International Journal of Clinical Obstetrics and Gynaecology
2018, Vol. 2, Issue 3, Part A
Clinical profile of antenatal cases undergoing uterine artery Doppler
Author(s): Dr. Prashanth Adiga, Dr. Kiranmai Tella and Dr. Shripad Hebbar
Abstract: In human placenta, an organ without autonomic innervations, the control of vascular tone is dependent on local release of vasoconstrictors and vasodilators, released from endothelial cells in response to mechanical and chemical stimuli triggered by cardiac output and blood flow requirements. In placental and systemic circulation, the main stimulus regarding control of vascular resistance and blood flow, is related to increments of shear stress by high placental perfusion throughout pregnancy. In addition to the routine scan, bilateral uterine artery Doppler was done. Both uterine arteries were identified at their crossing with the external iliac artery. Pulsed wave Doppler imaging was used with the sampling gate set at 2 mm to cover the entire diameter of the uterine artery and 1 cm distal to the crossing site. The quality of the flow velocity waveform was maximized by using the smallest possible angle of insonation and care was taken to obtain a good waveform with a clear and sharp outline. Pulsatility index (PI) for each uterine artery was obtained by averaging the value of three clear consecutive measurements of waveforms. The incidence of normal outcome was four fold higher in low risk women with normal Doppler than those with abnormal Doppler. This indicates that most of the low risk women with normal PI will have normal pregnancy outcome.