Relationships between embryo transfer results and ovarian response and in vitro fertilization rate: analysis of 186 human pregnancies

Oocyte and embryo cryopreservation in assisted reproductive technology: past achievements and current challenges

Cryopreservation has revolutionized the treatment of infertility and fertility preservation. This review summarizes the milestones that paved the way to the current routinary clinical implementation of this game-changing practice in assisted reproductive technology. Still, evidence to support "the best practice" in cryopreservation is controversial and several protocol adaptations exist that were described and compared here, such as cumulus-intact vs. cumulus-free oocyte cryopreservation, artificial collapse, assisted hatching, closed vs. open carriers, and others. A last matter of concern is whether cryostorage duration may impact oocyte/embryo competence, but the current body of evidence in this regard is reassuring. From social and clinical perspectives, oocyte and embryo cryopreservation has evolved from an afterthought when assisted reproduction was intended for immediate pregnancy with supernumerary embryos of secondary interest to its current purpose, which primarily is to preserve fertility long-term and more comprehensively allow for family planning. However, the initial consenting process, which still is geared to short-term fertility care, may no longer be relevant when the individuals that initially preserved the tissues have completed their reproductive journey. A more encompassing counseling model is required to address changing patient values over time.

Metaphase-II oocyte competence is unlinked to the gonadotrophins used for ovarian stimulation: a matched case-control study in women of advanced maternal age

PURPOSE

An impact of different gonadotrophins selection for ovarian stimulation (OS) on oocyte competence has yet to be defined. In this study, we asked whether an association exists between OS protocol and euploid blastocyst rate (EBR) per metaphase-II (MII) oocytes.

METHODS

Cycles of first preimplantation genetic testing for aneuploidies conducted by women ≥ 35 years old with their own metaphase-II oocytes inseminated in the absence of severe male factor (years 2014-2018) were clustered based on whether recombinant FSH (rec-FSH) or human menopausal gonadotrophin (HMG) was used for OS, then matched for the number of fresh inseminated eggs. Four groups were outlined: rec-FSH (N = 57), rec-FSH plus rec-LH (N = 55), rec-FSH plus HMG (N = 112), and HMG-only (N = 127). Intracytoplasmic sperm injection, continuous blastocyst culture, comprehensive chromosome testing to assess full-chromosome non-mosaic aneuploidies and vitrified-warmed euploid single embryo transfers (SETs) were performed. The primary outcome was the EBR per cohort of MII oocytes. The secondary outcome was the live birth rate (LBR) per first SETs.

RESULTS

Rec-FSH protocol was shorter and characterized by lower total gonadotrophin (Gn) dose. The linear regression model adjusted for maternal age showed no association between the Gn adopted for OS and EBR per cohort of MII oocytes. Similarly, no association was reported with the LBR per first SETs, even when adjusting for blastocyst quality and day of full blastulation.

CONCLUSION

In view of enhanced personalization in OS, clinicians shall focus on different endpoints or quantitative effects related to Gn action towards follicle recruitment, development, and atresia. Here, LH and/or hCG was administered exclusively to women with expected sub/poor response; therefore, we cannot exclude that specific Gn formulations may impact patient prognosis in other populations.

High Serum Estradiol Levels are not Detrimental to In Vitro Fertilization Outcome

OBJECTIVE

To evaluate the impact of high estradiol (E2) levels and a high number of retrieved oocytes on the outcome of in vitro fertilization (IVF) cycles.

MATERIALS AND METHODS

We retrospectively reviewed 274 IVF cycles. These patients were divided into five groups according to their peak E2 levels on the human chorionic gonadotropin day: < or = 2,000 pg/mL (130 cycles); 2,001-3,000 pg/mL (53 cycles); 3,001-4,000 pg/mL (46 cycles); 4,001-5,000 pg/mL (29 cycles); > 5,000 pg/mL (16 cycles). Fertilization, pregnancy, and implantation rates were analyzed between these groups. We also compared the outcome of IVF for high responders (> 15 retrieved oocytes) and normal responders (< or = 15 retrieved oocytes).

RESULTS

The oocyte fertilization and embryo cleavage rates were not significantly different among these five groups. Although decrease in pregnancy and implantation rates was observed when E2 levels were > 5,000 pg/mL compared with those having lower E2 levels, there were no statistically significant differences between these five groups. In addition, similar IVF outcome was detected for those cycles with > 15 oocytes and < or = 15 oocytes obtained.

