Níveis séricos de leptina e sua relação com a circunferência abdominal, com o ganho de peso gestacional e com o índice de massa corporal de gestantes do pré-natal de risco habitual, usuárias do SUS, atendidas em uma maternidade de Juiz de Fora, MG

Abstract

Obesity is associated with adverse pregnancy outcomes and increased gestational risk. Leptin is an adipocytokine synthesized in adipose tissue, particularly in visceral that, during pregnancy, is also produced by the placenta and plays an important role in the regulating of energy metabolism and physiological insulin resistance. Serum leptin levels higher than those found in normal pregnancy have been related with several obstetric complications. Considering the hypothesis that abdominal obesity (AO) in pregnancy could possibly result in a higher release of proinflammatory cytokines in the maternal circulation, increasing gestational risk, we elaborated this work that aimed to: to evaluate the correlation between maternal waist circumference (WC) measured before the 12th week of gestation and serum leptin levels during pregnancy; to compare the leptin levels of women with and without abdominal obesity (AO) diagnosed in early pregnancy; to evaluate the behavior of maternal weight and serum leptin levels during the pregnancy in overweight/obese and nonobese pregnant women; and to assess total and percent weight gain during pregnancy as possible factors that influence leptin levels. We perform a prospective study including 40 pregnant women receiving low-risk prenatal care. WC was measured before the 12th week and serum leptin levels were measured, by ELISA, between the 9th and 12th, 25th and 28th and 34th and 37th weeks pregnancy. According to WC measurement, the cohort was divided into two groups: with AO (WC ≥ 88 cm) and without AO (WC < 88 cm). Based on their pre-pregnancy body mass indices (BMIs), the sample was divided in: non-overweight weight (BMI of < 25 kg/m2) and overweight/obese (BMI of ≥25 kg/m2). The level of significance was set at p < 0.05. A positive correlation was obtained between the WC measured during the same period and the mean serum leptin levels (r=0.7; p<0.0001). The mean leptin levels in pregnant patients with AO (41.9±3.5 ng/mL) were higher than in patients without AO (23.6 ± 2.7ng/mL) (p<0.0002). There was an increased progressive maternal weight gain during pregnancy in both groups. There was an increased progressive in leptin levels in both groups, however, the increase was significantly higher in the patients without overweight (p <0.001). There was no difference between gestational total weight gain in both groups. The percent weight gain during pregnancy was significantly higher (p <0.001) in the group without overweight. In conclusion, there is a positive correlation between WC measured before the 12th week of pregnancy and the mean serum leptin levels during pregnancy; pregnant women with AO evaluated before the 12th week present higher levels of serum leptin during pregnancy, than those without AO; WC measure before the 12th week of pregnancy is a valid and simple method to predict serum leptin levels throughout pregnancy; maternal weight increase during pregnancy in both, non-overweight and overweight/obese patients; the serum leptin levels increase during pregnancy in nonoverweight patients; the percent weight gain in pregnancy is higher in non-overweight pregnant women compared to overweight/obese; the increase in serum leptin levels during pregnancy in non-overweight patients seems to be explained by the greater percent weight gain of these women, compared to overweight/obese.