One versus two embryo transfer after IVF and ICSI: a randomized study

BACKGROUND: The main reason for adverse treatment outcome in assisted reproduction is the high rate of multiple pregnancies. The only strategy to avoid dizygotic twins is to transfer one embryo at a time. METHODS: A total of 144 women, who had had at least four good quality embryos available after IVF/intracytoplasmic sperm injection (ICSI) and who had no more than one previous failed treatment cycle, were randomized to have either one or two embryos transferred. The treatment outcomes including those after frozen embryo transfer were compared between these groups. RESULTS: The clinical pregnancy rate per transfer was 32.4% in the one embryo transfer group and 47.1% in the two embryo transfer group, the difference being not significant. Eleven twin deliveries (n = 39) occurred in the two embryo transfer group and there was one pair of monozygotic twins in the one embryo transfer group. The cumulative pregnancy rate per patient after transfer of fresh and frozen embryos was 47.3% in the one embryo transfer group and 58.6% in the two embryo transfer group. CONCLUSIONS: Our results indicate that among women who have good quality embryos in their first IVF/ICSI, good treatment results can be achieved. They support the idea of changing embryo transfer policy towards one embryo transfer without any remarkable decrease in the success rate, while dizygotic twins can be avoided.     

Rescue ICSI of unfertilized oocytes after IVF

BACKGROUND: Failed fertilization after IVF occurs in 10-20% of cycles. Conflicting results of rescue fertilization by ICSI have been reported. We therefore compared the success rate in terms of fertilization and pregnancy of cycles in which rescue ICSI was performed with those from a matched control group of primarily ICSI cycles. METHODS: Unfertilized oocytes from IVF cycles with total fertilization failure where at least four metaphase II oocytes were available were treated by ICSI (group I; n = 120). A matched control group was established with patients undergoing ICSI during the same period (group II; n = 280). RESULTS: Both fertilization rate and the proportion of embryos with four blastomeres on day 2 after ICSI were significantly higher in the control group (P < 0.05). Embryo quality, however, was comparable in both groups. The pregnancy rate in the control group was 25.3% whereas in group I with rescue ICSI, no pregnancy was obtained. CONCLUSIONS: Although unfertilized oocytes after IVF can be fertilized by ICSI, the developmental potential of the ensuing embryos is very poor. Therefore, rescue ICSI after total failure of fertilization is not recommended.     

Results of IVF from a prospective multicentre study.

Part of a cost-effectiveness study of in-vitro fertilization was the evaluation of the medical results of this fertility treatment. Data were prospectively collected from greater than 3000 IVF treatments in five Dutch hospitals during a 2-year period. The average 'take-at-least-one-healthy-baby-home-rate' per started treatment was 10% (the average clinical pregnancy rate per embryo transfer was 20%). After more IVF treatments, about one in three to four couples were successful. Differences in results were mainly caused by patient characteristics, the treatment episode and the treating hospital. These differences remained in a multivariate logistic regression analysis.     

Low-dose aspirin does not improve ovarian responsiveness or pregnancy rate in IVF and ICSI patients: a randomized, placebo-controlled double-blind study

BACKGROUND: Poor ovarian and endometrial responses to gonadotrophin stimulation in assisted reproduction techniques lead to decreased pregnancy rates. The aim of the present study was to test the hypothesis that low-dose aspirin started prior to controlled ovarian stimulation improves ovarian responsiveness, pregnancy rate (PR) and pregnancy outcome. METHODS: A total of 374 women who were to undergo IVF/ICSI were randomized to receive 100 mg of aspirin (n=186) or placebo (n=188) daily. Treatment was started on the first day of controlled ovarian stimulation. It was continued until menstruation or a negative pregnancy test. Pregnant women continued the medication until delivery. The main outcome measures were the number of oocytes, number and quality of embryos, the clinical PR and pregnancy outcome. RESULTS: The mean (+/-SD) number of oocytes (12.0+/-7.0 versus 12.7+/-7.2), the total mean number of embryos (5.82+/-4.35 versus 5.99+/-4.66), the mean number of top quality embryos (0.99+/-1.39 versus 1.18+/-1.51) and the number of embryos transferred (1.64+/-0.64 versus 1.63+/-0.71) did not differ in the aspirin and placebo groups. Between the aspirin and placebo group, there was no statistically significant difference in clinical PR per embryo transfer (25.3%, n=44 out of 174 versus 27.4%, n=48 out of 175) or clinical PR per cycle initiated (23.7% versus 25.5%). Birth rate per embryo transfer did not differ significantly between the aspirin (18.4%) and placebo (21.1%) groups. The incidence of poor responders [12 (6.5%) versus 13 (6.9%)] was similar in both groups. CONCLUSIONS: The present results indicate that low-dose aspirin treatment does not have any beneficial effect on ovarian responsiveness, PR and pregnancy outcome in unselected women undergoing IVF/ICSI.     

