Introduction
In the United Kingdom (U.K.), although the overall maternal mortality rate (MMR) has remained low1, significant racial disparities within maternal outcomes have persisted. The most recent Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries-U.K. (MBRRACE-U.K.) report revealed that Black women are four times more likely to die than their White counterparts due to pregnancy related complications.1 Black women are also more likely to suffer from severe maternal morbidity, or so called “near-miss” events even when potential confounding factors such as socioeconomic and smoking status, and high Body Mass Index (BMI) are accounted for.2
Amongst indirect causes of maternal mortality, cardiovascular disease remains the most significant contributor.1Hypertensive disorders in pregnancy (HDP), which encompass gestational hypertension, pre-eclampsia and pre-existing hypertension, are classified as direct causes of maternal mortality, however it is irrefutable that HDP in addition to the physiological changes of pregnancy can considerably exacerbate pre-existing cardiovascular disease leading to increased morbidity and mortality.3HDP complicate up to 10 percent of pregnancies4 and having a diagnosis of HDP also increases the risk of developing cardiovascular disease in later life.5 It is therefore imperative that HDP is managed in an appropriate and timely manner.
In a non-pregnant patient, first line management of hypertension differs based on ethnicity.6 In the U.K., NICE guidelines recommend commencing Calcium Channel Blockers (CCB) initially for treatment of raised blood pressure in patients of any age from Black African and African Caribbean origin.7 The variance in initial pharmacological management is because in Black patients with hypertension, there is evidence to suggest that CCB monotherapy is more effective at reducing blood pressure than Beta Blocker monotherapy.8 Presently, the first line pharmacological management of all pregnant women with hypertension and pre-eclampsia in the U.K. is the non-specific alpha- and beta- blocker, Labetalol.9 Although, there have been numerous clinical trials investigating the management of hypertensive disorders in pregnancy, there is a lack of knowledge regarding whether the race based differences in first line anti-hypertensive management out with pregnancy should extend to pregnant women.
Therefore, our primary objective was to address this gap in evidence by undertaking a systematic review of all randomised control trials investigating pharmacological management of HDP to assess whether CCBs are the most effective anti-hypertensive agent in Black pregnant women.