UKPREG: UKPREGnancy study - a longitudinal international registry-based cohort study of pregnancy and heart disease

Date of Approval
Application Number
21_000494
Lay Summary
The aim of this study is to examine outcomes for the mother, her new born and her heart, in women with heart disease (HD), in order to develop actions to lower the rate of health complications.

The research questions that will be answered in this project are:
1. How many pregnant women have a diagnose of HD?
2. What are the differences in maternal and new born outcomes among women with HD compared to women without HD?
3. What are the differences in maternal and new born outcomes among women with HD from various ethnic and socioeconomic groups?
4. What are the differences in trends and long-term outcomes of pregnancy and birth in different types of HD?

This will be a retrospective, observational cohort study, including women in the UK and Sweden that have undergone pregnancy and birth between 2000-2020, diagnosed with HD who are included in the CPRD or the Swedish Medical Birth Register.

This project will contribute with numbers of pregnant women diagnosed with and severity of various HD, between different ethnic and socioeconomic groups of women with HD and long-term outcome of HD among women that have undergone pregnancy and birth. A comparison between the UK and Sweden could result in actions to reduce the number of maternal deaths due to HD. This project will lead to a more adequate risk assessment of women with HD that consider pregnancy and generate information both to help plan services in the future and counsel affected women.
Technical Summary
The aim of this study is to lower the rate of maternal morbidity and mortality and the results could lead to a more nuanced risk assessment of women with heart disease (HD) that consider pregnancy and generate information to help plan services and counsel affected women.

The research questions are:
1. What is the prevalence of HD among pregnant women in the UK and Sweden?
2. What are the differences in obstetric and foetal outcomes among women with HD
- compared to women without HD in the UK and Sweden?
- from various ethnic, immigrant and socioeconomic groups in the UK and Sweden?
3. Is the gap between the most and the least deprived women with HD that have undergone pregnancy lesser in Sweden compared to the UK?
4. What are the differences in trends and long-term outcomes of pregnancy in different HD in the UK and Sweden?

This will be a retrospective, observational cohort study of women with and without HD in the UK and Sweden who have undergone pregnancy between 2000-2020, and are included in the CPRD or the Swedish Medical Birth Register and those who have no diagnosis of HD. De-identified UK data from general practitioners will be linked to Hospital Episode Statistics data. The Swedish data will be linked to national health registers.

The sample size will be governed by the size of the datasets. Descriptive analyses will include prevalence of heart disease, maternal characteristics presented as frequencies and percentages, cardiac events and admissions together with mortality data presented with Cumulative incidence function curves. Comparison between groups will be analysed by Chi-square test, T-test, Mann-Whitney U- test, Log-rank and Cumulative incidence function tests as appropriate. Poisson regression for rate ratios, multinomial logistic regression for odds ratios, and survival analysis for time-to-event outcomes will be used.
Health Outcomes to be Measured
Primary outcomes
Miscarriage; abortion; hypertension in pregnancy; pregnancy-induced hypertension; pre-eclampsia; eclampsia; haemolysis elevated liver enzymes low platelet (HELLP) syndrome, placental abruption; anaesthesia; general anaesthesia; regional anaesthesia; mode of delivery; post-partum haemorrhage; stillbirth/live birth; full term birth; gestational age at birth; Apgar score <7 at 5 minutes; small for gestational age (SGA); birth weight; prevalence of heart disease; further cardiac events; further cardiac admission.

Secondary outcomes
Maternal death within 42 days post-partum; maternal death >42 days to one year postpartum; admission to hospital with mental health diagnose; foetal mortality; neonatal mortality; cause-specific mortality; all-cause mortality
Collaborators

Teresia Svanvik - Chief Investigator - University of Oxford

Teresia Svanvik - Corresponding Applicant - University of Oxford

Becky MacGregor - Collaborator - University of Warwick

Marian Knight - Collaborator - University of Oxford

Sarah Hillman - Collaborator - University of Warwick


Linkages
CPRD Mother-Baby Link;HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation Domains;Pregnancy Register