Resposta hemodinâmica e vascular durante o estresse mental em mulheres com histórico de parto prematuro

Abstract

Introduction: Women with a history of preterm birth have a higher risk of developing hypertension throughout life. In the general population, exaggerated hemodynamic responses to mental stress may precede the development of hypertension; however, it is unclear whether this behavior occurs in women with a history of preterm birth in the absence of cardiovascular disease. Objective: To compare the blood pressure and vascular responses of women with and without a history of preterm birth, free of cardiovascular disease, during a mental stress protocol. Methods: This cross-sectional study included 48 women, 16 with a history of preterm birth and 32 with term birth. Clinical blood pressure was assessed and recorded after ten minutes of rest using a sphygmomanometer. After this evaluation, participants underwent a mental stress protocol using the Stroop Color Word Test, consisting of 3 minutes of baseline followed by 3 minutes of mental stress. Throughout the protocol, blood pressure was continuously monitored minute-by-minute using an oscillometric method, and forearm blood flow was assessed using venous occlusion plethysmography (Hokanson®), four times per minute. Forearm vascular conductance was calculated as the ratio between forearm blood flow and mean arterial pressure, multiplied by 100 and expressed in arbitrary units. Data are presented as mean ± standard deviation. Student’s t test was used to compare age between groups. For comparison of variables during the mental stress protocol, baseline was defined as the mean of the three recorded minutes and compared with the minute-by-minute values obtained during the test. All variables were analyzed using a two-way repeated-measures ANOVA (group × time). A p value ≤ 0.05 was considered statistically significant. Results: Women with preterm birth and those with term birth were similar regarding age (35±6 vs. 34±5 years, p = 0.771) and heart rate (72±6 vs. 69±9 bpm, p = 0.217), respectively. Women with preterm birth exhibited significantly higher clinical systolic blood pressure (118±10 mmHg vs. 110±9 mmHg; p = 0.011) and diastolic blood pressure (70±7 mmHg vs. 66±6 mmHg; p = 0.050) compared with women who had term births. During mental stress, all variables—blood pressure, heart rate, forearm blood flow, and forearm vascular conductance—increased significantly and similarly compared with baseline. No statistical differences were observed between women with preterm or term birth from rest to stress for any of these variables. Conclusion: Women with a history of preterm birth exhibit higher resting clinical blood pressure but preserved blood pressure and vascular responses during mental stress.