Pregnancies following pre-conception diagnosis of common aneuploidies by fluorescent in-situ hybridization

Chromosomal aneuploidies contribute considerably to the lowpregnancy rate in in-vitro fertilization (IVF). The objectiveof this experimental work was to explore the possibility ofdetecting common aneuploidies in oocytes by polar body sampling.The study included 45 infertile patients of advanced maternalage participating in an IVF programme. The first polar bodywas removed prior to fertilization or both the first and secondpolar bodies were removed after fertilization and studied byfluorescent in-situ hybridization (FISH) using chromosome-specificprobes for chromosomes X, 18 and/or 13/21. Of 155 oocytes withFISH results, 36 demonstrated chromosomal abnormalities. Of119 oocytes predicted to be free from aneuploidy of chromosomesX, 18 and/or 13/21, 72 were normally fertilized, cleaved andtransferred in 23 treatment cycles, which resulted in two healthydeliveries and three ongoing pregnancies confirmed to be unaffectedby chorionic villous sampling. The method may appear usefulfor the detection of oocytes with common chromosomal aneuploidiesin IVF patients of advanced maternal age. chromosomal aneuploidies/fluorescent in-situ hybridization/human first and second polar bodies/pre-conception/preimplantation genetic diagnosis     

Chromosome analysis in human oocytes remaining unfertilized after in- vitro insemination: effect of maternal age and fertilization rate

The incidence of chromosomal abnormalities was studied in 719 unfertilized human oocytes obtained from our in-vitro fertilization (IVF) programme. To make chromosome preparations, a gradual fixation/air-drying method was utilized. Of 388 oocytes successfully karyotyped, 70 (18.0%) were abnormal. The abnormalities included 33 aneuploidies (8.5%) (14 hyperhaploidies and 19 hypohaploidies), 25 diploidies (6.4%) and 15 structural abnormalities (3.9%), three of them being accompanied by aneuploidy. Of the 33 aneuploidies, 16 (48.5%) showed the loss or gain of dyads (so-called non-disjunction), while 17 (51.5%) showed the loss or gain of monads (so-called predivision). There was no maternal age-dependent increase in the incidence of aneuploidy. Unfertilized oocytes from patients with a high fertilization rate (>25%) had a significantly higher (11.4%, P < 0.05) incidence of diploidy compared with the oocytes from the remaining patients (4.3 and 4.0%), suggesting that diploid oocytes might have a lower fertilizing ability.      

The incidence of chromosomal aneuploidy in stimulated and unstimulated (natural) uninseminated human oocytes.

The incidence of chromosomal aneuploidy in human oocytes is higher than for various animal species. Since this estimate for aneuploidies is based on data obtained from in-vitro fertilization (IVF) patients, it is possible that superovulation could be contributing to this phenomenon. In this study we determine the incidence of chromosomal aneuploidy in nonstimulated uninseminated human oocytes donated by IVF patients. Furthermore, we compare this incidence of aneuploidy to that obtained after superovulation using two different protocols for induction of multiple follicular growth. The rate of aneuploidy in non-stimulated oocytes was 20% (4/20). This is not significantly different from the rate of aneuploidy in oocytes obtained after superovulation with clomiphene/human menopausal gonadotrophin (HMG)/(HCG) (15/43 = 35%, chi 2 = 1.11; P > 0.20), buserelin-flare (8/25 = 32%; chi 2 = 0.32; P > 0.05), and the rate of aneuploidy in the total number of superovulated oocytes (23/68 = 34%; chi 2 = 82; P < 0.30). Furthermore, the incidence of chromosome aneuploidy in non-stimulated uninseminated oocytes (20%) was well within the range and not significantly different from that reported in the literature for both superovulated uninseminated oocytes (range, 21-57%; total aneuploidy rate, 67/216 = 31%; P < 0.30) and superovulated inseminated oocytes (range, 3-56%; total aneuploidy, 339/1480 = 23%; P < 0.95). Consequently, the data provide evidence that superovulation protocols used in IVF may not be responsible for the higher rate of aneuploidy in human oocytes. These results are discussed in relation to hypotheses on the occurrence of meiotic non-disjunction.     

