Human Development Index (HDI) of the maternal country of origin as a predictor of perinatal outcomes - a longitudinal study conducted in Spain

BACKGROUND In an era of worldwide population displacement, recent studies have identified strong associations between social situations and perinatal outcomes among immigrants. Little is known about the effect of maternal social background on pregnancy outcomes. The Human Development Index (HDI) assesses the following dimensions of human development: life expectancy, education level and income. The objective of our study was to determine if maternal HDI may be used to identify women at increased odds of poor pregnancy outcomes. METHODS We conducted a longitudinal population-based study in a tertiary centre in Madrid, Spain. The outcome variables were maternal and perinatal/antenatal mortality, preeclampsia (PE), low birth weight (LBW), gestational diabetes mellitus (GDM), preterm delivery (PTD) before 37 and 34 gestational weeks, abnormal cardiotocography (CTG) during delivery, C-section (CS) due to abnormal CTG, pH < 7.10 at birth, Apgar at 5 min ≤ 7, and resuscitation type ≥3. We performed multivariate logistic regression analyses adjusted for potential confounding variables to evaluate the associations between maternal HDI and perinatal outcomes. RESULTS In total, 38,719 singleton infants who were born in our maternity ward between 2010 and 2016 and had perinatal outcome data available were included in this study. The neonates of women from medium/low HDI countries had significantly lower odds of low birth weight (LBW) than their very high HDI country counterparts (OR 0.63, 95% CI 0.55-0.72). However, the odds of PTD before 37 gestational weeks and PE were higher in the medium/low HDI group than the very high HDI group (OR 1.26, 95% CI 1.04-1.53; OR 1.35, 95% CI 1.02-1.79, respectively). Poorer neonatal outcomes were identified in the medium/low HDI group than the very high HDI group, including greater odds of abnormal CTG, CS due to abnormal CTG and Apgar 2 ≤ 7 (p < 0.05). CONCLUSIONS Our findings suggest that the infants of mothers from medium/low HDI had lower odds of LBW but higher odds of PTD, PE and poor neonatal outcomes. These results support the hypothesis that maternal HDI can be used to understand the impact of maternal origin on pregnancy outcomes. Further studies are needed to confirm its validity.