Bacteria in the transfer catheter tip influence the live-birth rate after in vitro fertilization

Impact of Physician Performing Embryo Transfer on Pregnancy Rates in an Assisted Reproductive Program

PURPOSE

To evaluate the effect of the individual physician performing embryo transfer, on clinical pregnancy rates.

METHOD

Data from a total of 485 consecutive embryo transfers performed on 485 women aged 23-37 years were prospectively collected for this study. All patients underwent a standard downregulation long protocol for ovarian stimulation. Oocyte recovery was performed at 36 h after hCG administration. Embryo transfer took place at 48 h after insemination. The patients were matched in two groups that have been linked to two different ET providers (A and B). The same method of loading embryos into the embryo transfer catheter was used.

RESULTS

Clinical pregnancy rates varied significantly (p< or =0.01) between the two providers: 36.1% in group A and 20.6% in group B. The number and quality of embryos transferred did not differ between the groups.

CONCLUSION

The results suggest that the physician factor may be an important variable in embryo transfer technique.

A randomized controlled trial of prophylactic antibiotics (co-amoxiclav) prior to embryo transfer

BACKGROUND

Bacterial contamination of the transfer catheter during embryo transfer is associated with poor clinical outcomes. Antibiotics at the time of embryo transfer may improve outcomes. We evaluated the effect of co-amoxiclav on the rates of bacterial contamination of transfer catheters and clinical pregnancy.

METHODS

On the day of oocyte collection, 350 patients were randomized, with sequentially numbered opaque-sealed envelopes containing treatment allocation assigned randomly by computer, to receive co-amoxiclav on the day before and the day of embryo transfer, or no antibiotics. Following transfer, the catheter tips were cultured and assessed to identify the organism(s) isolated and to quantify the level of the contamination. Couples were followed for 8 weeks to determine whether they had achieved clinical pregnancy. Outcome assessors were blinded to the treatment allocation, and the analysis was by intention to treat.

RESULTS

Antibiotics significantly reduced catheter contamination rates (49.4 versus 62.3%, RR = 0.79, 95% CI: 0.64, 0.97, P = 0.03). There was no difference detected in clinical pregnancy rates between the two groups (36.0 versus 35.5%, P = 0.83) although there was a significant (P = 0.03) association between the level of bacterial contamination and clinical pregnancy rates.

CONCLUSIONS

Co-amoxiclav reduces catheter contamination, but this is not translated into better clinically relevant outcomes such as clinical pregnancy rates. Our findings do not support the routine use of antibiotics at embryo transfer.

Embryo transfer: factors involved in optimizing the success

PURPOSE OF REVIEW

Embryo transfer is arguably the most critical step in assisted reproduction. The purpose of this article is to review the different aspects of the procedure in the light of recent evidence.

RECENT FINDINGS

Randomized trials have shown that significantly higher pregnancy rates are obtained when embryo transfer is performed under ultrasound guidance, the embryos are deposited in the middle part of the uterine cavity, an atraumatic technique is used and when low-dose aspirin is routinely administered following the procedure. Blood in the catheter and leaving the embryos inside it for more than 120 s diminish the pregnancy rate significantly. Air in the catheter, immediate removal of the catheter, performing two transfers in the same cycle, prolonged bed rest, sexual intercourse after embryo transfer or the use of sildenafil do not affect the results. Based on currently available evidence, Cochrane reviews have concluded that the live birth rate is not increased by delaying embryo transfer from day two to three or to the blastocyst stage, and that single embryo transfer leads to lower live birth rates than the transfer of two embryos. The value of a mock transfer a few days before the actual procedure has been challenged as the position of the uterus may change. The effect of holding the cervix with a volsellum, routinely administering antibiotics and the superiority of one catheter over the others is still to be determined.

SUMMARY

Recent studies confirm the importance of the various aspects of embryo transfer. More randomized studies are needed to further evaluate them.

