ABSTRACT
BACKGROUND: A problem repeatedly reported in birth certificate data is the presence of missing data. In 2008, a Centre for Perinatal Epidemiology was created inter alia to assist the Health Departments of Brussels-Capital City Region to check birth certificates. The purpose of this study is to assess the changes brought by the Centre in terms of completeness of data registration for the entire population and according to immigration status. METHODS: Birth certificates from the birth registry of 2008 and 2009 of Brussels were considered. We evaluated the initial missing information in January 2008 (baseline situation) and the corresponding rate at the end of 2008 after oral and written information had been given to the city civil servants and health providers. The data were evaluated again at the end of 2009 where no reinforcement rules were adopted. We also measured residual missing data after correction in socio-economic and medical data, for the entire population and according to maternal nationality of origin. Changes in registration of stillbirths were estimated by comparison to 2007 baseline data, and all multiple births were checked for complete identification of pairs. RESULTS: Missing information initially accounted for 64.0%, 20.8% and 19.5% of certificates in January 2008, December 2008, and 2009 respectively. After correction with lists sent back to the hospitals or city offices, the mean residual missing data rate was 2.1% in 2008 and 0.8% in 2009. Education level and employment status were missing more often in immigrant mothers compared to Belgian natives both in 2008 and 2009. Mothers from Sub-Saharan Africa had the highest missing rate of socio-economic data. The stillbirth rate increased from 4.6 in 2007 to 8.2 in 2009. All twin pairs were identified, but early loss of a co-twin before 22 weeks was rarely reported. CONCLUSIONS: Reinforcement of data collection was associated with a decrease of missing information. The residual missing data rate was very low. The stillbirth rate was also improved but the early loss of a co-twin before 22 weeks seems to remain underreported.
ABSTRACT
OBJECTIVE: Preterm birth is an important indicator of neonatal wellbeing. Infants born preterm are at higher risk for severe morbidity and mortality. Apart from medical risk factors, social factors are also associated with preterm birth. This study aims to provide knowledge on factors which have a predictive role in relation to preterm birth. DESIGN: Cross-sectional population study. SETTING: The Brussels metropolitan region. POPULATION: Women who gave birth in the Brussels metropolitan region in 2004. In total, 8,586 birth registration forms were reviewed for this study. MAIN OUTCOME MEASURES: Associations between educational level, occupation, marital status, age, and origin with preterm birth (<37 weeks). METHODS: After bivariate analyses, significant correlations were explored in a stepwise logistic regression model. Odds ratios (OR) were calculated for each of the significant characteristics in the final model. RESULTS: The risk of preterm birth was found to be associated with age, origin, and marital status. After controlling for confounding factors, the two most important social risk factors for preterm birth were being a teenage mother (OR 2.15, 95% CI: 1.31-3.53) or single mother (OR 1.49, 95% CI: 1.17-1.91). CONCLUSIONS: Being a teenage or single mother are important social risk factors for preterm birth. We hypothesize that the increased risk is related to prenatal care trajectories. To obtain a better understanding of preterm birth occurrences, further research should focus on mapping these trajectories and specifically targeting the most vulnerable groups.
