Uterorelaxing effects of vaginal progesterone: comparison of two methodologies for assessing uterine contraction frequency on ultrasound scans

Objective: To assess the changes in uterine contractility induced. by increasing doses of P administered to estrogenized women and to compare two methodologies for assessing uterine contraction frequency from ultrasound scans. Design: Prospective double-blind parallel study. Setting: Academic tertiary center. Patient(s): Infertile women aged 21-39 years with premature ovarian failure. Intervention(s): P support set to duplicate the luteal phase was provided every 2 days by application of 1.125 g of Crinone 4% and 8% or 2.2-5 g of Crinone 8%, containing 45, 90, and 180 mg of P per application, respectively. Main Outcome Measure(s): Changes in uterine contraction frequency following exposure to three doses of vaginal P on ultrasound scans analyzed by visualizing accelerated image sequences and using a previously described three-dimensional (3D)-derived approach. Result(s): A decrease in uterine contraction frequency reached statistical significance on the third day of exposure to P without differences between the three dose groups. The two methods for measuring uterine contraction frequency on ultrasound scans were equivalent. Conclusion(s): At all three doses studied, the vaginal P gel Crinone administered to estrogenized women induced a profound decrease in uterine contraction frequency that duplicated the changes in contractility described in the luteal phase of the menstrual cycle. Analyzing uterine contraction frequency on accelerated image sequences is as effective as our more complex approach based on identifying contractions on time mode graphs electronically reconstructed using 3D-software. (Fertil Steril(R) 2001;76:736-40. (C) 2001 by American Society for Reproductive Medicine.).