Fertilization and early embryology: Cytogenetic and fluorescent in-situ hybridization chromosomal studies on in-vitro fertilized and intracytoplasmic sperm injected 'failed-fertilized' human oocytes

This study was undertaken to establish baseline data on thechromosomal status of ‘failed-fertilized’ oocytesderived from in-vitro fertilization (IVF) or intracytoplasmicsperm injection (ICSI) procedures. A cytogenetic analysis wasundertaken on 162 IVF and 51 ICSI oocytes. In all, 82.1% (133/162)of the IVF and 78.4% (40/51) of the ICSI oocytes had metaphaseII (Mil) plates, of which 50.4% of the IVF and 47.5% of theICSI oocytes were analysed further. Chromosomes of the G-group(21–22) were identified with the majority of the anomalies.No overall significant difference in the aneuploidy rate wasfound for the IVF (37.3%) or ICSI (31.6%) oocytes, or with maternalage. However, chromosome anomalies, e.g. diploidy, fragmentedand broken chromatids, single sperm and oocyte chromatids, werefound in oocytes from IVF patients aged >36 years and inthe ICSI oocytes throughout the maternal age range (31–38years). The status of the polar body chromatin indicated thatthere was no overall significant difference in the maturationof the IVF and ICSI oocytes. Evidence of successful sperm deliverywas found in 72.5% (37/51) of the ICSI failed-fertilized oocytes.In this group there was a significant increase in the incidenceof premature chromosome condensation: 19.6% (10/51) containedsperm chromosomes, 7.8% (4/51) had swollen sperm heads, andthe remaining 45.0% had condensed sperm heads. The presenceof both sperm and Mil oocyte chromosomes was found in 19.6%(10/51) of the ICSI and 8.6% (14/162) of the IVF failed-fertilizedoocytes. Specific fluorescent in-situ hybridization DNA probeswere used to re-analyse the chromosomes of karyotyped ‘failed-fertilized’IVF oocytes and, for the first time, applied to the karyotypedchromosomes of failed-fertilized ICSI oocytes. The hybridizationefficiency was 86–95% for the centromere probe and 100%for probes 21 and 18.     

Cytogenetic analysis of unfertilized oocytes retrieved after treatment with the LHRH analogue, buserelin

Chromosome analysis is reported on 155 oocytes from an in-vitro fertilization (IVF) programme in which the LHRH analogue, buserelin, was used in the superovulation regime. Seventy-one oocytes had the normal number of metaphase II chromosomes. Hyperhaploidy was apparent in four cases only; doubling this figure to include the reciprocally formed hypohaploid oocytes gave an aneuploidy rate due to non-disjunction of 10%. This is close to the figure for naturally occurring aneuploidy which may be calculated from data on recognized conceptions at a comparable maternal age. Taken together with the suggestion of a maternal age effect in our series these data suggest that follicular stimulation regimes which precede IVF do not necessarily add to the naturally high aneuploidy rate of the human species. Thirteen oocytes had failed to form the first polar body and the presence of diploid mitotic or sperm chromosomes provided evidence of fertilization and arrested development in 15. These figures for chromosomal anomalies following buserelin treatment are not significantly different from those obtained from comparable surveys following clomiphene citrate stimulation, providing no evidence that the improved pregnancy rate with buserelin is due to chromosomal factors.     

Fertilization and early embryology: Intracytoplasmic single sperm injection of 1-day-old unfertilized human oocytes

