Main findings
There are four main findings from the large FMF prospective study in women with singleton pregnancies living in England. First, multiple logistic regression analysis demonstrated that in addition to black racial origin, increased risk for PE is provided by increasing maternal age and weight, conception by IVF, history of chronic hypertension and diabetes type 1, family history of PE and previous pregnancy affected by PE; the risk for PE decreases with increasing height, cigarette smoking, and previous birth of small for gestational age neonate. Second, in black women, compared to white women, after adjustment for elements of maternal characteristics and medical history there is a 2-fold, 2.5-fold and 3-fold higher risk of total PE, preterm PE and early PE, respectively, and a 25% increase in the risk of GH. Third, in women of South Asian racial origin, compared to white women, there is a 1.5-fold higher risk of preterm and early PE but no significant difference in total PE or GH. Fourth, in women of East Asian racial origin, compared to white women, there is no significant difference in the risk of PE or GH.
The literature search identified only 19 studies that provided data on the incidence of PE in some of the racial groups as defined by the FMF study. In the assessment of the quality of the included studies only two were considered to be at low risk of bias. In the meta-analyses of data from previous studies combined with those of the FMF study the unadjusted risk of PE in black women, compared to white women was higher and in women of East Asian origin, compared to white women, the risk was lower; in women of South Asian racial origin, compared to white women, the risk was not significantly different. However, in the meta-analysis of three previous studies that provided adjusted ORs, albeit with adjustment for very few relevant maternal characteristics, combined with our data the risk of PE in women of black and South Asian racial origin, compared to white women, was increased, whereas in East Asian women the risk of PE was not significantly different from that in white women.