Uterine junctional zone contractions during assisted reproduction cycles

This study was designed to assess junctional zone contractions (JZ) during cycles of in-vitro fertilization (IVF) and embryo transfer in oocyte donors exposed to a long protocol regime for ovarian stimulation. Real-time transvaginal ultrasound and advanced audio-visual and computer technology were used to evaluate the contraction pattern, frequency and velocity. At the time of down-regulation JZ contractions were not observed. After 7 days of superovulation all patients displayed cervico-fundal, fundo-cervical and random contractions. Cervico-fundal waves dominated the picture at the time of human chorionic gonadotrophin injection. However, the activity was strongest on the day of oocyte retrieval. At that time the percentage of opposing waves increased and fundo-cervical waves disappeared. The highest wave frequency and velocity (4.29+/-0.68 waves/min and 2.73+/-0.54 mm/s respectively) were observed at the time of oocyte retrieval. All patients had some JZ activity on days 2, 3 and 4 after oocyte retrieval but regular wave-like contractility gradually decreased and only single random movements were seen on day 4 after oocyte retrieval. In conclusion, JZ activity throughout the IVF cycle is more exaggerated when compared to the results reported from observations of the natural cycle but follows a similar pattern. This fact can probably be explained by the vastly different hormone levels. Higher JZ activity and correspondingly increased mobility of the endometrium may impair its receptivity and affect implantation.