Hypertensive Disorders of Pregnancy - the Neonatal Burden of Disease

An Investigation of the Neonatal Burden of Disease of Hypertensive Disorders of Pregnancy: a Population-based Study Using the National Neonatal Research Database

Around one in ten women have high blood pressure in pregnancy. This is potentially serious, with risks to the woman and her baby. Whilst maternal deaths from high blood pressure in pregnancy are now rare in the UK, blood pressure problems in pregnancy still cause many stillbirths and early births. Studies have shown that women of Black and Asian backgrounds are more likely to have worse pregnancy outcomes when blood pressure problems in pregnancy develop.

This study aims to:

i) describe the burden of disease of high blood pressure in pregnancy amongst babies admitted to neonatal units on a national scale.

ii) investigate outcomes for babies born to women with high blood pressure in pregnancy admitted to UK neonatal units across maternal ethnic groups.

To complete this study, we will use the National Neonatal Research Database, which holds population-level data for all babies admitted to neonatal units (where unwell babies receive care) in the UK. We will look at records of babies admitted to neonatal units in England and Wales between 2012 and 2020. The records will include information on over half a million babies and their mothers. We will assess how many babies admitted to neonatal units were born to women who had high blood pressure in pregnancy. We will report the outcomes of these babies, and how they compare to babies born to women without high blood pressure in pregnancy. We will analyse whether outcomes for babies born to women with high blood pressure in pregnancy varies according to maternal ethnicity, and investigate what may be driving differences we find.

Study Overview

• Status: Active, not recruiting
• Conditions: Hypertension in Pregnancy

Detailed Description

Study Aims

This study aims to:

• quantify the proportion of all babies admitted to neonatal units born to women with a hypertensive disorder of pregnancy
• describe the national neonatal morbidity, mortality and resource use of babies admitted to neonatal units born to women with a hypertensive disorder of pregnancy
• examine ethnic disparities in neonatal outcomes of babies admitted to neonatal units born to women with hypertensive disorders of pregnancy.

The National Neonatal Research Database (NNRD)

The NNRD is an approved research database constituting real-world prospective clinical data extracted from point-of-care neonatal electronic health records with complete coverage of infants admitted for neonatal care to National Health Service (NHS) neonatal units in England and Wales (since 2012) and Scotland (since 2015). A defined data extract of approximately 450 items (the Neonatal Data Set) is transmitted quarterly to the Neonatal Data Analysis Unit at Imperial College London for data linkage and cleaning prior to entry into the NNRD. To date, the NNRD contains data for over a million babies (approximately 80,000 babies annually). High completeness and accuracy (>95%) of neonatal data held in the NNRD has been confirmed by formal comparison with a multicentre, randomised placebo-controlled trial.

Study Design

This study is a secondary analysis of an existing national electronic health record population cohort using anonymised, routinely recorded clinical data from the National Neonatal Research Database (NNRD). There will be no new patients recruited and there will be no changes made to patient care.

The research team will work with NNRD data analysts to extract anonymised data from the NNRD. A cohort of babies born to women with a hypertensive disorder of pregnancy (HDP) will be defined based on records of maternal medical problems prior to pregnancy, obstetrics problems during pregnancy, medications given during labour and neonatal discharge diagnoses. The morbidity, mortality and health resource use of this cohort will be described in depth. This cohort will also be compared to a cohort of babies born to women without a hypertensive disorder of pregnancy. The HDP cohort will also be stratified by maternal ethnicity to investigate disparities in outcomes.

