Transfer of zona-free embryos improves outcome in poor prognosis patients: a prospective randomized controlled study

Assisted zona hatching (AZH) has been used in IVF programmes for several years. Recently one group has reported successful pregnancies after transfer of zona-free blastocysts. The aim of our study was to evaluate outcomes after transfer of zona-free day 3 embryos. Two groups of women undergoing intracytoplasmic sperm injection (ICSI) were included in the study. Group A consisted of 52 women under the age of 40 years undergoing their first ICSI attempt. They were alternately randomized to receive zona-free embryos (27 women) and zona-intact embryos (25 women). The second group (group B) included 71 women with a poor prognosis, as defined by age 40 years or more, and/or at least two previous failed IVF/ICSI attempts. They were randomized in a 3:4 ratio (30 zona-free, 41 zona-intact). Acid Tyrode's solution was used to remove the zona pellucida before embryo transfer on day 3 after oocyte collection. The pregnancy rate in group A was not significantly improved when the zona pellucida was removed. However, in the poor prognosis group B, zona removal resulted in a significantly higher pregnancy rate when compared with controls (23 versus 7.3%). We conclude that complete removal of the zona pellucida can improve pregnancy rates in women with poor IVF/ICSI prognosis.     

The usefulness of ultrasound guidance in frozen-thawed embryo transfer: a prospective randomized clinical trial

BACKGROUND: Recent randomized controlled trials have shown that implantation and pregnancy rates were improved with ultrasound-guided embryo transfer compared with clinical touch in fresh IVF cycles associated with supraphysiological ovarian steroid levels. However, the usefulness of ultrasound guidance in frozen-thawed embryo transfer where potential hormonal influences are lacking has not been appropriately investigated. METHODS: A total of 184 consecutive patients undergoing thawed embryo transfer cycles with hormone replacement under pituitary suppression were randomized by computer-generated randomization table to two study groups: 93 had ultrasound-guided (group 1) and 91 had clinical touch (group 2) embryo transfer. RESULTS: There was equal distribution between the two study groups with respect to the main demographic and baseline characteristics of the patients as well as the characteristics of both prior IVF cycles from which embryos were generated and cryopreserved-thawed embryo transfer cycles. However, both pregnancy and implantation rates in group 1 (34.4 and 19.8% respectively) were significantly higher than the corresponding values (19.7 and 11.9%) in group 2. CONCLUSIONS: Ultrasound guidance in frozen-thawed embryo transfer significantly increases pregnancy and implantation rates.     

Live birth rates after transfer of equal number of blastocysts or cleavage-stage embryos in IVF. A systematic review and meta-analysis

BACKGROUND: Both cleavage-stage and blastocyst-stage embryo transfer policies have advantages and drawbacks. The number of embryos transferred, however, is a crucial parameter that needs to be considered before attempting any comparison. METHODS: An extensive literature search yielded initially 282 studies from which 8 randomized controlled trials met the inclusion criteria: (i) truly randomized design (ii) policy to transfer equal number of embryos in both the cleavage-stage and the blastocyst-stage groups and (iii) published as full text in a peer-review journal. Primary outcome was the live birth rate and secondary outcomes were clinical pregnancy rate, multiple pregnancy rate, cancellation rate and cryopreservation rate. RESULTS: A total of 1654 patients were reviewed. Live birth rate per randomized patient was significantly higher (n = 6 studies) in patients who had a blastocyst-stage transfer as compared to patients with cleavage-stage embryo transfer [odds ratio (OR): 1.39, 95% confidence interval (CI): 1.10-1.76; P = 0.005]. Clinical pregnancy rate (OR: 1.27, 95% CI: 1.03-1.55; P = 0.02) and cancellation rate per patient randomized (OR: 2.21, 95% CI: 1.47-3.32; P = 0.0001) were significantly higher in patients with a blastocyst-stage embryo transfer as compared to patients in whom a cleavage-stage embryo transfer was performed. The cryopreservation rate was significantly higher in the cleavage-stage group (OR: 0.28, 95% CI: 0.14-0.55; P = 0.0002). CONCLUSIONS: The best available evidence suggests that the probability of live birth after fresh IVF is significantly higher after blastocyst-stage embryo transfer as compared to cleavage-stage embryo transfer when equal number of embryos are transferred in the two groups compared.     

