Implantation sites after embryo transfer into the central area of the uterine cavity.

A total of 63 pregnancies (47 singleton, 15 twin, 1 triplet) from intracytoplasmic sperm injection cycles were analysed. In all embryo transfers, the catheter was introduced into the endometrial cavity guided by abdominal ultrasound, with the catheter tip placed at the middle point of the endometrial cavity. Gestational sacs (GS) were located 21-24 days after transfer (gestational age=5 weeks) by two-dimensional and three-dimensional transvaginal ultrasound. The uterine cavity was divided into three parts: upper, middle and lower. Furthermore, the upper region was subdivided into right, middle and left areas, and the middle region was subdivided into right and left areas. The frequency of gestational sacs in each area was evaluated. In singleton pregnancies 66.0% (31/47) of the GS were detected in the upper region, 29.8% (14/47) in the middle region and 4.2% (2/47) in the lower region. In multiple pregnancies (twins and triplet) 45.5% (15/33) of the GS were detected in the upper region, 51.5% (17/33) in the middle region and 3.0% (1/33) in the lower region. In conclusion, the results demonstrate that when embryos are transferred to the central area of the uterine cavity there is an increase in implantation rate in the middle region compared with the rate expected in naturally conceived pregnancies (9-15%).

Increased implantation and pregnancy rates obtained by placing the tip of the transfer catheter in the central area of the endometrial cavity.

The influence of endometrial cavity length (ECL) on implantation and pregnancy rates after 400 embryo transfers was studied prospectively in a population with the indication of IVF/intracytoplasmic sperm injection (ICSI). The tip of the transfer catheter was placed above or below the half point of the ECL in a randomized manner. Two analyses were performed: (i) absolute position (AP); embryo transfers were divided into three groups according to the distance between the end of the fundal endometrial surface and the catheter tip (DTC - distance tip catheter): AP1 (n = 212), 10-15 mm; AP2 (n = 158), 16-20 mm; and AP3 (n = 30), > or =21 mm. (ii) relative position (RP)--embryo transfers were divided into four groups according to their RP [RP = (DTC/ECL) x 100]: RP1 (n = 23), < or =40%; RP2 (n = 177), 41-50%; RP3 (n = 117), 51-60%; and RP4 (n = 83), > or =61%. Analysis based on relative distance revealed significantly higher implantation and pregnancy rates (P < 0.05) in more central areas of the ECL. However, analysis based on absolute position did not reveal any difference. In conclusion, the present results demonstrated that implantation and pregnancy rates are influenced by the site of embryo transfer, with better results being obtained when the catheter tip is positioned close to the middle area of the endometrial cavity. In this respect, previous analysis of the ECL is the fundamental step in establishing the ideal site for embryo transfers.

Best site for embryo transfer: the upper or lower half of endometrial cavity?

BACKGROUND: The objective of the present study was to determine the importance of the site of embryo transfer (upper or lower half endometrial cavity) on implantation and clinical pregnancy rates. METHODS: A total of 400 transfers guided by ultrasound were randomly assigned to two groups according to the distance between the uterine fundus and the catheter tip at the time of embryo placement. Group I (n = 200) consisted of transfers corresponding to a distance of < 50% of the endometrial cavity length (ECL), i.e. transfer in upper half of the cavity; and group II (n = 200) consisted of transfers corresponding to a distance of > or = 50%, of the ECL, i.e. transfer in lower half of cavity. The Student's t-test, Mann-Whitney test and Fisher's exact test were used where appropriate. RESULTS: The general characteristics of the study population and the main transfer cycle characteristics had an equal distribution (P > 0.05) between groups I and II. No significant difference in implantation or pregnancy rates was observed between groups I and II. CONCLUSION: The implantation or pregnancy rates were similar whether the embryos were deposited in the upper or lower half of the endometrial cavity.

Power Doppler endometrial evaluation as a method for the prognosis of embryo implantation in an ICSI program.

PURPOSE: The objective of the present study was to evaluate power Doppler of the endometrium as a parameter for the prognosis of embryo implantation in patients who underwent intracytoplasmic sperm injection (ICSI). METHODS: The power Doppler was performed on a transverse section at the level of the uterine fundus on the day of human chorionic gonadotropin in 185 patients who submitted to ovarian stimulation for ICSI. The endometrium was divided into four equal quadrants and classified as grade I, II, III, or IV according to the visualization of the power Doppler in the quadrants. The color Doppler signal was considered to be positive when it reached at least the basal layer of the endometrium. RESULTS: Age, number of days of stimulation, number of follicles > or = 16 mm, number of oocytes in metaphase II retrieved, and fertilization rate did not differ patients with the four different types of endometrial grades. Endometrial thickness and the pulsatility index of uterine artery also were similar for the four grades. The rate of embryo implantation also did not differ significantly (P = 0.53) among groups: grade I = 10%; grade II = 11.6%; grade III = 15.4%; grade IV = 10.5%. The pregnancy rates were grade I = 25%; grade II = 29.7%; grade III = 37.5%; grade IV = 23.8% (P = 0.44). CONCLUSIONS: Our data demonstrate that isolated evaluation of endometrial vascularization with power Doppler is not an important factor for the prediction of pregnancy in an ICSI program.