CONCLUSION

High serum E2 levels and high oocyte yield are not detrimental to IVF outcome. More studies are needed to characterize the threshold E2 levels above which implantation rates are reduced.

Estradiol production during controlled ovarian hyperstimulation correlates with treatment outcome in women undergoing in vitro fertilization–embryo transfer

OBJECTIVE

To study the value of E(2) production during controlled ovarian hyperstimulation (COH) in predicting IVF-ET outcome.

DESIGN

Historical cohort.

SETTING

Academic infertility center.

PATIENT(S)

A cohort of 270 patients who completed 324 consecutive IVF-ET treatment cycles.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Area under the curve for E(2) levels (AUC-E(2)) from the first day of COH until the day of hCG administration was calculated and cycles grouped into low, average, and high AUC-E(2) groups. Clinical pregnancy rates per cycle were compared among the three groups, and correlations with AUC-E(2) values were calculated for all patients and after sub-grouping according to age, COH protocol and infertility diagnosis.

RESULT(S)

Cycles with low and high AUC-E(2) values had significantly lower pregnancy rates particularly in patients 35 years or older. There was a positive correlation between AUC-E(2) and pregnancy rates up to a certain AUC-E(2) level above which a negative correlation was found. The turning point between positive and negative correlations occurred at a significantly lower AUC-E(2) level in patients 35 years or older.

CONCLUSIONS

Estradiol production during COH correlates with IVF-ET outcome. Women >35 years of age seem more vulnerable to high E(2) levels.

Percentile curves of serum estradiol levels during controlled ovarian stimulation in 905 cycles stimulated with recombinant FSH show that high estradiol is not detrimental to IVF outcome

BACKGROUND

High, normal and poor responders are usually defined by reference to subjectively selected estradiol E2 levels at days 4-6 and the day of hCG administration (d-hCG). The purpose of this study was to use E2 percentile curves from day 5 until d-hCG to determine high, normal and poor responders, and to predict IVF outcome.

METHODS

In this retrospective study, 762 patients underwent 905 cycles with a GnRH agonist/recombinant FSH short protocol. They were divided into three groups according to their age. Percentile E2 curves according to E2 levels were plotted. High responders were those patients with E2 levels above the 90th percentile, normal responders had E2 between the 10th and 90th percentiles, and poor responders had E2 below the 10th percentile.

RESULTS

IVF outcome, expressed as number of oocytes, total embryos obtained and number of high grade embryos, was significantly better for patients with E2 above the 90th percentile at d-hCG for the three age groups and at day 5 for group A (<35 years). Pregnancy rates were higher for high responders, but the difference did not reach statistical significance.

CONCLUSIONS

Percentile curves can be useful in controlled ovarian stimulation cycles to define high, normal and poor responders, and also to predict IVF outcome.

Predictive variables of in vitro fertilization and pre-implantation embryo development in the mouse

The present study aims to analyze the cause-effect relationships among several in-vitro fertilization and pre-implantation embryo development variables in the mouse. Superovulation of hybrid (C57Bl/6JIco female X CBA/JIco male) female mice of 4-6 weeks of age was induced by a priming injection of pregnant mare's serum gonadotropin at the estrus stage of the estrous cycle followed after a 48-hr interval by human chrorionic gonadotropin. Ovulated cumulus-enclosed oocytes were inseminated with sperm from hybrid males of 12-16 weeks of age. The multiple linear regression analyses performed indicated that (a) total number of ovulated oocytes is a good predictor of both fertilization frequency and total number of cells in day-5 blastocysts; (b) fertilization frequency predicts percentage of day-5 blastocysts; (c) total number of cells in day-5 blastocysts is predicted by percentage of day-5 blastocysts; and (d) total number of cells in day-5 blastocysts predicts percentage of apoptotic cells, number of inner cell mass (ICM) and trophectoderm (TE) cells, and ICM/TE ratio in day-5 blastocysts. Mitotic index in day-5 blastocysts was positively correlated with total number of ovulated oocytes, percentage of ovulated cumulus-enclosed oocytes, fertilization frequency, percentage of day-5 blastocysts and total number of cells in day-5 blastocysts. On the contrary, it was negatively correlated with percentage of apoptotic cells in day-5 blastocysts.

