The intrauterine to intra-arterial pressure ratio: a new parameter for the study of uterine contractility physiology

Abstract

The objective of the study was to examine the uterine contractions and the arterial perfusion pressure changes after application of oxytocin, endothelin 1, prostaglandins PGE(1), PGE(2) and PGF(2alpha), in order to identify the substance with the greatest intrauterine pressure (IUP)/intra-arterial pressure (IAP) ratio, which means the substance most suitable for inducing uterine contractility without raising the systemic vascular pressure. Increasing doses of oxytocin, endothelin 1, PGE(1), PGE(2) and PGF(2alpha) were applied as bolus injection through the uterine artery of perfused swine uteri and the intrauterine and intra-arterial pressure rises were recorded. All substances showed a significant cervicofundic pressure gradient and, with the exception of PGF(2alpha), the uterine peristalsis moved towards the cervix uteri. The perfusion pressure after application of oxytocin, PGE(1), PGE(2) and PGF(2alpha) reached a maximum value and started to decrease, whereas endothelin 1 caused a continuous increase in the perfusion pressure. Endothelin 1 showed the lowest IUP/IAP ratio and oxytocin the greatest. In conclusion, the IUP/IAP ratio provides a promising new parameter for the study of uterine contractility physiology. Besides oxytocin, PGE(2) and PGF(2alpha) emerged as the best candidate substances to improve uterine contractility without raising the intra-arterial pressure.

Pregnancy outcomes in patients with uterine fibroids treated with ultrasound‐guided high‐intensity focused ultrasound

“…Secondly, the high estrogen levels associated with fibroids leads to an overgrowth of the endometrium near the fibroid, resulting in abnormal metrorrhagia, failed implantation, and even pathological alteration of the intima, and impairment of the fertility . Thirdly, the uterine contraction and peristalsis dysfunction caused by uterine fibroids leads to ectopic pregnancy, retrograde menstruation, endometriosis and infertility . Fourthly, the change in the receptivity of the endometrium affects implantation and causes infertility .…”

“…In addition, the rate of miscarriage of women with uterine fibroids is 20–30%, two to three times higher than that of women without such fibroids . The common factors leading to infertility or miscarriage are: fibroid‐induced anatomical changes in the uterus, high estrogen, uterine contraction and dysmotility, and the decline of receptivity of the endometrium and ovulation dysfunction. The fibroids also increase the risk of pregnancy complication and are a cause of premature delivery, abnormal fetal position, premature rapture of membranes, placenta praevia, placental abruption, postpartum haemorrhage, and an increased rate of puerperal infection.…”