Study Selection
The primary outcome of this systematic review is excessive or inadequate
gestational weight gain according to the NAM recommendations, and
secondary outcomes include GDM, pre-eclampsia, preterm birth, delivery
mode and birth weight. Studies were included if they met the following
criteria: 1) Prospective cohort studies of women in the preconception
period or pregnancy recruited from the general population. 2) Diet
quality measured with pre-specified scoring scales and validated dietary
assessment methods. 3) Assessment of the association between diet
quality score and any of the systematic review outcomes. The
publications identified with the search process were uploaded to the
Covidence software. YY and IH independently screened the titles and
abstracts. All references that met the inclusion criteria or those for
which eligibility was uncertain were selected for full-text screening.
Reasons for exclusion at the time of full-text screening were recorded.
Any disagreements arising during the selection process were resolved by
discussion with a third reviewer (LD). The process of study selection is
reported using the PRISMA (Preferred Reporting Items for Systematic
Reviews and Meta-Analyses) flow diagram28.