Pre pregnancy obesity and infant deaths strongly related : study

"There is a need for more open, honest discussions about avoiding the possible risks of maternal obesity on infant health," Declercq added.

The study, published online in Obstetrics and Gynecology, claims to be the largest study to date of the relationship between pre-pregnancy obesity, prenatal weight gain and infant mortality.

It used birth and death records of more than six million newborns in 38 states from 2012-2013, which included information on the mother's height and pre-pregnancy weight, needed to compute BMI (Body Mass Index).

The researchers examined overall infant mortality in three major categories: Infants who died from preterm-related causes, congenital anomalies and sudden unexpected infant death.

Infant mortality rates from preterm causes increased at higher BMIs, with rates twice as high for obese women than for normal-weight women, the study found.