High serum oestradiol concentrations in fresh IVF cycles do not impair implantation and pregnancy rates in subsequent frozen-thawed embryo transfer cycles

High oestradiol concentrations may be detrimental to the success of in-vitro fertilization (IVF) treatment. A total of 1122 women aged <40 years who were undergoing their first IVF cycle were evaluated retrospectively. Serum oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration were categorized into three groups: group A <10 000 pmol/l; group B 10 000-20 000 pmol/l and group C >20 000 pmol/l. In fresh cycles, group A had significantly lower pregnancy rates per transfer (16.2 versus 23.7% respectively, P = 0.005, chi(2)) and implantation rates (8.7 versus 11.7% respectively, P = 0.037, chi(2)), when compared with group B. The pregnancy rate per transfer in group C was significantly lower than that in group B (12.1 versus 23.7%, P = 0.049, chi(2)) and group C had the lowest implantation rate (6.4%). In frozen-thawed embryo transfer cycles, implantation rates in groups A, B and C were similar (7.5, 8.1 and 9.6% respectively) and the pregnancy rates were also comparable in all groups. In conclusion, high serum oestradiol concentrations in fresh IVF cycles may adversely affect implantation and pregnancy rates. Embryo quality seemed unaffected as excess embryos from different groups had similar implantation and pregnancy rates in frozen-thawed embryo transfer cycles. The reduced implantation was probably due to an adverse endometrial environment resulting from high serum oestradiol concentrations.     

A prospective randomized study: day 2 versus day 5 embryo transfer

BACKGROUND: This randomized controlled study was performed in an unselected IVF/ICSI population to test the hypothesis that blastocyst transfers result in higher clinical pregnancy rates (CPR) per oocyte retrieval when compared with day 2 transfers. METHODS: Blind randomization for transfer on day 2 (group 1) or day 5/6 (group 2) was performed before stimulation. Oocytes and embryos were cultured in sequential media in 5.5% CO(2), 5% O(2), 89.5% N(2) and 90% humidity. A maximum of two embryos was transferred. RESULTS: The two groups were similar for age, IVF indication, number of treatment cycles, rate of ICSI/IVF, number of fertilized oocytes and number of embryos transferred. The CPR/oocyte retrieval was comparable in group 1 (32%) and in group 2 (44%), while the CPR/embryo transfer was significantly higher (P < 0.01) in group 2 (60%) than in group 1 (35%). Similarly, the implantation rate per embryo transferred was significantly higher (P < 0.03) in group 2 (46%) than in group 1 (29%). The cryo-augmented delivery rate/oocyte retrieval was comparable in group 2 (36.3%) and in group 1 (28.6%). CONCLUSION: This randomized study in an unselected population showed a significantly higher CPR/embryo transfer and a tendency toward a higher CPR/oocyte retrieval in patients receiving blastocysts when compared with day 2 transfers.     

Embryo transfer under ultrasound guidance improves pregnancy rates after in-vitro fertilization

Between October 1998 and January 1999, we examined the influence of ultrasound guidance in embryo transfer on pregnancy rate in 362 patients from our in-vitro fertilization (IVF)-embryo transfer programme. These patients were prospectively randomized into two groups: 182 had ultrasound-guided embryo replacement, and 180 had clinical touch embryo transfer. There were no statistically significant differences between the two groups with respect to age, cause of infertility and in the characteristics of the IVF cycle. The pregnancy rate was significantly higher among the ultrasound-guided embryo transfer group (50%) compared with the clinical touch group (33.7%) (P < 0.002). Furthermore, there was also a significant increase in the implantation rate: 25.3% in the ultrasound group compared with 18.1% in the clinical touch group (P < 0.05). In conclusion, ultrasound assistance in embryo transfer significantly improved pregnancy and implantation rates in IVF.     

Is there any benefit from the culture of a single oocyte to a blastocyst-stage embryo in unstimulated cycles?

