Successful treatment of cervical stenosis with hysteroscopic canalization before embryo transfer in patients undergoing IVF: a case series

The course of the transfer catheter through the cervical canal is one of the most important issues for a successful embryo transfer (ET) during in vitro fertilization (IVF) cycles. Technically difficult ETs due to cervical stenosis are associated with reduced chance of pregnancy after assisted reproductive procedures. In the current case series, we report on three patients with cervical stenosis who underwent IVF-ET cycles. These three patients, in whom ET was classified as "difficult," failed to conceive with previous ET attempts. An intervention to create a cervical tract was performed with operative hysteroscopy under general anesthesia before transcervical ET. After the hysteroscopic shaving procedure, we observed quite an improvement in access to the endometrial cavity during ET procedure. These patients had significantly easier ET procedures compared with previous attempts and achieved clinical pregnancies. Hysteroscopic revision of the cervical canal results in easier ET and improves pregnancy rates in patients with cervical stenosis and histories of difficult ET.     

Transvaginal ultrasound-guided embryo transfer improves outcome in patients with previous failed in vitro fertilization cycles

OBJECTIVE: To determine the effect of transvaginal ultrasound-guided ET in IVF cycles performed on patients who had previously failed to conceive from IVF and compare the results to previous cycles where ultrasound guidance was not used. DESIGN: Retrospective clinical study.Setting: Private practice IVF program. PATIENT(S): One hundred twenty-nine women undergoing consecutive cycles of IVF where fresh embryos were transferred. INTERVENTION(S): Transvaginal ultrasound guidance was used during transfer of embryos. MAIN OUTCOME MEASURE(s): Patient age, number of ampules of gonadotropin used, maximum E(2) level, number of oocytes retrieved, number of two pronuclei embryos obtained, number of embryos transferred, mean embryo score, implantation and pregnancy rate. RESULT(S): There was no difference in any of the clinical parameters measured in IVF cycles resulting in pregnancy when transvaginal ultrasound-guided ET was used compared to the failed cycles when there was no ultrasound guidance. Of the patients who previously had failed IVF cycles and subsequently had IVF cycles with ultrasound guidance, those who became pregnant had higher mean embryo scores than those who did not become pregnant. Overall implantation and pregnancy rates were higher during the study period when transvaginal ultrasound guidance was used than in the previous 3 years when it was not used. CONCLUSION(S): Transvaginal ultrasound-guided ET may be responsible for successful IVF cycles in patients who had previously failed to conceive when embryos were transferred by the clinical touch method. Transvaginal ultrasound guidance may also be responsible for an overall increase in embryo implantation and pregnancy compared to the use of the clinical touch method.     

Ectopic pregnancy after transmyometrial embryo transfer: case report.

OBJECTIVE: To report a case of ectopic pregnancy after transvaginal transmyometrial ET. DESIGN: Case report. SETTING: University-based IVF program. PATIENT(S): A woman with tubal subfertility and a history of difficult ETs. INTERVENTION(S): Transvaginal transmyometrial ET performed to avoid a difficult transcervical ET. MAIN OUTCOME MEASURE(S): Expected improvement in the pregnancy rate in a selected group of patients. RESULT(S): Tubal pregnancy. CONCLUSION(S): Transmyometrial ET is an attractive alternative to difficult transcervical ET but is not free of complications.     

How useful is cervical dilatation in patients with cervical stenosis who are participating in an in vitro fertilization-embryo transfer program? The Bourn Hall experience.

OBJECTIVE: To evaluate the place of cervical dilatation performed at the initial visit in an IVF-ET cycle in patients with known cervical stenosis. DESIGN: Retrospective study. SETTING: A tertiary care assisted conception unit. PATIENT(S): Fifty-seven patients who failed to conceive after a previous ET attempt and in whom the ET was classified as "difficult." INTERVENTION(S): Cervical dilatation under general anesthesia after pituitary suppression and before gonadotropin stimulation. MAIN OUTCOME MEASURE(S): Ease of the ET procedure and clinical pregnancy rate. RESULT(S): Eighteen (31.6%) of 57 women who failed to conceive after a previous attempt at IVF-ET achieved a clinical pregnancy after cervical dilatation. In 40 patients (70.2%), the subsequent ET was classified as "easy," whereas in the other 17 (29.8%), it remained difficult. The pregnancy rate was significantly higher when the ET was easy than when it was difficult (40% versus 11.8%, P<.05). CONCLUSION(S): In patients with cervical stenosis and a previous difficult ET, cervical dilatation during the initial visit leads to an easier subsequent ET and improves the pregnancy rate.     

