Ultrasound-guided embryo transfer improves pregnancy rates and increases the frequency of easy transfers

BACKGROUND: Recent reports have suggested that ultrasound (US) guidance during embryo transfer might improve pregnancy rates. METHODS: A prospective randomized (computer-generated random table) trial was performed to compare embryo transfer under abdominal US guidance (n = 255 women) with clinical touch embryo transfer (n = 260). RESULTS: The clinical pregnancy rate was 26.3% (67/255) in the US-guided transfer group compared with 18.1% (47/260) in the clinical touch transfer group (P < 0.05). The implantation rate was 11.1% (100/903) in the US group compared with 7.5% (66/884) in the clinical touch group (P < 0.05). US-guided transfer was associated with a decrease in the difficulty of the transfers: 97% of transfers were easy in the US-guided group compared with 81% in the clinical touch group (P < 0.05). CONCLUSIONS: US-guided embryo transfer increased pregnancy and implantation rates in IVF cycles, as well as the frequency of easy transfers. It is suggested that the decrease in cervical and uterine trauma can play a role in the increase in pregnancy rates associated with US-guided transfer. It is recommended that embryo transfer should be performed under US guidance.     

Embryo transfer: ultrasound-guided versus clinical touch.

In this prospective control study, the pregnancy and implantation rates were compared between ultrasound-guided and clinical touch uterine embryo transfers. In addition, a subset of patients was sought that would particularly benefit from embryo transfer under ultrasound guidance. A total of 187 patients (93 ultrasound and 94 clinical touch) was enrolled. Allocation was random and depended on whether their embryo transfers were done during the 1 h each day in which the ultrasound was available. Pregnancy and implantation rates of 37.8 and 20.4% respectively were achieved when ultrasound was used, compared with 28.9 and 16.2% respectively with clinical touch. This difference was not statistically significant. There was no significant difference in the pregnancy rate when the number of embryos transferred was controlled. Older women (>/=37 years old) had an apparently higher pregnancy rate (38.1 versus 20.4%; not significant) with ultrasound guidance during embryo transfer. In the subgroup where the clinician rated the transfer procedure as difficult, there appeared to be a substantial improvement in the pregnancy rate in the group that used ultrasound (54.5 versus 10.0%; not significant). Although our results were not statistically significant, we believe that ultrasound-guided embryo transfers should be used in clinically difficult embryo transfers and in older women, as it appears to improve the pregnancy rate over clinical touch transfers.     

Influence of position and length of uterus on implantation and clinical pregnancy rates in IVF and embryo transfer treatment cycles

In a prospective study of 807 consecutive women shown to have an apparently normal uterus after hysterosalpingography, hysteroscopy or pelvic ultrasonography prior to IVF or intracytoplasmic sperm injection (ICSI) and embryo transfer, the position and length of the uterine cavity was measured routinely at a pre-treatment mock transfer procedure. The apparent length of the uterine cavity was <7 cm in 128 women (group 1), 7-9 cm in 594 women (group 2) and >9 cm in 85 women (group 3). The uterus was noted to be retroverted in 38. 2% (308) women. The embryo transfer catheter was advanced to 5 mm from the uterine fundus based on the previously determined cavity length in all the embryo transfer procedures at 48 h after oocyte collection. Implantation and clinical pregnancy rates were not significantly different with respect to position of the uterus, difficulties encountered in passage of the catheter, mean age of the women, aetiology or duration of infertility or embryology events. An apparently greater cavity length was seen in older and/or parous women, but the difference was not statistically significant. Although the highest implantation and clinical pregnancy rates were seen in women with a cavity length of 7-9 cm (group 2) the differences were not statistically significant: group 1, 18.9 and 36. 7%; group 2, 21.0 and 46.5%; and group 3, 17.3 and 32.9% respectively. The incidence of ectopic pregnancy per reported clinical pregnancy was highest in group 1 women, being 14.9% (7/47) in comparison with group 2 (1.8%, 5/276) and group 3 (0%, 0/27) (P: < 0.0005), suggesting that the size of the uterus is a critical factor in the aetiology of ectopic pregnancy in IVF/ICSI-embryo transfer.     

