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 incre asing doses of P administered to estrogenized women and to compare two meth odologies 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 e very 2 days by application of 1.125 g of Crinone 4% and 8% or 2.2-5 g of Cr inone 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 visua lizing accelerated image sequences and using a previously described three-d imensional (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 fr equency on ultrasound scans were equivalent. Conclusion(s): At all three doses studied, the vaginal P gel Crinone admini stered to estrogenized women induced a profound decrease in uterine contrac tion frequency that duplicated the changes in contractility described in th e luteal phase of the menstrual cycle. Analyzing uterine contraction freque ncy on accelerated image sequences is as effective as our more complex appr oach based on identifying contractions on time mode graphs electronically r econstructed using 3D-software. (Fertil Steril(R) 2001;76:736-40. (C) 2001 by American Society for Reproductive Medicine.).