Simultaneous program of natural-cycle in vitro fertilization and cryopreserved-thawed embryo transfer

Purpose: This clinical study was designed to identify and compare the pregnancy rates of simultaneous program of natural-cycle IVF and cryopreserved-thawed ET (NICE) with those of natural-cycle IVF and cryopreserved-thawed ET. Methods: All three groups comprised spontaneously ovulating infertile women under the age of 40 and without any male factor present. The NICE program was performed in 36 patients (47 cycles) who had previously undergone IVF-ET resulting in cryopreserved embryos. As control groups, the natural-cycle IVF was performed in 45 patients (80 cycles), and the cryopreserved-thawed ET alone in 29 patients (40 cycles). Results: The cancellation rate of the initiated cycles prior to ET was 19.1% (9/47) in the NICE group, 23.8% (19/80) in the natural-cycle IVF group, and 2.5% (1/40) in the cryopreserved-thawed ET group. The mean number of embryos transferred was 4.0±1.1 (2–5) in the NICE group, 1.0 in the natural-cycle IVF group, and 4.2±1.8 (1–5) in the cryopreserved-thawed ET group. The clinical pregnancy rates per aspiration cycle (32.5%) and per ET cycle (34.2%) in the NICE group were significantly higher than those (14.9, 16.4%) in the natural-cycle IVF group. The clinical and delivered pregnancy rates per ET (34.2, 26.3%) in the NICE group were higher than those (20.5, 15.4%) in the cryopreserved-thawed ET group, without statistical significance. Conclusions: Since the NICE program results in saving the fresh oocyte for patients participating in cryopreserved-thawed ET, more favorable pregnancy rates may be obtained from NICE cycles in women ovulating normally who had previously undergone IVF-ET with embryo cryopreservation.Presented at the 50th Annual Meeting of the American Fertility Society, November 5–10, 1994, San Antonio, Texas.     

Effect of salpingectomy on ovarian response to superovulation in an in vitro fertilization–embryo transfer program

Objective: To investigate the effect of salpingectomy on the response of each ovary in patients undergoing an IVF-ET treatment cycle and to compare the results with those of patients who had not had surgery and were undergoing IVF-ET during the same period.

Design: A prospective study.

Setting: Tertiary referral academic IVF unit.

Patient(s): Twenty-nine ET cycles were evaluated in 29 patients who previously had undergone unilateral salpingectomy because of ectopic pregnancy (study group). Seventy-three patients with unexplained or male factor infertility served as controls.

Intervention(s): Ovulation induction and IVF-ET.

Main Outcome Measure(s): In the study group, mean ovarian volume, number of follicles, and number of oocytes recovered from each ovary were assessed and compared. The overall results, cycle characteristics, and pregnancy rates of the two groups were compared.

Result(s): Among the patients who had undergone salpingectomy, significantly fewer follicles developed and consequently fewer oocytes were retrieved from the ovary on the operated side (4.4 versus 8.2 follicles and 3.8 versus 6.0 oocytes). There were no differences in the total numbers of follicles and oocytes recovered from both ovaries, the cycle characteristics, or the pregnancy rates between study and control groups.

Conclusion(s): Salpingectomy has no detrimental effect on the total ovarian performance during IVF-ET treatment or on the outcome of IVF-ET. However, the ipsilateral ovary could be adversely affected. This could be detrimental in selected patients undergoing IVF-ET, in whom the second ovary already is compromised or missing.     

Blastocyst-stage embryo transfer in patients who failed to conceive in three or more day 2-3 embryo transfer cycles: a prospective, randomized study