Day 14 maternal serum progesterone levels predict pregnancy outcome in IVF/ICSI treatment cycles: a prospective study

BACKGROUND: Serum progesterone has been advocated as a tool in the diagnosis of early pregnancy failure. We conducted this prospective study in order to investigate the potential value of early (14 days after oocyte recovery) serum progesterone measurement, in women undergoing IVF/ICSI and receiving rectal progesterone supplements, in relation to pregnancy outcome. METHODS: 442 women consecutively treated by IVF or ICSI had serum progesterone and bhCG levels prospectively measured 14 days after oocyte retrieval (day 0). All women received natural progesterone 400 mg rectally until the pregnancy test on day 14. Pregnant women were followed up by serial transvaginal ultrasound scans to 8 weeks gestation. RESULTS: 115 women (26%) had a viable intra-uterine pregnancy at 8 weeks gestation, 80 (18.1%) had an abnormal pregnancy (biochemical, ectopic, miscarriage) and 247 (55.9%) failed to conceive. Women with on-going pregnancies had significantly higher serum progesterone levels (median: 430, 95%CI: 390-500 nmol/l) compared to those who had either an abnormal pregnancy (72, 48-96 nmol/l; P < 0.001) or failed to conceive (33, 28-37 nmol/l; P < 0.001). Receiver-operator curve analysis demonstrated that a single serum progesterone on day 14 post-oocyte retrieval, could highly differentiate between normal and abnormal pregnancies (area under the curve = 0.927, 95%CI = 0.89-0.96; P < 0.0001). CONCLUSIONS: In spite of exogenous progesterone supplementation, serum progesterone levels, from as early as 4 weeks gestation (day 14 post-oocyte retrieval) were significantly elevated and predicted women destined to have viable intra-uterine pregnancies. These high levels are suggestive that endogenous progesterone is already sufficient in viable pregnancies and that exogenous progesterone administration will not rescue a pregnancy destined to result in a miscarriage. Single serum progesterone measurement could be a useful indicator of pregnancy outcome in women undergoing IVF or ICSI treatment.     

Progesterone supplementation during early gestations after IVF or ICSI has no effect on the delivery rates: a randomized controlled trial

BACKGROUND: The aim was to study whether prolongation of luteal support during early pregnancy influences the delivery rate after IVF. METHODS: Dual centre study including 303 women who achieved pregnancy after IVF or ICSI was used. All were treated with the long protocol using GnRH agonists and given luteal support with 200 mg vaginal progesterone three times daily during 14 days from the day of transfer until the day of a positive HCG test. The study group (n = 150) withdrew vaginal progesterone from the day of positive HCG. The control group (n = 153) continued administration of vaginal progesterone during the next 3 weeks of pregnancy. RESULTS: The number of miscarriages prior to and after week 7 of gestation was seven (4.6%) and 15 (10.0%) in the study group and five (3.3%) and 13 (8.5%) in the control group respectively. The number of deliveries was 118 (78.7 %) in the study group and 126 (82.4 %) in the control group. The differences were not significant. CONCLUSIONS: Prolongation of progesterone supplementation in early pregnancy has no influence on the miscarriage rate, and thus no effect on the delivery rate. Progesterone supplementation can safely be withdrawn at the time of a positive HCG test.     