BACKGROUND: The aim of the study was to test the influence of 2- and 5-day cultivation of a single oocyte on the pregnancy rate in a non-stimulated cycle. METHODS: A retrospective chart review of 391 consecutive patients undergoing IVF and intracytoplasmic sperm injection in unstimulated cycles was performed. The embryos were kept in MediCult universal IVF medium for day 2 transfers and in BlastAssist System for day 5 transfers. RESULTS: The oocyte recovery rate in the group for 2-day cultivation and in the group for 5-day cultivation was similar, being 79.4 (162/204) and 83.6% (154/187) respectively. The same is true of the fertilization rate (73.8 versus 77.7%). The blastulation rate was 52.8%. The embryo transfer rate per cycle was higher when day 2 embryos were transferred: 64.8% (105/162) compared with 35.7% (55/154) if blastocyst-stage embryos were transferred. The pregnancy rate per transferred embryo was higher when a blastocyst was transferred (40.0%) instead of a day 2 embryo (23.8%). CONCLUSION: The expected pregnancy rate calculated per embryo available on day 2 of cultivation was similar in both groups (23.8 versus 22.2%) and it was not affected by oocyte culture to the blastocyst stage.     

Cryo-thawed embryos obtained from conception cycles have double the implantation and pregnancy potential of those from unsuccessful cycles

BACKGROUND: The purpose of this study was to evaluate the influence of fresh IVF/ICSI cycle outcome on the prognosis of the related frozen embryo replacement (FER) cycle. METHODS: 459 FER cycles, involving 2049 cleavage stage embryos with no or up to 10% fragmentation, were performed for which the outcome of the fresh cycle was recorded. The cycles were divided into two groups; group A included cycles in which cryopreserved embryos were obtained from fresh cycles in which conception occurred. Group B were cycles in which cryopreserved embryos originated from unsuccessful fresh cycles. RESULTS: Groups A and B were comparable with respect to mean (+/- SD) age at cryopreservation (33 +/- 3.9 versus 33.2 +/- 4 years, P = not significant), mean number of oocytes retrieved and fertilized normally in the fresh cycle (11 +/- 5.2 versus 11.2 +/- 4.8, P = not significant) and mean age at the cryo-thawed transfer (34.5 +/- 4.2 versus 33.9 +/- 4 years, P = not significant). No significant difference was found between the two groups with regard to mean number of embryos cryopreserved (6.5 +/- 3.9 versus 6.2 +/- 3.6) and subsequently thawed (4.5 +/- 2.5 versus 4.5 +/- 1.8) per cycle and number of cryo-thawed embryos transferred per cycle (2.0 +/- 0.7 versus 2.1 +/- 0.8). However, the implantation rate per transferred embryo in group A was double that in group B (23 versus 11.2%, P < 0.0001). Moreover, the clinical pregnancy and ongoing pregnancy rates per cycle were significantly higher in group A compared with group B (34.8 and 27.3% versus 15.6 and 13.1%, P < 0.0001 and P = 0.0003 respectively). The difference in FER cycle outcome could not be explained by confounding variables. CONCLUSIONS: After thawing, cryopreserved embryos originating from conception IVF/ICSI cycles achieve double the implantation and pregnancy rates of those obtained from unsuccessful cycles.     

Elective cryopreservation of all pronucleate embryos in women at risk of ovarian hyperstimulation syndrome: efficiency and safety.

In a prospective randomized study, we analysed 125 patients at risk of ovarian hyperstimulation syndrome (OHSS), selected in the period between January 1996 and July 1997. All the patients had blood oestradiol concentration >/=1500 pg/ml on the day of human chorionic gonadotrophin (HCG) administration and >/=15 oocytes were collected. The patients were matched in two groups: group A, control group (n = 67), had fresh embryo transfers; group B (n = 58) had cryopreservation of all obtained pronucleate embryos. Pregnancy, live birth rates and the incidence of OHSS were compared between the two groups. There were no significant differences in terms of pregnancies per patient (46.3 versus 48.3%) and live birth rates (38. 8 versus 39.6%). No cases of OHSS occurred in group B, while four patients developed the syndrome in group A. The implantation rate was slightly but not significantly lower in group B (chi2 = 1.03). These results suggest that elective cryopreservation of all zygotes might prevent the risk of OHSS in patients undergoing IVF treatment. In contrast to what has been reported by other authors, our results show that the elective cryopreservation of zygotes does not affect pregnancy and live birth rates.     