OBJECTIVE: To compare blastocyst-stage embryo transfers (ETs) with day 2-3 ETs in patients who failed to conceive in three or more day 2-3 IVF/ET cycles. DESIGN: Prospective, randomized. SETTING: Fertility unit in a university medical center. PATIENT(S): Fifty-four patients with an adequate ovarian response underwent oocyte retrievals. The patients were prospectively and randomly divided into blastocyst-stage and day 2-3 ET groups. INTERVENTION(S): Ovarian down-regulation was obtained using GnRH agonist, and controlled ovarian hyperstimulation was achieved using daily administration of gonadotropins. MAIN OUTCOME MEASURE(S): The rate of blastocyst formation, ET cancellations, pregnancies, implantation, multiple gestation, and live births. RESULT(S): The clinical pregnancy rates per oocyte retrieval were 21.7% and 12.9% per blastocyst and day 2-3 ETs, respectively. Although there was a significantly higher implantation rate for blastocyst embryos (21.2%) as compared with 48- to 72-hour embryos (6%), the multiple-pregnancy rate was not significantly different between both groups. An ET cancellation rate of 26% and 6.4% for blastocyst and day 2-3 ETs, respectively, was observed. The presence of two or more 8-cell embryos on day 3 in culture carried a high probability of obtaining blastocysts for transfer. CONCLUSION(S): This prospective randomized study suggests that in patients with an adequate ovarian response who failed to conceive in at least three IVF/ET cycles [1]. transfer of blastocyst-stage embryos carries a significantly higher implantation rate; [2]. the pregnancy rate per oocyte retrieval and ET are higher in the blastocyst-stage group, even if it did not reach statistical significance; [3]. a higher ET cancellation rate was observed in the whole blastocyst-stage group; [4]. the ET cancellation rate was reduced significantly if the decision to proceed to blastocyst transfer was made on day 3 after oocyte retrieval, which is a post hoc conclusion.     

Diagnosis of ectopic pregnancy after in vitro fertilization and embryo transfer

Objective: The combination of transvaginal sonography and serum hCG measurement is reliable in the diagnosis of ectopic pregnancy (EP) in spontaneous pregnancies. In patients who became pregnant through IVF-ET, transfer of multiple embryos after IVF could be responsible for the different performance of these tests. We evaluated the discriminative capacity of transvaginal sonography in combination with hCG measurement in the diagnosis of EP after IVF-ET.

Design: Prospective cohort study.

Setting and Patient(s): Consecutive patients, pregnant through IVF-ET, who presented with clinically suspected EP.

Intervention(s): Transvaginal sonography, serum hCG measurement at 6, 9, and 15 days after ET and after a negative transvaginal sonography.

Main Outcome Measure(s): Ectopic pregnancy confirmed at laparoscopy.

Result(s): Between September 1993 and May 1996, 86 women were included in the study, of whom 24 had an EP. Transvaginal sonography identified 46 intrauterine pregnancies and 5 EPs, but serum hCG could not diagnose EPs in patients in whom transvaginal sonography did not show a gestational sac. Serum hCG measurement 9 days after ET could identify pregnancy failure with 100% specificity at a cut-off value of 18 IU/L, but it could not identify patients with EP with enough certainty to justify immediate treatment.

Conclusion(s): We recommend single serum hCG measurement 9 days after ET to discriminate between viable and nonviable pregnancies. Transvaginal sonography can be postponed until 5 weeks after ET, except for patients with abdominal pain and/or vaginal bleeding, or patients with a serum hCG level of <18 IU/L.     

A reassessment of comparative pregnancy and implantation rates following embryo transfer in recipients vs their infertile donors also trying to conceive in the background of performing salpingectomy for hydrosalpinx

PURPOSE: To compare pregnancy and implantation rates in egg donors trying to conceive vs their recipients in the background of salpingectomy for hydrosalpinx prior to IVF-ET. METHODS: A retrospective six-year review of all donor egg cycles where the eggs are supplied by an infertile donor trying to conceive herself was carried out. Salpingectomy for hydrosalpinx was performed prior to IVF-ET. RESULTS: Clinical and delivered pregnancy rates (PRs) following fresh ET were not significantly different in donors vs recipients (60.0%, 45.8% vs 56.8%, 50.8%). Implantation rates were 27.3% vs 32.6%. The respective implantation rates following frozen ET were 13.8% and 14.4%. CONCLUSIONS: In the background of salpingectomy for hydrosalpinges the much higher PRs in recipients vs donors is no longer seen. The trend for higher implantation rates in recipients (about 20%) following fresh but not frozen transfer could still reflect some adverse effect of the controlled ovarian hyperstimulation regimen in a minority of women.     