Is intracytoplasmic sperm injection (ICSI) a safe procedure? What do we learn from early pregnancy data about ICSI?

The aim of this study was to evaluate the safety of the intracytoplasmicsperm injection (ICSI) procedure by analysing early pregnancydata from ICSI and in-vitro fertilization (IVF) patients. Inall, 50 ICSI pregnancies were compared with 226 FVF pregnancies.Comparisons were made during the first 9 weeks after the theoreticallast menstrual period (7 weeks after oocyte retrieval) withregard to epidemiological data, plasma hormonal concentrationsand transvaginal ultrasonographical findings. Although patientswere significantly (P < 0.001) younger in ICSI (31 years)than in IVF pregnancies (33 years), their duration of infertilitywas similar. Miscarriage and multiple gestation rates were notsignificantly different in ICSI pregnancies (respectively 24and 24%) from those found after IVF (32 and 29%). The probabilityof developmental arrest of the intrauterine sac (miscarriagesand vanishing twins) was similar in both ICSI (16%) and IVF(25%) cases. The mean plasma hormonal concentrations startingfrom day 11 after oocyte retrieval were similar in both groups.Every ICSI and IVF pregnancy showed an embryo with cardiac activityat 7 weeks. Early pregnancy data did not show any abnormal findingsfor pregnancies achieved using ICSI compared to those achievedby FVF.     

Cumulative probability of achieving an ongoing pregnancy after in-vitro fertilization and intracytoplasmic sperm injection according to a woman's age, subfertility diagnosis and primary or secondary subfertility

The aim of this study was to estimate reliable cumulative probabilities of achieving an ongoing pregnancy after successive in-vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) cycles, according to a woman's age, subfertility diagnosis and primary or secondary subfertility. Therefore reasons for quitting treatment without achieving an ongoing pregnancy were taken into account. Moreover, we studied whether there were trends in cumulative probabilities after adjustment for potential confounding effects of the other two characteristics, duration of subfertility, year of first treatment and reason for quitting treatment. In total, 2984 IVF/ICSI cycles were performed in 1315 couples at the University Hospital Nijmegen, The Netherlands, between 1991 and 1998. The 'realistic' cumulative probability of achieving an ongoing pregnancy was 54.5% after five consecutive IVF/ICSI cycles, which was about 10% lower (absolute value) than the optimistic probability calculated by life-table analysis and about 10% higher (absolute value) than the most pessimistic estimate. Women of 35 years or younger had a higher probability of achieving an ongoing pregnancy than the older women. As ICSI is now an option, there were no obvious differences between the subfertility diagnosis subgroups. The cumulative probability after the first two IVF/ICSI cycles was higher in women with secondary subfertility than in those with primary subfertility; this advantage disappeared after further treatment. These trends remained valid after adjustment for confounding factors.     

Neonatal outcome in a Danish national cohort of 3438 IVF/ICSI and 10,362 non-IVF/ICSI twins born between 1995 and 2000