Although the average fertilization rate in most in-vitro fertilization(IVF) centres is 60–70%, there are cases of complete orvirtually complete fertilization failures. The aim of our workwas to study the fertilization and the subsequent cleavage characteristicsof 1-day-old human oocytes treated by intracytoplasmic singlesperm injection (ICSI) after failing to fertilize during thestandard IVF procedure. A total of 115 metaphase II 1-day-oldunfertilized oocytes were collected from 23 patients. No additionaltreatment was applied to the oocytes or to the semen sample.A single spermatozoon from the patient's husband was injectedinto the cytoplasm of each of these oocytes 21–33 h afterovum retrieval. Injected oocytes were observed at 16–18h and again 42–44 h after the ICSI procedure. Of the injectedoocytes, 92% (n = 106) were intact after ICSI, 38% (n = 44)had two distinct pronuclei and there was no difference in thefertilization rate of oocytes when andrological and non-andrologicalpatients were compared. Similarly, there was no difference inthe fertilization rate after ICSI where patients with acceptableor good (> 15%) fertilization after standard IVF were comparedto patients who had poor (<15%) fertilization after IVF.There was no significant difference in the sperm concentrationor in the progressive forward motility (a + b motility) in thesegroups except where a + b motility of andrological and non-adrologicalpatients was compared. The majority (84%) of the normally fertilizedoocytes cleaved and most (77%) of these embryos showed <20%fragmentation 2 days after the ICSI procedure. From this studyit can be concluded that 1-day-old metaphase II oocytes whichhave failed to be fertilized after standard IVF procedure canbe fertilized and cleave when ICSI is performed on them theday after oocyte retrieval.     

Comparison between intracytoplasmic sperm injection and in-vitro fertilization (IVF) with high insemination concentration after total fertilization failure in a previous IVF attempt.

The aim of this prospective study was to evaluate whether couples with total fertilization failure in a previous in-vitro fertilization (IVF) attempt should be offered an additional IVF treatment with elevated insemination concentration or should be treated with intracytoplasmic sperm injection (ICSI). In 23 cycles 228 sibling metaphase II (MII) oocytes were randomly divided: 143 and 85 oocytes were utilized for ICSI and IVF respectively. Of the 143 injected (ICSI) oocytes, 90 (62.9%) were normally fertilized (two pronuclei), whereas 21 (14.7%) oocytes were damaged by the ICSI procedure. Of the fertilized oocytes 72 (80%) developed into transferable embryos. No fertilization at all was observed in the 85 sibling MII oocytes which were inseminated (P < 0.001). In all 23 cycles at least one embryo, obtained by ICSI, could be replaced. Eight pregnancies were achieved of which six resulted in the delivery of nine healthy children. In conclusion, for couples with no or almost no fertilization of oocytes in previous IVF attempts, ICSI appeared to be far superior to an additional IVF attempt with further elevated insemination concentrations.     

Cytoskeletal organization defects and abortive activation in human oocytes after IVF and ICSI failure

In this study, we analysed the distribution of beta tubulins to detect spindle and cytoplasmic microtubules, alpha acetylated tubulins for sperm microtubules and chromatin configuration in oocytes showing fertilization failure after conventional IVF or intracytoplasmic sperm injection (ICSI). A total of 450 human oocytes that failed to fertilize were studied 20-40 h after IVF or ICSI. In all, 287 oocytes were stained for immunofluorescence and chromosomal spreads were performed by Tarkowski's air-drying method in 163 IVF or ICSI oocytes that did not develop pronuclei after the extrusion of a second polar body. Immunofluorescence analysis showed that the main reason of fertilization failure after IVF was no sperm penetration (55.5%). The remaining oocytes showed different abnormal patterns, e.g. oocyte activation failure (15.1%) and defects in pronuclei apposition (19.2%). On the other hand, fertilization failure after ICSI was mainly associated to incomplete oocyte activation (39.9%), and to a lesser extent with defects in pronuclei apposition (22.6%) and failure of sperm penetration (13.3%). A further 13.3% of the ICSI oocytes arrested their development at the metaphase of the first mitotic division. The chromosomal spreads allowed the analysis of abortive activations, in which no pronuclei formed but a second polar body was extruded. Immunofluorescence and cytogenetic analysis provided a useful tool to improve infertility diagnosis and prognosis in each particular case.     

