The Risk of Pregnancy Related Hypertension Disorder Associated with Sickle Cell Trait in US Service Women

Introduction The health impact of the heterozygous (Hb Ss) Sickle Cell Trait (SCT) among the estimated one million females of reproductive age in the United States on pregnancy related hypertensive disorders (PRHD) including preeclampsia is not as well understood or researched as Sickle Cell Disease (SCD). Materials and Methods This retrospective cohort study included 25,020 U.S. enlisted, active duty service women during 1992 to 2013. Race within the sample is primarily black (84%) given that blacks have the highest prevalence of SCT. All 5,004 SCT positive individuals and a matched sample of 20,016 from those considered SCT negative were followed while on active duty for PRHD outcomes including gestational hypertension (GHTN), preeclampsia and eclampsia. Results The adjusted incidence rate ratio (IRR) for any PRHD in SCT positive compared to negative individuals was 1.46 (95% CI 1.32 - 1.62). SCT positive versus negative subjects had higher health care utilization rates and utilization rate ratios (URR) for all PRHD diagnoses combined 2.03 (95%CI: 1.97 - 2.10) and for each specific PHRD diagnosis. The prevalence of preeclampsia or eclampsia did not vary by SCT status. The overall PRHD attributable risk due to SCT was 30.4% (95% CI 23.1-37.1%) and the overall number needed to screen to detect a case of PRHD was 156 (95% CI 117-220). Conclusions The results of this study indicate that being SCT positive is a risk factor for PRHD and provides evidence that SCT status may have an adverse effect on reproductive health. Future research needs to include other known risk factors for PRHD to include gravity and parity history, BMI, past history of PRHD prior to enlistment as well as to examine the association with maternal/child pregnancy outcomes.