Hypertension in pregnancy: Prevalence, risk factors and outcomes for women birthing in Ireland.

Objectives: The purpose of this study was to identify the number of pregnancies affected by hypertension in Ireland and report on possible risk factors and adverse pregnancy outcomes for women and their babies.

Study Design: Data on maternity hospital discharges for women giving birth in Ireland in 2016 were extracted from the national Hospital In-Patient Enquiry data system. Women with a diagnosis of a hypertensive disorder of pregnancy were identified using relevant ICD codes. Descriptive statistics were used to present prevalence, and Pearson's Chi-square and multivariable regression analyses were conducted to identify risk factors and pregnancy outcomes. Differences between proportions were analysed by Pearson's Chi-squared test of independence.

Results: Of 60,188 maternities reported for the year 2016, 5.9% of women (n = 3531) had a hypertensive disorder of pregnancy and 4.6% (n = 2790) had pre-eclampsia. Rates were higher among women with pre-existing diabetes, gestational diabetes, obesity and those aged ≥40 years. After adjusting for maternal age, pre-existing DM, GDM, obesity and tobacco use, obesity (AOR 4.3; 95% CI: 3.2-5.7; p < 0.001), pre-existing diabetes (AOR 3.5; 95% CI: 2.5-4-9; p < 0.001), gestational diabetes (AOR 1.5; 95% CI: 1.3-1.8; p < 0.001) and being aged ≥40 years (AOR 1.5; 95% CI: 1.3-1.7; p < 0.001) remained significantly associated with being diagnosed with a hypertensive disorder of pregnancy in the Republic of Ireland.

Conclusion: In Ireland where maternal age at childbirth is increasing, the association of hypertension with advancing age will undoubtedly contribute to a greater prevalence of hypertensive disorders of pregnancy and their potential adverse outcomes for pregnant women and their babies. This retrospective study highlights the prevalence rates in Ireland while also identifying possible risk factors and associated adverse pregnancy outcomes. They pinpoint the need for further research to look in more detail at risk factors and adverse outcomes for the 79% (n = 2790) of women presenting with pre-eclampsia among this large nationally representative sample of women.