The main objective of this study was to assess whether clinical, anthropometric, and biochemical variables of the mother were associated with changes in the methylation of the PPARg promoter region (-351 to -260). Methodology: This was a matched cohort study with two groups: a) normal weight (NW) pregnant women (n = 21) and their offspring, and b) overweight (OW) pregnant women (n = 20) and their offspring. DNA was extracted from leukocytes (4000-10,000 cells) in the MagnaPure (Roche) using the MagNAPure LC DNA Isolation Kit 1 (Roche, Germany). The treatment of DNA (2 µg) was performed with sodium bisulfite (EZ DNA Methylation-Direct Kit, ZymoResearch). Real-time polymerase chain reaction (qPCR) was performed in a LightCycler 2.0 (Roche) using the SYBR® Advantage® qPCR Premix Kit (Clontech).

Women were recruited in the first trimester of pregnancy not including cases with congenital heart and disabling or autoimmune diseases. Those whose clinical follow-up were lost or, if in the postpartum period, who had to be attended in the obstetric intensive care unit were eliminated from the study.

A clinical visit per month was established. Body weight and height were measured in an overnight fasting status using an adult scale (Seca, Hamburg, Germany). Prepregnancy Body Mass Index (BMI) was calculated as weight in kg divided by height in meters squared based on the prenatal chart or on the self-reported weight of women with no prenatal chart.

Blood pressure was recorded at each visit using a standard sphygmomanometer (Riester Big Ben® Square, Germany). Preeclampsia was diagnosed and classified according to the American College of Obstetricians and Gynecologists (ACOG).

Fasting blood samples (10 ml) were taken at the HMPMP laboratory in an early morning after an overnight fasting. Serum samples were analyzed for glucose and lipid profile (Dimension Rx L Max, Dade Behring, USA). At the end of pregnancy, 1 to 2 ml of neonatal peripheral blood sample for leukocyte DNA extraction was taken.

Dietetic treatment was calculated according to height, weeks of gestation, and weight, considering an energy intake of 30 kcal/kg of ideal weight and a macronutrient distribution of: 55-65% carbohydrates, 10-20% fat, and the remainder as proteins. On each nutritional visit, the Healthy Eating Index for Pregnancy (HEI) was evaluated, and all women were recommended to include methionine-rich foods (beans, eggs, fish, garlic, lentils, onion, and soy) and those containing folic acid and vitamin B12 (beef liver, cereals, whole grains, yeast, etc.) in adequate quantities in their diet. The information was complemented with the Food Frequency Questionnaire (FFQ), and the diet adherence was considered adequate with 80% compliance to the indicated calories, at least in four visits.

This project had no risk to pregnant women and their infants, according to the regulations of the General Health Research Law of Mexico. We followed the Declaration of Helsinki, and all patients were asked to sign the written informed consent.

Inclusion Criteria: Women attended in the first trimester of pregnancy -

Exclusion Criteria: congenital heart and disabling or autoimmune diseases

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Pregnant women attended at the Maternal-Perinatal Hospital "Mónica Pretelini Sáenz".