• Study Type: Observational
• Enrollment (Actual): 823957

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom
    • Imperial College London

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Babies born between 1st January 2012 and 31st December 2020 and admitted to a neonatal unit in England or Wales

Description

Inclusion Criteria:

• Must be born between 1st January 2012 and 31st December 2020
• Must be admitted to and received all care in a National Health Service (NHS) neonatal unit in England or Wales

Exclusion Criteria:

• None

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Neonatal population - hypertensive disorder of pregnancy; All babies born to a woman with a hypertensive disorder of pregnancy (HDP) and admitted to a neonatal unit in England and Wales between 1st January 2012 and 31st December 2020
Neonatal population - no hypertensive disorder of pregnancy; All babies born to a woman without a hypertensive disorder of pregnancy (HDP) and admitted to a neonatal unit in England and Wales between 1st January 2012 and 31st December 2020

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Survival to discharge from neonatal care	Survival to discharge from neonatal care	From birth to discharge or death, assessed up to 1 year
Primary recorded reason for neonatal unit admission	Primary recorded reason for neonatal unit admission	From birth to discharge or death, assessed up to 1 year
Length of stay in neonatal unit	Length of stay in neonatal unit	From birth to discharge or death, assessed up to 1 year
Number of days of intensive care	Number of days of intensive care	From birth to discharge or death, assessed up to 1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Survival to discharge from neonatal care without comorbidity	Survival to discharge from neonatal care without comorbidity	From birth to discharge or death, assessed up to 1 year
Cause of death	Cause of death	From birth to discharge or death, assessed up to 1 year
Age at death	Age at death	From birth to discharge or death, assessed up to 1 year
Discharge weight SDS (standard deviation score)	Discharge weight SDS (standard deviation score)	From birth to discharge or death, assessed up to 1 year
Birthweight centile (z-score)	Birthweight centile (z-score)	From birth to discharge or death, assessed up to 1 year
Clinical diagnoses potential specific to hypertensive disorders of pregnancy	Fetal growth restriction/intrauterine growth restriction, hypoglycaemia	From birth to discharge or death, assessed up to 1 year
General neonatal complications	Brain injury on imaging, necrotising enterocolitis, sepsis, jaundice, GI perforation	From birth to discharge or death, assessed up to 1 year
Preterm complications	Chronic lung disease/bronchopulmonary dysplasia, retinopathy of prematurity	From birth to discharge or death, assessed up to 1 year
Number of days of high-dependancy care	Number of days of high-dependancy care	From birth to discharge or death, assessed up to 1 year
Number of days of special care	Number of days of special care	From birth to discharge or death, assessed up to 1 year
Number of days of invasive respiratory support	Number of days of invasive respiratory support	From birth to discharge or death, assessed up to 1 year
Number of days of non-invasive respiratory support	Number of days of non-invasive respiratory support	From birth to discharge or death, assessed up to 1 year
Transfusion of blood products	Transfusion of blood products	From birth to discharge or death, assessed up to 1 year
Number of days of parenteral nutrition	Number of days of parenteral nutrition	From birth to discharge or death, assessed up to 1 year
Method of feeding (number of days of each e.g. NG, breast etc)	Method of feeding (number of days of each e.g. NG, breast etc)	From birth to discharge or death, assessed up to 1 year
Type of feeding (number of days of each e.g. breastmilk, formula etc)	Type of feeding (number of days of each e.g. breastmilk, formula etc)	From birth to discharge or death, assessed up to 1 year
Number of days nil by mouth	Number of days nil by mouth	From birth to discharge or death, assessed up to 1 year
Line type(s)	Line type(s)	From birth to discharge or death, assessed up to 1 year
Surfactant administered	Surfactant administered	From birth to discharge or death, assessed up to 1 year
Surfactant administered on first day	Surfactant administered on first day	From birth to discharge or death, assessed up to 1 year

Collaborators and Investigators

• Sponsor: Imperial College London
• Investigators: Principal Investigator: Cheryl Battersby, Imperial College London; Principal Investigator: Lucy Chappell, King's College London

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2021
• Primary Completion (Anticipated): September 1, 2023
• Study Completion (Anticipated): December 1, 2023

Study Registration Dates

• First Submitted: August 10, 2021
• First Submitted That Met QC Criteria: August 17, 2021
• First Posted (Actual): August 20, 2021

Study Record Updates

• Last Update Posted (Estimate): January 26, 2023
• Last Update Submitted That Met QC Criteria: January 24, 2023
• Last Verified: January 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Infections; Pregnancy Complications; Toxemia; Hypertension; Hypertension, Pregnancy-Induced
• Other Study ID Numbers: 295875

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No