Prospective follow-up study of 423 children born after intracytoplasmic sperm injection

Evolution of intracytoplasmic sperm injection: From initial challenges to wider applications

Background

In vitro fertilization (IVF) has revolutionized infertility treatment. Nevertheless, male infertility requires more effective solutions. In 1992, the first-ever case of human birth via intracytoplasmic sperm injection (ICSI) was reported. ICSI involves microscopically injecting a sperm into an ovum. Successful ICSI has become a reliable therapy for couples facing infertility, a significant milestone. However, it has also introduced various challenges. This study also delves into ethical dilemmas arising from widespread ICSI use.

Methods

This review traces the history of ICSI, presenting pioneering attempts, first successful attempts, and critical reports on account of the initial skepticism toward the technology. The review also focuses on chronological progress until ICSI was recognized as effective and became widely applied.

Main findings

The review reveals that ICSI, although transformative, presents challenges. Successes include addressing male infertility and aiding fertilization. However, concerns arise regarding optimal sperm and embryo selection, genetic mutations, and long-term health implications. Ethical considerations surrounding ICSI's broad applications also surface.

Conclusions

Despite its success and effectiveness, ICSI is still evolving as a therapeutic method. By comprehensively evaluating the historical progress and the current status of ICSI and exploring its future prospects, this study highlights the importance of ICSI in infertility treatment.

Chromosomal abnormalities after ICSI in relation to semen parameters: results in 1114 fetuses and 1391 neonates from a single center

STUDY QUESTION

Is there a relationship between karyotype abnormalities in fetuses and children conceived by ICSI and their father's semen parameters?

SUMMARY ANSWER

The de novo chromosomal abnormality rate in pre- and postnatal karyotypes of ICSI offspring was higher than in the general population and related to fathers' sperm parameters.

WHAT IS KNOWN ALREADY

Several studies have reported a higher rate of de novo chromosomal anomalies in ICSI fetuses but recent data from large cohorts are limited. Overall, reported prevalences of non-inherited karyotype aberrations are increased in fetuses conceived after ICSI and vary between 1.6% and 4.2%. Only a few studies focus on the relation between karyotype anomalies in ICSI offspring and semen parameters of their fathers. Furthermore, an increased incidence of abnormal karyotypes in ICSI neonates has been described, but the rates vary widely across studies.

STUDY DESIGN, SIZE, DURATION

We report on karyotype results from prenatal testing by means of chorionic villus sampling and amniocentesis and results from postnatal blood sampling in offspring conceived by ICSI in a single center. Ongoing pregnancies resulting from an oocyte retrieval between January 2004 and December 2012 and after transfer of fresh ICSI embryos obtained using ejaculated or non-ejaculated sperm (fresh or frozen-thawed) were considered. Pregnancies following frozen embryo transfer, oocyte or sperm donation, IVF, preimplantation genetic testing and IVM were excluded. All abnormal prenatal results after sampling are reported irrespective of the outcome of the pregnancy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

From the 4816 ongoing ICSI pregnancies, information on pregnancy outcome was available for 4267 pregnancies. Prenatal testing was performed in 22.3% of the pregnancies, resulting in a diagnosis in 1114 fetuses. A postnatal karyotype was obtained in 29.4% of the pregnancies in which no invasive prenatal diagnosis was performed, resulting in a total of 1391 neonates sampled. The prevalence of chromosomal anomalies according to maternal age and semen quality was analyzed with logistic regression. For definitions of normal semen quality, the World Health Organization reference values for human semen characteristics were adopted.

MAIN RESULTS AND THE ROLE OF CHANCE

An abnormal fetal karyotype was found in 29 singletons and 12 multiples (41/1114; 3.7%; 95% CI 2.7-4.9%): 36 anomalies were de novo (3.2%; 95% CI 2.3-4.4), either numerical (n = 25), sex (n = 6) or structural (n = 5), and five were inherited. Logistic regression analysis did not show a significant association between maternal age and a de novo chromosomal fetal abnormality (odds ratio (OR) 1.05; 95% CI 0.96-1.15; P = 0.24). In all but one case, fetuses with an abnormal karyotype were conceived by ICSI using ejaculated sperm.Abnormal karyotypes were found in 14 (1.0%; 95% CI 0.6-1.7) out of 1391 postnatal samples of children born after ICSI who were not tested prenatally: 12 were de novo anomalies and two were inherited balanced karyotypes. The 14 abnormal karyotypes were all found in children born after ICSI using ejaculated sperm.The odds of a de novo karyotype aberration increased with maternal age when combining pre- and postnatal data (OR 1.11; 95% CI 1.04-1.19). A higher rate of de novo chromosomal abnormalities was found in fetuses and children of couples with men having a sperm concentration <15 million/ml (adjusted OR (AOR) 2.10; 95% CI 1.14-3.78), sperm concentration <5 million/ml (AOR 1.9; 95% CI 1.05-3.45) and total sperm count <10 million (AOR 1.97; 95% CI 1.04-3.74).

LIMITATIONS, REASONS FOR CAUTION

We cannot exclude that the observation of a higher prevalence of karyotype anomalies in ICSI offspring compared to literature data in the general population is due to enhanced surveillance after ART given the lack of a control group. Although we did not find more chromosomal anomalies after ICSI with non-ejaculated sperm, the small numbers do not allow firm conclusions.

WIDER IMPLICATIONS OF THE FINDINGS

The observed increased risk of a de novo karyotype anomaly after ICSI conception in couples with poor sperm warrants continued counseling toward prenatal testing.The current and widespread use of innovative non-invasive prenatal testing will result in larger datasets, adding to a balanced estimation of the prevalence of karyotype anomalies in ICSI offspring.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Methusalem grants issued by the Vrije Universiteit Brussel. All authors declared no conflict of interest related to this study.

TRIAL REGISTRATION NUMBER

N/A.

Pregnancy and birth outcomes in couples with infertility with and without assisted reproductive technology: with an emphasis on US population-based studies