Ultrasound-guided embryo transfer: a prospective randomized controlled trial.

BACKGROUND: Recent reports suggested that ultrasound guidance during embryo transfer might improve the pregnancy rate. METHODS: A prospective randomized controlled trial was performed to compare embryo transfer under ultrasound guidance versus the clinical touch method. A total of 800 embryo transfers was studied; 400 were randomized to ultrasound-guided transfers and 400 were randomized to the clinical touch group. Of these, 441 were fresh cycles and 359 were frozen-thawed cycles. RESULTS: The clinical pregnancy rate was 26.0% in the ultrasound-guided group and 22.5% in the clinical touch group; the difference was not statistically significant. The ongoing pregnancy rate was 23.5% in the ultrasound-guided group compared with 19.0% in the clinical touch group and the difference was again not statistically significant. The implantation rate was slightly higher in the ultrasound-guided group (15.3%) than the clinical touch group (12.0%) (P = 0.048). There were no differences in the incidences of ectopic pregnancy, miscarriage and multiple pregnancy between the two groups. CONCLUSIONS: A significant improvement in implantation rate was observed following the use of ultrasound guidance during embryo transfer. The extent of improvement in the pregnancy rate may depend on the specific techniques and methods of embryo transfer used in individual centres.     

Junctional zone contractions and embryo transfer: is it safe to use a tenaculum?

Applying a tenaculum to the cervix is a common practice when the correction of uterine position prior to embryo transfer is required. Our study was designed to assess junctional zone contractility before and after this procedure in 20 patients at the time of mock embryo transfer (mid-luteal phase, at commencement of down-regulation). Real-time transvaginal ultrasound and computer technology was used to evaluate the contraction pattern and frequency. When a tenaculum was applied, the total number of contractions, the number of cervico-fundal, random and opposing contractions all increased significantly (P values 0.0003, 0.005, 0. 001 and 0.007 respectively). Eleven women displayed cervico-fundal contractions, prominent opposing and random contractions were observed in all 20 patients and four patients generated fundo-cervical waves not seen in any case before stimulation with the instrument. In conclusion, manipulation with a tenaculum in the cervical area stimulates junctional zone contractions and is best avoided at the time of embryo transfer.     

Ultrasound-guided embryo transfer maximizes the IVF results on day 3 and day 4 embryo transfer but has no impact on day 5

BACKGROUND: The use of ultrasound-guided embryo transfer has been reported to affect success rates in some centres but not others. In a prospective study, we examined the influence of ultrasound guidance in embryo transfer performed on different days after oocyte retrieval. METHODS: Two different methods of embryo transfer were evaluated in 1069 consecutive transfers. The ultrasound-guided embryo transfer was used in 433 cases, whereas 636 embryo transfers were performed with the tactile assessment ('clinical feel') method. RESULTS: Ultrasound-guided embryo transfer yielded a higher overall pregnancy rate than the 'clinical feel' approach, 47 versus 36% (P < 0.001). This difference was statistically significant where embryos were transferred after 3 or 4 days of culture, 45.9 versus 37.1% (P = 0.001) and 42.3 versus 27% (P = 0.035) respectively but not significant (P = 0.112) on day 5 embryo transfer (56.3 versus 45.7%). Likewise, the implantation rate was significantly different between the two groups on day 3 and 4 embryo transfer, 23.3 versus 15.8% (P < 0.01) and 21.6 versus 15.7% (P < 0.05%) respectively but no statistical difference was noted on day 5 embryo transfer, 26.7 versus 23.6%. CONCLUSION: Ultrasound assistance in embryo transfer on day 3 and 4 significantly improved pregnancy rates in IVF but had no impact on day 5.     

