Objective: Fetal growth in the first trimester is estimated by measuring the crown to rump length of the fetus (CRL). There are no data on the relation between fetal growth and fat distribution in pregnant women. The objective was to investigate the influence of fat distribution in pregnant women on fetal growth in the first trimester of pregnancy.Methods: This was a controlled observation using a random sampling method. Newly registered pregnant women were included in the sample during a 12-18-month period. The study included 400 pregnant women from Bjelovarsko-bilogorska County, Croatia. Participants were divided into three groups according to their pregravid BMI values, normal weight (n = 254), overweight (n = 103), and obese (n = 43). In the 12th week of pregnancy, the CRL was measured by transvaginal ultrasound. The subcutaneous and preperitoneal fat was measured by transabdominal ultrasound, using the Suzuki method. The correlation was tested by the Pearson's coefficient, and a linear regression analysis was performed on the variables with good correlation.Results: In normal weight pregnant women, there is no correlation between the adipose tissue and fetal length, but there is a significant correlation between overweight and obese ones.Conclusion: The distribution of adipose tissue in obese and overweight pregnant women is associated with fetal length in the first trimester of pregnancy, with a stronger correlation between visceral fat and fetal length. The influence of this correlation on the overall fetal growth should be investigated by longitudinal monitoring of these variables during the entire pregnancy.