P–737 Effect of dietary patterns on clinical pregnancy and live birth outcomes in men and women receiving assisted reproductive technologies: a systematic review and meta-analysis
Authors: Kellow N , LeCerf J 
Published: August 2021

Abstract

Study question
Is there a relationship between dietary patterns and clinical pregnancy or live birth outcomes in men and women of reproductive age undergoing assisted reproductive technologies (ART)?

Summary answer
While the Mediterranean and pro-fertility diets show potential to improve fertility outcomes, the association between dietary patterns and ART success is currently inconsistent.

What is known already
The nutritional status of reproductive-aged couples can have a significant impact on fertility. While the consumption of individual foods and nutrients are known to influence reproductive success, the effect of dietary patterns on clinical pregnancy and live birth outcomes in people using assisted reproductive technologies (ART) is currently unknown.

Study design, size, duration
Six electronic databases were systematically searched for original research published in English between January 1978 and December 2020 reporting on the effect of pre-defined dietary patterns on either clinical pregnancy and/or live birth rates following invitro fertilisation or intracytoplasmic sperm injection in men and women aged 18–49 years. Screening of all retrieved articles was performed independently by two review authors. Eligible studies underwent quality assessment and qualitative and quantitative synthesis using random-effects model meta-analyses.

Participants/materials, setting, methods
Studies eligible for inclusion in this systematic review were cross-sectional, cohort, clinical trial, and randomised controlled trial study designs. Eligible participants were both males and females, aged 18–49 years, who were undergoing invitro fertilisation or intracytoplasmic sperm injection. Studies were excluded if their primary analysis assessed consumption of individual foods, food groups, vitamins, or minerals, rather than dietary patterns. Studies measuring proxy estimates of fertility status such as sperm quality or quantity were not included.

Main results and the role of chance
Twelve studies (11 prospective cohort studies, 1 randomised controlled trial) reporting on 3144 participants (92% female) were included in the review. Six studies were of positive methodological quality, and six were of neutral quality. Eleven studies used validated food frequency questionnaires to quantify dietary pattern adherence. In individual studies, three dietary patterns (Mediterranean diet, pro-fertility diet, Iranian traditional medicine diet) were associated with increased likelihood of achieving a clinical pregnancy, while two dietary patterns (pro-fertility diet, Mediterranean diet) were associated with increased probability of live birth. Meta-analyses of five Mediterranean diet cohort studies showed no association between dietary pattern and clinical pregnancy (OR 1.3; 95% CI: 0.73- 1.72, P = 0.59), and meta-analysis of three Mediterranean diet cohort studies found no relationship between dietary pattern and live birth (OR 1.51; 95% CI: 0.83–2.76, P = 0.18).

Limitations, reasons for caution
Males were under-represented in the included studies, and half of the studies were of neutral methodological quality. All studies completed dietary assessments at baseline only, however dietary assessments should ideally be undertaken at regular intervals throughout the duration of cohort studies, in the event that dietary patterns change over time.
Wider implications of the findings: Further research utilising higher quality nutrition research methodologies is required to better understand the association between dietary patterns and fertility outcomes during assisted reproductive technologies.

Trial registration number
Not applicable