Soft versus firm embryo transfer catheters for assisted reproduction: a systematic review and meta-analysis*

BACKGROUND

The true impact of the embryo transfer catheter choice on an IVF programme has not been fully examined. We therefore decided to systematically review the evidence provided in the literature so that we may evaluate a single variable in relation to a successful transfer, the firmness of the embryo transfer catheter.

METHODS

An extensive computerized search was conducted for all relevant articles published as full text, or abstracts, and critically appraised. In addition, a hand search was undertaken to locate any further trials.

RESULTS

A total of 23 randomized controlled trials (RCT) evaluating the types of embryo transfer catheters were identified. Only ten of these trials, including 4141 embryo transfers, compared soft versus firm embryo catheters. Pooling of the results demonstrated a statistically significantly increased chance of clinical pregnancy following embryo transfer using the soft (643/2109) versus firm (488/2032) catheters [P = 0.01; odds ratio (OR) = 1.39, 95% confidence interval (CI) = 1.08-1.79]. When only the truly RCT were analysed, the results were again still in favour of using the soft embryo transfer catheters [soft (432/1403) versus firm (330/1402)], but with a greater significance (P < 0.00001; OR = 1.49, 95% CI = 1.26-1.77).

CONCLUSION

Using soft embryo transfer catheters for embryo transfer results in a significantly higher pregnancy rate as compared to firm catheters.

Prevention of iatrogenic pelvic infection during in vitro fertilization--current practice in the UK

Uterine instrumentation can provoke pelvic inflammatory disease in women infected with Chlamydia trachomatis. During an IVF treatment cycle, a fine plastic catheter is passed into the endometrial cavity to transfer the embryos. The objective of this survey was to find out what measures are being taken by IVF clinics to prevent ascending infection. Postal questionnaires were sent to 75 clinics in the UK, asking about their sexually transmitted infection screening policies and their protocols on antibiotic prophylaxis. Seventy clinics (93%) responded, of which 37 (53%) neither screen the female partner for C. trachomatis, nor give appropriate antibiotic prophylaxis. Approximately half of UK IVF clinics make no attempt to either detect or treat chlamydial infection prior to embryo transfer. More research is required to evaluate whether embryo transfer does pose a significant risk factor for pelvic inflammatory disease.

Does intravaginal probiotic supplementation increase the pregnancy rate in IVF–embryo transfer cycles?

This study investigated the effect of intravaginal administration of probiotics immediately after oocyte retrieval on vaginal colonization and outcome of the IVF-embryo transfer cycle. One hundred and seventeen women who underwent ovarian stimulation and IVF were randomized immediately after oocyte retrieval into two groups: those who received intravaginal probiotics (study group, n = 50) and those who did not (control group, n = 67). Vaginal colonization with lactobacilli and pregnancy rate were compared between the two groups. No significant between-group differences were observed in patient age, oestrogen and progesterone concentrations on day of human chorionic gonadotrophin administration, number of oocytes retrieved, fertilization rate, number of embryos transferred, or pregnancy rate. The presence of lactobacilli in the vagina during oocyte retrieval or embryo transfer did not improve the pregnancy rate. Furthermore, intravaginal administration of lactobacilli following oocyte retrieval did not affect the prevalence of lactobacilli during embryo transfer, or the pregnancy rate. Intravaginal probiotic supplementation immediately after oocyte retrieval has no effect on vaginal colonization or pregnancy rate in IVF cycles.

Implantation Failure in Assisted Reproduction Technology and a Critical Approach to Treatment

In this article, we review the literature and our personal experience regarding the many factors that appear to influence implantation rate. Oocyte quality, as determined by patient age and aneuploidies, probably plays a major role in RIF. However, a panoply of other factors have been brought under investigation, quite often with contradictory results and additional intriguing questions to be studied. Infections of the vagina, cervix, and endometrium, the role of mucus aspiration and washing of the cervix on transfer, the role of catheter guidance for a correct transfer and potion of embryos, the effect of mock transfer, and the role of hysteroscopy and its timing before transfer procedures are analyzed both as a review of the literature and as opinions and data from our experience. Many of these factors are interlaced and from the apparently simple issue of trauma, to infections and immune modulation of hatching and implantation, a biological continuum can easily be identified. The impact of abnormalities of the immune system and of homeostasis abnormalities is also covered in a brief overview of reported works and our experience. These latter areas probably constitute the common biological background of all other external factors that, however, the skilled must equip themselves for improving implantation success.