High rates of embryonic loss, yet high incidence of multiple births in human ART: is this paradoxical?

Humans have low natural fecundity, as the probability of establishing a viable conception in any one menstrual cycle is 20-25% for a healthy, fertile couple. There are numerous underlying causes for this low rate of human fertility, not the least of which are intrinsic abnormalities within the oocyte and/or embryo, which likely account for greater than 50% of failed conceptions. During assisted reproduction technology (ART) interventions, controlled ovarian stimulation is used to obtain several oocytes in attempts to increase the likelihood of having at least one developmentally competent embryo available for transfer. However, current techniques for identifying the competent embryo(s) are by no means perfect. These limitations, coupled with pressures to maximize the chance of pregnancy, typically result in the transfer of multiple embryos. Not surprisingly, this practice has resulted in an unacceptably high rate of multiple pregnancies arising from ART. During the last few years, concerted efforts have focused on reducing these rates. Programs for ART are developing patient-specific policies, restricting the number of embryos to transfer. In addition, strategies are being adopted to improve the accuracy for selecting viable embryos for transfer. One such strategy involves further refinement of morphological criteria associated with improved viability by considering, for example, pronuclei disposition, nucleolar organization, and identification of the fast-cleaving embryos with only mononucleate blastomeres. Another strategy employs pre-implantation genetic diagnosis (PGD) whereby a biopsied blastomere is tested for ploidy using fluorescence in situ hybridization (FISH). A final strategy involves extending the duration of culture to the blastocyst stage, thereby allowing self-selection of those embryos capable of proceeding to blastulation and exclusion of those less viable embryos that succumb to developmental arrest. Together, these strategies are enabling fewer embryos of higher quality to be transferred. Accordingly, the overall pregnancy rate from ART continues to increase, while the rate of triplet and higher order multiple births continues to decline. Nevertheless, the high incidence of intrinsic developmental anomalies in human oocytes inevitably will continue to result in a high degree of embryonic loss in ART.

Effects of controlled ovarian hyperstimulation on oocyte quality in terms of the incidence of apoptotic granulosa cells

PURPOSE

The aim was to investigate which ovarian hyperstimulation protocol performed in the same patients causes development of oocytes of good quality.

METHODS

Twenty normo-ovulatory women underwent three different controlled ovarian hyperstimulation protocols for in vitro fertilization-embryo transfer. Patients underwent follicle aspiration after administration of human chorionic gonadotropin (hCG). The total number of retrieved oocytes, the number of mature oocytes, and the rate of mature oocytes were examined. Recovered granulosa cells were stained with Hoechst 33258 and examined by fluorescence microscopy to estimate the incidence of apoptotic cells.

RESULTS

The total number of oocytes and the number of mature oocytes in gonadotropin-releasing hormone agonist (GnRHa) + human menopausal gonadotropin (hMG) + hCG and hMG + hCG cycles were higher than those in the natural cycle (P < 0.0001). The rate of mature oocytes in hMG + hCG cycle was the highest among the three protocols (P < 0.04). In the mural granulosa cells, the incidence of apoptotic cells in the GnRHa + hMG + hCG cycle was significantly higher than those of the natural (P < 0.002) and hMG + hCG cycles (P = 0.0002). The incidence of apoptotic cumulus granulosa cells in the GnRHa + hMG + hCG cycle was significantly higher than those of natural and hMG + hCG cycles (P < 0.002). Moreover, the incidence of apoptotic cumulus granulosa cells in the hMG + hCG cycle was significantly lower than that in the natural cycle (P < 0.01).

CONCLUSIONS

These results indicated that hMG + hCG is the most appropriate controlled ovarian hyperstimulation protocol among the three examined with regard to oocyte quality.

Preretrieval predictors of pregnancy in IVF

PURPOSE

This study was designed to evaluate the predictive value of preretrieval parameters of ovarian stimulation in patients undergoing IVF-ET.

METHODS

Women diagnosed with infertility due to tubal factor were compared to women with other and/or multiple diagnoses. Stepwise logistic regression evaluated 389 cycles to identify the best predictors of pregnancy among the following variables: age, primary or secondary infertility, cycle number, type and dose of gonadotropin, duration of gonadotropin administration, serum estradiol level, and number and size of follicles.

