L Zhu1, L Xiao, H S Che, Y P Li, J T Liao. 1. Department of Reproductive Medicine, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha City, Hunan Province, P.R. China 410008.
Abstract
STUDY QUESTION: What is the effect of uterine peristalsis on fluid migration after mock embryo transfer? SUMMARY ANSWER: Uterine peristaltic wave frequency was positively correlated with the distance that fluid moved after it was deposited in the uterine cavity. WHAT IS KNOWN ALREADY: Embryos have been found outside the uterine cavity after embryo transfer. It has been suggested that uterine contractions expelled these embryos. STUDY DESIGN, SIZE, DURATION: A prospective cohort study of a total of 112 infertile women was conducted between March 2013 and May 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS: Uterine peristaltic activity was assessed before and after a mock embryo transfer, in which 20 µl of ultrasound contrast agent was placed in the uterine lumen 3 days after ovulation in a natural cycle. The movement of this fluid was measured by ultrasound at 0, 15 and 30 min after placement. MAIN RESULTS AND THE ROLE OF CHANCE: The uterine peristaltic wave frequency was significantly higher after than before mock transfer (3.06 ± 0.99 versus 2.24 ± 0.74, P < 0.01). At the conclusion of the 30-min monitoring period, the fluid had remained in place (N = 94), leaked into the cervix (N = 5), or moved into the Fallopian tubes or the cornua of the uterus (N = 11). The fluid movement was positively correlated with uterine peristaltic wave frequencies before (r = 0.518, P < 0.01) and after embryo transfer (r = 0.371, P < 0.01) and uterine peristaltic wave frequency was significantly higher both before and after embryo transfer in cases where the fluid was extruded. LIMITATIONS, REASONS FOR CAUTION: Mock embryo transfer was performed in the luteal phase of a natural cycle instead of a controlled ovarian stimulation cycle. The endometrial environment and uterine peristalsis may be different in a stimulated cycle. WIDER IMPLICATIONS OF THE FINDINGS: Uterine peristalsis exerts control over embryo migration and could adversely affect the chances of pregnancy if the wave frequency is too high. It could be used as a predictor of uterine irritability before embryo transfer. STUDY FUNDING/COMPETING INTEREST(S): The authors declare that they have not received any particular study funding and do not have competing interests in this study.
STUDY QUESTION: What is the effect of uterine peristalsis on fluid migration after mock embryo transfer? SUMMARY ANSWER: Uterine peristaltic wave frequency was positively correlated with the distance that fluid moved after it was deposited in the uterine cavity. WHAT IS KNOWN ALREADY: Embryos have been found outside the uterine cavity after embryo transfer. It has been suggested that uterine contractions expelled these embryos. STUDY DESIGN, SIZE, DURATION: A prospective cohort study of a total of 112 infertile women was conducted between March 2013 and May 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS: Uterine peristaltic activity was assessed before and after a mock embryo transfer, in which 20 µl of ultrasound contrast agent was placed in the uterine lumen 3 days after ovulation in a natural cycle. The movement of this fluid was measured by ultrasound at 0, 15 and 30 min after placement. MAIN RESULTS AND THE ROLE OF CHANCE: The uterine peristaltic wave frequency was significantly higher after than before mock transfer (3.06 ± 0.99 versus 2.24 ± 0.74, P < 0.01). At the conclusion of the 30-min monitoring period, the fluid had remained in place (N = 94), leaked into the cervix (N = 5), or moved into the Fallopian tubes or the cornua of the uterus (N = 11). The fluid movement was positively correlated with uterine peristaltic wave frequencies before (r = 0.518, P < 0.01) and after embryo transfer (r = 0.371, P < 0.01) and uterine peristaltic wave frequency was significantly higher both before and after embryo transfer in cases where the fluid was extruded. LIMITATIONS, REASONS FOR CAUTION: Mock embryo transfer was performed in the luteal phase of a natural cycle instead of a controlled ovarian stimulation cycle. The endometrial environment and uterine peristalsis may be different in a stimulated cycle. WIDER IMPLICATIONS OF THE FINDINGS: Uterine peristalsis exerts control over embryo migration and could adversely affect the chances of pregnancy if the wave frequency is too high. It could be used as a predictor of uterine irritability before embryo transfer. STUDY FUNDING/COMPETING INTEREST(S): The authors declare that they have not received any particular study funding and do not have competing interests in this study.