L’antibiothérapie prophylactique (amoxicilline + acide clavulanique) avant transfert pour fécondation in vitro est inutile

OBJECTIVES

We studied the implantation rate during IVF cycles according to the prescription or not of antibiotics.

MATERIALS AND METHODS

During a 5-month period all the patients aged less than 38 years were randomized into two groups according to an independent personal variable. In group 1 amoxicilline + clavulanic acid 1g/125 mg were administrated from the ovum pick-up day for 6 days. In the group 2 no antibiotic treatment was administered.

RESULTS

The two groups were identical for all the criteria (type of stimulation, IVF/ICSI report, indications, average age). The average number of collected oocytes, obtained embryos and transferred embryos was similar in the two groups. The implantation rate per transfer was similar in the two groups (36.9% versus 36.5%; p>0.95). The pregnancy loss rate (biological pregnancy, early and late miscarriages or extra uterine pregnancy) was increased in a non significant manner (p=0.15) in the group with antibiotic: 33.3% (16/48) versus 20.8% (11/53) in the group without antibiotic.

CONCLUSION

This prospective randomised study leads us not to recommend this antibiotic prescription at the time of the embryo transfer during in vitro fertilisation attempt.

Bacterial vaginosis and miscarriage

PURPOSE OF REVIEW

This review aims to summarize current knowledge about the relationship between bacterial vaginosis and miscarriage.

RECENT FINDINGS

Studies investigating the relationship between bacterial vaginosis and infertility, implantation and early pregnancy loss have produced conflicting results. One study demonstrated a beneficial effect of colonization with hydrogen peroxide producing lactobacilli. A community based study found no association between bacterial vaginosis and first trimester loss, but a positive association with early second trimester loss. In a randomized controlled trial, treatment of bacterial vaginosis with oral clindamycin was associated with a fivefold reduction in the incidence of late miscarriage.

SUMMARY

The relationship between bacterial vaginosis and infertility and first trimester loss needs further elucidation. Measures to support a healthy lactobacillus flora such as probiotic therapy warrant study. The randomized controlled trials of clindamycin treatment need to be replicated in different settings.

Colonisation bactérienne vaginale anormale et implantation en assistance médicale à la procréation

OBJECTIVE

To evaluate the efficiency of our treatment of vaginal infection for couples included in an IVF program.

PATIENTS AND METHODS

Microbiologic screening of vaginal flora and semen has been performed one month prior to in vitro fertilization for 951 couples in 2000. Antibiotic treatment was prescribed in case of positive culture.

RESULTS

Positive microbial growths were observed from endocervical and vaginal cultures in 218 women (22.9%). The clinical pregnancy rate was 30.29% in the group of patients without growth and 30.27% in the group with positive microbial growth. The implantation rate was significantly diminished in case of bacterial growth: 14.6 compared to 19.3% (P <0.02) for sterile endocervical culture. Five main bacterial species were found at the cervical level: Candida albicans (69 cases), Ureaplasma urealyticum (49 cases), Gardnerella vaginalis (43 cases), Streptococcus B or D (24 cases) and Escherichia coli (22 cases). Positive cultures from both vagina and semen were observed for 77 couples whose clinical pregnancy rate was 19.5 vs 36.2% in case of vaginal infection alone (P <0.01) with a spontaneous miscarriage rate of 46.7 compared to 17.6% (P <0.01).

DISCUSSION AND CONCLUSION

Endocervical microorganisms, even treated with adapted antibiotics, may affect embryonic implantation. Positive culture from both female and male partner may enhance this negative effect. In this case, the best strategy would be to cancel the IVF treatment.