RESULTS

In the tubal disease group, probability of pregnancy was greater in cycles with serum estradiol levels below 1100 pg/ml on the day of hCG (odds ratio, 4.7) and with administration of gonadotropins for less than 10 days (odds ratio, 3.7). In contrast, in the other/mixed diagnoses group, a serum estradiol below 1100 pg/ml was associated with a decreased probability of pregnancy (odds ratio, 0.6).

CONCLUSIONS

Optimal parameters of ovarian stimulation may vary according to the etiology of infertility. In patients with tubal disease, the beneficial effects of greater stimulation, and thus the greater number of available oocytes, may be offset by adverse effects on the endometrium and on the quality of oocytes and embryos. In contrast, in other diagnostic groups, the advantage of an increased number of oocytes may outweigh the potential adverse effects of prolonged stimulation and higher estradiol levels.

The results of an in vitro fertilization program: two regimens of superovulation

Gonadotropin-releasing hormone (GnRH) agonists are increasingly used in ovarian hyperstimulation protocols in in vitro fertilization (IVF) programs. From March 1992 to June 1993, 565 patients attending our Institute underwent superovulation in 1104 IVF program cycles. Of these cycles, 650 were stimulated with clomiphene citrate and gonadotropins (human menopausal gonadotropin/hMG), and 454 with the GnRH agonist buserelin and hMG in a group of patients who had earlier failed to respond or did not conceive after clomiphene citrate/hMG stimulation. The ovarian response was similar in both groups, however, with the use of buserelin more oocytes were recovered -4.9 +/- 3.2 and 3.5 +/- 2.3 oocytes, respectively. The clinical pregnancy rate per transfer in the group of patients superovulated with buserelin/hMG was twice that of the clomiphene citrate/hMG group (21.0% vs. 10.4%). The relatively high pregnancy rate with the buserelin/hMG regimen in the group of 'poor responders' may be connected with GnRH agonist-induced pharmacological hypophysectomy and the sequelae thereof: normalization of some endocrinopathies, absence of an endogenous luteinizing hormone (LH) surge and better endometrium receptivity, oocytes and embryo quality.

Comparison of natural with clomiphene citrate-stimulated cycles in in vitro fertilization: a prospective, randomized trial

OBJECTIVE

To compare the outcome of natural with clomiphene citrate (CC)-stimulated cycles in IVF.

DESIGN

Prospective, randomized study.

SETTING

Tertiary referral center for assisted conception.

SUBJECTS

Thirty patients randomized to receive either no treatment (n = 14) or CC, 100 mg, from days 2 to 6 (n = 16).

INTERVENTIONS

Daily ultrasound (US) scan and measurements of serum LH and E2. Ovarian morphology was assessed on baseline US scan. Human chorionic gonadotrophin was administered when the mean diameter of the dominant follicle reached 17 mm. Transvaginal US-directed oocyte recovery was performed 35 hours later.

MAIN OUTCOME MEASURES

The number of patients reaching oocyte recovery; numbers of oocytes collected, fertilized and embryos transferred; and clinical pregnancy and multiple pregnancy rates (PRs) were recorded.

RESULTS

Ten cycles in the natural cycle group were abandoned before oocyte recovery compared with none in the CC group. There were significantly more follicles > 14 mm (2.4 +/- 0.3 [SE] compared with 0.9 +/- 0.2) and higher peak levels of E2 (375 +/- 67 pg/mL (1,378 +/- 247 pmol/L) compared with 204 +/- 17 pg/mL (748 +/- 61 pmol/L)) in those receiving CC compared with those receiving no drug. All 16 patients treated with CC had oocyte retrieval (mean, 1.8 +/- 0.3 oocytes) compared with only 4 in the natural cycle group (1 oocyte each). The oocyte recovery rate was 95%. Two patients conceived in the CC group (PR per ET, 18%) compared with none in the natural cycle group. Patients with polycystic ovaries developed more large follicles than those with normal ovaries. No patient developed ovarian hyperstimulation syndrome.

