The contribution of hypertensive disorders of pregnancy to late preterm and term admissions to neonatal units in the UK 2012-2020 and opportunities to avoid admission: A population-based study using the National Neonatal Research Database

Abstract

Objective: To quantify maternal hypertensive disorder of pregnancy (HDP) prevalence in late preterm and term infants admitted to neonatal units (NNU) and assess opportunities to avoid admissions.

Design: A retrospective population-based study using the National Neonatal Research Database.

Setting: England and Wales.

Population: Infants born ≥34 weeks' gestation admitted to NNU between 2012 and 2020.

Methods: Outcomes in HDP infants are compared with non-HDP infants using regression models.

Main outcome measures: Hypertensive disorder of pregnancy, primary reason for admission, clinical diagnoses and resource use.

Results: 16 059/136 220 (11.8%) of late preterm (34⁺⁰ to 36⁺⁶ weeks' gestation) and 14 885/284 646 (5.2%) of term (≥37 weeks' gestation) admitted infants were exposed to maternal HDP. The most common primary reasons for HDP infant admission were respiratory disease (28.3%), prematurity (22.7%) and hypoglycaemia (16.4%). HDP infants were more likely to be admitted with primary hypoglycaemia than were non-HDP infants (odds ratio [OR] 2.1, 95% confidence interval [CI] 2.0-2.2, P < 0.0001). 64.5% of HDP infants received i.v. dextrose. 35.7% received mechanical or non-invasive ventilation. 8260/30 944 (26.7%) of HDP infants received intervention for hypoglycaemia alone (i.v. dextrose) with no other major intervention (respiratory support, parenteral nutrition, central line, arterial line or blood transfusion).

Conclusions: The burden of maternal HDP on late preterm and term admissions to NNU is high, with hypoglycaemia and respiratory disease being the main drivers for admission. Over one in four were admitted solely for management of hypoglycaemia. Further research should determine whether maternal antihypertensive agent choice or postnatal pathways may reduce NNU admission.

Keywords: hypertension; hypoglycaemia; neonatal units; pregnancy.

FIGURE 1

(A,B) Percentage of live‐born babies admitted to Neonatal Units in England and Wales 2012–2020 with a maternal record of hypertensive disorder of pregnancy by gestational age at delivery (A) and by year of birth (B). (C) Bar plot of proportion of infant admissions to a neonatal unit with primary diagnosis of prematurity, respiratory disease, hypoglycaemia, infection and growth restriction by gestational age (late preterm [34⁺⁰ to 36⁺⁶] by gestational week, early term [37⁺⁰ to 38⁺⁶], term [39⁺⁰ to 41⁺⁶] and post‐term [≥42⁺⁰]) stratified by exposure to maternal HDP. FGR, fetal growth restriction; HDP, hypertensive disorder of pregnancy; SGA, small for gestational age.

FIGURE 2

Venn diagram of recognised hypoglycaemia risk factors as defined in British Association of Perinatal Medicine 2017 Guidelines on Hypoglycaemia in term infant risk factors: maternal diabetes (DM, diabetes mellitus [Type 1 or 2]; GDM, gestational diabetes mellitus), birthweight [BW] <2nd centile and late preterm birth [34⁺⁰ to 36⁺⁶ weeks], in addition to hypertensive disorder of pregnancy [HDP] in late preterm and term infants admitted to NNU in England and Wales 2012–2020 who received primary management of hypoglycaemia alone (special care [SC] level care only, i.v. dextrose and no other major intervention). Total n = 89 381.