Assessment of target organ damage in hypertensive pregnancy

This editorial refers to ‘Temporal patterns of pre- and post-natal target organ damage associated with hypertensive pregnancy: a systematic review’, by H. R. Cutler et al., https://doi.org/10.1093/eurjpc/zwad275.

Pregnancy is associated with numerous pathophysiological changes including vascular adaptations, hormonal fluctuations, and immune system modifications.¹ These changes impact nearly all organ systems, encompassing the cardiovascular, respiratory, renal, gastrointestinal, and haematologic systems.¹ Hypertension is the most common medical disorder encountered during pregnancy.² Hypertensive disease in pregnancy (HDP) encompasses a spectrum of conditions, including gestational hypertension, pre-eclampsia/eclampsia, chronic hypertension, and HELLP syndrome (haemolysis, elevated liver enzymes, and low platelets).³ These conditions affect 5–10% of pregnancies worldwide and contribute to maternal mortality rates of 2–7% annually in the USA alone.^4,5 Hypertensive disease in pregnancy significantly elevates the risk of long-term cardiovascular morbidity and mortality, persisting for decades following delivery.^6,7 Hypertensive disease in pregnancy can lead to multiorgan dysfunction.⁸ Early management for HDP is necessary to prevent progression to severe hypertension and maternal complications.⁹

Cutler et al.¹⁰ conducted a systematic review to gain insight into the potential benefits of early preventive interventions by examining the temporal patterns of targeted organ damage associated with hypertensive pregnancy, both pre- and post-natal. Cutler et al. observed that women experiencing hypertensive pregnancies initially displayed signs of left ventricular hypertrophy, white matter lesions, proteinuria, and changes in retinal microvasculature. Notably, despite a reduction in blood pressure shortly after childbirth, cardiac, cerebral, and retinal abnormalities continued to be present both in the early and late postpartum periods. Furthermore, cognitive dysfunction was noted during the late postpartum period. This study is characterized by several significant strengths, notably its comprehensive exploration of hypertensive targeted organ damage across various physiological systems at different time points ranging from pregnancy through the postpartum period. It significantly contributes to the body of knowledge due to its inclusion of a substantial number of studies (a total of 76) and a remarkable sample size involving 1 742 698 pregnancies, which collectively bolster the reliability and generalizability of the findings. This study also employs a meticulous methodology conducted across reputable databases, rigorous assessment of potential bias, and a discerning focus on high-quality studies, thereby ensuring the robustness and credibility of the data used for analysis.

However, its utilization of a synthesis approach without meta-analysis, while serving as a valuable qualitative tool, inherently limits its capacity to quantitatively assess overall effect sizes and statistical significance, potentially neglecting crucial nuances in the data. There is the possibility of introducing publication bias since the study predominantly relies on published articles, which could inadvertently exclude studies with non-significant results. The inherent diversity in study designs and patient populations may result in heterogeneity, posing challenges in synthesizing findings cohesively. While the study adeptly identifies the timing of targeted organ damage emergence, it may not delve comprehensively into the exploration of causality or the underlying mechanisms at play. Lastly, the extent of generalizability of the findings may be contingent upon various factors, such as geographic location, socioeconomic status, and healthcare access, which warrant further discussion and consideration. This study did not address potential confounding factors, such as maternal age, lifestyle, underlying disease in the maternal etc., that could influence the development of hypertensive targeted organ damage during pregnancy and postpartum.

Understanding the temporal patterns of organ damage from pregnancy to the postpartum period offers numerous advantages in healthcare and medical research. This knowledge enables early detection of health issues, allowing healthcare professionals to promptly intervene and manage potential complications. Pregnancy prompts coordinated changes in various organ systems to support both mother and fetus.¹¹ The female reproductive system adapts with uterus enlargement and hormonal control.¹² Cardiovascular adjustments include increased cardiac output, while systemic vascular resistance decreases, impacting blood pressure.¹³ Pulmonary changes affect lung capacity and ventilation.¹⁴ Gastrointestinal shifts lead to morning sickness and slower bowel motility.¹⁵ Renal adaptations involve increased filtration rate and kidney size.¹⁶ Haematological modifications result in dilutional anaemia.¹⁷ Endocrine alterations affect thyroid, aldosterone, cortisol, and prolactin levels.¹⁸ Musculoskeletal and dermatologic adjustments include posture shifts and skin pigmentation.^19,20 Pregnancy metabolism involves hormonal influences on insulin resistance, lipid levels, and increased nutritional demands.^21,22

Tailored monitoring and screening protocols can be implemented for pregnant individuals with a history of hypertension, ensuring that any emerging organ damage is identified in a timely manner. For researchers, it provides valuable insights into the mechanisms underlying organ damage, aiding in the development of improved strategies for both prevention and management. Finally, healthcare resource allocation can be more efficient; hospitals and healthcare systems are more prepared to address potential postpartum complications based on the anticipated timing, ensuring that the necessary infrastructure and expertise are readily available. In sum, comprehending the temporal dynamics of organ damage during and after pregnancy contributes to enhanced clinical care, advances in research, and improved patient outcomes in the context of hypertensive pregnancies.

Funding

E.T. is supported by the National Heart, Lung, and Blood Institute HL121776.