Human fetal cardiac function during the first trimester of pregnancy

• Published in: Heart (British Cardiac Society) Vol. 91; no. 3; pp. 334 - 338
• Main Authors: Mäkikallio, K, Jouppila, P, Räsänen, J
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Cardiovascular Society 01.03.2005; BMJ; BMJ Publishing Group LTD; Copyright 2005 by Heart
• Subjects: atrioventricular valve regurgitation; AVVR; Biological and medical sciences; Blood Flow Velocity - physiology; Cardiac function; Cardiology. Vascular system; Cardiovascular Medicine; Diastole - physiology; Doppler; early pregnancy; Female; Fetal Heart - diagnostic imaging; Fetal Heart - physiology; fetus; Fetuses; Gestational age; Heart rate; Heart Rate - physiology; Hemodynamics; Humans; ICT; IRT; Longitudinal studies; mean velocity; Medical sciences; Physiology; Pregnancy; Pregnancy Trimester, First; proportion of isovolumetric contraction time; proportion of isovolumetric relaxation time; Prospective Studies; pulsatility index; Systole - physiology; Tricuspid Valve Insufficiency - physiopathology; Ultrasonic imaging; Ultrasonography, Doppler - methods; Umbilical Arteries - physiology; Veins & arteries; Velocity; ventricular function; Vmean; Pregnancy; Human; Fetus; First trimester; Cardiac performance
• ISSN: 1355-6037; 1468-201X
• DOI: 10.1136/hrt.2003.029736

Objective: To investigate first trimester human fetal cardiac function in relation to cardiac volume blood flow, and peripheral arterial and venous blood flow patterns. Methods: Transvaginal Doppler ultrasonography was performed in 16 uncomplicated pregnancies at 6+, 7+, 8+, 9+, and 10+ gestational weeks. The shape of the inflow waveform and the presence of atrioventricular valve regurgitation (AVVR) were noted. The outflow mean velocity (Vmean) was calculated. The proportions of the isovolumetric relaxation (IRT%) and contraction times (ICT%) of the cardiac cycle were defined. Ductus venosus and umbilical artery pulsatility indices (PI) were obtained. Results: Every inflow waveform was monophasic before 9+ weeks. At 9+ weeks 11 of 16 and at 10+ weeks all waveforms were biphasic. At 7+ and 8+ weeks AVVR was documented in one case. At 9+ and 10+ weeks AVVR was present in four and seven fetuses, respectively. Mean (SD) outflow Vmean increased between 6+ and 8+ weeks from 3.6 (1.5) to 8.4 (3.0) cm/s (p < 0.05). IRT% decreased significantly from 6+ to 7+ weeks (39.8 (2.6) to 19.2 (6.2), p < 0.001). ICT% decreased between 8+ and 9+ weeks from 13.2 (4.0) to 8.5 (2.5) (p < 0.05). Ductus venosus PIs were unchanged. Umbilical artery Vmean increased between 7+ and 10+ weeks from 1.59 (0.51) to 5.06 (1.06) cm/s (p < 0.001) and PIs remained unchanged. Conclusions: The first trimester of pregnancy is characterised by significant improvements in cardiac diastolic and systolic function with a concomitant increase in cardiac volume blood flow. At 10+ weeks AVVR is a common finding. Placental volume blood flow increases significantly with no change in the placental vascular impedance.