BACKGROUND: In Denmark, one-third of twin pregnancies are the result of IVF/ICSI treatment. Limited data on neonatal outcome in IVF/ICSI twins are available in the literature. METHODS: A register study was conducted on neonatal morbidity and mortality in a complete national twin cohort including all 3438 (3393 live-born) IVF/ICSI and 10,362 (10,239 live-born) non-IVF/ICSI twins born between 1995 and 2000. Twins were identified in the National Medical Birth Registry and dichotomized into IVF/ICSI and non-IVF/ICSI by cross-reference with the Danish IVF Registry. Data on neonatal morbidity and mortality were retrieved from the Danish Patient Registry and the Danish Registry of Causes of Deaths. In order to exclude monozygotic twins, sub-analyses on unlike-sex twins were conducted. RESULTS: A birth weight discordance of >20% was observed in 20.6% of IVF/ICSI versus 15.7% of control twin pairs (P < 0.001). The risk of discordant birth weight >20% was OR 1.29 (95% CI 1.04-1.58) in unlike-sex IVF/ICSI twins versus control twins. The risk of delivery at <37 completed weeks and birth weight <2500 g was similar in the two cohorts; however, in unlike-sex IVF/ICSI versus control twins the risk of delivery at <37 weeks and birth weight <2500 g was OR 1.22 (95% CI 1.09-1.38) and OR 1.25 (1.11-1.40) respectively. After stratification for maternal age and parity, these risks disappeared. IVF/ICSI twins carried a higher risk of admittance to a neonatal intensive care unit (NICU) than control twins (OR 1.18, 95% CI 1.09-1.27), and this was even more pronounced in unlike-sex twins [OR 1.34 (95% CI 1.19-1.51)]. No differences were observed in malformation or mortality rates between the two cohorts. CONCLUSIONS: Despite higher birth weight discordance and more NICU admissions among IVF/ICSI twins, neonatal outcome in IVF/ICSI twins seems to be comparable with that of non-IVF/ICSI twins, when only dizygotic twins were considered in the comparisons.     

Current Internet use and preferences of IVF and ICSI patients

BACKGROUND: Nowadays, the Internet has a tremendous impact on modern society, including healthcare practice. The study aim was to characterize current Internet use by IVF and ICSI patients and to identify their preferences regarding Internet applications in fertility care. METHODS: A total of 163 couples with fertility problems awaiting an IVF or ICSI procedure in the University Medical Centre Nijmegen, The Netherlands, was asked to complete a written questionnaire on Internet use in general, and also for fertility-related problems, preferences regarding Internet applications in fertility care and demographic characteristics. RESULTS: The response rate was 82%. In total, 81% of infertile couples used the Internet. Multivariate logistic regression analysis showed ethnic background and annual family income to be significant predictors of Internet use. Some 66% of Internet users and 54% of the total study population used the Internet for fertility-related problems. The female partners were the main Internet users with regard to fertility-related issues. In terms of preferences of the study participants, the majority favoured personal medical information online. CONCLUSIONS: Most infertile couples used the Internet with respect to fertility-related problems and were interested in implementation of Internet applications in fertility care. Healthcare providers should actively participate in the development and implementation of Internet applications in fertility care.     

Hospital care utilization of IVF/ICSI twins followed until 2-7 years of age: a controlled Danish national cohort study

BACKGROUND: IVF/ICSI twins are likely to have a higher risk of prematurity associated with higher morbidity. The aim of this study was to assess the use of hospital care resources in IVF/ICSI twins on data retrieved until 2-7 years of child age. METHODS: National controlled cohort study on hospital admissions and surgical interventions in 3393 IVF twins, 10,239 spontaneously conceived twins and 5130 IVF singletons born between 1995 and 2000 in Denmark. Cross-linkage of data from the Danish IVF Registry and the National Patient Registry enabled us to identify children who were admitted to hospital or underwent an operation. RESULTS: The frequency of hospitalized children was 69.8, 69.6 and 49.8%, and of children who underwent a surgical intervention 10.6, 11.2 and 8.5% in IVF/ICSI twins, control twins and IVF/ICSI singletons respectively. Odds ratios (OR) (95% confidence intervals) of hospitalization in IVF/ICSI twins versus control twins and IVF/ICSI singletons were 1.04 (0.96, 1.14) and 2.44 (2.22, 2.63) and OR adjusted for year of birth, maternal age and parity were 1.00 (0.91, 1.11) and 2.38 (2.17, 2.63) respectively. Also for term birth infants, IVF/ICSI twins were more likely to be hospitalized than IVF/ICSI singletons: adjusted OR 1.37 (1.22, 1.51). Similar risk of a surgical procedure was observed in IVF/ICSI versus control twins. However, IVF/ICSI twins more often underwent a surgical intervention than IVF/ICSI singletons: adjusted OR 1.26 (1.08, 1.47). This risk disappeared when restricted to term infants: adjusted OR 1.00 (0.81, 1.22). Different sex IVF/ICSI and control twins had equal risk of admissions and surgical interventions, and ICSI children had the same risk as children born after conventional IVF. CONCLUSIONS: Though the use of hospital care resources was similar in IVF/ICSI and control twins, the over-use in IVF/ICSI twins versus IVF/ICSI singletons adds to the arguments for implementing elective single embryo transfer as our standard procedure.     