The influence of the depth of embryo replacement into the uterine cavity on implantation rates after IVF: a controlled, ultrasound-guided study

BACKGROUND: Traditionally, embryo transfer after IVF has been performed blindly and placing the embryos approximately 1 cm below the fundal endometrial surface. However, it has been suggested that transferring embryos rather lower in the uterine cavity or high in the uterus may improve implantation rates. Nevertheless, there has not yet been a controlled trial to prove this theory. This prospective randomized study investigates the influence of the depth of embryo replacement on the implantation rate after embryo transfer carried out under transabdominal ultrasound guidance. METHODS: A total of 180 consecutive patients undergoing ultrasound-guided embryo transfer were randomized to three study groups according to the distance between the tip of the catheter and the uterine fundus at the moment of the embryo deposition in the lumen of the endometrial cavity: group 1: 10 +/- 1.5 mm; group 2: 15 +/- 1.5 mm; group 3: 20 +/- 1.5 mm. RESULTS: There was equal distribution between all three study groups regarding the main demographic and baseline characteristics of the patients, ovarian response, oocyte retrieval and IVF outcome, as well as the characteristics of embryo transfer and luteal phase support. The position of the catheter tip in relation to the fundal endometrial surface in groups 1 (10.2 +/- 0.9 mm), 2 (14.6 +/- 0.7 mm) and 3 (19.3 +/- 0.8 mm) was significantly different. Implantation rate was significantly higher (P < 0.05) in groups 2 (31.3%) and 3 (33.3%) compared with group 1 (20.6%). CONCLUSIONS: The depth of the embryo replacement into the uterine cavity may influence implantation rates, and thus it should be considered as an additional procedure among factors recently proposed as associated with successful embryo transfer after IVF.     

Surgery: A successful in-vitro fertilization and embryo transfer treatment in a woman with previous vaginoplasty for congenital absence of vagina

A mock embryo transfer under ultrasound guidance helped to planan embryo transfer in a woman with previous vaginoplasty.     

Immunology: Mock embryo transfer with a full bladder immediately before the real transfer for in-vitro fertilization treatment: the Birmingham experience of 113 cases

The technique of embryo transfer can have a great impact onthe outcome of in-vitro fertilization (IVF) treatment. Transcervicalembryo transfer is a blind procedure and difficulty can unexpectedlyarise. Many IVF programmes therefore perform a ‘mock’embryo transfer prior to the treatment cycle to determine themost suitable catheter and technique for transfer. This, however,adds an extra separate procedure with time and cost implications.Moreover, as the uterus is mobile, its direction may vary onthe day of the embryo transfer from what it was during the mockembryo transfer. Performing mock embryo transfer immediatelybefore the real transfer would circumvent these problems. Wereport here on 113 embryo transfer procedures where a ‘step-wise’mock embryo transfer protocol was performed with a full bladderimmediately before the embryo transfer. The number of embryostransferred (mean ± SD) was 2.6 ± 0.67, the pregnancyrate per embryo transfer was 45.1%, and the intrauterine implantationrate per embryo transferred was 20.6%.     

Potentially important variables identified by transvaginal ultrasound- guided embryo transfer

Transvaginal ultrasound-guided embryo transfer was performed on 121 consecutive patients. Observation was made of guiding cannula and transfer catheter placement in relation to the endometrial surface and uterine fundus during embryo transfer. The position and movement of a transfer-associated air bubble and the impact of subendometrial myometrial contraction leading to endometrial movement was observed. Results indicate that tactile assessment of embryo transfer catheter placement is unreliable: in 17.4% of transfers the outer guiding catheter inadvertently abutted the fundal endometrium. The outer guiding cannula indented the endometrium in 24.8% and the transfer catheter embedded in the endometrium in 33.1%. Unavoidable sub- endometrial transfers occurred in 22.3% of transfers. Ultrasound-guided transfer avoided accidental tubal transfer in 7.4% of transfers. Transfer catheter withdrawal did not significantly affect embryo transfer-associated air bubble position. Endometrial movement due to sub-endometrial myometrial contraction was obvious in 36.4% of cases, with active motion of the transfer-associated air bubble occurring in 28.1%. Pregnancies occurred in 45.5% of transfers with endometrial movement compared to 15.6% (P < 0.001) without.      