Infertility, defined as the inability to conceive within 1 year of unprotected intercourse, affects an estimated 80 million individuals worldwide, or 10-15% of couples of reproductive age. Assisted reproductive technology includes all infertility treatments to achieve conception; in vitro fertilization is the process by which an oocyte is fertilized by semen outside the body; non-in vitro fertilization assisted reproductive technology treatments include ovulation induction, artificial insemination, and intrauterine insemination. Use of assisted reproductive technology has risen steadily in the United States during the past 2 decades due to several reasons, including childbearing at older maternal ages and increasing insurance coverage. The number of in vitro fertilization cycles in the United States has nearly doubled from 2000 through 2013 and currently 1.7% of all live births in the United States are the result of this technology. Since the birth of the first child from in vitro fertilization >35 years ago, >5 million babies have been born from in vitro fertilization, half within the past 6 years. It is estimated that 1% of singletons, 19% of twins, and 25% of triplet or higher multiples are due to in vitro fertilization, and 4%, 21%, and 52%, respectively, are due to non-in vitro fertilization assisted reproductive technology. Higher plurality at birth results in a >10-fold increase in the risks for prematurity and low birthweight in twins vs singletons (adjusted odds ratio, 11.84; 95% confidence interval, 10.56-13.27 and adjusted odds ratio, 10.68; 95% confidence interval, 9.45-12.08, respectively). The use of donor oocytes is associated with increased risks for pregnancy-induced hypertension (adjusted odds ratio, 1.43; 95% confidence interval, 1.14-1.78) and prematurity (adjusted odds ratio, 1.43; 95% confidence interval, 1.11-1.83). The use of thawed embryos is associated with higher risks for pregnancy-induced hypertension (adjusted odds ratio, 1.30; 95% confidence interval, 1.08-1.57) and large-for-gestation birthweight (adjusted odds ratio, 1.74; 95% confidence interval, 1.45-2.08). Among singletons, in vitro fertilization is associated with increased risk of severe maternal morbidity compared with fertile deliveries (vaginal: adjusted odds ratio, 2.27; 95% confidence interval, 1.78-2.88; cesarean: adjusted odds ratio, 1.67; 95% confidence interval, 1.40-1.98, respectively) and subfertile deliveries (vaginal: adjusted odds ratio, 1.97; 95% confidence interval, 1.30-3.00; cesarean: adjusted odds ratio, 1.75; 95% confidence interval, 1.30-2.35, respectively). Among twins, cesarean in vitro fertilization deliveries have significantly greater severe maternal morbidity compared to cesarean fertile deliveries (adjusted odds ratio, 1.48; 95% confidence interval, 1.14-1.93). Subfertility, with or without in vitro fertilization or non-in vitro fertilization infertility treatments to achieve a pregnancy, is associated with increased risks of adverse maternal and perinatal outcomes. The major risk from in vitro fertilization treatments of multiple births (and the associated excess of perinatal morbidity) has been reduced over time, with fewer and better-quality embryos being transferred.

Use of ICSI in IVF cycles in women with tubal ligation does not improve pregnancy or live birth rates

STUDY QUESTION

Does ICSI improve outcomes in ART cycles without male factor, specifically in couples with a history of tubal ligation as their infertility diagnosis?

SUMMARY ANSWER

The use of ICSI showed no significant improvement in fertilization rate and resulted in lower pregnancy and live birth (LB) rates for women with the diagnosis of tubal ligation and no male factor.

WHAT IS KNOWN ALREADY

Prior studies have suggested that ICSI use does not improve fertilization, pregnancy or LB rates in couples with non-male factor infertility. However, it is unknown whether couples with tubal ligation only diagnosis and therefore iatrogenic infertility could benefit from the use of ICSI during their ART cycles.

STUDY DESIGN, SIZE, DURATION

Longitudinal cohort of nationally reported cycles in the Society for Assisted Reproductive Technology Clinic Outcomes Reporting System (SART CORS) of ART cycles performed in the USA between 2004 and 2012.

PARTICIPANTS/MATERIALS, SETTING, METHODS

There was a total of 8102 first autologous fresh ART cycles from women with the diagnosis of tubal ligation only and no reported male factor in the SART database. Of these, 957 were canceled cycles and were excluded from the final analysis. The remaining cycles were categorized by the use of conventional IVF (IVF, n = 3956 cycles) or ICSI (n = 3189 cycles). The odds of fertilization, clinical intrauterine gestation (CIG) and LB were calculated by logistic regression modeling, and the adjusted odds ratios (AORs) with 95% confidence intervals were calculated by adjusting for the confounders of year of treatment, maternal age, race and ethnicity, gravidity, number of oocytes retrieved, day of embryo transfer and number of embryos transferred.

MAIN RESULTS AND THE ROLE OF CHANCE

The main outcome measures of the study were odds of fertilization (2PN/total oocytes), clinical intrauterine gestation (CIG/cycle) and live birth (LB/cycle). The fertilization rate was higher in the ICSI versus IVF group (57.5% vs 49.1%); however, after adjustment this trend was no longer significant (AOR 1.14, 0.97-1.35). Interestingly, both odds of CIG (AOR 0.78, 0.70-0.86), and odds of LB were lower (AOR 0.77, 0.69-0.85) in the ICSI group. Plurality at birth, mean length of gestation and birth weight did not differ between the two groups.

LIMITATIONS, REASONS FOR CAUTION

This was a retrospective study, therefore only the available parameters could be included, with parameters of interest such as smoking status not available for inclusion. Smoking status may have led practitioners to use ICSI to improve pregnancy and LB outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

Studies have shown that in the USA there is an increasing usage of ICSI for non-male factor infertility despite a lack of evidence-based benefit. Our study corroborates this increasing use over the last 8 years, specifically in the tubal ligation only patient population. Even after adjusting for multiple confounders, the patients who underwent ICSI had no statistically significant improvement in fertilization rate and actually had a lower likelihood of achieving a clinical pregnancy and LB. Therefore, our data suggest that the use of ICSI in tubal ligation patients has no overall benefit. This study contributes to the body of evidence that the use of ICSI for non-male factor diagnosis does not improve ART outcomes over conventional IVF.

STUDY FUNDING/COMPETING INTERESTS

None.

Safety of intracytoplasmic sperm injection

Early follow-up studies of IVF children showed that the frequency of birth anomalies resembled those arising with natural conception. More detailed analyses confirmed these findings, reinforcing the concept of the preimplantation period as teratologically "safe." The use of intracytoplasmic sperm injection (ICSI) to achieve fertilization introduced another variable.ICSI's safety has often been criticized because the fertilizing spermatozoon neither binds to the zona pellucida nor fuses with oolemma. Bypassing these physiologic steps together with the arbitrary selection of the spermatozoon has been reason for concern. Thus far, ICSI offspring undergoing adolescence and beyond has provided sufficient information to reassure these qualms. In fact, the health of the offspring generated through ICSI, once taken into consideration the gestational order, the age and the genetic makeup of the couples are generally reassuring.

Treatment of male infertility

Major difficulties exist in the accurate and meaningful diagnosis of male reproductive dysfunction, and our understanding of the epidemiology and etiology of male infertility has proven quite complex.The numerous spermatozoa produced in mammals and other species provides some degree of protection against adverse environmental conditions represented by physical and chemical factors that can reduce reproductive function and increase gonadal damage even resulting in testicular cancer or congenital malformations. The wide fluctuations of sperm production in men, both geographical and temporal, may reflect disparate environmental exposures, occurring on differing genetic backgrounds, in varying psychosocial conditions, and leading to the diversified observed outcomes.Sperm analysis is still the cornerstone in diagnosis of male factor infertility, indeed, individually compromised semen paramaters while adequately address therapeutic practices is progressively flanked by additional tests. Administration of drugs, IUI, correction of varicocele, and, to a certain extent, IVF although they may not be capable of restoring fertility itself often result in childbearing.

Does infertility treatment increase male reproductive tract disorder?

OBJECTIVE

To determine the association between assisted human reproduction and male reproductive disorders in infants conceived by this means.

