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.