The Impact of Embryo Transfer on Implantation—A Review

Embryo transfer has received little clinical attention and has been, until recently, the most inefficient step in in-vitro fertilization (IVF). In this article, the authors review the literature and their personal experience regarding the process of intrauterine transfer of embryos, which remains the object of much discussion. Factors which appear to influence implantation rates are: contamination of the catheter tip with cervical bacteria, stimulation of uterine contractions during the procedure, the type of catheter, ultrasound guidance during the transfer, and the position of the embryos in the uterine cavity. Easy and atraumatic transfer is essential for successful implantation and the embryos need to be placed in the middle of the cavity, away from the fundus. Knowing, beforehand, the position and length of the uterus can provide better results and may reduce the rate of ectopic pregnancies. Evidence from randomized studies has supported this claim. Despite the number of available studies controlling certain variables, most authors, even using the same catheter, ultrasound guidance and/or a trial transfer use different protocols or similar instruments in different ways. Standardization of the transcervical intrauterine transfer of embryos in a large randomized study is needed before definitive conclusions can be drawn. The goal of improved implantation and pregnancy rates deserve these efforts.

Relationship of vaginal bacteria and inflammation with conception and early pregnancy loss following in-vitro fertilization

OBJECTIVE

The aim of this study was investigate the impact of vaginal flora and vaginal inflammation on conception and early pregnancy loss following in-vitro fertilization (IVF).

METHODS

We enrolled 91 women who were undergoing IVF. At embryo transfer (ET), all of the women had quantitative vaginal culture, ET catheter-tip culture, and vaginal Gram stain scored for bacterial vaginosis and quantitated for polymorphonuclear leukocytes (PMNs). Conception and early pregnancy loss were compared with culture and Gram stain results. Statistical analyses included the Chi-square test, Fisher's exact test and the Mann-Whitney U-test.

RESULTS

The overall live birth rate (LBR) was 30% (27/91), and the rate of early pregnancy loss was 34% (14/41). In women with bacterial vaginosis, intermediate flora and normal flora, the conception rates were 30% (3/10), 39% (12/31) and 52% (26/50), respectively (p = 0.06 for trend). Early pregnancy loss occurred in 33% (1/3), 42% (5/12) and 31% (8/26) of women, respectively (p = 0.06, comparing intermediate and normal flora). The vaginal log concentration of hydrogen peroxide-producing lactobacilli was 7.3 +/- 1.7 in women with a live birth (n = 27) and 4.9 +/- 2.5 in those with early pregnancy loss (n = 14) (p = 0.1).

CONCLUSIONS

IVF patients with bacterial vaginosis and with a decreased vaginal log concentration of hydrogen peroxide-producing lactobacilli may have decreased conception rates and increased rates of early pregnancy loss. A larger prospective treatment trial designed to evaluate the impact on IVF outcomes of optimizing the vaginal flora prior to IVF may be warranted.

A randomized controlled trial of a soft double lumen embryo transfer catheter versus a firm single lumen catheter: significant improvements in pregnancy rates

BACKGROUND

Embryo transfer has changed little since originally described in 1978. Clinicians rate the type of catheter used as the third most important variable in embryo transfer, but there are no adequately powered randomized trials. We compared the clinical pregnancy rates with the single lumen catheter (TCC) and the double lumen catheter (CC) in a randomized single blind trial.

METHODS

A total of 650 cycles of women from the Adelaide University reproductive medicine units in Australia were included in this trial. Patients were <40 years of age undertaking IVF and embryo transfer. Exclusion criteria were: known uterine abnormality, day 3 FSH >10 IU/l, previous difficult embryo transfer and pre-implantation genetic diagnosis. Cycles were randomized from numbered sealed envelopes immediately prior to embryo transfer with stratification for fresh or frozen cycles.

RESULTS

There was a significantly higher pregnancy rate in the group treated with the CC compared with the TCC catheter [29.6 versus 20.5% per embryo transfer, odds ratio (OR) = 1.63 (95% confidence interval: 1.14-2.30), P = 0.0076]. The point estimate for the OR was similar for fresh and frozen cycles.

CONCLUSIONS

The pregnancy rate was increased by 50% and this justifies the increased cost of the soft double lumen catheter and the training of clinical staff required.

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.