Heart sympathetic activity and pulmonary function in obese pregnant women.

Objective: To estimate autonomic balance and pulmonary function in obese women according to their baseline weight and weight gain during pregnancy.

Design: A cohort study.

Setting: Hospital of Gynecology and Obstetrics in Leon, Mexico.

Population: One hundred and seventy-eight healthy pregnant women (88 obese and 90 non-obese).

Methods: At first visit of pregnancy and in the third trimester blood pressure, anthropometric measurements, glucose, insulin, and leptin levels were evaluated and spirometry, oximetry, and 60 minutes electrocardiograph monitoring were performed.

Main Outcome Measures: Heart rate variability and pulmonary function.

Results: Blood pressure levels, glucose, insulin, and leptin levels were higher in obese women, whereas total power of heart rate variability was lower in this group than in non-obese women at the beginning of pregnancy. In the third trimester, the standard deviation of all the normal R-R intervals was lower in obese women, whereas blood pressure and glucose levels remain higher. In the multiple regression analysis, the change in forced expiratory volume at 1 second/forced vital capacity (FEV1/FVC) ratio and leptin levels independently of weight gain were associated to low-frequency/high-frequency (LF/HF) index at third trimester (R2=0.21; p<0.001 for the model) only in obese women.

Conclusions: LF/HF index at third trimester of pregnancy is associated with increase in leptin levels and decrease in FEV1/FVC in obese women independently of weight gain.