The influence of ethnicity on blood pressure trajectories in pregnancy: Analysis using data from the born in bradford cohort

Publication authors

Farrar D.; Santorelli G.; Tuffnell D.; Sheldon T.; Lawlor D.; Macdonald-Wallis C.


Introduction Hypertensive disorders of pregnancy (HDP) are associated with increased maternal and infant morbidity and mortality. Early identification of women likely to develop HDP affords an opportunity to increase surveillance and provide preventative interventions. It is unclear however if blood pressure (BP) trajectories are influenced by ethnicity. We aim to determine BP trajectories, patterns of BP change and HDP prevalences, in Pakistani (P) and white British (WB) women, using UK NICE recommended criteria. Methods Linear spline models, with five parameters (8, 8-24, 24- 30, 30-36, >36 weeks of gestation) with adjustment for covariates including gestational length were produced along with prevalence estimates of HDP, using data from the Born in Bradford cohort. Results Of 8818 eligible women, 4721 were P and 4097 were WB. Analysis shows that P compared to WB women who were normotensive, developed gestational hypertension or preeclampsia had lower BP trajectories. For example, mean SBP (mmHg) at 8 and 36 weeks for normotensive P and WB women was 108.6 (CI: 108.4-108.7) and 113.6 (113.5-113.8) and 111.6 (111.3-111.8) and 116.9 (116.6-117.1) respectively. Similar differences in mean SBP and DBP for women who developed gestational hypertension and pre-eclampsia were observed between the two ethnic groups. 599 (12.7%, CI: 11.8-13.7) P and 961 (23.5%, 22.2-24.8) WB women developed gestational hypertension and 313 (6.6%, 6.1-7.4) P and 468 (11.4%, 10.5-7.6) WB women developed pre-eclampsia. Conclusion P compared to WB women have significantly lower BP trajectories early in pregnancy; this pattern continues to term. P women are less likely than WB women to develop a HDP