Effects of lifestyle intervention in obese pregnant women on gestational weight gain and mental health: a randomized controlled trial

OBJECTIVE: Lifestyle intervention could help obese pregnant women to limit their weight gain during pregnancy and improve their psychological comfort, but has not yet been evaluated in randomized controlled trials. We evaluated whether a targeted antenatal lifestyle intervention programme for obese pregnant women influences gestational weight gain (GWG) and levels of anxiety or depressed mood. DESIGN AND SUBJECTS: This study used a longitudinal interventional design. Of the 235 eligible obese pregnant women, 205 (mean age (years): 29 +/- 4.5; body mass index (BMI, kg m(-2)): 34.7 +/- 4.6) were randomized to a control group, a brochure group receiving written information on healthy lifestyle and an experimental group receiving an additional four antenatal lifestyle intervention sessions by a midwife trained in motivational lifestyle intervention. Anxiety (State and Trait Anxiety Inventory) and feelings of depression (Edinburgh Depression Scale) were measured during the first, second and third trimesters of pregnancy. Socio-demographical, behavioural, psychological and medical variables were used for controlling and correcting outcome variables. RESULTS: We found a significant reduction of GWG in the brochure (9.5 kg) and lifestyle intervention (10.6 kg) group compared with normal care group (13.5 kg) (P = 0.007). Furthermore, levels of anxiety significantly decreased in the lifestyle intervention group and increased in the normal care group during pregnancy (P = 0.02); no differences were demonstrated in the brochure group. Pre-pregnancy BMI was positively related to levels of anxiety. Obese pregnant women who stopped smoking recently showed a significant higher GWG (beta = 3.04; P = 0.01); those with concurrent gestational diabetes mellitus (GDM) (beta = 3.54; P = 0.03) and those who consumed alcohol on a regular base (beta = 3.69; P = 0.04) showed significant higher levels of state anxiety. No differences in depressed mood or obstetrical/neonatal outcomes were observed between the three groups. CONCLUSIONS: A targeted lifestyle intervention programme based on the principles of motivational interviewing reduces GWG and levels of anxiety in obese pregnant women.