Analysis of the first polar body: preconception genetic diagnosis

In women who are heterozygous for a genetic disease, genetic analysis of the first polar body allows the identification of oocytes that contain the maternal unaffected gene. These oocytes can be fertilized and transferred to the mother without risk of establishing a pregnancy with a genetically abnormal embryo. We have demonstrated that removal of the first polar body has no effect on subsequent fertilization rates or embryonic growth to the blastocyst stage. We have developed a PCR technique to successfully analyze the PI type Z and PI type M genotypes of alpha-1-antitrypsin deficiency and applied this technique for a couple at risk for PI type ZZ alpha-1-antitrypsin deficiency. After standard IVF treatment to stimulate multiple follicle development, eight oocytes were aspirated transvaginally. Polar bodies were removed by micromanipulation from seven oocytes and fertilization occurred in six cases. PCR analysis was successful in five oocytes. One was PI type M, two were PI type Z and two were heterozygous MZ due to crossing over. Embryos from the two oocytes containing the unaffected gene (polar body PI type Z) were transferred in the same cycle 48 h after insemination. No pregnancy was established. The accuracy of the polar body diagnosis was confirmed by polymerase chain reaction (PCR) analysis of an oocyte that failed to fertilize.     

Chromosome investigations in early life. I. Human oocytes recovered in an IVF programme

Fifty-five oocytes recovered in an in-vitro fertilization (IVF)programme and remaining unfertilized when observed 42 h afterinsemination were prepared for chromosomal analysis. Sixteenoocytes displayed no polar body at the time of fixation andwere supposed to be in metaphase I. In fact only two of themwere in diakinesis, the others containing a diploid set of metaphaseII chromosomes indicating that in 89% of the cases oocytes achievedmeiosis without any extrusion of the first polar body. Thirty-nineoocytes in metaphase II were analysed. Nine were abnormal showingthree D nullosomies, one G disomy, one double disomy for a 3and a D chromosome, one deletion of the long arm of a G chromosome,one cell with extra chromosomes and/or chromosome breaks, oneendoreduplication and one tetraploidy. The overall rate of abnormalitiesreached 22%. This high rate of chromosome anomalies can be explainedby the nature of this population of fertilization failure, thefrequently advanced maternal age and the use of superovulationtreatments     

Andrology: Successful treatment of severe male factor infertility in 100 consecutive cycles using intracytoplasmic sperm injection

In this report, we present the results of our first 100 consecutivecycles of intracytoplasmic sperm injection (ICSI). Overall,fertilization occurred in 98% of cycles and embryos were transferredin 94% (2.6 embryos per cycle). About 50% of patients had embryosfrozen. The overall fertilization rate was 71%, of which 4%were abnormally fertilized (three pronuclei). A total of 30clinical pregnancies were established (32% per transfer), resultingin 18 singleton, six twin and one triplet ongoing pregnancies.The implantation rate per embryo was 15%. There were no significantdifferences in the fertilization or pregnancy rates betweenpatients Who had only occasional motile spermatozoa in the ejaculate,semen that was too poor for routine in-vitro fertilization (IVF),or who had failed routine IVF and/or subzonal sperm injection(SUZI). A group of 18 patients were treated with both ICSI androutine IVF on their first cycle because of the high likelihoodof failed fertilization due to poor sperm morphology (<20%normal). In this group, ICSI oocytes had a fertilization rateof 76% compared to only 15% for the routine IVF (control) oocytes,and six patients conceived after transfer of ICSI embryos (33%),indicating that ICSI can be used successfully on 50% of theoocytes if fertilization failure is expected. Similarly, patientswho had failed to become pregnant with SUZI achieved excellentresults after ICSI. There were no significant differences betweenICSI and routine IVF in the proportions of grade 1, 2 or 3 embryoson day 3 post-oocyte recovery. In conclusion, we have achievedresults comparable to those reported from Belgium and we havefound that ICSI is universally applicable to all forms of severemale factor infertility. ICSI produces fertilization, pregnancyand freezing rates comparable to routine IVF with normozoospermicsamples and has none of the drawbacks of other assisted fertilizationtechniques.     

