ULTRA-PROCESSED food consumption around conception may influence fertility and early pregnancy development, according to new research tracking couples from preconception into early gestation.
The study examined how diets high in ultra-processed food—industrial products typically rich in sugar, salt, and additives but low in nutrients and fibre—relate to reproductive outcomes. Researchers found that higher intake in men was associated with reduced fertility, while in women it was linked to subtle changes in early embryo growth.
Why Ultra-Processed Food Matters Before Pregnancy
The period spanning conception and early pregnancy is a critical window for long-term health of the child. During these early weeks, the embryo develops rapidly, supported by structures such as the yolk sac, which provides nutrients before the placenta is fully formed. Impairments at this stage have been linked to risks including preterm birth, low birth weight, and an unfavourable cardiovascular profile later in childhood.
Diet has been increasingly recognised as a modifiable factor in reproductive health, particularly as ultra-processed food consumption rises globally, accounting for a substantial proportion of daily intake in certain high-income countries.
Tracking Diet and Early Development
The findings come from a population-based cohort involving 831 women and 651 male partners. Dietary intake was assessed using food frequency questionnaires in early pregnancy, with ultra-processed food measured as a proportion of total intake.
Researchers also examined time to pregnancy as a measure of fertilitity, with fecundability defined as the probability of conceiving within a month. Ultrasound scans were conducted at 7, 9, and 11 weeks to measure embryonic growth and yolk sac development.
Median ultra-processed food intake was 22% of total food consumption in women and 25% in men.
Subtle but Distinct Effects in Women and Men
In women, ultra-processed food intake was not consistently linked to fertility outcomes. However, higher intake was associated with slightly smaller embryo size and reduced yolk sac volume at 7 weeks’ gestation. These associations weakened later in the first trimester.
In men, higher intake was linked to a lower probability of conception within a given month and a higher likelihood of subfertility, defined as taking 12 months or more to conceive or requiring assisted reproduction. No consistent association was observed between paternal diet and early embryonic development.
Implications for Preconception Care
The researchers noted that the study population was relatively healthy, which may limit how widely the findings apply. Dietary intake was assessed at a single time point in early pregnancy, and the analysis only included couples who successfully conceived, both of which could influence the results.
As an observational study, the research identifies associations rather than direct cause-and-effect relationships.
The findings suggest that dietary habits of both partners may play a role in reproductive outcomes. While further research is needed, the results support growing interest in including nutritional guidance for both men and women in preconception care to potentially improve fertility and early developmental health.
Featured image: Moving Moment on Adobe stock
Reference
Lin CHX et al. Periconceptional ultra-processed food consumption in women and men, fertility, and early embryonic development. Hum Reprod. 2026;DOI:10.1093/humrep/deag023
