Hypertension is an important cause of other cardiovascular diseases, and its pathophysiological mechanisms have not yet been fully understood. This thesis explored risk factors of hypertension, and attempted to validate whether these associations were causal. Meanwhile, we also focused on global prevalence of menopausal symptoms. By collecting and utilizing data from middle-aged Chinese women, global data on menopausal symptoms, and the general population in Europe, we screened risk factors of hypertension in midlife women (Chapter 2), explored the association between total bilirubin and perimenopausal hypertension (Chapter 3), pooled global prevalence of menopausal symptoms (Chapter 4), and further verified causal effects of hemoglobin and counts of red blood cells and platelets on blood pressure (Chapter 5 & 6). In summary, this thesis found that hemoglobin, red blood cell and platelet counts were positively associated with hypertension in midlife women. Second, serum total bilirubin was negatively associated with hypertension in perimenopausal women. Third, the majority (85%) of global peri- and postmenopausal women experienced menopausal symptoms with around 50% of women suffering from vasomotor symptoms. Fourth, bidirectional associations were found between genetically determined hemoglobin and red blood cell counts with diastolic, but not with systolic blood pressure in the general European population. Finally, consistent but small associations of genetically determined platelet counts with systolic and diastolic blood pressure were observed in the general European population.