Worldwide, close to 50% of pregnancies are unintended. Unintended pregnancies are associated with a higher likelihood of maternal smoking during pregnancy, delayed prenatal care, less likely to initiate and continue breastfeeding, and increased risk for poorer maternal mental health.
Various maternal and paternal exposures are associated with a longer time to pregnancy, including higher maternal age, smoking, drug, and alcohol use. With high rates of unplanned pregnancies, attempts to improve diet and lifestyle factors are likely minimal and likely to be achieved by only a small proportion of the population.
There has been a recent surge in the assessment of dietary intake and time to pregnancy which was essentially generated from a prospective cohort study in more than 5000 pregnant women from the United Kingdom, Australia, Ireland, and New Zealand. The median time to pregnancy was up to 0.6 months longer with decreasing levels of fruit intake, corresponding to an absolute increase of 1%-4% in infertility. Decreasing levels of fast food intake correspond with up to 0.9 months shorter time to pregnancy and an absolute reduction of 3%-8% in infertility.
In a prospective cohort of 3828 women planning a pregnancy and 1045 of their male partners in North America, compared with no intake of sugar-sweetened beverages, an intake of at least 7 of those beverages per week impaired fecundity, for example, a longer time to pregnancy by approximately 20%.
There was no association between total fish intake and time to pregnancy in a cohort of 5598 women of whom approximately 50% consumed seafood at least 1 time/week.
In a small sample of 501 couples planning a pregnancy, men and women who consumed at least 8 servings/cycle of seafood, had increased fecundity (shorter time to pregnancy) by 61%, and a 13% lower absolute difference in the incidence of infertility compared with couples consuming less seafood.
There are no clear associations between coffee/caffeine and fecundity. There is little evidence of an association between fecundability and intakes of total fat and fatty acids.
Overall, there is a small amount of evidence demonstrating higher frequency of healthier food intake; specifically a higher intake of fruit, a minimal intake of fast food and sugar-sweetened beverages, and a diet lower in glycemic load, prior to pregnancy reduces time to pregnancy.
The evidence needs to be supported by further large studies, but also assessment of holistic diets rather than single food groups or nutrients. Quantification of differences in high and low consumers and time to pregnancy also should be reported to highlight the potential impact of improvements to dietary intake.
Source: Preconception diet, fertility, and later health in pregnancy