Diagnosing and preventing inherited disease: The use of first polar bodies for preimplantation diagnosis of aneuploidy

A large proportion of patients undergoing in-vitro fertilization(IVF) are aged 35 years. It has been estimated that in thisage group, 50% of embryos are chromosomally abnormal, with aneuploidybeing the major contributing factor. Since the origin of mostaneuploidies is maternal meiosis I non-disjunction, unfertilizedoocytes could be safely screened for aneuploidy by analysingtheir first polar bodies. To determine the feasibility of firstpolar body aneuploidy analysis, polar bodies were analysed byfluorescence in-situ hybridization (FISH) using probes simultaneouslyfor chromosomes X, Y, 18, 13/21 or X, Y, 18 and 16. Within 6h of retrieval, 88% showed a normal segregation involving asingle chromosome of each kind, with double-dotted hybridizationsignals, corresponding to dyads (chromosomes in metaphase Icomposed of two chromatids). The rest showed non-disjunctionof full dyads (6%), or an unbalanced pre-division of dyads (6%),which gives a segregation of one chromatid or one dyad and achromatid with the first polar body. But only 34% of polar bodiesanalysed 24 h after retrieval or later showed a normal segregation,with most of the other polar bodies showing balanced pre-division,with two separated hybridization signals for all the chromosomesanalysed. The rates of non-disjunction and unbalanced pre-divisionafter 24 h in culture were similar to the rates in fresh oocytes.When both types of aneuploidy were considered together, an increaseof aneuploidy with maternal age was detected, which althoughslight, was significant (P = 0.025). Because dyads seem to undergorapid pre-division shortly after polar body retrieval, performanceof FISH aneuploidy analysis of polar bodies is therefore onlyrecommended when conducted within 6 h of their retrieval.     

Mechanisms of non-disjunction in human female meiosis: the co-existence of two modes of malsegregation evidenced by the karyotyping of 1397 in-vitro unfertilized oocytes

BACKGROUND: Although numerous studies have been published on the chromosomal constitution of in-vitro unfertilized human oocytes, data remain highly variable and controversial because of the size of oocyte samples, technical reservations and potential misinterpretation. METHODS: A cytogenetic study was undertaken on 3042 unfertilized human oocytes recovered from 792 women participating in an IVF programme for various infertility problems. Both a gradual fixation technique and an R-banding procedure were used. RESULTS: The analysis was successful in 1397 oocytes (45.9%) for which interpretable metaphases were obtained. Of the 1397 oocyte karyotypes, 1088 (77.9%) were normal (23,X). The overall frequency of chromosomal abnormality was 22.1%. No correlation was found between the rate of abnormalities and the type of infertility. Aneuploidy was observed in 151 cells (10.8%), consisting of 5.4% hypohaploidies, 4.1% hyperhaploidies, 0.8% complex aneuploidies and 0.05% extreme aneuploidies with less than 18 chromosomes. Both whole chromosome non-disjunction and chromatid predivision contributed to the formation of aneuploid oocytes, but the numerical abnormalities due to single chromatids significantly exceeded conventional non-disjunctions. Abnormalities also included 5.4% diploid oocytes, 3.8% sets of chromatids alone and 2.1% structural aberrations. Aneuploidy was found in all chromosome groups. However, groups E and G exhibited significantly higher frequencies of non-disjunction than expected, whereas groups A and B showed a significantly low incidence of aneuploidy. CONCLUSIONS: The implication of both chromosome and chromatid abnormalities in the occurrence of non-disjunction are discussed in relation to the recent data on chromatid cohesion throughout cell division. The results were consistent with the hypothesis of an unequal occurrence of non-disjunction among the chromosome groups in female meiosis.     

