Pre-pregnancy obesity has been proposed as a risk factor related to gestational diabetes and hypertensive disorders during pregnancy. Identify pregnancy related diseases associated with pre-pregnancy obesity as a risk factor ina high risk preganancy patient population. 600 patients whose pre-pregnancy obesity had been assessed as a high risk factor were included in the study. The means, standard deviation, median, interquartile intervals, Pearson and Spearman correlation and logistic regression to estimate risk with the odds ratio and 95% confidence intervals were calculated. The mean pre-pregnancy body mass index was 29.59 ± 6.42 kg/m2. The mean for recommended pregnancy weight gain was 2.31 ± 1.03 kg, but the mean of real weight gain was 8.91 ± 6.84 kg. A significant correlation between pre-pregnancy obesity and family history of diabetes mellitus (p=0.000), systemic hypertension (p=0.003), cardiac diseases (p=0.000), dyslipidemia (p=0.000) and obesity (p=0.000) was identified. Pre-pregnancy obesity was identified as a risk factor for the development of gestational diabetes (OR: 1.95; IC95%: 1.39 to 2.76; p=0.000) in this kind of patient. 75% of high risk pregnancy women in a high specialty hospital in West Mexico are overweight or obese when they become pregnant. These are risk factors in the development of gestational diabetes. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.