BACKGROUND: Obstructive sleep apnea (OSA), a common and serious disorder in which breathing repeatedly stops during sleep, is associated with excess weight and obesity. Little is known about the co-occurrence of OSA among pregnant women from low and middle-income countries. METHODS: We examined the extent to which maternal pre-pregnancy overweight or obesity status are associated with high risk for OSA, poor sleep quality, and excessive daytime sleepiness in 1032 pregnant women in Lima, Peru. The Berlin questionnaire was used to identify women at high risk for OSA. The Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) were used to examine sleep quality and excessive daytime sleepiness, respectively. Multinomial logistic regression procedures were employed to estimate odds ratios (aOR) and 95% confidence intervals (CI) adjusted for putative confounding factors. RESULTS: Compared with lean women (<25 kg/m(2)), overweight women (25-29.9 kg/m(2)) had 3.69-fold higher odds of high risk for OSA (95% CI 1.82-7.50). The corresponding aOR for obese women (≥30 kg/m(2)) was 13.23 (95% CI: 6.25-28.01). Obese women, as compared with their lean counterparts had a 1.61-fold higher odds of poor sleep quality (95% CI: 1.00-2.63). CONCLUSION: Overweight or obese pregnant women have increased odds of sleep disorders, particularly OSA. OSA screening and risk management may be indicated among pregnant women in low and middle income countries, particularly those undergoing rapid epidemiologic transitions characterized by increased prevalence of excessive adult weight gain.