[Relationship between fetus growth and maternal anthropometrics in Uruguay]

There are no data available about the combined influence of the pregestational body mass index (PG-BMI) and the gestational weight gain (GWG) on the birth-weight (<3000 g, ≥4000 g) in Uruguay.

To determine the prevalence of different categories of PG-BMI and GWG and then find out combined and independent risk at birth: <3000 g or intrauterine growth restriction (IUGR) and ≥ 4000 g (macrosomia) on a nationwide sample of mothers and newborns.

Cohort study with prospective data from 23,832 pregnant women, with classification of the pregestational nutrition status according to the US PG-BMI pattern. GWG was classified according to a proposal from Denmark. The independent and combined risks from the different categories of PG-BMI and GWG with IUGR and macrosomia were determined by means of relative risk (RR).

RR for RCIU and macrosomia were statistically relevant in their independent association with PGBMI and GWG. A high risk for IUGR was identified in pregnant women with low PG-BMI and a high risk for macrosomia in those with a high PG-BMI (overweight or obesity). Also the analysis of the combined influence revealed significant associations between PG-BMI and GWG.

There is an independent and combined effect of the mothers variables on the perinatal results. We suggest comparing this study results, where categories were taken from the US PG-BMI pattern and from the Danish GWG pattern, with other patterns.