Ultrasound-guided soft catheter embryo transfers will improve pregnancy rates in in-vitro fertilization

Attempts to improve clinical pregnancy rates after in-vitro fertilization (IVF) and embryo transfer are constantly being made. Two changes in technique of embryo transfer of potential clinical importance were evaluated over two contiguous time periods in order to observe any corresponding change in clinical pregnancy (CP) rate per transfer: (i) embryo transfer catheter; (ii) ultrasound guidance. Catheter choices were hard: Tefcat, Tom Cat, or Norfolk; or soft: Frydman or Wallace. Ultrasound visualization was considered to be excellent/good when the catheter could be followed from the cervix to the fundus by transabdominal ultrasound with retention of the embryo-containing fluid droplet; fair/poor if visualization could not document the sequence of events. Embryo transfers were performed in 518 cycles. CP rates per transfer using soft and hard catheters was 36 and 17% (P < 0.000) respectively. CP rates per transfer for transfers performed with and without ultrasound guidance were 38 and 25% (P < 0.002) respectively. A statistically significant difference was also noted when visualization ranks were compared. CP rates per transfer in all excellent/good ultrasound-guided transfers was 41.5 versus 16.7% for fair/poor transfers (P < 0.038). In conclusion, performance of embryo transfer with a soft catheter under ultrasound guidance with good visualization resulted in a significant increase in clinical pregnancy rates.     

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 fertilization (IVF)/embryo transfer cycles. A transvaginal ultrasound scan was performed on the day of down regulation (D0), on day 8 of ovulation induction (D8), on the day of human chorionic gonadotrophin (HCG) injection, at the time of oocyte retrieval, and at embryo transfer. Thicknesses of endometrium, junctional zone, myometrium and full thickness of the uterus were recorded for every patient and comparisons made at all the assessment points. Differences between measurements on D0 and all other measurements (temporal changes) and between every subsequent measurement (dynamic changes) were also compared. There were no statistically significant differences in endometrial thickness between pregnant and non-pregnant groups at any time. The diameter of the uterus increased during therapy and was significantly greater 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 administration (P < 0.03, 0.004 and 0.02). There was a decrease in junctional zone thickness in both groups during the first week of ovulation induction, and on D8 the junctional zone in pregnant patients was significantly thinner (P < 0.04). The junctional zone became significantly thicker at embryo transfer in the pregnant group (P < 0.01). This was confirmed by significant temporal and dynamic changes at the time of oocyte retrieval and embryo transfer (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 occurred in other uterine layers that were more pronounced in conception cycles. The responsiveness of the junctional zone seems to be associated with implantation, and its measurements at the time of downregulation and embryo transfer can be used to predict treatment outcome.     

Comparison of pulsatility indices on the day of oocyte retrieval and embryo transfer

Transvaginal ultrasonography with colour blood flow imagingand analysis of impedance to uterine arterial blood flow hasbeen used to provide an index of uterine receptivity for implantationafter IVF/embryo transfer. A mean uterine arterial pulsatilityindex (PI) >3.0 at the time of embryo transfer predicted35% of failures to become pregnant. Cryopreserving embryos innon-receptive cycles and transferring them in receptive cycleswould be expected to improve pregnancy rates. Earlier decisionsregarding embryo cryopreservation can be made if receptive cyclescan be predicted at the time of oocyte retrieval rather thanat embryo transfer. To assess differences in uterine arteryimpedance, PI were measured serially in 107 women on both theday of oocyte retrieval and the day of embryo transfer. MeanPI on the day of oocyte retrieval was 2.52 ± 0.59, andon the day of embryo transfer was 2.78 ± 0.45. No significantdifference was observed when PI determined on the day of oocyteretrieval were compared with PI on the day of embryo transfer.These data suggest that the PI measurement done on the day ofoocyte retrieval could substitute for the measurement done onthe day of embryo transfer. This would allow prediction of non-receptiveendometria earlier in the cycle. Further studies are neededto evaluate whether cryopreservation of embryos and transferwhen the uterus is more receptive will increase the implantationrates.     

