Country of first birth and neonatal outcomes in migrant and Norwegian-born parous women in Norway: a population-based study

Eline S Vik,Roy M Nilsen,Dag Moster,Vigdis Aasheim,Rhonda Small,Erica Schytt

doi:10.1186/s12913-020-05415-y

Abstract

BackgroundThis study compares subsequent birth outcomes in migrant women who had already had a child before arriving in Norway with those in migrant women whose first birth occurred in Norway. The aim of this study was to investigate the associations between country of first birth and adverse neonatal outcomes (very preterm birth, moderately preterm birth, post-term birth, small for gestational age, large for gestational age, low Apgar score, stillbirth and neonatal death) in parous migrant and Norwegian-born women.MethodsNational population-based study including second and subsequent singleton births in Norway from 1990 to 2016. Data were retrieved from the Medical Birth Registry of Norway and Statistics Norway. Neonatal outcomes were compared between births to: 1) migrant women with a first birth before immigration to Norway (n = 30,062) versus those with a first birth after immigration (n = 66,006), and 2) Norwegian-born women with a first birth outside Norway (n = 6205) versus those with a first birth in Norway (n = 514,799). Associations were estimated as crude and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) using multiple logistic regression.ResultsMigrant women with a first birth before immigrating to Norway had increased odds of adverse outcomes in subsequent births relative to those with a first birth after immigration: very preterm birth (22–31 gestational weeks; aOR = 1.27; CI 1.09–1.48), moderately preterm birth (32–36 gestational weeks; aOR = 1.10; CI 1.02–1.18), post-term birth (≥42 gestational weeks; aOR = 1.19; CI 1.11–1.27), low Apgar score (< 7 at 5 min; aOR = 1.27; CI 1.16–1.39) and stillbirth (aOR = 1.29; CI 1.05–1.58). Similar results were found in the sample of births to Norwegian-born women.ConclusionsThe increased odds of adverse neonatal outcomes for migrant and Norwegian-born women who had their first births outside Norway should serve as a reminder of the importance of taking a careful obstetric history in these parous women to ensure appropriate care for their subsequent pregnancies and births in Norway.

Highlights

IntroductionWith the growing proportion of migrant women giving birth in high-income countries [1, 2], increased knowledge about their pregnancy outcomes is needed [3]
This study compares subsequent birth outcomes in migrant women who had already had a child before arriving in Norway with those in migrant women whose first birth occurred in Norway
We have previously reported that migrant women who gave birth to their first baby before immigration to Norway had an increased risk of stillbirth in later births compared with migrant women who gave birth to their first baby in Norway [11]

Summary

Introduction

With the growing proportion of migrant women giving birth in high-income countries [1, 2], increased knowledge about their pregnancy outcomes is needed [3]. Half of women giving birth in high income countries are parous [9] and maternity care is mainly tailored to the host population with particular focus on first-time mothers and those with a complicated first pregnancy and childbirth [10]. We explore whether this increased risk applies to other adverse neonatal outcomes, and whether the findings are unique to migrant women or if they apply to Norwegian-born women who return to Norway after a first childbirth abroad

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