OBJECTIVES: 1. To compare the level of health service user satisfaction (US) with antenatal care in hospitals where a program of continuous quality improvement (CQI) was implemented, in comparison to a reference group of patients seen at hospitals that did not participate in the program. 2. To compare the reasons for dissatisfaction in both groups of users. 3. To identify the factors associated with US. METHODS: A quasi-experimental study of a representative sample of pregnant women attending prenatal care services. The women in the intervention group (n = 191) and the reference group (n = 185) were interviewed on leaving the prenatal care clinic. The dependent variable was satisfaction with prenatal care, and the independent variables were satisfaction of expectations, amiability, level of health information, perception of the equipment, waiting time, cleanliness and comfort. Descriptive and multivariate statistics were calculated. RESULTS: The intervention group showed higher rates of US (67.5% versus 55.1% in the reference group, P = 0.014). The main reasons for dissatisfaction were long waiting times and discourteous treatment, which were more frequent in the reference group. The multivariate analysis identified cordiality of the health professionals, information provided during the visit, satisfaction of expectations and implementation of the CQI program as the factors that were significantly associated with US. CONCLUSIONS: Our findings show that the CQI program in maternal and perinatal health services was positively associated with US. These results reinforce the need for cordiality during prenatal care contacts with providers, and the need to provide appropriate information to the user, in order to help increase acceptability of and adhesion to health care recommendations among pregnant women.