Protein-rich food intake and risk of spontaneous abortion: a prospective cohort study

Eur J Nutr. 2022 Aug;61(5):2737-2748. doi: 10.1007/s00394-022-02849-4. Epub 2022 Mar 13.

Abstract

Purpose: Diet quality is increasingly recognized as important for human reproductive capacity. We studied the association between intake of protein-rich foods and risk of spontaneous abortion (SAB).

Methods: During 2013-2020, we recruited pregnancy planners from the United States and Canada (Pregnancy Study Online; PRESTO) and Denmark (SnartForaeldre.dk; SF). Participants completed a baseline questionnaire and a validated cohort-specific food frequency questionnaire. We estimated preconception intake of red meat, poultry, processed meat, seafood, eggs, plant-based proteins, and dairy from individual foods and mixed recipes. We included 4,246 PRESTO and 2,953 SF participants who reported a pregnancy during the study. Data on SAB were derived from questionnaires and population registries. We used Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CI), representing the effect of substituting one type of protein-rich food for another.

Results: SAB risk was 23% in PRESTO and 16% in SF. In PRESTO, substitution of seafood with other protein-rich foods was associated with higher SAB risk [for example, the HR for replacing 100 g of seafood/week with 100 g of red meat was 1.10 (95% CI 1.00, 1.20)]. In contrast, in SF, substituting seafood with other protein-rich foods was associated with lower SAB risk [HR for replacing 100 g of seafood/week with 100 g of red meat was 0.89 (95% CI 0.82, 0.98)]. Other protein-rich food substitutions were not meaningfully associated with SAB risk.

Conclusions: Preconception intake of protein-rich foods was largely unrelated to SAB risk, with the exception of seafood, which was associated with higher risk of SAB in Denmark, but a lower risk in North America.

Keywords: Meat; Preconception cohort; Pregnancy loss; Protein; Seafood; Spontaneous abortion.

MeSH terms

  • Abortion, Spontaneous*
  • Cohort Studies
  • Diet / adverse effects
  • Eating
  • Female
  • Humans
  • Pregnancy
  • Prospective Studies
  • Red Meat* / adverse effects
  • Risk Factors
  • United States