Simple enumerations of peripheral blood natural killer (CD56+ NK) cells, B cells and T cells have no predictive value in IVF treatment outcome

BACKGROUND: To evaluate the association between the absolute counts of the peripheral natural killer (NK) cells (including total CD56(+) NK cells, CD56(dim) NK cells and CD56(bright) NK cells), B cells and T cells on the implantation rate and miscarriage rate after IVF treatment. METHODS: This was a prospective observation study. A total of 138 patients who underwent IVF treatment from December 2002 to July 2003 were recruited to the study. Blood samples were obtained on the day of vaginal oocyte retrieval prior to the procedure. The absolute counts of lymphocytes, NK cells, B cells and T cells were identified by flow cytometry. These absolute counts and their relationships to IVF treatment outcome and miscarriage rate were analysed. RESULTS: There were no significant differences with regard the mean values of absolute lymphocyte count, T cell count, B cell count and NK cell count (including total CD56(+) NK, CD56(dim) NK and CD56(bright) NK cells) between the pregnant and non-pregnant groups and also between the ongoing pregnancy and miscarriage groups. The cause of infertility, duration of infertility, basal FSH levels, number of previous failed IVF treatments, number of previous miscarriages and stimulation characteristics were not significantly different between the pregnant and non-pregnant groups. Previous studies have suggested that women with a history of recurrent miscarriage and those with infertility accompanied by recurrent failed IVF treatments are associated with a peripheral blood NK cell percentage >12%, therefore further analysis of peripheral CD56(+) NK cell levels <12% (group A) and >12% (group B) was performed. There was no significant difference in implantation rate (group A: 17.0%; group B: 23.2%), pregnancy rate (group A: 36.6%; group B: 47.7%) or miscarriage rate (group A: 23.3%; group B: 28.6%). CONCLUSION: There were no significant differences between simple enumerations of peripheral blood NK cells (including total CD56(+) NK, CD56(dim) NK and CD56(bright) NK cells), B cells and T cells with IVF treatment outcome and pregnancy outcome. Women who had a peripheral NK cell level >12% did not have higher number of previous pregnancy losses. Importantly their pregnancy rate was not reduced and their miscarriages were not increased compared to women who had a peripheral NK cells level <12%.     

Infertility: Avoidance of triplet pregnancies by elective transfer of two good quality embryos

Attempts to increase the probability of a successful pregnancyin in-vitro fertilization (IVF) treatment by increasing thenumber of embryos transferred automatically also increase theprobability of multiple pregnancies and their attendant risks.Even where the number of transferred embryos is limited to amaximum of three as in this and other centres, there is a highincidence of twins and triplets. The question therefore ariseswhether the number of transferred embryos should be furtherlimited to a maximum of two in cases where the prognosis isotherwise good. The only objection to this idea is a possiblelowering of pregnancy rate. The present study set out to investigatethis question. No significant lowering of pregnancy rate wasfound, so that limiting the number of transferred embryos totwo where the prognosis is otherwise good has now become standardpractice in our centre. A good IVF prognosis was defined bythe following criteria: first attempt for IVF, less than 37years old, and good embryo development. From 183 patients fulfillingthese criteria, 80 agreed to the transfer of two embryos (group1) and 103 opted for a triple transfer (group 2). Patient characteristicsand embryology results were similar in the two groups. In group1, 34 patients (42.5%) became pregnant and in group 2, 50 (48.5%).This difference is not significant. Similarly, twin pregnancyrates in both groups were high; eight twin pregnancies (23.5%)in group 1 and 12 (24%) in group 2. For the triplet pregnancyrate of 18% (nine triplet pregnancies) in group 2, there wasobviously no parallel in group 1. After thawing about half ofthe cryopreserved embryos and subsequently replacing them, preliminarycumulative pregnancy rates of 52.5% in group 1 and 53.4% ingroup 2 were obtained. Future results from cryopreservationshould provide relatively better outcomes for group 1 sinceall the patients in this group had at least one embryo frozenand fewer embryos replaced in the fresh cycle.     