CONCLUSIONS

Patients undergoing natural cycle IVF are more likely to have abandoned cycles, produce fewer follicles and oocytes, and are less likely to reach ET than patients treated with CC alone. Clomiphene citrate should be considered for use in the context of a conventionally organised IVF-ET program if a mild degree of ovarian stimulation is desired.

The reproductive outcome following a superhigh response to stimulation in gamete intrafallopian transfer program

A retrospective analysis was carried out to assess the outcome of gamete intrafallopian transfer (GIFT) in cycles when more than 10 oocytes were retrieved (superhigh responders) from October 1987 through June 1989. There were 276 (13%) cycles with more than 10 oocytes retrieved among all GIFT cycles initiated during the period. Clomiphene citrate and gonadotropin were employed for ovarian stimulation in 105 (38%) cycles, and gonadotropin releasing hormone agonist in the remaining 171 (62%) cycles, employing either the flare (104 cycles) or the pituitary down-regulation (67 cycles) protocol. A maximum number of four oocytes was transferred per GIFT (3.5 +/- 0.4). The mean number of oocytes retrieved was 14.7 +/- 4.4 (range, 11 to 35). A significantly younger age group (less than 30 years) of patients was noticed in the study (31.9), and fewer women aged 40 and over (6.2%), compared to the general population of our patients. The pregnancy rate was 33.3% (n = 92) per cycle, with a delivery rate of 23.6% (n = 64) per cycle; the pregnancy loss rate was 30.8%. The reproductive outcome was lower in women aged 40 and over (pregnancy rate was 23.5%, but delivery rate was only 5.8% per cycle). The delivery rate was lower in the clomiphene citrate- and gonadotropin-stimulated cycles (51.7% per pregnancy) in relation to gonadotropin-releasing analogue and gonadotropin cycles (76.6% per pregnancy) and significantly so compared with the pituitary down-regulation protocol (83.3% per pregnancy). We conclude that a superhigh response develops more in younger women, and in such circumstances, the use of pituitary down-regulation with gonadotropin-releasing hormone will improve the reproductive outcome.

Relationships between in vitro progesterone production by granulosa-luteal cells and certain characteristics of human stimulated cycles

OBJECTIVE

To explore the conditions of a suitable luteal phase in human stimulated cycles, progesterone (P) production by cultured granulosa cells from preovulatory follicles was related to preovulatory serum estradiol (E2) and number of oocytes.

DESIGN

Progesterone production was measured in the presence or absence of human chorionic gonadotropin (hCG) using radioimmunoassay; data were compared using Student's t-test; correlations used linear regression.

SETTING

In vitro fertilization and embryo transfer (IVF-ET) for infertility treatment at hospital Antoine Beclère, Clamart, France; scientific studies at Institut National de la Santé et de la Recherche Médicale, Unit 187, Clamart, France.

PATIENTS, PARTICIPANTS

Nineteen women, 33 +/- 4 years old, undergoing IVF-ET for nonovarian causes.

MAIN OUTCOME MEASURES

High preovulatory E2 usually correlates with high luteal P level. Atretic follicle has reduced follicular E2 production combined with a loss of responsiveness to gonadotropins.

RESULTS

Granulosa-luteal cell P production correlated with E2 level (P less than 0.0002). Six cycles, with 14 oocytes recovered per cycle on average, showed reduced plasma E2 per oocyte (P less than 0.001) combined with reduced responsiveness to hCG by granulosa-luteal cells (P less than 0.02).

CONCLUSION

Recovery of numerous oocytes might be associated with follicular atresia and deficient luteal phase.

Outpatient gamete intrafallopian transfer: a clinical analysis of 710 cases

From February 1986 to June 1989 445 infertile couples were treated with a total of 710 treatment cycles involving laparoscopic gamete intrafallopian transfer (GIFT). The median age of the female partner was 33.5 years (range, 24 to 49 years) and the median duration of infertility was 4 years (range, 2 to 20 years). The final outcome of all 217 clinical pregnancies is known. There were 150 live births among which all but one baby survived, comprising 112 singleton births, 28 twin births, nine triplet births and one quadruplet birth. There were no still births, but there were two premature, multiple live births (one triplet, one quadruplet) among which no babies survived the neonatal period. Overall, 40 of the 152 potentially viable pregnancies were multiple (26.3%). Three of 206 potentially viable babies were born with congenital anomalies (1.5%). There were 50 clinical spontaneous abortions (24.8% of uterine pregnancies), one termination of pregnancy for Down's syndrome, and 14 ectopic pregnancies rate was 30.6% per laparoscopy and, among 740 initiated cycles, a live and surviving birth-per-initiated-cycle rate of 20.2%, or 33.7% to date per couple entering the programme. The 710 laparscopies resulted in two serious complications (0.3%), one of which required laparotomy. Eight other patients were admitted to hospital for rest and observation because of painful ovarian enlargement in the luteal phase. The total inpatient admission rate was 1.4%. Outpatient laparoscopic GIFT under general anaesthesia is a safe and effective procedure when conventional treatment for infertility has been unsuccessful.