IVF versus ICSI in sibling oocytes from patients with polycystic ovarian syndrome: a randomized controlled trial

BACKGROUND: This study compares the fertilization rate and embryonic development of oocytes randomly inseminated by conventional IVF or ICSI in patients with polycystic ovarian syndrome (PCOS) and normozoospermic semen during IVF cycles. METHODS: Sibling oocytes were randomized to be inseminated either by ICSI or IVF. Fertilization rate (two pronuclei/COC), day 2 embryonic morphology and rate of development were assessed. RESULTS: A total of 1089 cumulus-oocyte complexes (COC) were collected in 60 cycles (mean+/-SD, 18.2 +/- 7.2). Totals of 541 and 548 COC were inseminated by IVF and ICSI respectively, with a significantly higher fertilization rate in the ICSI group (ICSI versus IVF, 72.3 +/- 15.5 versus 44.8 +/- 25.1%). No fertilization failure occurred in the group of oocytes inseminated by ICSI, whereas the COC in nine patients (15%) inseminated by IVF had complete fertilization failure. The day 2 embryonic morphology and rate of development were not different regardless of the insemination method. CONCLUSIONS: Our results suggested that another randomized controlled study, randomizing patients instead of sibling oocytes, should be undertaken to compare the pregnancy rate per started cycle and to see whether ICSI should be performed on all, or at least on a portion of, oocytes for patients with PCOS undergoing IVF cycles.     

High and low BMI increase the risk of miscarriage after IVF/ICSI and FET

BACKGROUND: The extremes of BMI are associated with an increased risk ofmiscarriage both in spontaneously conceived pregnancies andafter fertility treatment. The aim of the present study wasto study the effect of BMI on miscarriage rate (MR) in freshIVF/ICSI, and in spontaneous and hormonally substituted frozen-thawedembryo (FET) cycles. METHODS: Analysis was carried out on 3330 first pregnancy cycles, performedduring the years 1999–2004, of which 2198 were fresh,666 were spontaneous and 466 were hormonally substituted FETcycles. A categorical, a linear and a quadratic models of theeffect of BMI on miscarriage were studied by logistic regression.Factors related to patient characteristics, protocol and embryoparameters were also examined. RESULTS: MR was higher in hormonally substituted FET (23.0%), comparedwith the fresh cycles (13.8%) and spontaneous FET (11.4%, P< 0.0001). Multivariate logistic regression revealed thatthe relationship between BMI and the risk of miscarriage isnot linear but quadratic (U-shaped) (P = 0.01), indicating ahigher risk of miscarriage in underweight and obese women. Hormonalsubstitution for FET was also associated with a 1.7-fold higherMR, compared with the fresh cycles (P = 0.002, 95% confidenceinterval 1.2–2.3). CONCLUSIONS: Obese and underweight women have an increased risk of miscarriage,and hormonally substituted FET is associated with an even higherMR.     

Rare association of ovarian implantation site for patients with heterotopic and with primary ectopic pregnancies after ICSI and blastocyst transfer

Two cases of patients with ruptured ovarian pregnancies (P1 = ovarian heterotopic and P2 = primary ovarian ectopic) after intracytoplasmic sperm injection and blastocyst transfer are presented. Laparoscopy was performed on day 40 and day 27 after transfer in cases P1 and P2 respectively. In both cases the ectopic pregnancies were located on the left ovary and were successfully removed by laparoscopy preserving the ovaries. In case P1 the intrauterine pregnancy was not affected. A healthy boy was born after 37 weeks of pregnancy. In this way, potential fertility of the patients and the intrauterine pregnancy were maintained. These cases occurred during a series of blastocyst transfers in which 129 pregnancies were obtained. There were no cases of ovarian ectopic/heterotopic pregnancies from January 1996 to September 1999 in 814 pregnancies obtained from day 2 or day 3 embryo transfers. Because the ovarian ectopic pregnancies occurred in patients with day 5 embryo transfer who otherwise did not have any predisposing factors for ectopic pregnancy, it is advisable to conduct a large scale analysis of future data about the possible association between blastocyst-stage embryo transfer and the somewhat higher risk of unexpected complications of clinical outcome.     

