Ultrasound evaluation of the uterine zonal anatomy during in-vitro fertilization and embryo transfer

This study was designed to establish if ultrasound could detect differences in uterine zonal anatomy between conception and non-conception in-vitro fe rtilization (IVF)/embryo transfer cycles. A transvaginal ultrasound scan wa s performed on the day of downregulation (DO), on day 8 of ovulation induct ion (D8), on the day of human chorionic gonadotrophin (HCG) injection, at t he time of oocyte retrieval, and at embryo transfer. Thicknesses of endomet rium, junctional zone, myometrium and full thickness of the uterus were rec orded for every patient and comparisons made at all the assessment points, Differences between measurements on DO and all other measurements (temporal changes) and between every subsequent measurement (dynamic changes) were a lso compared. There were no statistically significant differences in endome trial thickness between pregnant and non-pregnant groups at any time. The d iameter of the uterus increased during therapy and was significantly greate r in the pregnant subset at the time of HCG injection, oocyte retrieval and embryo transfer (P < 0.02, 0.03 and 0.02 respectively). The myometrium was significantly thicker in the pregnant group on D0, on D8 and at HCG admini stration (P < 0.03, 0.004 and 0.02), There was a decrease in junctional zon e thickness in both groups during the first week of ovulation induction, an d on D8 the junctional zone in pregnant patients was significantly thinner (P < 0.04). The junctional zone became significantly thicker at embryo tran sfer in the pregnant group (P < 0.01). This was confirmed by significant te mporal and dynamic changes at the time of oocyte retrieval and embryo trans fer (P < 0.01, 0.0001 and P < 0.05, 0.01 respectively). In the patients who did not conceive, changes in the junctional zone were less pronounced. In conclusion, it was not possible to predict the likelihood of pregnancy from endometrial thickness at any time during the IVF cycle, but changes occurr ed in other uterine layers that were more pronounced in conception cycles. The responsiveness of the junctional zone seems to be associated with impla ntation, and its measurements at the time of downregulation and embryo tran sfer can be used to predict treatment outcome.