Performance of different embryo transfer catheters in a human in vitro fertilization program

In a prospective and randomized study on 400 consecutive embryo transfers (ETs), the performance of three different transfer catheters was evaluated. In cases of difficult ET, the TDT catheter (Prodimed, Neuilly-en-Thelle, France) performed the best. However, the pregnancy rate with this catheter was the lowest (9.2%/ET). A better pregnancy rate (19.4%/ET) can be achieved when TDT catheter was used under ultrasound guidance. The Frydman catheter (Prodimed, Neuilly-en-Thelle, France) yielded the highest pregnancy rate (32.3%/ET) but also the highest frequency of difficult transfer procedures. The Wallace catheter (H.G. Wallace Limited, Colchester, England) showed similar performance, but the pregnancy rate was lower (19.2%/ET) compared with the Frydman catheter. Therefore, the Frydman catheter is used as the first choice, and for difficult transfers the TDT catheter under ultrasound guidance can be recommended.

Follicular aspiration and in vitro fertilization associated with pelvic reconstructive surgery

Between August 1982 and May 1987, 103 patients underwent in vitro fertilization-embryo transfer (IVF-ET) in association with pelvic reconstructive surgery for infertility. Follicular stimulation was induced with clomiphene citrate and laparotomy scheduled day 12 to 15 of the menstrual cycle. Ultrasound measurements of follicular diameter and number of follicles were obtained on the day of human chorionic gonadotropin (hCG) administration, and laparotomy and ovum retrieval performed 36 hours later. Embryo transfer was performed 48 to 72 hours after insemination. Patients were treated postoperatively with intramuscular progesterone. In addition to evaluating the overall pregnancy rate, the outcome of patients having one or more follicles greater than or equal to 1.4 cm in mean diameter (group A) were compared to those in group B (no follicles greater than or equal to 1.4 cm in diameter). The number of oocytes obtained and the fertilization rate and polyspermic fertilization rate were not significantly different between groups; 10.1% of patients in group A conceived but no patient conceived in group B, yielding an overall pregnancy rate of 8.7%. These data suggest that physicians having IVF-ET at their disposal offer patients IVF during pelvic reconstructive surgery.

An assessment of alternative policies for embryo transfer in an in vitro fertilization-embryo transfer program

Conventionally, in in vitro fertilization (IVF) programs, all embryos obtained up to three are freshly transferred in the IVF cycle and supernumerary embryos frozen if cryopreservation facilities exist. This study was concerned with assessing alternative policies for embryo transfer (ET). When three or fewer embryos were obtained in the IVF cycle, fresh embryo transfer was either excluded (group I, n = 69) or only one embryo was immediately transferred (group II, n = 46), the remainder being transferred after freezing and thawing. The pregnancy rate in these two policies was compared to that in a control group of patients (group III, n = 115) in whom all the embryos were transferred in the IVF cycle. The ongoing pregnancy rate was similar in all three groups. No multiple pregnancies occurred in groups I and II compared with one in the controls. The consequences of these policies for pregnancy rates and the incidence of multiple gestation are discussed. It is concluded that the deliberate limitation of fresh ET to a maximum of one embryo followed by one or more cycles of thawed frozen ET is not detrimental to the pregnancy rate and is less likely to be associated with multiple gestations. Conversely, this policy increases the workload of the laboratory staff and raises certain ethical questions.