MATERIALS AND METHODS

Between January 2008 and December 2011, 15,332 neonates were born in our hospital. We assessed the birth weight, gestational age, and other characteristics of the 7752 male infants and determined the association between methods of conception and male reproductive disorders in the infants. We also analyzed the influence of male factor on the occurrence of these disorders.

RESULTS

Ninety-nine newborns (1.3%) were diagnosed with cryptorchidism, 8 (0.1%) were diagnosed with hypospadias, and 4 (0.05%) were diagnosed with both. Cryptorchidism was more common in children conceived through in vitro fertilization (IVF) and IVF/intracytoplasmic sperm injection (IVF/ICSI; P <.05), and hypospadias was more common in children conceived through IVF/ICSI (P <.05). Children conceived through intrauterine insemination (IUI), IVF, and IVF/ICSI had higher rates of low birth weight and preterm birth. Logistic regression analysis showed that low birth weight and preterm birth were significantly associated with male reproductive disorders, whereas the method of conception was not. Male factor was not significantly associated with these disorders.

CONCLUSION

IVF and IVF/ICSI increase the risks of low birth weight and preterm birth, resulting in increased rates of hypospadias and cryptorchidism. Male factor was not associated with reproductive disorders in male infants.

Effects of assisted reproduction technology on placental imprinted gene expression

We used placental tissue to compare the imprinted gene expression of IGF2, H19, KCNQ1OT1, and CDKN1C of singletons conceived via assisted reproduction technology (ART) with that of spontaneously conceived (SC) singletons. Of 989 singletons examined (ART n = 65; SC n = 924), neonatal weight was significantly lower (P < .001) in the ART group than in the SC group, but placental weight showed no significant difference. Gene expression analyzed by real-time PCR was similar for both groups with appropriate-for-date (AFD) birth weight. H19 expression was suppressed in fetal growth retardation (FGR) cases in the ART and SC groups compared with AFD cases (P < .02 and P < .05, resp.). In contrast, CDKN1C expression was suppressed in FGR cases in the ART group (P < .01), while KCNQ1OT1 expression was hyperexpressed in FGR cases in the SC group (P < .05). As imprinted gene expression patterns differed between the ART and SC groups, we speculate that ART modifies epigenetic status even though the possibilities always exist.

A physiological replacement for polyvinylpyrrolidone (PVP) in assisted reproductive technology

The technique of intracytoplasmic sperm injection (ICSI) requires mechanical immobilization of the sperm that are to be injected; damage thus caused to the sperm membrane is considered to be necessary to activate the sperm for fertilization. Mechanical immobilization and the injection procedure are facilitated by introducing the sperm into a viscous medium that will hinder motility: a solution of polyvinylpyrrolidone (PVP) has been used successfully for this purpose. PVP is an artificial polymer, which has been regarded as chemically inert, although adverse effects have been reported as a result of its use both in vivo and in vitro. Therefore, the use of hyaluronate, the natural component of the extracellular matrix of the cumulus-oocyte complex, was investigated as a replacement for PVP during ICSI. A solution of hyaluronate was found to be as effective as PVP in facilitating the injection procedure, its effect on sperm motility was readily reversible, and its use did not affect the outcome of the treatment cycles in terms of fertilization, pregnancy and live birth rates. Every attempt should be made to eliminate artificial factors in assisted reproductive procedures. Hyaluronate, a natural and readily degradable glycosaminoglycan can be used as a substitute for the artificial PVP polymer without jeopardising the outcome of the treatment cycle.

Genetic and epigenetic characteristics of ICSI children

The outcome of pregnancy and the developmental wellbeing of children conceived from 12,866 consecutive intracytoplasmic sperm injection (ICSI) cycles was assessed. A total of 3277 couples delivered 5891 neonates. There was a higher than normal incidence of de-novo chromosomal abnormalities in a small sample of ICSI offspring. Controlling for maternal age showed that the incidence of low birth weight and gestational length were comparable with the naturally conceived counterpart. Rates of malformation in ICSI offspring ranged from 3.5 to 6.2%. At 3 years of age (n = 811), the proportion of children at risk for developmental delays was 10.4% in ICSI and 10.7% in IVF singletons. However, high order gestations were characterized by 19.4% of the children having compromised development. Epigenetic analysis of assisted reproductive technique conceptuses found minor imprinted gene expression imbalances. ICSI offspring presented with genetic defects that were inherited or arose de novo. Obstetric and neonatal outcomes of singleton pregnancies appeared to be dependent upon maternal age. ICSI and IVF appeared to exert a negative effect on the wellbeing of offspring mainly because of the association with multiple gestations. All assisted reproduction procedures should be monitored for the eventual effect of environmental aggressors on offspring epigenesis.

Risk of birth defects increased in pregnancies conceived by assisted human reproduction

OBJECTIVE

To assess the risk of birth defects in infants born after assisted human reproduction (AHR).

DESIGN

Retrospective cohort study.

SETTING

Niday Perinatal Database for the province of Ontario, 82 sites, both primary and tertiary centers.

PATIENT(S)

In 2005, information about reproductive assistance was reported for 61,569 deliveries.

INTERVENTION(S)

The prevalence of birth defects diagnosed in the prenatal period or at birth was estimated for all types of AHR together and then by type of procedure.

MAIN OUTCOME MEASURE(S)

The excess risks of birth defects by AHR were calculated by unconditional logistic regressions using spontaneously conceived pregnancies as the reference and were expressed by odds ratio and 95% confidence intervals and adjusted for maternal age, smoking, infant gender, gestation, and parity.

RESULT(S)

The prevalence of birth defects with AHR procedures was 2.91%, which was 1.55-fold higher (95% confidence interval [CI], 1.03-2.38) than in the non-AHR population (1.86%). Specific anomalies that increased with AHR were gastrointestinal (odds ratio [OR], 9.85; 95% CI, 3.44-28.44), cardiovascular (OR, 2.30; 95% CI, 1.11-4.77), and musculoskeletal defects (OR, 1.54; 95% CI, 0.48-4.94). The risks of birth defects by types of AHR were 2.35% for ovulation induction, 2.89% for IUI, and 3.45% for IVF.

CONCLUSION(S)

There is a significant increased risk of birth defects associated with AHR, and the risk is higher in IVF and IUI. The potential risk of anomalies associated with AHR may be considered in the counseling that is offered to infertile couples.

Intracytoplasmic sperm injection (ICSI)--what are the risks?

In vitro fertilization used in combination with intracytoplasmic sperm injection allows otherwise sterile couples to become parents. Despite recent studies on the safety of these technologies, there is still only an incomplete picture of the risks associated with the usage of these assisted reproductive techniques to offspring. The risk of multiple gestations continues to be of major concern because of its association with low birth weight, preterm delivery, and increased perinatal mortality. This article outlines the risks associated with in vitro fertilization/intracytoplasmic sperm injection as a well-defined treatment for couples with severe male factor infertility.

