors using logistic regression models adjusted for age and socioeconomic status (SES). Using a generalised linear model, we explored whether magnesium supplementation potentially affects pregnancy duration. RESULTS: During their current pregnancy, 60.0% (647/1078) of the women supplemented mono-magnesium, and 70.8% (763/1078) supplemented magnesium through mono- and/or combination preparations (overall magnesium). In 215 women, information on physicians' recommendations/prescriptions was collected: In 84.2% (181/215) of those women, a physician prescribed (104/215, 48.4%) or recommended (77/215, 35.8%) the mono-magnesium supplement. Increasing age was positively associated with magnesium supplementation with overall magnesium use increasing from 57.8% at age 20 years to 84.3% at age 45. Women with medium (OR 2.93; 95% CI 1.20-7.37) or high SES (OR 3.82; 95% CI 1.54-9.77) were more likely to supplement overall magnesium than women with low SES. Mono-magnesium supplementation was more likely in women with premature contractions (OR 2.97; 95% CI 1.36-7.47) with a still positive but not significant effect for overall magnesium (OR = 1.78, 95% CI 0.81-4.49). Magnesium supplementation did not affect pregnancy duration. CONCLUSION: Magnesium supplementation during pregnancy is widespread. Increasing age, higher SES, and premature contractions seem to have the potential to influence magnesium supplementation during pregnancy. TRIAL REGISTRATION: LIFE Child is registered under the trial number: NCT02550236.