Pregnancies and deliveries after in vitro maturation culture followed by in vitro fertilization and embryo transfer without stimulation in women with polycystic ovary syndrome

OBJECTIVE: To improve the efficacy of an IVF-ET program for unstimulated patients with polycystic ovary syndrome (PCOS) with the use of culture for oocyte maturation. DESIGN: Prospective studies with the comparison of different ET procedures from March 1995 through February 1998. SETTING: University-affiliated hospital. PATIENT(s): Ninety-four cycles in 64 consenting patients with PCOS. INTERVENTION(s): Immature oocytes were retrieved from unstimulated patients with PCOS and subsequently cultured and fertilized in vitro. Zygote intrafallopian transfer (ZIFT), uterine ET, or a combined approach of ZIFT + uterine ET was subsequently performed. MAIN OUTCOME MEASURE(s): Laboratory and clinical data. RESULT(s): Among 1, 280 immature oocytes (13.6 +/- 7.5 oocytes per patient) retrieved, 89% (1,139) were morphologically normal, and 62.2% (708/1,139) of the normal oocytes matured in vitro after culture for 48 hours. When intracytoplasmic sperm injection was performed, 68% (481/708) developed to the normal pronuclear stage, and 88.1% of the embryos cocultured with Vero cells (266/302) cleaved. Eighty-five ET cycles were conducted and pregnancy was established in 23 cycles (27.1%), which consisted of 8 after uterine ET and 15 after a combined approach. Seventeen patients delivered 20 normal infants. CONCLUSION(s): The IVF-ET method using no ovarian stimulation followed by in vitro maturation culture can be a feasible assisted reproductive technology for treatment of PCOS with various complications.     

Relationship between the day of embryo transfer and the outcome in human in vitro fertilization and embryo transfer

Purpose To clarify the optimal date of embryo transfer (ET), we retrospectively analyzed the relationship between the day of ET and the outcome in human in vitro fertilization and embryo transfer (IVF-ET).Method Of a total of 307 human IVF-ET cycles performed at Kyoto University Hospital between January 1990 and March 1994, we focused on 207 cases of IVF-ET cycles in which two or three good-quality embryos were transferred. These 207 IVF-ET cycles consisted of 54 Day 2 ET cycles, 79 Day 3 ET cycles, 46 Day 4 ET cycles, and 28 Day 5 ET cycles. We compared the pregnancy and live-birth (plus ongoing pregnancy) rates among these four ET groups.Results The pregnancy rates of ET on Days 2 to 4 were not significantly different, whereas Day 5 ET produced a significantly lower pregnancy rate (Day 2, 29.6%; Day 3, 32.9%; Day 4, 30.4%; Day 5, 10.7%). Similar results were obtained for the live-birth (plus ongoing pregnancy) rates (Day 2, 20.3%; Day 3, 18.9%; Day 4, 17.9%; Day 5, 7.1%).Conclusions These results suggest that the day of ET does not fundamentally affect the pregnancy rate in human IVF-ET provided that transfer is made before Day 5.     

Different influence of incongruent follicular development on in vitro fertilization–embryo transfer and gamete intrafallopian transfer pregnancy rates

Objective: To compare the influence of incongruent (asymmetric) follicular development on treatment outcome in IVF-ET and GIFT cycles.

Design: A retrospective comparative study.

Setting: Tertiary referral center for infertility.

Patient(s): Five hundred forty-three consecutive assisted reproduction cycles (428 IVF-ET and 115 GIFT) in 422 infertile patients.

Intervention(s): Controlled ovarian hyperstimulation (COH) and IVF-ET or GIFT.

Main Outcome Measure(s): The incongruity ratio as a parameter of the asymmetry in follicular development and pregnancy rate (PR).

Result(s): For GIFT cycles, the PRs were 37.8% and 15.7% in cycles with congruent and incongruent follicular development, respectively. However, for IVF-ET cycles, the PR was not affected by incongruent follicular development: 28.2% and 29.0%, respectively. An inverse relationship was observed between the degree of incongruity and the estimated probability of pregnancy in GIFT cycles but not in IVF-ET cycles. Neither the side of the dominant ovary nor the degree of incongruity were consistent in consecutive cycles.

Conclusion(s): Incongruent follicular development during COH has a significantly negative influence on the outcome of GIFT cycles but not on the outcome of IVF-ET cycles. The reason for this difference is not clear. We recommend considering IVF-ET instead of GIFT if incongruent follicular development occurs.     

