Trajectory of blood pressure levels and weight gain in pregnant women: A group-based approach

Abstract

Background and objectives: Morbidities associated with increased blood pressure levels during pregnancy represent one of the main causes of maternal mortality. The objective was to identify patterns of systolic blood pressure (SPB) trajectory in pregnant women undergoing prenatal care at the Unified Health System, and associations with weight gain trajectory, demographic, obstetric, anthropometric data, and health related behaviors.

Methods and results: Cohort study with pregnant women using the public health services in Brazil. Data were collected through questionnaires and medical records. Trajectory patterns of SBP and weight gain were identified by a group-based trajectory model. For trajectory analysis, 460 women had SBP information available, totaling 2839 measurements, with an average of 6.2 measurements during pregnancy. Three SBP trajectory patterns were identified and classified as "Group 1" (48.0%), with a mean of 103 mmHg (95% CI 102.5-103.7 mmHg), "Group 2" (42.7%) with a mean of 114 mmHg (95% CI 113.7-114.9 mmHg), and "Group 3" (9.1%) with the highest mean SBP value of 130 mmHg (95% CI 128.8-131.5 mmHg). It was observed that regardless of the weight gain trajectory group, women classified in the group with the highest SBP had the highest SBP levels. The probability of being classified in Group 3 was higher among women with higher education, who started pregnancy presenting obesity, and who were using antihypertensive drugs.

Conclusion: The probability of belonging to groups with a greater trajectory of SBP during pregnancy was associated with obesity, education, and hypertension under treatment.

Keywords: Blood pressure trajectory; Longitudinal studies; Pregnancy; Weight gain.