Safety of assisted reproduction, assessed by risk of abnormalities in children born after use of in vitro fertilization techniques

Assisted reproductive technologies are increasingly used in the treatment of both male and female infertility. The techniques, including in vitro fertilization, with or without intracytoplasmic sperm injection as an adjunctive treatment, represent a tremendous step forward for infertile couples who previously had no treatment options. As we move towards the 30(th) anniversary of the birth of the first baby conceived by in vitro fertilization, questions about the safety of these procedures linger. We review here the available literature regarding the safety of assisted reproductive technologies; these data are made far more robust by the inclusion of long-term follow-up data from the first generation of children arising after the introduction of these technologies.

Obstetric Outcomes and Congenital Abnormalities After In Vitro Maturation, In Vitro Fertilization, and Intracytoplasmic Sperm Injection

OBJECTIVE

To compare obstetric outcome and congenital abnormalities in pregnancies conceived after in vitro maturation (IVM), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI) with those in spontaneously conceived controls.

METHODS

Data were collected from the McGill Obstetrics and Neonatal Database (MOND). All children were examined and classified in a standard manner. Final data were reviewed 12 months after delivery. Pregnancies by IVM, IVF, and ICSI were compared with those of age- and parity-matched controls. Congenital abnormality, gestational age, birth weight, Apgar scores, cord pH, growth restriction, pregnancy complications, mode of delivery, and multiple pregnancy were compared.

RESULTS

A total of 432 children were born from 344 pregnancies after assisted reproductive technology (ART) during the study period (IVM 55, IVF 217, ICSI 160). The observed odds ratios (ORs) for any congenital abnormality were 1.42 (95% confidence interval [CI] 0.52-3.91) for IVM, 1.21 (95% CI 0.63-2.62) for IVF, and 1.69 (95% CI 0.88-3.26) for ICSI. Twin pregnancy (IVM 21%, IVF 20%, ICSI 17%) and triplet pregnancy (IVM 5%, IVF 3%, ICSI 3%) were higher than those in controls (1.7% twins and 0% triplets) (P<.001). Cesarean delivery rates were higher after ART, even in singleton pregnancies (IVM 39%, IVF 36%, ICSI 36%; controls: 26.3%) (P<.05). Apgar scores, cord pH, growth restriction, and pregnancy complications were comparable in all groups.

CONCLUSION

All ART pregnancies are associated with an increased risk of multiple pregnancy, cesarean delivery, and congenital abnormality. Compared with IVF and ICSI, IVM is not associated with any additional risk.

Evaluation of the vervet (Clorocebus aethiops) as a model for the assisted reproductive technologies

The vervet monkey was evaluated as a primate model for use in assisted reproductive technologies (ARTs). Eight adult female vervets were hormonally monitored for their potential use as egg donors and those six females displaying regular menstrual cycles were subjected to controlled ovarian stimulation with recombinant human gonadotropins. Three animals failed to respond while laparoscopic follicular aspiration was performed on the other three females at 27-30 h post-human chorionic gonadotropin administration. A total of 62, 40, and 18 oocytes was recovered from these three animals of which 30, 20, and 4, respectively, matured to the metaphase II stage and were subsequently inseminated using intracytoplasmic sperm injection. An average of 40+/-15% (SEM) of the inseminated oocytes were fertilized based on pronucleus formation and timely cleavage. One embryo from each of the two stimulated females developed into expanded blastocysts. Two adult male vervets were assessed as sperm donors. Neither adjusted well to the restraint and collection procedure required for penile electroejaculation. Samples collected via rectal electroejaculation were very low in sperm motility and concentration; however, cauda epididymal aspirations from one male yielded an adequate concentration of motile sperm. These results emphasize the need to establish species-specific ovarian stimulation protocols and semen collection techniques if vervets are to be considered for basic and applied (ARTs) research on primate gametes or embryos.

Epigenetics in assisted reproductive technology

It has been reported that the rates of epigenetic disorders such as Angelman syndrome (AS) and Beckwith-Wiedemann syndrome (BWS) are high in offspring conceived by assisted reproductive technology (ART). Angelman Syndrome is characterized by intellectual disability and BWS is known as large offspring syndrome (LOS). Weight abnormalities have also been reported in cloned animals. Possible factors underlying these findings include inherent gamete characteristics, influence of in vitro culture and peculiarity of ART methods. It is important to conclusively determine whether such epigenetic abnormalities are present in children conceived by ART, so as to consider the health of next generations.

DNA damage of human spermatozoa in assisted reproduction: origins, diagnosis, impacts and safety

Sperm DNA contributes half the offspring's genomic material and abnormal DNA can lead to derangements in the reproductive process. Normal sperm genetic material is required for successful fertilization, as well as for further embryo and fetal development that will result in a healthy child. Thus, the damage to sperm DNA is critical in assisted reproductive techniques which are increasingly used to treat infertile couples. There has been improving data about the effects of human sperm DNA damage or fragmentation. As well, increasing knowledge concerning the effects of DNA damage on embryo and fetal development has been attained. This review aims to summarize the present knowledge on the impact of human sperm cell DNA damage on male infertility and outcome in the context of safety.

Use and outcomes of intracytoplasmic sperm injection for non-male factor infertility

OBJECTIVE

To determine whether intracytoplasmic sperm injection (ICSI) is associated with improved outcomes for non-male factor infertility.

DESIGN

We examined the patient characteristics associated with treatment choice-ICSI and conventional in vitro fertilization (IVF)-among patients without a diagnosis of male factor infertility and compared outcomes between the two groups, adjusting for patient characteristics using multivariate regression models.

SETTING

Academic fertility center.

PATIENT(S)

We evaluated 696 consecutive assisted reproductive technology (ART) cycles performed for couples with normal semen analysis at the Stanford Reproductive Endocrinology and Infertility Center between 2002 and 2003. We compared patient characteristics, cycle details, and outcomes for ICSI and IVF.

MAIN OUTCOME MEASURE(S)

Fertilization, pregnancy, and live birth rates.

RESULT(S)

Patient characteristics were similar between the two groups, except the proportion of patients with unexplained infertility (IVF 15.1% vs. ICSI 23.5%), previous fertility (IVF 62.6% vs. ICSI 45.5%), and previous ART cycle (IVF 41.2% vs. ICSI 67.7%). More oocytes were fertilized per cycle for the IVF group (6.6 oocytes versus 5.1 oocytes). Fertilization failure, pregnancy, and live birth rates did not differ between IVF and ICSI. Using logistic regressions, having had previous ART was found to be positively associated with ICSI. Treatment choice of ICSI was not associated with fertilization, pregnancy, or live birth rates.

CONCLUSION(S)

No clear evidence of improved outcomes with ICSI was demonstrated for non-male factor infertility.