Couples' experiences with in vitro fertilization

In vitro fertilization (IVF) is one of the newest techniques for treatment of infertility. While the medical aspects of IVF have been extensively reported, little research has explored this procedure from the couple's point of view. In this descriptive study, 28 couples who had experienced at least one IVF procedure were interviewed. The results indicate that while IVF offers hope for infertile couples, the procedure, if unsuccessful, can be emotionally traumatic. In addition, the results suggest that comprehensive anticipatory information and emotional support are the primary needs of couples undergoing IVF.

The value of oocyte reinsemination in human in vitro fertilization

The value of oocyte reinsemination in human in vitro fertilization (IVF) was evaluated in this study. Two groups of 25 cycles each were studied. In group 1 cycles, insemination of mature/questionably mature oocytes (judged by cumulus and corona cell appearance) at 6.5 hours postcollection yielded a fertilization rate of 42.3%. This value was significantly lower than that obtained with reinsemination (70.8%). In group 2, questionably mature oocytes were treated as immature and inseminated 24 to 30 hours postcollection. The fertilization rate of mature eggs in group 2 was 68.2%, with a reinsemination success rate of 40%. Triploidy rates and cleavage rates of mature eggs, fertilized either at initial insemination or reinsemination and of fertilized immature eggs, were similar within group 1 and group 2 cycles. In group 1, two pregnancies resulted from transfer of embryos arising solely from successful reinsemination, with one infant delivered. These results indicate that reinsemination offers a useful adjunct for IVF in cases where fertilization failure occurs.

Factors influencing the success rate of human embryo freezing in an in vitro fertilization and embryo transfer program

Certain factors influencing the success of embryo cryopreservation were analyzed from 124 cycles of in vitro fertilization and embryo transfer (IVF-ET) program in which 193 1- or 2-day embryos were frozen and had already been thawed. There were 100 transfers of one or two surviving embryos from which 26 pregnancies were initiated. Several factors significantly influenced embryo survival after thawing. They were: the developmental stage of frozen embryos; the appearance of the embryo at the time of freezing; and the mode of ovarian stimulation in the IVF cycle. The pregnancy rate after frozen-thawed embryo transfer was higher with 4-cell frozen embryos than with embryos at all other stages combined. There were also tendencies for the pregnancy rate to be higher if a spontaneous luteinizing hormone surge occurred in the transfer cycle or if the duration of embryo storage did not exceed 1 to 2 months. The results obtained support a new policy in IVF-ET programs: it should be advantageous for the sterile couple if the immediate fresh embryo transfer is only performed with the categories of embryos that demonstrate a poor aptitude for survival following cryopreservation procedures.

Evidence of uterine inadequacy to egg implantation in stimulated in vitro fertilization cycles

From 104 IVF cycles 166 embryos were immediately transferred (63 embryo transfers, ET), whereas 151 embryos were frozen until later transfer (77 embryo transfers). There were 8 (12.7%) or 19 (24.7%) pregnancies after fresh or frozen-thawed ET, respectively. Sixteen pregnancies (29.1%) originated from 55 ETs of frozen-thawed embryos coming from IVF cycles in which pregnancy was not induced by fresh ET. The pregnancy rate after fresh ET (10.5%) was lower than that obtained when the same patients received frozen-thawed embryos (27.1%, P less than 0.02). It is concluded that a normal pregnancy rate may result if the embryos originating from an unsuccessful IVF-ET cycle are transferred in a favorable uterus.

High pregnancy rate after early human embryo freezing

Human embryos produced by in vitro fertilization (IVF) were frozen with 1,2-propanediol as a cryoprotectant. Embryo survival after thawing was related to the presence of a nucleus in frozen cells and decreased with the increasing number of cells in the frozen embryo. None of five embryos frozen 3 or 4 days after IVF survived when thawed. Of 48 early embryos (35 patients) frozen 1 or 2 days after IVF, 42 (87.5%) were transferred in 32 patients. Ten pregnancies were initiated after frozen embryo transfer (ET). If we exclude the three infertile patients who had sexual intercourse in the fertile period, the pregnancy rate for each patient who had 1- or 2-day frozen embryo(s) was 22% (7 of 32). One of the pregnancies was obtained after ET of a 1-cell pronucleated frozen and thawed embryo. The rate of ongoing pregnancies after triple fresh ET was 23%. In patients having four embryos obtained in a single IVF cycle, the expected overall liveborn rate in an IVF-ET program including embryo cryopreservation could theoretically equal that of natural human fertility.