Birth characteristics and perinatal outcome of babies conceived from cryopreserved embryos

The objective of this retrospective study was to compare thebirth characteristics and perinatal mortality of babies conceivedfrom the use of cryopreserved embryos with those resulting fromin-vitro fertilization (IVF) and fresh embryo transfer. A totalof 232 consecutive births, one pregnancy termination and a totalof 283 babies in the cryopreserved group were studied. The IVFdata included 763 births, three terminations and 961 babies,based on a previous analysis. There was no difference in theincidence of twin (18 versus 19%) and triplet births (2 versus3%) in the cryopreserved and IVF groups respectively. The meangestational age and birthweight of singleton, twin and tripletbirths were not significantly different between the groups.No difference was found in the perinatal mortality rates. Theincidence of major congenital malformations in the cryopreservedgroup (1%) was significantly lower than that in the IVF group(3%, P < 0.05). It is concluded that the birth characteristicsof babies conceived from cryopreserved/thawed embryos are similarto those from fresh embryos. There are fewer congenital malformationsin the cryopreserved group.     

The couple's decision-making in IVF: one or two embryos at transfer?

BACKGROUND: The aim of this study was to evaluate the decision-making process and factors that contribute to the decision of IVF participants to choose one or two embryos at transfer. METHODS: Two hundred and seventy-four IVF patients equally distributed in males and females were personally interviewed using a semi-structured questionnaire which included 82 items. RESULTS: In the whole study population, previous childbirth [odds ratio (OR) 2.1; 95% confidence interval (CI) 1.9-3.6], and spare embryos to freeze (OR 23.6; 95% CI 11.2-54.5) emerged as the most important variables in patients who had one embryo transferred, while previous IVF treatments (OR 0.3; 95% CI 0.1-0.6) and the assumed increased pregnancy chance (OR 0.1; 95% CI 0.05-0.3) were the most important decision-making factors among those who had two embryos. The women were more satisfied with the information (83 versus 71%; P = 0.02), and more aware of the risks with twin pregnancies (77 versus 66%; P = 0.03) than the males. The women were also more concerned about their age. Knowledge about risks of multiple pregnancies was higher in females (77%) than in males (66%, P = 0.03). CONCLUSION: The results of this study indicate that despite good information about the risks for complications with multiple pregnancies, many patients wish to have two embryos transferred. Spare embryos to freeze, improvement of pregnancy rate in single embryo transfer and young age of the woman are predictive of choosing single embryo transfer. However, the final decision must always be made in agreement with the physician.     

Extended embryo culture in human assisted reproduction treatments

In order to evaluate the niche of extended embryo culture in an IVF programme, retrospective analysis of non-selected IVF patients, who underwent ovarian stimulation from April 1998 to June 1999 in a single private practice assisted reproductive technology centre, was performed. Embryos were cultured for 48 h in S1/G1.2 medium followed by 48 to 72 h of culture in S2/G2.2 to day 5 or day 6. Only fertilized oocytes exhibiting two pronuclei from donor and non-donor IVF and intracytoplasmic sperm injection (ICSI) cases were examined to determine the relationship between embryo cell number on day 3 and subsequent rate of blastocyst formation. Results indicated that a proportional relationship existed between the number of blastomeres present in day 3 embryos and the rate of blastocyst formation. Fifty-four per cent of embryos that had six cells on day 3 formed blastocysts, while 76% of those embryos with eight cells formed blastocysts. Blastocyst development did not increase further when embryos had more than eight cells on day 3, indicating that embryos with greater cell numbers on day 3 are not always predictive of a greater likelihood of blastocyst formation. Fertilized oocytes exhibiting two pronuclei from donors produced significantly more blastocysts (67%) than those from IVF patients (52%; P < 0.01), and had a significantly higher implantation rate (54%) compared with IVF patients (30%; P < 0.01). Furthermore, blastocyst cryopreservation resulted in significantly higher implantation rates than cryopreserved cleavage stage embryos (P < 0.001).     

