Trends in sociodemographic and health care factors in Portuguese and non-Portuguese mothers giving birth in Portugal, 1995-2014

Abstract

Background

Time-trend disparity in adverse pregnancy outcomes according to maternal nationality or immigration status has been well documented. In this study, we investigated time changes in individual-level risk factors for adverse pregnancy outcomes that have not been given the needed attention. Objective

To compare 20-year trends in sociodemographic, obstetric, health care factors, and adverse pregnancy outcomes in Portuguese and non-Portuguese women. Methods

We studied 2 105 497 livebirths from Portuguese national birth registry (1995-2014). We compared maternal sociodemographic characteristics (age, education, employment, and marital status), obstetric, and health care factors (parity, number of foetuses, place and type of delivery) in Portuguese and non-Portuguese at four periods (1995-1999, 2000-2004, 2005-09, and 2010-2014). Time-trend analysis using joinpoint regression method was performed to identify trends (joinpoints) and compare time changes in the prevalence of sociodemographic, obstetric, and health care factors expressed as annual percentage change (APC). Results

The proportion of livebirths in non-Portuguese mothers increased between 1995 and 1999 (2.9%), 2000-2004 (6.3%), 2005-2009 (9.5%), and 2010-2014 (9.8%). The proportion of women aged ≥ 35 years among Portuguese mothers varied from 11.1% (1995-1999), 14.4% (2000-2004), 18.6% (2005-2009) to 25.5% (2010-2014); among non-Portuguese women, the corresponding proportions were 15.7% (1995-1999), 14.6% (2000-2004), 16.1% (2005-2009), and 19.0% (2010-2014), respectively. The rate of change in maternal age ≥ 35 years had 2 joinpoints in both Portuguese (APC = 6.5%, 95% confidence interval [CI] 6.2, 6.9; 2005-2014) and non-Portuguese (3.3%, 95% CI 2.5, 4.0; 2002-2014). Increase in caesarean rate was higher for non-Portuguese (24.0%-36.1%) than the Portuguese (30.6%-31.6%) between 1995 and 2014. Conclusions

Sociodemographic, obstetric, and health care factors have divergent time trends and rate of change for Portuguese and non-Portuguese.