Increased frequency of severe major anomalies in children conceived by intracytoplasmic sperm injection

The neurodevelopmental outcome of children born after intracytoplasmic sperm injection (ICSI) is controversial. We compared the medical and developmental outcome of 34 singletons born after ICSI (20 males, 14 females; mean ages of 18 mo and 40 mo [SD 9 mo]; range 2 y 10 mo-4 y 8 mo) with 39 case control studies (21 males, 18 females; mean ages of 18 mo and 40 mo [SD 4 mo]; range 3 y-4 y 1 mo). Each child was assessed physically and tested in three development domains (fine motor, gross motor, and language). Five children born after ICSI versus two control children (p=0.2) had major congenital anomalies (MaCAs). Four children born after ICSI versus no control children had severe MaCAs (p=0.04). These were defined as having a significant impact on development or causing chronic disease: Angelman syndrome (n=1), lissencephaly (n=1), Hanhart syndrome (n=1), and persistent hyperinsulinemic hypoglycaemia of infancy (n=1). Karyotyping in 23 children born after ICSI revealed no abnormalities. An imprinting defect was found in the child with Angelman syndrome. Results of developmental assessment were in all cases normal at the age of 18 months except for the three children with Angelman and Hanhart syndromes, and lissencephaly. At the second assessment, five more children born after ICSI and four control children showed abnormalities in one or more developmental domains. We conclude that there seems to be a higher frequency of severe major anomalies in children born after ICSI. An increased risk for imprinting defects cannot be excluded. If we exclude children with severe MaCAs, the incidence of an abnormal somatic or neurodevelopmental outcome in the fourth year of life in children born after ICSI is similar to that of spontaneously conceived children.

The risk of neuro-orthopaedic malformations following in-vitro fertilization

The purpose of this study was to assess the risk of neuro-orthopaedic malformations after in-vitro fertilization. We compared the prevalence of neuro-orthopaedic malformations in two groups of pregnancies conceived either naturally or by in-vitro fertilization, and used multivariate analysis to study the impact of each variable. The results showed a prevalence of 0.89% neuro-orthopaedic malformations in the in-vitro fertilization cohort and 0.32% in the natural conception cohort. The three times greater risk of malformations in the in-vitro fertilization cohort was reduced after adjustment to other variables. We concluded that the increased risk of neuro-orthopaedic malformations after in-vitro fertilization is not due to the technique itself but rather to factors associated with it.

Do children born after assisted reproductive technology have a higher incidence of birth defects?

Recent studies seem to find a significant increase in the incidence of birth defects among children conceived with assisted reproductive technologies. Those data should lead to proper counseling of couples treated with these techniques.

Two-year neurodevelopmental outcome in children conceived by intracytoplasmic sperm injection: prospective cohort study

OBJECTIVE

Primary outcome was to compare neurodevelopmental outcome at two years in intracytoplasmic sperm injection (ICSI) conceived children versus matched controls. Secondary outcome was to determine incidence of major congenital malformations and study perinatal outcome.

DESIGN

Prospective cohort study.

SETTING

Tertiary care perinatal centre over a period of 13 months.

POPULATION

Seventy-six ICSI conceived children and 261 matched controls selected by matching for maternal age, sex, date of delivery, race, plurality and parity.

METHODS

Mental Development Index (MDI) and Psychometric Development Index (PDI) of the Bayley's Scale of Development (BSID-II) and Vineland Adaptive Behaviour Scale (VABS) were used to assess the neurodevelopmental and functional outcome. The congenital malformations were classified according to ICD-9 code.

MAIN OUTCOME MEASURES

Primary outcome measure--neurodevelopmental and functional outcomes. Secondary outcome measure--congenital malformations and perinatal outcomes.

RESULTS

Neurodevelopmental and functional outcome were comparable in both groups. The mean MDI score was 92 [16] versus 90 [14] in the study and control groups respectively. Fourteen (18.4%) in the ICSI group had MDI <85 compared with 87 (33%) controls (P= 0.002). On linear regression the MDI was independently affected by plurality (P= 0.001), maternal education and socio-economic status (P= 0.01). The study group had a lower gestation (36 [3] vs 37.1 [2] weeks; P= 0.005) and a higher incidence of prematurity <34 weeks [19 (25%)] vs [31 (12%)] P= 0.012]. Six (7.9%) of the ICSI babies and seven (2.7%) of the controls had a major congenital malformation (P= 0.05).

CONCLUSIONS

Children born by ICSI pregnancies did not have an adverse neurodevelopmental outcome. The incidence of major congenital malformations in ICSI needs further evaluation.

Ovulation induction, assisted conception and childhood cancer

Rapid advances have been made in the treatment of infertility over the last 30 years following the introduction of in vitro fertilisation and intracytoplasmic sperm injection. Whilst effects of assisted reproductive technology (ART) on birth outcomes are well documented little is known about effects on child health after the neonatal period. Childhood cancer is one area warranting further examination. The hypothesis that cancer in children may be initiated during early fetal development means that events leading up to and around conception may be important. Whilst the few large-scale epidemiological studies that have looked at childhood cancer incidence following ART have failed to find any significant increased risk, some case-control studies have reported an increased risk of specific cancers. However, it is important not to over interpret these findings as the reason for the infertility may be the predisposing factor, rather than the procedure itself. Recent recommendations by the UK's National Health Service to offer intra-uterine insemination and one free treatment cycle for infertile couples will result in increasing numbers of children born following ART. More detailed investigations that include larger numbers plus sufficient follow-up periods and information on the underlying causes of the infertility are needed since long term outcomes for these children, in particular the risk of developing cancer, remain largely unknown.

Development of children born after IVF and ICSI

Follow-up studies of pregnancies as well as children born following assisted reproductive technologies are of utmost interest to provide a reliable basis for patient counselling. Especially in recent years, studies of high quality have been performed and published, showing some slight but significantly increased risk for pregnancy complications as well as major malformation rate following IVF and intracytoplasmic sperm injection (ICSI). The health status and subsequent development of children born seems to be comparable to those after spontaneous conception up to the age of 5 years. The study of Bonduelle and co-workers, published in this issue of Reproductive Biomedicine Online, contributes further to the follow-up information available for children born after ICSI. However, there are some limitations for all these follow-up studies, which have to be taken into account, when interpreting results. These are discussed in this commentary.

Perinatal outcome of ICSI pregnancies compared with a matched group of natural conception pregnancies in Flanders (Belgium): a cohort study

A retrospective cohort study was conducted with an intracytoplasmic sperm injection (ICSI) group and a naturally conceived comparison group. A total of 1655 singleton and 1102 twin ICSI births were studied with regard to perinatal outcome. Control subjects (naturally conceived pregnancies) were selected from a regional registry and were matched for maternal age, parity, place of delivery, year of birth and fetal sex. The main outcome measures were duration of pregnancy, birth weight, Apgar score <5 after 5 min, neonatal complications, perinatal death and congenital malformations. Twin births, when compared with singletons, carry a much higher risk of poor perinatal outcome. For both ICSI singletons and ICSI twins, no significant difference was found between ICSI and naturally conceived pregnancies for all investigated parameters. After excluding like-sex twin pairs, ICSI twin pregnancies were at increased risk for perinatal mortality (OR = 2.74, CI = 1.26-5.98), prematurity (OR = 1.38, CI = 1.10-1.75) and low birth weight (OR = 1.34, CI = 1.06-1.69) compared with spontaneously conceived different-sex twin pairs. In conclusion, the perinatal outcome of ICSI singleton and twin pregnancies was very similar to that of spontaneously conceived pregnancies in this large cohort study. After excluding like-sex twin pairs, ICSI twins were at increased risk for prematurity, low birth weight and higher perinatal mortality compared with the natural conception comparison group.

