Calcium supplementation during pregnancy and long‐term offspring outcome: a systematic literature review and meta‐analysis

Systematic review and meta-analysis of randomized trials in pregnant women, with offspring followed from infancy to childhood in Argentina, the United States, Australia, Egypt, The Gambia, and Brazil. Outcomes included offspring blood pressure, growth, and selected metabolic and neurodevelopmental measures.

Pregnant participants received oral calcium supplementation, most commonly calcium carbonate at 1500 to 2000 mg/day, started at about 13 to 21 weeks or 20 weeks' gestation and continued during pregnancy. One Brazilian trial used 600 mg calcium plus 200 IU vitamin D starting at 26 weeks' gestation; control groups received placebo in the randomized trials.

Maternal calcium supplementation during pregnancy showed a possible benefit for offspring blood pressure, but the overall evidence was inconclusive and did not show consistent long-term effects on growth or most other outcomes. In the Argentine trial, high systolic blood pressure in offspring aged 5 to 9 years was lower with calcium than placebo (RR 0.59, 95% CI 0.39 to 0.90), while mean systolic blood pressure was not clearly different (MD -1.4 mmHg, 95% CI -3.3 to 0.5). Height and length outcomes were also not meaningfully changed in that trial (MD -0.71 cm, 95% CI -2.38 to 0.95). The review concluded that evidence is insufficient to support meaningful long-term offspring health effects beyond the newborn period.

The evidence was limited by conflicting trial results, high attrition bias, and incomplete follow-up into later childhood. Doses, start times, and offspring ages varied across studies, and many outcomes of interest, including glucose intolerance, lipid profiles, neurodevelopment, and behavior, were sparsely reported or unavailable. Several analyses were based on small follow-up subsets rather than the full randomized cohorts.