RESUMEN
BACKGROUND: To determine the effect of preconception body mass index (BMI) and/or gestational weight gain (GWG) on the occurrence of sleep disorders over the whole pregnancy. METHODS: A sample of 2,366 pregnant women, recruited in their 1st trimester (TM), was evaluated until delivery for their sleeping characteristics, using the Pittsburgh Sleep Quality Index (PSQI). Mixed or multinomial logistic modeling was applied, as appropriate. RESULTS: When compared with TM 1, PSQI score was the lowest at TM 2 (ß = -1.03; 95% CI: -1.17 to -0.89) and highest in TM 3 (ß = 0.27; 95% CI: 0.10-0.45). Obese (ß = 0.48; 95% CI: 0.17-0.78) and overweight women (ß = 0.24; 95% CI: 0.00-0.48) exhibited an overall greater PSQI than normal-weight women over the whole pregnancy. When sociodemographic factors were accounted for, the effect size was reduced by 25% among obese women (ß = 0.36; 95% CI: 0.06-0.68), but was no more not significant in overweight women (ß = 0.06; 95% CI: -0.17 to 0.30). Both obese and overweight women still exhibited, although at a lower extend, a greater PSQI than normal-weight women. Further adjustment for GWG had no effect on these observations. Obese women almost had a four-fold increased risk (OR = 3.89; 95% CI: 2.50-6.06) of being snorers in the three TMs. While GWG had only a minor effect (aOR = 3.83; 95% CI: 2.43-6.03), sociodemographic factors increased the odds of being habitual snorer (aOR = 4.04; 95% CI: 2.57-6.35). CONCLUSIONS: High prepregnancy BMI together with sociodemographic correlates appear as the most critical for sleep disturbances across pregnancy. GWG is of marginal importance, especially regarding snoring. These findings confirm the importance of considering the initial body weight status of women in tailoring sleep hygiene advises irrespective of the recommendations for weight gain during pregnancy. The results also underscore the need to providing as early as possible during a pregnancy, supportive tools to ethnic minorities, multiparous, and women from deprived socioeconomic neighborhoods.