Impact of patients' choice for single embryo transfer of a top quality embryo versus double embryo transfer in the first IVF/ICSI cycle

BACKGROUND: The aim of this study was to evaluate the impact of transferring a single top quality embryo in the first IVF/ICSI cycle of patients <38 years old who chose to have one or two embryos transferred. METHODS: A total of 262 patients participated in the study, and 243 transfers were performed: 156 (64%) patients chose the transfer of a single top quality embryo, if available, and two non-top quality embryos if not available; 87 (36%) patients chose to have a double embryo transfer regardless of embryo quality. RESULTS: In the first group an ongoing pregnancy rate of 40% (63/156) with a twin pregnancy rate of 2% (1/63) was achieved. In the second group the ongoing pregnancy rate was 44% (38/87) with 26% (10/38) twin pregnancies. In the patient group with only one embryo transferred, irrespective of the patient's choice, the ongoing pregnancy rate was 43% (54/127) with no twin pregnancies. For the study population as a whole, the ongoing pregnancy rate was 42% (101/243) with 11% (11/101) twins. CONCLUSION: We conclude that the introduction of single embryo transfer in the first IVF/ICSI cycle is highly acceptable in women <38 years old.     

Number of embryos for transfer after IVF and ICSI: a Cochrane review

BACKGROUND: The most common complication of IVF is multiple pregnancy, which occurs in 25% of pregnancies following the transfer of two embryos. Single embryo transfer can minimize twin pregnancies but could also lower live birth rates. Our aim was to perform a systematic review of randomized trials to determine the effectiveness of single versus double embryo transfer. METHODS: Cochrane Collaboration review methods were followed. Randomized controlled trials comparing single and double embryo transfers were identified by searching Medline, EMBASE and the Cochrane register of controlled trials. Contents of specialist journals and proceedings from meetings of relevant societies were hand searched. Data were pooled with Rev Man software using the Peto-modified Mantel-Hanzel method. RESULTS: Pooled results from four trials indicate that although double embryo transfer leads to a higher live birth rate per woman [odds ratio (OR) 1.94, 95% confidence interval (CI) 1.47-2.55] in a fresh IVF cycle, comparable results are obtained by subsequent transfer of a frozen embryo (OR 1.19, 95% CI 0.87-1.62). The multiple pregnancy rate is significantly higher (OR 62.83, 95% CI 8.52-463.57) after double embryo transfer. CONCLUSIONS: Single embryo transfer significantly reduces the risk of multiple pregnancy, but also decreases the chance of live birth in a fresh IVF cycle. Subsequent replacement of a single frozen embryo achieves a live birth rate comparable with double embryo transfer.     

Human embryos with unevenly sized blastomeres have lower pregnancy and implantation rates: indications for aneuploidy and multinucleation

Uneven blastomere cleavage in human embryos of 'good morphology', i.e. those normally used for transfer, is a phenomenon which has been poorly investigated. The main objective in this study was to probe deeper into the aetiology behind previous findings that embryos with uneven cell cleavage have a lower developmental capacity in comparison with evenly cleaved embryos. Our hypothesis was that uneven cleavage may result in embryos with a higher degree of aneuploidy and/or multinuclear rate, which in turn might help to explain their low implantation rate. In the first part of the study, 378 embryo transfers performed over a 3-year period were analysed retrospectively, where all the transferred embryos in each cycle were of identical morphology score and cleavage stage. In the second part of the study, multicolour fluorescence in-situ hybridization (FISH) analyses on good quality embryos, representing the uneven (n = 11) and even (n = 13) study groups were performed. When comparing day 2 transfers between 4-cell embryos, it was found that unevenly cleaved embryos had significantly lower implantation (23.9 and 36.4%) and pregnancy rates (37.6 and 52.9%) compared with evenly cleaved embryos. A significantly higher degree of aneuploidy (29.4 and 8.5%) and multinuclear rate (21.1 and 2.1%) in blastomeres from uneven embryos was also found. It is concluded that uneven blastomere cleavage has a negative effect on both pregnancy and implantation rates in human IVF, and that this can partly be explained by a higher degree of aneuploidy/multinuclear rate. In the light of the results obtained, a new approach in the current embryo scoring system, placing more emphasis on blastomere size, is recommended.     

