STUDY OBJECTIVE: Our purpose was to study the relationship between snoring and pregnancy-induced hypertension and growth retardation of the fetus. DESIGN: Retrospective, cross-sectional, consecutive case series. SETTING: The Department of Gynecology and Obstetrics, University Hospital, Umeâ, Sweden. Participants and measurements: On the day of delivery, 502 women with singleton pregnancies completed a questionnaire about snoring, witnessed sleep apneas, and daytime fatigue. Data concerning medical complications were taken from the women's casebooks. RESULTS: During the last week of pregnancy, 23% of the women reported snoring every night. Only 4% reported snoring before becoming pregnant. Hypertension developed in 14% of snoring women, compared with 6% of nonsnorers (p < 0.01). Preeclampsia occurred in 10% of snorers, compared with 4% of nonsnorers (p < 0.05). An Apgar score < or = 7 was more common in infants born to habitual snorers. Growth retardation of the fetus, defined as small for gestational age at birth, had occurred in 7.1% of the infants of snoring mothers and 2.6% of the remaining infants (p < 0.05). Habitual snoring was independently predictive of hypertension (odds ratio [OR], 2.03; p < 0.05) and growth retardation (OR, 3.45; p < 0.01) in a logistic regression analysis controlling for weight, age, and smoking. CONCLUSIONS: Snoring is common in pregnancy and is a sign of pregnancy-induced hypertension. Snoring indicates a risk of growth retardation of the fetus.