Genetics of gametes and embryos

Chromosome analysis of oocytes, sperm and embryos has mainly relied on fluorescent in situ hybridisation (FISH) and karyotyping. FISH studies have been performed on sperm from fertile and infertile men as well as men carrying known chromosomal translocations. Molecular DNA analyses has aided in the identification and treatment of men with Y chromosome deletions. In oocytes FISH and karyotyping have identified non-disjunction of univalents and predivision of chromatids. Analysis of the chromosomes from human embryos has shown that a high proportion of embryos are mosaic or chaotic, in addition to embryos beings uniformly and abnormal. FISH and PCR have also been used clinically for preimplantation genetic diagnosis (PGD). For patients at risk of transmitting a specific genetic or chromosomal abnormality, 1-2 blastomeres are biopsied from embryos and specific genes or chromosomes analysed. Normal embryos are then transferred to the uterus.

Assisted reproductive technologies in rhesus macaques

The assisted reproductive technologies (ARTs) have been used in the production of rhesus monkey offspring at the Oregon National Primate Research Center (ONPRC) and that experience is summarized here. Additionally these technologies serve as a source of oocytes/embryos for monozygotic twinning, embryonic stem (ES) cell derivation and cloning. High fertilization efficiencies were realized with conventional insemination or following the use of intracytoplasmic sperm injection (ICSI) and approximately 50% of the resulting embryos grew in vitro to blastocysts. Both fresh and frozen sperm were employed in fertilization by ICSI and the resulting embryos could be low temperature stored for subsequent thawing and transfer when a synchronized recipient female was available or after shipment to another facility. Following the transfer of up to 3 embryos, an overall pregnancy rate of 30% was achieved with increasing rates dependent upon the number of embryos transferred. Singleton pregnancy outcomes following the transfer of ART produced embryos were similar to those observed in a control group of animals in the timed mated breeding colony at ONPRC. ICSI produced embryos were used in efforts to create monozygotic twins by blastomere separation or blastocyst splitting. While pregnancies were achieved following the transfer of demi-embryos, only one was a twin and it was lost to spontaneous abortion. ICSI produced embryos have also served as the source of blastocysts for the derivation of embryonic stem cells. These pluripotent cells hold potential for cell based therapies and we consider the monkey an important translational model in which to evaluate safety, efficacy and feasibility of regenerative medicine approaches based on the transplantation of stem cell-derived progeny. Finally, efforts to produce genetically-identical monkeys by nuclear transfer have been briefly summarized.

The risk of birth defects in children born after assisted reproductive technologies

PURPOSE OF REVIEW

This review addresses the question of whether there is evidence of an increased risk of birth defects in children born following assisted reproductive technologies compared with spontaneously conceived children.

RECENT FINDINGS

Three recent studies added relatively little new information given their modest size (56-472 assisted reproductive technology children). We therefore considered all published papers that compared birth defects in children born following assisted reproductive technologies with those in children born following spontaneous conception. Overall, only six of the 26 relevant papers concluded there was an increased risk of birth defects following assisted reproductive technologies. The interpretation of many studies was based on statistical significance testing alone. When results showed a greater proportion of defects in the assisted reproductive technology group compared with the spontaneous group, but the results were not statistically significant, this was often interpreted as showing no increase in risk, rather than an increase in risk that may have been due to chance. The vast majority of individual studies were too small to have sufficient power to detect, as statistically significant, clinically relevant results. We found that although only eight (30%) of the studies had statistically significant results, 24 (89%) had an odds ratio estimate comparing assisted reproductive technology with spontaneously conceived children of over 1.0; 19 (70%) had an estimate of 1.20 or greater; and 14 (52%) had an estimate of 1.5 or greater.

SUMMARY

Current evidence suggests there is an elevated risk of birth defects in children born following assisted reproductive technologies. Whilst others may disagree with our interpretation, one certainly cannot exclude this possibility on the basis of the current evidence.

Use of assisted reproductive technologies in the propagation of rhesus macaque offspring

The assisted reproductive technologies (ARTs) as tailored to the production of rhesus monkeys at the Oregon National Primate Research Center (ONPRC) are described. Efficient fertilization of mature oocytes recovered by aspiration from females subjected to follicular stimulation was achieved with fresh or frozen sperm by intracytoplasmic sperm injection (ICSI). Embryo development to the early cleavage stage occurred at high frequency. Cryopreserved embryos showed high postthaw survival and were also transferred in efforts to establish pregnancies. Three methods of transfer were evaluated, two involving embryo placement into the oviduct, laparoscopy and minilaparotomy, and a nonsurgical, transcervical approach that resulted in uterine deposition. Early cleaving embryos (Days 1-4) were transferred into the oviducts of synchronized recipients with optimal results and pregnancy rates of up to 36%. Pregnancy rates were similar when two fresh or frozen embryos were transferred (28- 30%), although more than two embryos had to be thawed to compensate for embryo loss during freeze-thawing. Normal gestational lengths, birth weights, and growth curves were seen with ART-produced infants compared with infants produced by natural mating in the timed mated breeding (TMB) colony at the ONPRC. In 72 singleton pregnancies established following the transfer of ART-produced embryos, the live-birth rate, at 87.5%, was statistically identical to that for the TMB colony. Further development of the ARTs should result in increasing use of these techniques to augment conventional approaches to propagating monkeys, especially those of defined genotypes.

A prospective longitudinal study of the physical, psychomotor, and intellectual development of singleton children up to 5 years who were conceived by intracytoplasmic sperm injection compared with children conceived spontaneously and by in vitro fertilization

OBJECTIVE

To assess the somatic, psychomotor, and intellectual development of children conceived through intracytoplasmic single sperm injection (ICSI) over the whole preschool period.

DESIGN

Prospective, controlled, cohort study.

SETTING

Fertility clinic in Brussels, Belgium.

PATIENT(S)

Sixty-six ICSI-conceived children prospectively compared with 52 IVF-conceived and 59 spontaneously conceived children. All children were full-term singletons.

INTERVENTION(S)

Home visits by a trained psychologist. Standardized interviews. Assessments using the revised Brunet-Lézine scale and the revised Wechsler preschool and primary scale of intelligence.

MAIN OUTCOME MEASURE(S)

Physical growth and general health. Formal developmental and intellectual assessments.

RESULT(S)

Children conceived by ICSI were healthy: no significant differences appeared in the incidence of combined congenital malformations (11.3%), health problems (44.1%), surgical interventions (18.6%), and hospitalizations (6.8%), nor for the developmental assessments (mean developmental quotient at 9 months: 93.9; at 18 months: 102.0). For the intellectual assessments, the between-group differences disappeared when adjusted for levels of parental education (mean intelligence quotient at 3 years: 97.0; at 5 years: 103.3).

