Uterine contractility and elastography as prognostic factors for pregnancy after intrauterine insemination

Abstract

Objective: To determine the impact of the frequency and intensity of uterine contractions (UCs) at the time of IUI on subsequent fertility.

Design: Observational pilot study.

Setting: University hospital.

Patient(s): One hundred volunteer women scheduled for IUI between April 2011 and July 2013, in whom UCs were assessed during the ultrasound before IUI.

Intervention(s): A two-dimensional sagittal uterus elastography was recorded for 5 minutes. The elasticity index, defined as the mean ratio of elastographic measurements between the subendometrial area (of interest) and the endometrial area (control), was computed. UC frequency, endometrial thickness and volume, and subendometrial vascularisztion were also measured.

Main outcome measure(s): These parameters, along with characteristics of the IUI cycle, were entered into a logistic regression model for predicting ongoing pregnancy.

Result(s): The elasticity index was significantly higher (2.4 ± 1.3 vs. 1.5 ± 0.7, i.e., with stiffer myometrium), and the endometrium was significantly less echogenic in future pregnant women. Factors closely reaching significance were age, previous fertility, day 3 hormonal assessments, number of inseminated spermatozoa, endometrial thickness, and UC count. In multivariate analysis, low UC frequency (<2.8/minute; odds ratio [OR] = 0.039), high elasticity index (>1.7; OR = 63.26), high endometrial thickness on the ovulation triggering day (>8 mm; OR = 28.21), and low patient age (<32 years; OR = 0.001) were predictive of pregnancy after IUI.

Conclusion(s): A low frequency and high intensity of UCs at the day of IUI appears associated with a higher pregnancy rate. Elastography provides a promising innovative tool for IUI monitoring.

Keywords: Uterine contraction; artificial insemination; elastography; pregnancy rates; ultrasonography.