Transmyometrial embryo transfer and junctional zone contractions

BACKGROUND: Embryo transfer is a crucial step in IVF-embryo transfer cycles. Several studies have explored transmyometrial embryo transfer, but although this procedure has several favourable characteristics, its role in assisted reproduction has not yet been established. Junctional zone (JZ) contractions during embryo transfer are associated with a negative outcome and factors which increase JZ contractions should be avoided. METHODS: In this study, we have investigated the effect of transmyometrial embryo transfer on JZ contractions. Ten patients with a previously difficult embryo transfer, or a difficult mock embryo transfer, underwent transmyometrial embryo transfer. Before and after this procedure a transvaginal ultrasound scan was performed and this was recorded on videotape for 5 min. The recordings were digitized and then analysed for JZ contractions. RESULTS: Transmyometrial embryo transfer causes a significant increase in JZ contractions. CONCLUSION: The increase in JZ contractions after transmyometrial embryo transfer forms a theoretical objection to this procedure. However, its alternative, a difficult transcervical embryo transfer, is also associated with an increase in JZ contractions. We therefore suggest a large prospective study to investigate the most effective method of embryo transfer in cases where a difficult transcervical embryo transfer is anticipated due to cervical factors.     

Ultrasound measurement of the uterocervical angle before embryo transfer: a prospective controlled study

BACKGROUND: The study aim was to determine whether moulding the embryo transfer catheter according to the uterocervical angle measured by ultrasound could improve pregnancy and implantation rates. METHODS: Patients were alternately allocated to one of two groups. In the ultrasound-guided group (n = 320), the catheter was moulded according to the uterocervical angle measured by abdominal ultrasound. In controls (n = 320), embryo transfer was performed using the "clinical feel" method. RESULTS: Moulding the embryo transfer catheter according to the uterocervical angle significantly increased clinical pregnancy [(OR = 1.57, 95% CI (1.08-2.27)] and implantation rates [(OR = 1.47, 95% CI (1.10-1.96)] compared with the "clinical feel" method. It also significantly reduced difficult transfers [(OR = 0.25, 95% CI (0.16-0.40)] and blood during transfers [OR = 0.71, 95% CI (0.50-0.99)]. Patients with large angles (>60 degrees ) had significantly lower pregnancy rates compared with those with no angle [OR = 0.36, 95% CI (0.16-0.52)]. CONCLUSIONS: Moulding the embryo transfer catheter according to the uterocervical angle measured by ultrasound increases clinical pregnancy and implantation rates and diminishes the incidence of difficult and bloody transfers.     

Transvaginal ultrasound-guided embryo transfer improves pregnancy and implantation rates after IVF.

BACKGROUND: Attempts are constantly being made to improve clinical pregnancy rates after IVF and embryo transfer. Since November 1998, we have gradually been adopting transvaginal ultrasound guidance during embryo transfer. We retrospectively examined the efficacy of this method on pregnancy and implantation rates. METHODS: The results of 846 cycles from our IVF-embryo transfer programme were analysed and comparisons were made between those carried out using ultrasound guidance and those by the clinical touch method. RESULTS: Higher pregnancy and implantation rates (28.9 and 15.2% respectively) were found in the group using the transvaginal ultrasound guidance during embryo transfer compared with those in the group using the clinical touch method (13.1 and 7.0% respectively). The differences were statistically significant (P < 0.01). There was no significant difference in ectopic pregnancy rates between the two groups. CONCLUSION: The use of transvaginal ultrasound-guided embryo transfer significantly improved both pregnancy and implantation rates. Although technically difficult, we suggest its use may maximize the chances of achieving a successful pregnancy outcome.     

Monozygotic twinning associated with day 5 embryo transfer in pregnancies conceived after IVF