Uterine cavity findings and hysteroscopic interventions in patients undergoing in vitro fertilization-embryo transfer who repeatedly cannot conceive

OBJECTIVE: To assess hysteroscopic findings in patients undergoing IVF-ET who repeatedly failed to conceive despite transfer of good-quality embryos. DESIGN: Prospective, observational study. SETTING: Clinical research unit for reproductive medicine in a private clinic. PATIENT(S): Fifty-five patients with a normal uterine cavity on hysterosalpingography before the initial IVF-ET cycle and two previous failed IVF-ET attempts despite transfer of a minimum of two good-quality embryos on each occasion. INTERVENTION(S): Standard transvaginal ultrasonography and diagnostic and therapeutic hysteroscopy. MAIN OUTCOME MEASURE(S): Endometrial findings on transvaginal ultrasonography and hysteroscopy and outcome of the cycles after surgical hysteroscopy and antibiotic therapy. RESULT(S): Twenty-five (45%) patients had abnormal endometrial findings and underwent treatment to correct the lesions. All patients underwent a third IVF-ET cycle. Pregnancy (50% vs. 20%) and implantation (19% vs. 5.5%) rates were significantly higher in patients who were treated for uterine abnormalities than in patients who had normal uterine cavities on hysteroscopy. CONCLUSION(S): The incidence of pathologic findings on hysteroscopy is high in patients with repeated failures of IVF-ET. Evaluation of endometrial integrity by hysteroscopy is highly valuable and should be applied to all such cases.     

A matched controlled study to evaluate the efficacy of acupuncture for improving pregnancy rates following in vitro fertilization-embryo transfer

PURPOSE: To determine if acupuncture performed during the follicular phase and luteal phase but not on the day of embryo transfer could improve the outcome following IVF-ET compared to controls. METHODS: Acupuncture was started biweekly from day 5 of the follicular phase through the luteal phase but not on the day of the transfer. Controls were matched according to age, same number of previous failed IVF cycles and same type of embryo transfer (fresh or frozen). RESULTS: The clinical and ongoing (delivered pregnancy rates per transfer) for 32 women undergoing IVF-ET and acupuncture was 40.6% and 37.5%, respectively vs 53.1% and 43.7% for controls. The median number of previous failed IVF cycles was three. CONCLUSIONS: Acupuncture performed twice weekly during the follicular and luteal phase does not seem to improve pregnancy rates following IVF-ET.     

In vitro fertilization and embryo transfer during natural cycles

OBJECTIVE: To report the results of in vitro fertilization and embryo transfer (IVF/ET) performed during natural cycles. STUDY DESIGN: A prospective clinical study. RESULTS: Thirty-two cycles were started in 19 patients who had regular ovulatory cycles and tubal factors or unexplained infertility only as the cause of infertility. Egg collection was performed in 12 cycles, and four pregnancies resulted from ET in eight cycles. The pregnancy rates were 12.5% per cycle initiated, 33.3% per retrieval cycle and 50% per transfer. CONCLUSION: Natural cycle IVF/ET offers a low-cost alternative to patients with infertility.     

Local injury to the endometrium doubles the incidence of successful pregnancies in patients undergoing in vitro fertilization

OBJECTIVE: Exploration of the possibility that local injury of the endometrium increases the incidence of implantation. DESIGN: Prospective study. SETTING: Clinical IVF unit. PATIENT(S): A group of 134 patients, defined as good responders to hormonal stimulation, who failed to conceive during one or more cycles of IVF and embryo transfer (ET). INTERVENTION(S): The IVF treatment and ET were preceded by repeated endometrial biopsies, in a randomly selected 45 of a total of 134 patients. MAIN OUTCOME MEASURES: Outcome of IVF-ET treatments. RESULT(S): Transfer of a similar number of embryos (3.4 +/- 1.0 and 3.1 +/- 0.9 in the experimental and control patients, respectively) resulted in rates of implantation (27.7% vs. 14.2%, P =.00011), clinical pregnancy (66.7% vs. 30.3%, P =.00009), and live births per ET (48.9% vs. 22.5%, P =.016) that were more than twofold higher in the experimental group as compared to controls. CONCLUSION(S): These results suggest that IVF treatment that is preceded by endometrial biopsy doubles the chance for a take-home baby.     

Clinical application of a new assisted hatching method using a piezo-micromanipulator for morphologically low-quality embryos in poor-prognosis infertile patients

Objective: To assess the effect of a assisted hatching technique using a piezo-micromanipulator on pregnancy rates in poor-prognosis infertile patients.

Design: A prospective randomized study.

Setting: The Infertility and IVF unit of the Kyoto University Hospital.

Patient(s): Infertile patients who had been treated for >4 years and failed in previous IVF trials at least twice.