Pregnancy outcome after IVF and ICSI in unexplained, endometriosis-associated and tubal factor infertility

BACKGROUND: This study was undertaken in order to compare pregnancy outcome after IVF and ICSI in unexplained and endometriosis-associated infertility using tubal factor infertility as controls. METHODS: This was a retrospective cohort study of early IVF/ICSI pregnancies verified by serum hCG measurement, comparing the subsequent outcome in unexplained (n = 274) and minimal endometriosis-associated (n = 212) with tubal factor (n = 540) infertility as controls. From January 1990 to December 2002, 1026 conception cycles after treatment with IVF or ICSI complied with the inclusion criteria. RESULTS: Live birth rate, twin birth rate after transfer of two embryos and abortion rate prior to 6 weeks of gestation were superior for the unexplained (78.8, 23.5 and 11.7%) compared to endometriosis-associated (66.0, 15.0 and 19.3%) and tubal factor (66.7, 18.1 and 18.0%) infertility groups (P < 0.05). Compared to the endometriosis-associated, the unexplained infertility group attained a higher pregnancy rate after the first treatment cycle (P < 0.05). CONCLUSIONS: The overall better outcome for the unexplained infertility group with respect to live birth rate, twin birth rate and early abortion rate compared to the minimal peritoneal endometriosis-associated and tubal factor infertility groups might be a guide to select diagnostic groups for single embryo transfer and be useful in patient counselling.     

Elevated progesterone at initiation of stimulation is associated with a lower ongoing pregnancy rate after IVF using GnRH antagonists

BACKGROUND: The objective of this prospective study was to assessthe impact of elevated serum progesterone levels on day 2of the cycle on pregnancy rates in patients treated by IVF usingGnRH antagonists. METHODS: Ovarian stimulation was started onday 2 of the cycle if progesterone levels were normal (normal-Pgroup, n = 390). In the presence of elevated progesterone, initiationof stimulation was postponed for 1 or 2 days (high-P group,n = 20) and was started if repeat progesterone levels returnedto normal range (n = 16). Stimulation was performed with recombinantFSH (rFSH) and GnRH antagonist was always started on day 6of stimulation. RESULTS: A significantly higher exposure toprogesterone and a significantly lower exposure to estradiolwas present in the high-P as compared with the normal-P groupfrom day 1 to day 8 of stimulation. In addition, a significantlylower ongoing pregnancy rate both per started cycle (5.0% versus31.8%; P = 0.01) and per embryo transfer (6.3% versus 36.9%;P = 0.01) was present in the high-P compared with the normal-Pgroup, respectively. CONCLUSIONS: The presence of elevated serumprogesterone on day 2 of the cycle is associated with a decreasedchance of pregnancy in patients treated with rFSH and GnRH antagonists.     

Developmental outcome at 2 years of age for children born after ICSI compared with children born after IVF