Cytogenetic study of human oocytes uncleaved after in-vitro fertilization

Chromosome analysis of oocytes uncleaved after IVF allows the cause of the failure of cleavage to be determined and shows the incidence of chromosome disorders among human oocytes. A total of 198 uncleaved oocytes fixed 40 h after insemination were successfully analysed according to Tarkowski's air-drying method: 78.3% were unfertilized and arrested in metaphase II. Among them, 70% were normal (23,X) and 30% aneuploid (16% were hypohaploid, 14% were hyperhaploid). The incidence of chromosome breaks was 18%. In 12.1% of the oocytes, sperm chromosome condensation appeared premature usually in the G1 phase. This was especially observed in idiopathic infertility (7% of fertilized oocytes versus 2% in tubal infertility cases). In 8.1% of the cases, chromosome analysis showed diploidy which may be interpreted by either an absence of extrusion or a reintrusion of the polar body or by first cleavage failure during mitosis. In 1% of the cases triploidy was observed. Our results show that the main reason for failure of cleavage is related to failure of fertilization (78.3%). However, premature condensation of sperm chromosomes at the G1 phase appears to be quite frequent. This may be involved in the aetiology of some cases of idiopathic infertility. Finally, the high rate of chromosomal disorders (30%) in human oocytes may explain the high rate of chromosomal abnormalities in preimplantation embryos.     

Should ICSI be the treatment of choice for all cases of in-vitro conception?

The objective of this study was to examine different clinical scenarios of in-vitro conception, viz. fertilization with conventional IVF, IVF with high insemination concentration (HIC) and intracytoplasmic sperm injection (ICSI), and assess on a sibling oocyte comparison the hypothesis that ICSI should be performed in all cases requiring in-vitro conception. ICSI with husband's spermatozoa had a higher incidence of fertilization as compared with IVF or IVF with HIC with donor spermatozoa (if previous failure of fertilization had occurred) for unexplained infertility. Similarly, ICSI with husband's spermatozoa had as high an incidence of fertilization as IVF with donor spermatozoa for patients with severe oligozoospermia, asthenozoospermia and/or teratozoospermia, even when the spermatozoa were not selected for their morphology. Two studies were performed to assess ICSI in potential oocyte-related failure of IVF, viz. when fertilization occurred in >50% of oocytes for one group of patients, and in <50% of oocytes in a second group. In both of these studies a significant proportion of the oocytes that failed to fertilize with conventional IVF eventually fertilized after ICSI. The overall conclusion was that ICSI as a first option offers a higher incidence of fertilization, maximizes the number of embryos and minimizes the risk of complete failure of fertilization for all cases requiring in-vitro conception. However, among other concerns, current knowledge of ICSI as an outcome procedure does not provide the confidence to use this process in all cases of IVF for the time being.     

Birth following vitrification of a small number of human oocytes: case report

We report the birth of a healthy baby girl at 37 weeks gestation to a 47 year old recipient, after vitrification of mature oocytes from four in-vitro fertilization (IVF) patients. A total of 17 oocytes was vitrified in 1-2 microl of ethylene glycol (40%) and 0.6 mol/l sucrose (20.54%) in open pulled straws. Eleven oocytes survived after vitrification and five pronuclear zygotes were obtained after intracytoplasmic sperm injection (ICSI). Three embryos were transferred to three patients, two of whom were the original oocyte donors and pregnancy was not established. The third embryo was donated to a 47 year old infertile woman after preimplantation diagnosis had confirmed euploidy for chromosomes X, 13, 14, 15, 16, 18, 21 and 22. The successfully completed pregnancy is encouraging for further research to explore the potential benefits of vitrification for the cryopreservation of human oocytes, given the relatively low success of conventional freezing of human oocytes by slow cooling methods.     

Immunology: Intravenous immunoglobulin for in-vitro fertilization failure

The aim of this study was to determine the effectiveness ofintravenous (i.v.) immunoglobulin (Ig) for treatment of individualsexperiencing failure after in-vitro fertilization (IVF) andembryo transfer. A total of 29 women with unexplained infertilitywho failed to become pregnant after IVF/embryo transfer weredivided into two groups based on performance in previous IVFcycles: 16 women had fertilization of 50%of oocytes retrievedand/or produced 3 embryos each cycle and 13 had fertilizationof<50% of oocytes retrieved and/or produced <3 embryoseach cycle. Each woman had received at least 12 transferredembryos (95th percentile for successful IVF patients) or hadexperienced two or more biochemical pregnancies without ultrasonicconfirmation of implantation during previous IVF/embryo transferattempts. All women received i.v. Ig 500 mg/kg prior to thenext embryo transfer. Only one of the 13 (8%) women with suboptimalfertilization and embryo yield became pregnant in the treatmentcycle. Of 16 women who had previously had fertilization of atleast 50% of oocytes retrieved and produced at least three embryos,nine (56%) became pregnant in the treatment cycle. The differencein pregnancy rates between the two groups is significant (P=0.02).Intravenous Ig is useful in the treatment of unexplained IVFfailure in women who have oocyte fertilization rates 50% andgenerate at least three embryos per cycle.     

