The association between hypertensive disorders during pregnancy and adverse neonatal outcomes

Abstract

Introduction: Hypertensive disorders in pregnancy (HDP) are among the most common complication of pregnancy. Delivery, often after induction of labour (IOL) is often the only treatment for severe HDP. Women with HDP are at an increased risk of adverse neonatal outcomes. The aim of this study is to assess the incidence rates of HDP and IOL in women with HDP in Iceland and assess the association between HDP and adverse neonatal outcomes.Methods: Data was obtained from the Icelandic Medial Birth Registry. Final data included all singleton births from 1997-2018 (n = 92 289). Exposure and outcome variables were registered according to ICD-10 and NCSP treatment codes. Rates of HDP, IOL and EC among hypertensive women was registered. Logistic regression was used to calculate the risk of adverse neonatal outcomes among hypertensive women compared to normotensive women.Results: The study included 92 289 women who gave birth to singletons in Iceland in 1997-2018, of whom 7.0% were diagnosed with HPD and HDP was more common among primiparas than multiparas. The rate of HDP among women who gave birth to live singletons in Iceland increased during the study period and there was an increase in IOL among all Icelandic women after 2008. Delivery rates increased among women with HDP who had IOL and EC at 37-40 weeks’ gestation and decreased after 40 weeks’ gestation during the study period. Infants of women with HDP were at increased risk of SGA for both primiparas (aOR=2.83, CI= 2.42-3.28) and multiparas (aOR=3.92, CI=3.16-4.86), of admittance to NICU for both primiparas (aOR=2.01, CI=1.76-2.29) and multiparas (aOR=2.33, CI=1.96-2.77), of low Apgar score for both primiparas (aOR=1.64, CI=1.51-1.79) and multiparas (aOR=1.61, CI=1.45-1.8) and of RSD for both primiparas (aOR=1.36, CI=1.06-1.74) and multiparas (aOR=1.57, CI=1.18-2.09). The risk of premature birth was higher for hypertensive women, for both primiparas (aOR=3.07, CI=2.74-3.44) and multiparas (aOR=4.51, CI=3.98-5.11).Conclusions: The rate of HPD diagnosis has increased in Iceland over the study period. The rate of IOL among hypertensive women increased. Hypertensive women are at increased risk of adverse neonatal outcomes compared to normotensive women. This study provides information of the rates of HDP diagnosis, IOL and EC, as well as the association between HDP and adverse neonatal outcomes in Icelandic population.