Intervention(s): Two hundred forty-eight IVF cycles from 173 patients were divided into two groups: cycles with the transfer of embryos treated by assisted hatching and cycles with the transfer of nontreated embryos. Each group was subdivided into two groups according to embryo morphology: cycles in which three or two morphologically good-quality embryos were transferred and cycles in which one or no morphologically good-quality embryos were transferred. Assisted hatching was performed by a piezo-micromanipulator.

Main Outcome Measure(s): The clinical pregnancy rates and implantation rates.

Result(s): The clinical pregnancy and implantation rates were significantly higher in the assisted hatching group of patients with three or two good-quality embryos than in the other three groups.

Conclusion(s): The assisted hatching using a piezo-micromanipulator improved the pregnancy and implantation rates in poor-prognosis infertile patients with good-quality embryo transfer but had no effect in patients with low-quality embryo transfer.     

Tubal ectopic pregnancy after in vitro fertilization and embryo transfer: a role for proximal occlusion or salpingectomy after failed distal tubal surgery?

OBJECTIVE: To assess predisposing factors to tubal pregnancy after in vitro fertilization-embryo transfer (IVF-ET). DESIGN: Retrospective analysis of 891 ET cycles. SETTING: University-based IVF program. PATIENTS, PARTICIPANTS: All ET cycles performed in the study period were included; the indication for IVF was tubal factor in 640 (72%) and other (nontubal) factors in 251 (28%) cycles. INTERVENTIONS: None. MAIN OUTCOME MEASURE: Observing a higher than expected number of tubal pregnancies in our program; we examined subgroups to determine those at highest risk. RESULTS: Tubal pregnancies comprised 12% of clinical pregnancies in the tubal factor group but only 2.6% in the cycles nontubal factor group (P less than 0.05). Of 640 ET cycles in the tubal factor group, 359 were performed in patients who had prior tubal reconstructive surgery; tubal pregnancies comprised 15.6% of the clinical gestations in this subgroup. In the remainder of the tubal factor group (no prior tubal surgery), 281 ET cycles yielded a tubal pregnancy rate of only 5.5% (P less than 0.05). CONCLUSIONS: Women with prior reconstructive surgery for distal tubal disease are at highest risk of developing tubal pregnancy after IVF.     

IVF-ET失败者行宫腔镜检查的临床价值

目的:探讨IVF-ET失败者行宫腔镜检查的意义及其临床应用价值。方法:选取38例既往有IVF-ET失败史的患者行宫腔镜检查及手术(研究组),与同期常规行宫腔镜检查的不孕患者45例(对照组),就子宫内膜形态的不同表现类型临床结局等方面进行比较。结果:研究组宫腔内膜异常的发生率为84.21%,明显高于对照组的48.89%,其中宫腔粘连、子宫内膜不规则增生以及子宫内膜息肉的发生率均高于对照组(P<0.05)。研究组的32例于宫腔镜术后一年内再次行IVF/ICSI或冷冻胚胎移植术,17例获得临床妊娠。余6例术后至今未行IVF-ET,不避孕未孕。结论:宫腔镜检查、干预有利于改善子宫内膜的形态,提高临床妊娠率,可作为再次IVF前的常规筛查手段。     

Ultrasound guided embryo transfer significantly improves pregnancy rates in women undergoing oocyte donation.

OBJECTIVES: Recent reports suggest ultrasound (US) guided embryo transfer (ET) improves pregnancy rates. Using the ovum donation model to eliminate confounding variables, we assessed the impact of US guided ET on pregnancy rates, implantation rates, and multiple gestation rates. METHODS: All women who underwent IVF-ET cycles using donated oocytes from November 1997 to September 1998 (n = 137) were evaluated retrospectively. ET from November 1997 to April 1998 were performed without US, while all ET from May 1998 to September 1998 were performed using transvaginal or transabdominal US. ET was further categorized as easy or difficult. Difficult ET was defined as requiring at least two attempts and/or the presence of blood on the catheter and/or > 5 min. RESULTS: Pregnant patients (n = 73) were similar with respect to the number and morphology of the embryos transferred compared to non-pregnant patients (n = 65). US guidance significantly improved implantation and pregnancy rates in cycles with easy transfers [28.8 vs. 18.4% and 63.1 vs. 36.1%, respectively (P < 0.05)] without impacting multiple pregnancy rates. CONCLUSION: US guided ET is simple and reassuring and appears to significantly improve pregnancy outcomes in ovum donation cycles by optimizing the placement of embryos.