Aim: To characterise maternal haemodynamic changes using non-invasive methods throughout normal healthy pregnancy. Method: The Task Force haemodynamic monitor (CNSystems, Austria) was used to assess 54 healthy pregnant women aged 20-41 years at 15.1±1.8 weeks (T1, n=26), 26.0±1.0 weeks (T2, n=18) and 35.8±1.1 weeks (T3, n=10). Cardiac interval (RR), stroke volume (SV), cardiac output (Q), left ventricular ejection time (LVET), end diastolic volume index (EDI), acceleration index (ACI), systolic and diastolic blood pressure (BPs, BPd) and vascular compliance (C) were quantified. Participants performed postural manoeuvres (supine, standing), stepping exercise, seated recovery (all 6 minute blocks), mental arithmetic, controlled and spontaneous breathing (all 3 minute blocks). Mixed between-within repeated measures ANOVA assessed the influence of main factors ‘Protocol Stage’ and ‘Trimester’ on each haemodynamic variable. Post-hoc analysis with Bonferroni correction identified the locations of significant differences. One way ANOVA additionally assessed the stage-specific influence of trimester on haemodynamic variables. Results: When subjects moved from supine to standing we observed the following responses (Δ indicates change between stage, + or – indicates a positive or negative between-state change, ≡ indicates no change): During the supine-to-standing change (1) ΔRR- in T1 was diminished during T3 (p=0.002), (2) ΔSV- in T1 increased to ΔSV≡ in T3 (p<0.002), (3) ΔQ- in T1 increased to ΔQ+ in T3 (p<0.05), (4) ΔLVET- was diminished between T1, T2 and T3 (p<0.01), (5) ΔEDI- increased to ΔEDI+ in T2 and T3 (p<0.05). During the metronomic-to-spontaneous breathing change we observed that: (7) ΔC- in T1 increased to ΔC+ in T3 (p<0.01), (8) ΔACI- became more pronounced from T1 to T2 and T3 (p<0.0001). Conclusion: Despite these being early results, we observed marked gestation-related changes in cardiovascular and haemodynamic responses to postural change and breathing rate. The altered physiology during the change from supine to standing might be related to autonomic function changes as pregnancy progresses and also due to increased systemic blood flow with gestation. At the early stage of pregnancy (T1) metronomic breathing is associated with greater compliance of the blood vessels whereas in T3 the opposite applies. This might be associated with haemodynamic restrictive changes caused by the baby. We are planning to develop this protocol to be used as a screening tool in the future to help assess pathophysiological complications during pregnancy.