Social deprivation and adverse perinatal outcomes among Western and non-Western pregnant women in a Dutch urban population

Abstract

Social deprivation is considered a key factor in adverse perinatal outcomes. Rotterdam, the second largest city in The Netherlands, has large inequalities in perinatal health and a high number of deprived neighbourhoods. Social deprivation is measured here through a composite variable: ‘Social Index’ (SI). We studied the impact of the SI (2008–2009; 5 categories) in terms of perinatal mortality, congenital anomalies, preterm birth, small for gestational age (SGA) and low 5-minute Apgar score as registered in The Netherlands Perinatal Registry (Rotterdam 2000–2007, n = 56,443 singleton pregnancies). We applied ethnic dichotomisation as Western (European/North-American/Australian) vs. Non-Western (all others) ethnicity was expected to interact with the impact of SI. Tests for trend and multilevel regression analysis were applied. Gradually decreasing prevalence of adverse perinatal outcomes was observed in Western women from the lowest SI category (low social quality) to the highest SI category (high social quality). In Western women the low-high SI gradient for prevalence of spontaneous preterm birth (per 1000) changed from 57.2 to 34.1, for iatrogenic preterm birth from 35.2 to 19.0, for SGA from 119.6 to 59.4, for low Apgar score from 10.9 to 8.2, and for perinatal mortality from 14.9 to 7.6. These trends were statistically confirmed by Chi2-tests for trend (p < 0.001). For non-Western women such trends were absent. These strong effects for Western women were confirmed by significant odds ratios for almost all adverse perinatal outcomes estimated from multilevel regression analysis. We conclude social deprivation to play a different role among Western vs. non-Western women. Our results suggest that improvements in social quality may improve perinatal outcomes in Western women, but alternative approaches may be necessary for non-Western groups. Suggested explanations for non-Western ‘migrant’ groups include the presence of ‘protective’ effects through knowledge systems or intrinsic resilience. Implications concern both general and targeted policies.

Introduction

In The Netherlands perinatal mortality exceeds the European average, despite a high standard of mother and child healthcare with free access (Mohangoo et al., 2008). Perinatal health in the larger cities is even worse, with the highest rates of perinatal mortality and morbidity being observed in deprived neighbourhoods (de Graaf et al., 2008). The high prevalence of ethnic minority groups and disseminated social deprivation in urban areas are generally put forward as key aetiologic factors (Agyemang et al., 2009; Goedhart, van Eijsden, van der Wal, & Bonsel, 2008a, 2008b; de Graaf et al., 2008; Poeran, Denktas, Birnie, Bonsel, & Steegers, 2011). Social deprivation is a very broad term and can be defined as ‘reduction or prevention of culturally normal interaction with the rest of society’. Indeed, aspects of social deprivation such as material poverty and lack of social cohesion are both related to ill health, and also strongly connected; the combined reinforcing presence of these factors might be particularly important for perinatal ill health (Fang, Madhavan, Bosworth, & Alderman, 1998; Halpern & Nazroo, 2000; Jonkers, Richters, Zwart, Ory, & van Roosmalen, 2011). Numerous studies have shown ethnicity and social deprivation to be strongly related to adverse perinatal outcomes such as preterm birth and small for gestational age (Agyemang et al., 2009; Auger, Giraud, & Daniel, 2009; Elo et al., 2009; Farley et al., 2006; Goedhart et al., 2008a; O'Campo et al., 2008; Timmermans et al., 2011). However, many recent studies have been conducted in the United States and Canada where ethnic minorities differ considerably from those in Europe and, more specifically, The Netherlands (Agyemang et al., 2009; Elo et al., 2009; Genereux, Auger, Goneau, & Daniel, 2008; Goedhart et al., 2008a, 2008b; de Graaf et al., 2008; Janevic et al., 2010; O'Campo et al., 2008; Poeran et al., 2011). In the United States, the majority of ethnic minorities either comprise African Americans or Hispanics; in Europe, they mainly originate from former colonies (for example in the United Kingdom or The Netherlands) or they result from the 1960s labour migration from countries such as Turkey or Morocco (for example in Germany and France, respectively). Findings from these studies do not necessarily apply to European countries.

Another motivation for our study pertains to findings from a recent Dutch study, which showed Western (European/North-American/Australian) women in deprived neighbourhoods to have an increased risk of adverse perinatal outcomes as opposed to non-Western women (de Graaf et al., 2008).

Rotterdam, the second largest city of The Netherlands, has the highest proportion of non-Western inhabitants as well as the highest number of deprived neighbourhoods, and the highest rate of adverse perinatal outcomes, creating a suitable population in which to study the effect of social deprivation on perinatal outcomes (de Graaf et al., 2008). In continuation of previous work, we investigated the background and the association of social deprivation with adverse perinatal outcomes, for Western and non-Western women separately, as we hypothesise differential effects. We use a composite variable, the so-called ‘Social Index’ (SI) as deprivation indicator at the neighbourhood level in the city of Rotterdam. As social deprivation is considered an important metric of neighbourhood quality, policy makers have created the SI and its underlying domains to measure this. It is used to measure the effectiveness of efforts to reduce area-based social deprivation. The SI conceptually resembles the less detailed Scottish Carstairs index (Carstairs & Morris, 1990). We use the unaltered SI values to facilitate communication of study results to policy makers.