CONCLUSION(S)

This pilot study shows that throughout the preschool period, ICSI-conceived children have psychomotor and intellectual development similar to that of IVF-conceived and spontaneously conceived children. These conclusions need to be confirmed by multicenter studies.

Relationship between the outcomes of assisted reproductive techniques and sperm DNA fragmentation as measured by the sperm chromatin structure assay

OBJECTIVE

To investigate how moderate and/or high levels of DNA fragmentation (DFI), as measured by the sperm chromatin structure assay (SCSA), affect either IVF or IVF with intracytoplasmic sperm injection (ICSI) fertilization, cleavage, blastulation, implantation, and pregnancy.

DESIGN

Retrospective clinical study.

SETTING

Academic human reproduction laboratory.

PATIENT(S)

Eighty-nine couples undergoing IVF with conventional fertilization or ICSI.

INTERVENTION(S)

Sperm chromatin structure assay testing (SCSA) of semen aliquot taken from ejaculate used for assisted reproductive technology (ART).

MAIN OUTCOME MEASURE(S)

Related DFI to conventional semen parameters and cycle-specific outcomes after ART.

RESULT(S)

No patients achieved clinical pregnancy if SCSA values exceeded the DFI (27%, P<.01), moderate DFI (15%, P<.01), or high DFI (15%, P<.05) thresholds. Dividing the DFI sperm population into moderate-fragmentation and high-fragmentation categories did not improve the prognostic value of the SCSA. No coefficient of determination (r(2)) between SCSA parameters and conventional parameters exceeded 0.29.

CONCLUSION(S)

Sperm chromatin structure assay identified thresholds for negative pregnancy outcome after ART not identified using conventional semen parameters. This is the first study analyzing the clinical value of sperm DFI to [1] include a large number of ART patients (n = 89), [2] perform SCSA analysis on a semen aliquot from the ejaculate used for ART, and [3] examine how the extent (moderate and high DFI) of DFI influenced ART outcomes.

Is intracytoplasmic sperm injection safe?

OBJECTIVE

To review the pregnancy and birth outcomes of patients undergoing intracytoplasmic sperm injection (ICSI).

DESIGN

Selective review of the literature.

SETTING

Couples undergoing either conventional IVF or ICSI and their resulting offspring.

PATIENT(S)

None.

MAIN OUTCOME MEASURE(S)

None.

INTERVENTION(S)

None.

RESULTS

These observational studies are unfortunately inherently biased. Regardless, the information and experiences from these large centers cannot be ignored. These experiences reveal that birth weight may be decreased by an amount that is generally not clinically relevant. Chromosomal and genetic abnormalities are increased probably only as a direct corollary to the underlying parental risk. Congenital malformations reveal no clustering of any single specific abnormality. Developmental assessment is available for up to 2 years, and no major delays have been identified in either motor or mental function.

CONCLUSION(S)

Intracytoplasmic sperm injection appears to be a safe alternative for couples who otherwise would be unable to achieve pregnancy. The inherent risks associated with these genetically "at risk" couples mandate thorough evaluation and counseling before undertaking ICSI.

Development to blastocyst is impaired when intracytoplasmic sperm injection is performed with abnormal sperm from infertile mice harboring a mutation in the protein phosphatase 1cgamma gene

Idiopathic azoospermia, characterized by abnormal spermatogenesis, is commonly treated by performing intracytoplasmic sperm injection (ICSI) with sperm retrieved from testicular biopsies. However, no controlled experiments have been performed using an animal model to assess the efficacy or safety of the procedure. We have performed ICSI with testicular sperm obtained in a similar manner from testes of male mice homozygous for a null mutation in the protein phosphatase 1cgamma gene (PP1cgamma) or those of their wild-type littermates. PP1cgamma mutant testicular sperm are less resistant to sonication than are wild-type sperm and display a range of morphological abnormalities, similar to those reported for testicular sperm from idiopathic azoospermic men. PP1cgamma mutant sperm are unable to support development to the blastocyst stage, resulting in arrested development either before or just after compaction. A comparison of testicular and epididymal sperm from wild-type males revealed that the epididymal sperm caused embryos to fragment at an elevated rate. These results suggest that ICSI with any kind of testicular sperm carries an increased risk of embryo fragmentation and that abnormal testicular sperm has an added risk of embryo wastage at later preimplantation stages.

Comparison of sibling oocyte outcomes after intracytoplasmic sperm injection and in vitro fertilization in severe teratozoospermic patients in the first cycle

To follow up the outcome of sibling oocytes subjected to both conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in the first cycles of severe teratozoospermic patients with normal sperm morphology (NSM)<or=4%, a total of 1193 sibling metaphase II oocytes (MII) in 85 cycles were randomly allocated into two groups: 588 underwent IVF and 605 ICSI and the embryo outcomes between the two groups were compared. The fertilization rate was significantly higher in the ICSI groups than in the IVF group (p < 0.05) and fertilization failure rate in the ICSI group (2.3%) was lower than in the IVF group (28.2%). Subsequently, the rates of embryo arrest as well as grade 1 and 2 embryo formation before day 3, >or=6 cell embryos on day 3 and blastocyst formation on days 5 and 6, did not differ significantly between the two groups. There was a trend towards a high pregnancy rate cycle in mixed ICSI/IVF embryo transfer (ET) (49.1%). In conclusion, this study showed that in couples with only severe teratozoospermia, there was a benefit in subjecting sibling oocytes to both IVF and ICSI in the first cycle because 24 (28.2%) cycles of total fertilization failure were avoided. Furthermore, despite initially significant higher fertilization rates in ICSI than IVF oocytes, subsequent rates of development from >or=6 cells up to blastocyst stage were the same suggesting that ICSI should be used with caution, as after day 3, ICSI-derived embryo development was compromised compared with IVF.

Current and future genetic screening for male infertility

Although much of male infertility is currently unexplained, it is likely that underlying defects in critical genes or entire gene pathways are responsible. Because powerful technologies exist to bypass severe male-factor infertility, improving the diagnosis of genetic infertility is important for the infertile couple, not only to explain the problem but also to inform them of conditions potentially transmissible to offspring.

Chromosome analysis of spontaneous abortions after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI)

OBJECTIVE

To verify the hypothesis that the incidence of chromosomal abnormalities significantly increases in the products of conception of males with sub-fertility, treated with assisted reproduction techniques (ART).

STUDY DESIGN

All removed products of conception tissues were analyzed with standard cytogenetic techniques. A karyotype of the abortions was possible in 35 cases of IVF and 29 of ICSI.

RESULTS

15/35 (43%) IVF abortions and 14/29 (48%) ICSI abortions, respectively, have shown a chromosomal abnormality. The most frequent abnormality was monosomy X (45,X0).

CONCLUSION

No significant difference in the incidence of embryonic anomalies was found between IVF and ICSI group. However, both IVF and ICSI allow pre-implantation diagnosis and embryo chromosomal evaluation should be considered, before transfer. Genetic counselling and consideration of prenatal diagnosis is suggested as integral part of planning of treatment strategies for 'at risk couples'.