BACKGROUND: This study examines the association between day of embryo transfer and monozygotic (MZ) twinning. METHODS: We used a population-based sample of 108,36 IVF/embryo transfer procedures in which the patients oocytes' were freshly fertilized (non-frozen; non-donor) and 39,98 resultant pregnancies from US clinics in 1999 and 2000. Cases were pregnancies for which the number of fetal hearts observed on ultrasound exceeded the number of embryos transferred. These pregnancies were considered to contain at least one set of MZ twins. A total of 226 MZ pregnancies were compared with two control groups: 23,880 singleton pregnancies (one fetal heart) and 15,092 other multiple-gestation pregnancies (> or = 2 fetal hearts but the number of fetal hearts on ultrasound was less than or equal to the number of embryos transferred). RESULTS: Cases of presumed MZ multiple-gestation pregnancies were more likely to have had a day 5 embryo transfer compared with day 3 embryo transfers than singleton pregnancies [adjusted odds ratio (AOR) = 3.92, 95% confidence interval (CI) = 2.97-5.17] or other multiple-gestation pregnancies (AOR = 3.91, 95% CI = 2.96-5.17) conceived with IVF/embryo transfer. CONCLUSIONS: Day 5 embryo transfer may be associated with increased MZ twinning.     

Nurses performing embryo transfer: the development and results of the Birmingham experience

Although in-vitro fertilization treatment is doctor-led, many of its steps are performed by nurses. The embryo transfer step, however, is performed exclusively by doctors in the majority of units. In our unit, doctors performed embryo transfers from June 1994 until December 1995 (period I). From January 1996 until May 1997 (period II) the nurses, after appropriate training, performed the procedure. When they experienced difficulties during the mock transfer performed immediately before the real transfer, or if they were not available to do the procedure, a doctor performed it. In period I, 488 embryo transfers were performed (all by doctors), with a pregnancy rate per transfer of 35% and an implantation rate of 16%. In period II, 522 embryo transfers were performed. Nurses performed 371 (71%) and doctors 151 (29%) of the procedures. The pregnancy rate per nurse-transfer was 40.2% and per doctor-transfer 41%. The corresponding implantation rates were 16.9% and 17%. None of these differences were statistically significant (P > 0.05). These data indicate that, with appropriate training and medical back-up, nurses can perform the majority of embryo transfers with ease and outcome comparable to that of doctor embryo transfer.      

Embryo transfer--can we learn anything new from the observation of junctional zone contractions?

To assess whether embryo transfer can alter junctional zone contractility, we studied the effect of easy and difficult mock transfers in 14 oocyte donors during in-vitro fertilization (IVF) cycles. An Echovist bolus (30 microl) was used to represent embryos and transfer medium. An 'easy' transfer was judged to be an atraumatic insertion of the catheter without touching the uterine fundus. A 'difficult' embryo transfer was mimicked by deliberately touching the uterine fundus twice with the soft end of the cannula. Transvaginal scan images were recorded, digitized and converted into five times normal speed to allow us to evaluate junctional zone contractility. Easy mock embryo transfers did not change endometrial mechanical activity. Echovist remained in the upper part of the uterine cavity and was not dispersed after 45 min. A difficult procedure generated strong random waves in the fundal area and waves from fundus to cervix which relocated the Echovist in six out of seven cases. We observed movements of the transfer bolus from the upper part of the uterus towards the cervix (four cases) and into Fallopian tubes (two patients). Our study confirms that the mechanical activity of the uterus is capable of relocating intrauterine embryos and that this activity depends on physical stimulation. Junctional zone contractions can be implicated in cases of IVF/embryo transfer failure or ectopic gestation.      

Cervical dilatation with hygroscopic rods prior to ovarian stimulation facilitates embryo transfer

BACKGROUND: Embryo transfer is a critical factor affecting the success of IVF-the ease of embryo transfer has a direct impact on the success rate. The aim of this study was to assess the value of cervical dilatation with hygroscopic cervical rods (Dilapan-S) in patients with difficult embryo transfer. METHODS: Fifty-four patients undergoing IVF treatment, who either failed to conceive after previous difficult embryo transfer or were noted to have difficult mock embryo transfer were retrospectively included in the study. In this way the patients acted as control for themselves. The Dilapan-S rods were placed intracervically and left for 4 h prior to starting gonadotrophin stimulation as an outpatient procedure. RESULTS: Of the 54 patients who originally had difficult embryo transfer, 43 patients (79.5%) had subsequent easy embryo transfer. Thirty patients managed to conceive, giving a clinical pregnancy rate of 55%. CONCLUSIONS: Cervical dilatation using hygroscopic dilators facilitates difficult embryo transfer and helps to improve the pregnancy rate.