Oocyte euploidy, pronuclear zygote morphology and embryo chromosomal complement

BACKGROUND: Pronuclear morphology has been proposed as an indicator of embryo development and chromosomal complement. In this study, the morphology of pronuclear zygotes generated from euploid oocytes [diagnosed by first polar body (PB1) analysis] was evaluated and compared with the configurations observed in chromosomally normal embryos (diagnosed by blastomere analysis). MATERIALS AND METHODS: Group 1--238 patients underwent 273 assisted conception cycles in combination with the screening of aneuploidy on PB1 for the chromosomes 13, 15, 16, 18, 21 and 22. Only normal oocytes were inseminated. Group 2--218 patients underwent 318 assisted conception cycles with aneuploidy screening on day 3 embryos. In both groups, oocytes were checked for fertilization and pronuclear morphology at 16 h after insemination. RESULTS: Seventy-three percent of zygotes from Group 1 had the configurations with centralized and juxtaposed pronuclei, large-size aligned or scattered nucleoli and PB located in the longitudinal or perpendicular axis of pronuclei. In Group 2, these configurations corresponded to those with the highest proportion of chromosomally normal embryos. Accordingly, in both groups, these configurations had a higher implantation rate than all the others. CONCLUSIONS: These observations confirm that some patterns of pronuclear morphology are associated with a higher proportion of euploidy and implantation reaffirming the relevance of this scoring system for the prediction of zygote viability.     

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.     

Outcome of conventional IVF and ICSI on sibling oocytes in mild male factor infertility

BACKGROUND: Decisions concerning the treatment choice for assisted reproduction (IVF or ICSI) are usually made after the evaluation of male fertility factors, or after taking into account the results of previous IVF attempts. There are no widely accepted criteria, so decisions for couples with male subfertility are often empirical and may lead to complete fertilization failure after IVF, or to the unnecessary use of ICSI. METHODS: A study was conducted in which half the oocytes from each of 58 couples with moderate oligo +/- astheno +/- teratozoospermia were inseminated (conventional IVF) and the other half microinjected (ICSI). The technique used for subsequent cycles depended on the results of the first cycle. RESULTS: Nineteen of the 58 IVF/ICSI attempts resulted in fertilization after ICSI only (32.8%) and 39 in fertilization after IVF and ICSI (67.2%). For patients with oocyte fertilization only after ICSI, 61.5% of the oocytes microinjected were fertilized. A mean of 2.2 embryos per patient were transferred, leading to eight clinical pregnancies (42.1%).The implantation rate was 21.4%. All subsequent cycles were carried out with ICSI. Couples with oocyte fertilization after both IVF and ICSI had slightly better semen characteristics than those with oocyte fertilization only after ICSI, but this difference was not significant. Overall, no statistically significant difference was observed between IVF and ICSI in sibling oocytes for any of the variables studied: fertilization rate, embryo morphology and rates of development, pregnancy and implantation. Although only small numbers of oocytes or embryos were available for each couple, six couples had lower fertilization rates after IVF and eight had lower embryo quality after IVF. Eight patients had lower sperm quality in the second cycle, and only seven couples underwent subsequent IVF cycles. CONCLUSIONS: This strategy enabled us to avoid 32.8% of complete fertilization failures after IVF, but not to decrease significantly the number of ICSI attempts in subsequent cycles. However, the uncertainties concerning the safety of ICSI suggest that ICSI should be used cautiously and judiciously.