Haemodynamic changes from prepregnancy to very early pregnancy among women planning to conceive in Southwestern Uganda.

Introduction: Normal pregnancy is associated with cardiovascular changes that enable adaptation to the pregnancy state. We sought to describe the haemodynamic changes from prepregnancy to very early pregnancy in women planning to conceive in southwestern Uganda.

Methods: In this prospective cohort study, we enrolled women in southwestern Uganda planning to conceive. Brachial and central blood pressure, heart rate, cardiac output, stroke volume, and peripheral vascular resistance were assessed prepregnancy and repeated in very early pregnancy.

Results: We studied 86 women with a mean age of 27.8 years (SD ± 4.4). The mean gestational age was 7 (±2) weeks at the time of repeat blood pressure measurement. Brachial systolic and diastolic blood pressure decreased in very early pregnancy (116 ± 11 to 114 ± 8 mmHg and 68 ± 6 to 65 ± 5 mmHg, respectively; P  < 0.001). Central systolic and diastolic blood pressure also decreased (112 ± 10 to 109 ± 8 mmHg, P  = 0.003 and 68 ± 6 to 65 ± 5 mmHg, P  < 0.001, respectively), as did peripheral vascular resistance (1450 ± 581 to 1311 ± 276 dyn/s/cm 5P  = 0.038). There was no significant difference in cardiac output (5.3 ± 1.2 vs 5.5 ± 1.1 l/min P  = 0.146) or stroke volume (64 ± 13 to 66 ± 12 ml, P  = 0.172).

Conclusion: Significant haemodynamic changes occur in very early pregnancy. Using late first trimester measurements as a baseline for pregnancy induced changes may not be suitable for understanding the full extent of pregnancy induced haemodynamic changes, or provide a reliable substitute for prepregnancy states.