Absence of prenatal ultrasound surveillance: Data from the Portuguese congenital anomalies registry.

BACKGROUND: In Portugal, prenatal care guidelines advocate two prenatal ultrasound scans for all pregnant women. Not following this recommendation is considered inadequate prenatal surveillance. The National Registry of Congenital Anomalies (RENAC in Portuguese) is an active population-based registry and an important instrument for the epidemiological surveillance of congenital anomalies (CA) in Portugal. Regarding pregnancies with CA, this study aims to describe the epidemiology of absent prenatal ultrasound scans and factors associated with this inadequate surveillance. METHODS: A cross-sectional comparative study from 2008 to 2013 was carried out using data from RENAC. Associations of nonuptake of prenatal ultrasound screening with socio-demographic health behaviors and obstetric history data were evaluated using multiple logistic regression. Potential confounders were investigated and included if they changed the crude odds ratio estimate by at least 10% after adjustment by the Mantel-Haenszel method. The statistical significance level was set at 5%. RESULTS: Overall, 6090 notifications of congenital anomalies were reported to RENAC, and 2% of the pregnant women reported no prenatal ultrasound screening surveillance. These women were on average aged 30.0 years, and 52.8% had no professional occupation. The odds of not performing an ultrasound scan during their pregnancy increased 2.47 times with lack of professional activity, 4.67 times in non-Caucasian women, and decreased 46% for any previous miscarriage. CONCLUSION: For pregnant women who did not receive an ultrasound screening examination during pregnancy, the strongest statistically associated factors were professional occupation, ethnicity, and number of miscarriages in previous gestations. Birth Defects Research (Part A) 106:489-493, 2016. © 2016 Wiley Periodicals, Inc.