INTRODUCTION It would be useful to have diagnostic indices for obesity phenotypes in pregnant women based on morphological traits and the specific distribution of abdominal adipose tissue. This type of practical resource would allow for the classification of obesity phenotypes in normal-weight women in early pregnancy and would contribute to primary healthcare followup of pregnant women.

OBJECTIVES Validate a new diagnostic index for the metabolically unhealthy obese, normal-weight phenotype, as a determinant for cardiometabolic risk in normal-weight pregnant Cuban women in the first trimester of pregnancy.

METHODS A cross-sectional study of 526 pregnant women at a gestational age of 12 to 14 weeks seen at the ultrasound service of the Chiqui Gómez Lubián Teaching Polyclinic, Santa Clara municipality, Villa Clara province, Cuba, was conducted from January 2016 through July 2020. Subcutaneous, preperitoneal and visceral abdominal fats, as well as anthropometric and blood chemistry variables, were measured. The women were divided into three groups based on metabolic phenotypes, taking into account body mass index in the normal weight range, visceral adiposity index values and the lipid accumulation product starting at the 75th percentile.

The new index, called the abdominal adipose deposit index, was obtained by multiplying the subcutaneous fat thickness by visceral fat thickness, both measured by ultrasound. A cutoff point was established that facilitated discernment of an unhealthy phenotype: normal weight but metabolically obese, a cardiometabolic risk factor.

RESULTS Receiver operating characteristic (ROC) analysis of the abdominal adipose deposit index to distinguish the metabolically unhealthy obese, normal-weight phenotype in normal-weight pregnant women showed an area under the curve of 0.707 (95% CI: 0.62‒0.79, p <0.001), greater than that of the body fat index (0.630; 95% CI: 0.54‒0.72), the fat accumulation index (0.637; 95% CI: 0.55‒0.73) and other established ultrasound indices of abdominal adiposity, with a prevalence of 6.3%.

CONCLUSIONS The abdominal adipose deposit index is better than other traditional indicators at detecting the risk of metabolic obesity in early pregnancy in normal-weight women, facilitating early intervention in clinical practice to prevent or delay progression of cardiometabolic disease in these women.

KEYWORDS Abdominal adipose tissue, abdominal fat, pregnant woman, phenotype, metabolic syndrome, diagnostic ultrasound, Cuba