Lipid changes throughout pregnancy according to pre-pregnancy BMI: results from a prospective cohort.

OBJECTIVE

To evaluate the rate of change in serum lipids and the factors associated with their variations, stratifying for pre-pregnancy body mass index (BMI) categories.

DESIGN

Prospective cohort.

SETTING

Public Health centre, Rio de Janeiro, Brazil.

POPULATION

Two hundred and twenty-five healthy pregnant women recruited between 2009 and 2011.

METHODS

Women were evaluated during the three trimesters of pregnancy (5th-13th, 20th-26th and 30th-36th gestational weeks). Pre-pregnancy BMI (kg/m²) was classified as normal weight (NW = 18.5-24.9), overweight (OW = 25.0-29.9) or obese (OB ≥ 30.0). The independent variables included maternal socioeconomic, demographic, biochemical and lifestyle factors. We performed linear mixed-effects models adjusted for gestational age and body weight, reporting coefficient (β) and 95% confidence interval (95% CI).

MAIN OUTCOME MEASURES

Longitudinal total cholesterol (TC), high-density lipoprotein (HDL-c), low-density lipoprotein (LDL-c) and triglyceride (TG) measurements.

RESULTS

OW and OB women presented higher mean TG, TC and LDL-c compared with their NW counterparts (P < 0.05). The mean HDL-c concentrations were higher in NW than in OB women (P = 0.03). OW and OB women presented lower serum TC (βOW  = -0.014; 95% CI = -0.026 to -0.002; P = 0.022; βOB  = -0.015; 95% CI -0.015 to 0.001; P = 0.066) and LDL-c (βOW  = -0.012; 95% CI = -0.021 to -0.002; P = 0.017; βOB  = -0.018; 95% CI = -0.031 to -0.005; P = 0.005) rates of change (mmol/l per gestational week) compared with the NW. Pre-gestational BMI was the main factor associated with the rate of changes in TC and LDL-c concentrations.

CONCLUSION

Pre-pregnancy BMI was the main factor associated with the rate of change in TC and LDL-c throughout pregnancy, and OW and OB women presented lower rates of change compared with NW controls.