Does laparoscopic ovarian diathermy affect the outcome of IVF-embryo transfer in women with polycystic ovarian syndrome? A retrospective comparative study

Controlled ovarian stimulation for IVF and embryo transfer and outcome parameters were compared retrospectively in 31 women with clomiphene-resistant polycystic ovarian syndrome (PCOS). Of these women, 15 had previously undergone laparoscopic ovarian diathermy before IVF (group A, total 22 cycles) and 16 had not had surgical treatment (group B, total 24 cycles). No statistically significant differences were observed in the number of oocytes retrieved, although the number of embryos available for transfer was significantly higher in group B (7.1 +/- 3.8 versus 4.6 +/- 2.7, P < 0.01). The clinical pregnancy rate per embryo transfer appeared to be higher in group B (63.2 versus 41.2%), as did the miscarriage rate (66.7 versus 28.6%), giving an apparent improved ongoing pregnancy rate per embryo transfer in group A (29.4 versus 10.5%), but this was not statistically significantly different. The incidence of severe ovarian hyperstimulation syndrome (OHSS) was apparently higher in group B (4.2 versus 0%), but this difference was not statistically significant. No cases of severe OHSS were seen in group A. Ovarian diathermy does not appear to have a deleterious effect on controlled ovarian stimulation, and the outcome of IVF-embryo transfer may be beneficial in decreasing the risk of severe OHSS and improving the ongoing clinical pregnancy rate.     

Embryo quality and uterine receptivity in in-vitro fertilization cycles with or without agonists of gonadotrophin-releasing hormone

The proportion of abnormal oocytes or embryos per recovered oocyte in in-vitro fertilization (IVF) cycles had no influence on the occurrence of pregnancy following the transfer of normal embryo(s) derived from oocytes capable of fertilization. There were more implantations per transferred embryo in stimulated IVF cycles using long-acting buserelin (30.0%) compared with short-acting decapeptyl (17.3%) or no gonadotrophin-releasing hormone agonist (GnRHa, 15.2%) treatments. However, the chances of implantation per embryo transferred being in excess of one in patients who became pregnant tended to be higher in non-GnRHa (23.5%) compared to buserelin- (16.4%) or decapeptyl- (13.3%) treated IVF cycles. Moreover, frozen--thawed embryos had a higher implantation rate (P less than 0.05) when originating from IVF cycles without GnRHa (11.7%) compared to GnRHa-treated cycles (buserelin, 4.3%; decapeptyl, 5.9%). It can be concluded that GnRHa associated with gonadotrophins produced embryos of a poorer aptitude for development than stimulation treatments without GnRHa. The clinical efficacy of GnRHa in IVF--ET cycles could be the result of an improved uterine receptivity to the transferred embryos.     

One year's experience with elective transfer of two good quality embryos in the human in-vitro fertilization and intracytoplasmic sperm injection programmes

High incidences of multiple pregnancies, after transferringa maximum of three embryos, were observed after in-vitro fertilization(IVF) treatment. In a randomized study, it was demonstratedthat, after taking into account embryo quality and other positivelyinterfering parameters, an elective transfer of two good qualityembryos does not significantly influence the pregnancy rate.The intracytoplasmic sperm injection (ICSI) technique was successfullydeveloped in the meantime and high incidences of multiple pregnancieswere also obtained after ICSI. The question arose whether afterICSI there was also room for elective double embryo transferin a well-defined patient group. This report covers 1 year of IVF and ICSI treatment and theresults are presented in relation to the number of embryos transferred.The embryo development is similar for zygotes obtained afterIVF and ICSI; for both techniques 63% of the zygotes developto type A-B embryos and 13% to type C embryos. There is alsono difference in the pregnancy rate after ICSI or IVF. Globally,after IVF, 307 out of the 766 double and triple transfers (40.1%)and 317 out of 774 double and triple transfers (40.9%) afterICSI resulted in a positive HCG. After IVF, 73.9% (227) andafter ICSI 76.3% (242) of the pregnancies were evolutive. Neitherwas there any difference between the two techniques as regardsthe implantation rate per transferred embryo. After IVF, 22.8%of the transferred embryos implanted compared with 21.8% afterICSI. When the elective double embryo transfers were compared,no difference was found between IVF and ICSI. After IVF, 102of the 211 elective double transfers (48.1%) resulted in a pregnancyversus 93 out of 225 (41.3%) after ICSI [not significant (NS)].A high implantation rate per transferred embryo (IVF: 33.2%;ICSI: 26.9%, NS) was obtained in this elective double transfercategory, as was also reported in the randomized study. Thesedata confirm the results obtained in our randomized study andthe effectiveness of the elective double embryo transfer forIVF as well as for ICSI.