BACKGROUND: Since the introduction of ICSI in 1991, medical outcome studies on ICSI children have been performed, but few have addressed developmental outcome. Hence, this outcome was assessed by performing a standard developmental test on children born after ICSI as compared with children born after IVF, at the age of 2 years. METHODS: In a prospective study, the medical and developmental outcome of 439 children born after ICSI (378 singletons, 61 twins) were compared with those of 207 children born after IVF (138 singletons, 69 twins), at the age of 24-28 months. These children were part of a cohort of children followed since birth. Of children reaching the age of 24-28 months between May 1995 and March 2002, 44.3% (2375/5356) were examined by a paediatrician who was unaware of the type of treatment used for each couple. Of all the children born, 12.2% (439/3618) in the ICSI group and 11.9% (207/1738) in the IVF group underwent a formal developmental assessment using the Bayley Scale of Infant Development (mental scale) by a paediatrician blinded to the type of treatment. RESULTS: There was no significant difference in maternal educational level, maternal age, gestational age, parity, birthweight, neonatal complication rate or malformation rate at 2 years between ICSI and IVF singletons, or between ICSI and IVF twins. No significant difference was observed in the developmental outcome using the Bayley scale at the age of 24-28 months (raw scores or test age) between ICSI children or IVF children. A multivariate regression analysis for the singleton children indicated that parity, sex (boys had lower scores than girls) and age had a significant influence on the test result, but that the fertility procedure (ICSI versus IVF) did not influence the test result. ICSI children from fathers with low sperm concentration, low sperm motility or poor morphology had a similar developmental outcome to that of children from fathers with normal sperm parameters. There were no significant differences between the initial cohort and the group lost to follow-up, nor between the psychologically tested and the non-tested group for a number of variables such as maternal educational level, birthweight in singletons and neonatal malformation rate. Although only some of the cohort of ICSI children were evaluated, a representative sample of both ICSI and IVF children was compared. CONCLUSIONS: There is no indication that ICSI children have a lower psychomotor development than IVF children. Paternal risk factors associated with male-factor infertility were found not to play a role in developmental outcome.     

The effect of insemination/injection time on the results of IVF and ICSI

BACKGROUND: The aim of this study was to investigate whether a pre-incubation time between oocyte retrieval and insemination or injection had any effect on the success rate of IVF or intracytoplasmic sperm injection (ICSI). Based on previously published data, many laboratories retain a time interval of several hours between oocyte retrieval and insemination/injection. In our setting, insemination and injection times are dependent only on the laboratory workload. METHODS: Totals of 881 IVF and 432 ICSI cycles performed between 1997 and 1999 were analysed retrospectively. Oocyte retrieval occurred 36 h after human chorionic gonadotrophin administration, and insemination or injection took place 1--7 or 0.5--8 h after oocyte retrieval respectively. RESULTS: No statistically significant differences were found between these time periods and outcome of IVF and ICSI with respect to fertilization rate, embryo quality, implantation rate, abortion and ongoing pregnancy rates, except for the abortion rate after IVF. As this finding may be due to chance and no differences were found in the ongoing pregnancy rates, this finding was considered to be of less importance. CONCLUSIONS: If laboratory control and efficiency demands early insemination or injection, it could be performed without reservation.     

Comparison of Ca2+ and CaMKII responses in IVF and ICSI in the mouse

Novel methods of egg activation in human assisted reproductive technologies and animal somatic cell nuclear transfer are likely to alter the signalling process that occurs during normal fertilization. Intracytoplasmic sperm injection (ICSI) bypasses the normal processes of the acrosome reaction, sperm-egg fusion, and processing of the sperm plasma membrane, as well as alters some parameters of intracellular calcium ([Ca(2+)](i)) dynamics (reported previously by Kurokawa and Fissore (2003)). Herein, we extend these studies to determine if ICSI alters the activity of the Ca(2+)-dependent protein, Ca(2+)/calmodulin-dependent kinase II (CaMKII), which is responsible for the completion of meiosis in vertebrate eggs. After ICSI or in vitro fertilization (IVF), individual mouse eggs were monitored for their relative changes in both [Ca(2+)](i) and CaMKII activity during the first [Ca(2+)](i) rise and a subsequent rise associated with second polar body extrusion. The duration of the first [Ca(2+)](i) rise was greater in ICSI than in IVF, but the amplitude of the rise was transiently higher for IVF than ICSI. However, a similar mean CaMKII activity was observed in both procedures. During polar body extrusion, the amplitude and duration of the Ca(2+) rises were increased by a small amount in ICSI compared with IVF, whereas the CaMKII activities were similar. Thus, compared with IVF, ICSI is not associated with decreased or delayed CaMKII activity in response to these Ca(2+) signals in the mouse.