Intracytoplasmic sperm injection (ICSI): risks reconsidered

The aim of this article is to address some of the questions raised by the introduction of new techniques to alleviate infertility, using intracytoplasmic sperm injection (ICSI) as an example. Although any new technique has the potential to cause unanticipated harm and it is probably true that no treatment is risk-free, current practice demands that risks are, as far as possible, minimized during trials and when offered as treatment. It is expected that those taking part in trials, possibly even more than patients, should be given information on potential hazards so that they may choose whether to participate. However, particular problems arise when dealing with techniques to assist reproduction, since there may be risks not only to the recipients of treatment but also to the children who may result from the treatment. Therefore, risks to the children, as much as to the parents, deserve consideration and these potential subjects of risk will be the focus of this article. The different types of risk will be considered and the issue of whether children can be regarded as being harmed as a result of being conceived by such procedures will also be explored.

Intracytoplasmic sperm injection in assisted reproductive technology: an evaluation

Since the first reports of successful pregnancies in humans after treatment with intracytoplasmic sperm injection (ICSI), intensive investigations have focused on several important aspects of this form of assisted reproductive technology. In addition to the technical development of ICSI and increasing understanding of the biochemical and biophysical processes involved during fertilization after injection of an immobilized sperm, studies have aimed to define the indications for patients for a first-line ICSI treatment. One of the major concerns is of course the safety of the technique in terms of the health and reproductive life of the babies born after ICSI. The rhesus monkey is an excellent model to investigate all aspects of this micromanipulation technique. This article provides an evaluation of ICSI.

Chromosomal anomalies in human gametes and pre-implantation embryos, and their potential effect on reproduction

This paper reviews the latest data on chromosomal abnormalities in human gametes and embryos. A close relationship between such anomalies and reproduction failure in humans has been postulated, thereby underscoring the importance of ongoing studies into the mechanisms leading to anomalies. Until recently, knowledge of chromosomal anomalies in human gametes and embryos has been limited. Newly developed strategies (in vitro fertilization combined with micromanipulation techniques followed by multicolour fluorescence in situ hybridization, and PCR analyses) allow precise investigation of this problem. This review of the available information on the etiology of chromosomal anomalies indicates that some of the genetic anomalies in human gametes and early embryos result in reproductive failure.

A prospective controlled study of karyotyping for 430 consecutive babies conceived through intracytoplasmic sperm injection

OBJECTIVE

To compare the karyotype of babies conceived through ICSI with that of naturally conceived babies.

DESIGN

Prospective controlled study.

SETTING

The Egyptian IVF-ET Center, Cairo, Egypt.

PATIENT(S)

Four hundred and thirty babies conceived through ICSI and 430 babies conceived naturally.

INTERVENTION(S)

ICSI and karyotyping.

MAIN OUTCOME MEASURE(S)

Abnormal karyotype.

RESULT(S)

Four hundred and thirty consecutive babies conceived through ICSI who were delivered in one hospital had 15 abnormal karyotypes (3.5%). Of the 15 babies, 7 were of female phenotype and 8 of male phenotype. Six babies had sex chromosome anomalies, 8 had autosomal anomalies, and 1 had combined sex chromosome and autosomal anomalies. A control group of 430 consecutive babies conceived naturally who were delivered in one hospital had no abnormal karyotype. The difference between the two groups was significant (P<.001).

CONCLUSION(S)

ICSI carries a small but significant increased risk of abnormal karyotyping to the offspring. This risk appears to be equally distributed between autosomal and sex chromosome anomalies.

Prediction of unexpectedly poor fertilization and pregnancy outcome using the strict criteria for sperm morphology before and after sperm separation in IVF-ET

This study was performed to investigate if unexpectedly poor fertilization and in-vitro fertilization (IVF) outcome could be predicted using sperm morphology as diagnosed by the strict criteria. Sperm morphology was assessed in 137 IVF-ET cycles with at least three oocytes collected. The lowest amount of normal forms was 5% in 137 samples, indicating there were no patients belonging to 'poor prognosis' (<5% normal forms). Treatment using intracytoplasmic sperm injection (ICSI) was also excluded. Before sperm separation by the swim-up method, sperm morphology demonstrated a significant correlation with the fertilization rate (p < 0.0001). The fertilization rate (80.5%) in 110 'normal' samples (>14% normal forms) was significantly higher (p < 0.01) than that (55.4%) in 27 samples with 'good prognosis' (those with 5--14% normal forms). No embryo was available for transfer (ET) in 4 (3.6%) of 110 'normal' cycles and in 3 (11.1%) of 27 'good prognosis' cycles (not significant). Fresh ET was intentionally cancelled to avoid severe ovarian hyperstimulation syndrome (OHSS) in six of 110 'normal' cycles as well as in one of 27 'good prognosis' cycles. The pregnancy rate per ET was 31.0% (31/100) in the former group, while it was 26.1% (6/23) in the latter group. There was no difference between the two groups. In the post swim-up evaluation of sperm characteristics, morphology was significantly correlated with the fertilization rate in IVF-ET (p < 0.05) while other sperm parameters were not. When the cut off level for the post swim-up sperm morphology was set at 25%, there was a significant difference in the fertilization rates between patients (78.6%) with post-swim-up >25% and those (55.0%) with post-swim-up < or =25% (p < 0.01). Taken together, a relative indication for ICSI using sperm morphology before and after swim-up was established. Category A includes < or =14% normal forms in the ejaculate and post-swim-up < or =25%, while Category B includes < or =14% in the ejaculate and post-swim-up >25%. There was a significant difference in the fertilization rates between patients (47.2%) in Category A and those (60.2%) in Category B (p < 0.05). The clinical pregnancy rate was 11.1% for patients in Category A compared with 35.7% for patients in Category B. However, there was no significant difference between the two categories. These results indicate that the strict criteria provide a reliable estimation of the fertilizing ability of human spermatozoa. ICSI might be considered in Category A patients to avoid poor fertilization and pregnancy outcome.

The status of controlled prospective clinical trials for efficacy of intracytoplasmic sperm injection in in vitro fertilization for non-male factor infertility

PURPOSE

Intracytoplasmic sperm injection (ICSI) of some sibling oocytes may have a beneficial effect in couples going through in vitro fertilization for causes of infertility not related to the male factor. Our purpose was to critically appraise the randomized controlled studies done in this area and arrive at some recommendations.

METHODS

The four controlled trials done so far have utilized similar methodology, i.e., they randomly allotted sibling oocytes to ICSI versus standard insemination in patients going through in vitro fertilization and embryo transfer.

RESULTS

In the first trial reported in 1995 there was no difference in fertilization rate, whereas the later trials reported in 1997, 1999, and 2000 showed improvement with ICSI that reached statistically significant level in the last two studies.

CONCLUSIONS

Total fertilization failure of an in vitro fertilization cycle can be prevented and fertilization can be improved if half of sibling oocytes are subjected to ICSI.