Need for developing case definitions and guidelines for data collection, analysis, and presentation for the hypertensive disorders of pregnancy as adverse events following immunization:
There is no universally accepted case definition of gestational hypertension, preeclampsia or eclampsia that occurs following immunisations. This is a missed opportunity, as data comparability across trials or surveillance systems would facilitate data interpretation and promote the scientific understanding of the event. As immunization is considered an essential element of care in pregnancy, the potential complications of this procedure should be understood. Additionally, vaccine studies may be conducted in a variety of settings, including those with fewer resources to perform the same diagnostic testing as in higher resource settings. It is important to provide definitions that can be utilized widely.
Around 10% of all pregnant women will be affected by a hypertensive disorder during pregnancy [1]. Hypertensive disorders of pregnancy are a significant contributor to maternal and neonatal morbidity and mortality, and are implicated in 10–15% of maternal deaths worldwide [1], [2]. The exact mechanism responsible for hypertensive diseases of pregnancy, in particular preeclampsia, is not known. One leading hypothesis is that abnormalities in the development of the uteroplacental unit lead to increased hypoxemia and oxidative stress, which in turn lead to endothelial dysfunction and abnormalities in vascular tone and coagulation [3], [4].
Hypertensive disease in pregnancy encompasses a spectrum of conditions, including gestational hypertension, preeclampsia (which can be further qualified as having severe features), eclampsia, chronic hypertension with superimposed preeclampsia and HELLP (Hemolysis, Elevated Liver Enzymes, Low Platelets) syndrome. Because of differences among the guidelines issued by international societies, diagnosis can occasionally become confusing as terminology may vary. Nevertheless, it is important to differentiate hypertensive disorders that predate pregnancy from those that occur during pregnancy, as well as to categorize patients into more or less serious cases. Furthermore, the specific diagnosis has important treatment implications, such as timing of delivery. The definitive treatment for hypertensive diseases of pregnancy is delivery.
