Preconception dietary patterns in association with live birth and pregnancy loss: a couples-based approach.

OBJECTIVE

To examine associations of traditional healthy and fertility-focused preconception dietary patterns in female and male partners, individually and combined, with clinical fertility outcomes.

DESIGN

Prospective cohort study.

SUBJECTS: Heterosexual couples planning infertility treatment at four United States reproductive endocrinology and infertility care centers, June 2013-April 2019.

EXPOSURE: Four a priori dietary patterns: two traditional healthy patterns (Healthy Eating Index-2015 and Mediterranean Diet) and two fertility-focused patterns (Fertility Diet and Pro-fertility Diet). Preconception dietary intake of each partner was assessed by a validated food frequency questionnaire. Each partner's score was calculated for all four patterns; a combined score for each pattern was the sum of the partners' individual scores.

MAIN OUTCOME MEASURES: Live birth and pregnancy loss before 20 weeks' gestation. Log-binomial models estimated crude and adjusted risk ratios per SD increase in dietary pattern score of female partners, male partners, and couples combined.

RESULTS

Of 2,370 couples, 1,054 experienced a pregnancy, 287 a pregnancy loss, and 821 a live birth. Greater alignment of reported dietary intake with traditional healthy patterns, as reflected by increases in Healthy Eating Index-2015 (females, adjusted risk ratio = 1.06 [95% confidence interval, 1.00-1.13]; males, 1.05 [0.99-1.11]; combined, 1.05 [ 0.99-1.12]) and Mediterranean Diet scores (females, 1.05 [0.99-1.12]; males, 1.05 [0.99-1.11]; combined, 1.06 [1.00-1.12]), by females, males, or couples combined was associated with a higher likelihood of live birth. For female partners only, alignment of reported dietary intake with a Fertility Diet showed a similar association (1.05 [0.99-1.12]). Alignment of reported intake with a Pro-fertility Diet was not associated with live birth. None of the dietary patterns was associated with pregnancy loss.

CONCLUSION

Among couples experiencing infertility, following established, broadly recommended dietary patterns known to improve overall health also may offer modest benefits for fertility. In contrast, fertility-focused patterns may offer little or no fertility benefits and likely are more difficult to follow than traditional healthy dietary patterns.