Introduction
First 1000 days of life, including the prenatal period, offers a unique opportunity for the children and future generations to develop their ability to grow and prosper in society1-3. Mounting evidence from human and animal studies have shown that the maternal environment regulates embryonic epigenetic modulation and can predispose to later development of diseases4,5. Maternal nutrition in particular appears to be a key driver of epigenetic programming3,5,6.
Although women in preconception and pregnancy have been advised to achieve a good quality of diet7, little evidence was available on the benefits until the last few decades. The publication of the results of pregnancy and birth cohorts with high quality dietary data has facilitated the research on the health impacts of diet quality on perinatal adverse outcomes8,9, including excessive/inadequate gestational weight gain, gestational diabetes (GDM), hypertensive disorders of pregnancy (HDP), cesarean delivery, preterm birth, and extremes of birthweight.10-15
Several systematic reviews reported the associations between maternal dietary patterns and rates of GDM, HDP, preterm birth and fetal growth.16-20 However, the validity of these studies has been limited by the inclusion of a single publication database18, lack of a meta-analysis16-18, and reporting of only a few of the relevant perinatal outcomes19. These reviews are also limited by the absence of registered or published protocols, which hinders the evaluation of a potential reporting bias.21 Most importantly, the inclusion of studies using a posteriori dietary patterns16-20 limits the relevance of these results to guide dietary interventions as they are data-driven and vary greatly between studies.
Diet quality, a relatively new concept, can be measured by scoring diet in terms of ‘a priori ’ defined adherence to dietary guidelines or a specific pattern.22,23 To date, no systematic review has evaluated the association between diet quality and adverse perinatal outcomes. The objective of this study is to synthesize the evidence and quantify the association between diet quality in preconception or pregnancy and perinatal adverse outcomes in prospective cohort studies.