Preterm subtypes by immigrants' length of residence in Norway: a population-based study
MetadataShow full item record
Background: The reduction of the preterm delivery (PTD) rate is a maternal and child health target. Elevated rates have been found among several immigrant groups, but few studies have distinguished between PTD according to the mode of birth start. In addition, migrants’ birth outcomes have further been shown to be affected by the time in residence; however, the association to PTD subtypes has not previously been assessed. In this study we examined if the risk of spontaneous and non-spontaneous, or iatrogenic, PTD among immigrants in Norway varied according to the length of residence and the country of birth, and compared with the risks among the majority population.
Methods: We linked population-based birth and immigration data for 40 709 singletons born to immigrant women from Iraq, Pakistan, the Philippines, Somalia, Sri Lanka and Vietnam and 868 832 singletons born to non-immigrant women from 1990–2009. Associations between the length of residence and subtypes of PTD were estimated as relative risks (RRs) with 95% confidence intervals (CIs) from multivariable models.
Results: In total, 48 191 preterm births occurred. Both spontaneous and non-spontaneous PTD rates were higher among immigrants (4.8% and 2.0%) than among non-immigrants (3.6% and 1.6%). Only non-spontaneous PTD was associated with longer lengths of residence (p trend <0.001). Recent immigrants (<5 years of residence) and non-immigrants had a similar risk of non-spontaneous PTD, whereas immigrants with lengths of residence of 5–9 years, 10–14 years and ≥15 years had adjusted RRs of 1.18 [95% CI 1.03,1.35], 1.43 [95% CI 1.20,1.71] and 1.66 [95% CI 1.41,1.96]. The association was reduced after further adjustments for maternal and infant morbidity. Conversely, the risk of spontaneous PTD among immigrants was not mitigated by length of residence, but varied with country of birth according to the duration of pregnancy in term births.
Conclusions: Non-spontaneous PTD increased with the length of residence whereas spontaneous PTD remained elevated regardless of the length of residence. Policies to improve birth outcomes in ethnically mixed populations should address the modifiable causes of PTD rather than aiming to reduce absolute PTD rates.
CitationBMC Pregnancy and Childbirth
SubjectPreterm deliveryImmigrantsLength of residenceCountry of birthSpontaneous preterm deliveryNon-spontaneous preterm deliveryIatrogenic preterm delivery
Ingvil K Sørbye et al.; licensee BioMed Central Ltd.
Showing items related by title, author, creator and subject.
Risk factors and outcomes of preterm birth. A study of the associations of preterm birth with cerebral palsy and atopic diseases Trønnes, Håvard (The University of Bergen, 2014-10-03)Background: Children born preterm are at increased risk for a number of chronic diseases, including cerebral palsy and asthma. Asthma is usually categorised among the atopic diseases, but whether preterm birth also affects ...Doctoral thesis
Children born preterm at the turn of the millennium had better lung function than children born similarly preterm in the early 1990s. Vollsæter, Maria; Skromme, Kaia; Satrell, Emma; Clemm, Hege; Røksund, Ola; Øymar, Knut; Markestad, Trond; Halvorsen, Thomas (PLOS ONE, 2015-12-07)Objective. Compare respiratory health in children born extremely preterm (EP) or with extremely low birthweight (ELBW) nearly one decade apart, hypothesizing that better perinatal management has led to better outcome. Design. ...Journal article
Health-related quality of life and emotional and behavioral difficulties after extreme preterm birth: developmental trajectories Vederhus, Bente Johanne; Eide, Geir Egil; Natvig, Gerd Karin; Markestad, Trond; Graue, Marit; Halvorsen, Thomas (PeerJ, 2015-01-20)Background: Knowledge of long-term health related outcomes in contemporary populations born extremely preterm (EP) is scarce.We aimed to explore developmental trajectories of health-related quality of life (HRQoL) and ...Journal article