Follicular fluid protein content (FSH, LH, PG4, E2 and AMH) and polar body aneuploidy.

PURPOSE: Our objective was to identify a marker for oocyte aneuploidy in follicular fluid (FF) in women with an increased risk of oocyte aneuploidy after controlled ovarian hyperstimulation. MATERIALS AND METHODS: Three groups of oocytes were constituted for polar body screening by FISH (chromosomes 13, 16, 18, 21 and 22): Group 1, advanced maternal age (n = 156); Group 2, implantation failure (i.e. no pregnancy after the transfer of more than 10 embryos; n = 101) and Group 3, implantation failure and advanced maternal age (n = 56). FSH and other proteins were assayed in the corresponding FF samples. RESULTS: Of the 313 oocytes assessed, 35.78 % were abnormal. We found a significant difference between the follicular FSH levels in normal oocytes and abnormal oocytes (4.85 ± 1.75 IU/L vs. 5.41 ± 2.47 IU/L, respectively; p = 0.021). We found that the greater the number of chromosomal abnormalities per oocyte (between 0 and 3), the higher the follicular FSH level. CONCLUSION: High FF FSH levels were associated with oocyte aneuploidy in women having undergone controlled ovarian hyperstimulation.

Stability of aneuploidy rate in polar bodies in two cohorts from the same patient.

The aim of this study was to evaluate the stability of the aneuploidy rate of the first polar body. Knowing the stability of the oocyte aneuploidy rate for each patient would allow the first analysis to be used as a prognostic tool for further attempts at intracytoplasmic sperm injection (ICSI). After a first unsuccessful ICSI attempt with preconceptional screening, 24 women underwent a second attempt. First polar body aneuploidy rates were compared in the course of two successive ovarian stimulations. The first polar body was biopsied after laser dissection of the zona pellucida and five chromosomes were analysed using the MultiVysion polar body multicolour probe panel. A total of 200 polar bodies were analysed; 91 and 109 in the first and second ICSI attempts, respectively. The total aneuploidy rate was identical in the first and second attempts; 44.0% (40/91) and 44.0% (48/109), respectively. The first evaluation of the aneuploidy rate was statistically (P = 0.0007) correlated with the second, with a correlation coefficient, r = 0.707. The stability of the aneuploidy rate in different cohorts from the same patient, if confirmed in a larger series, makes this parameter a useful tool for counselling couples.

Oocyte aneuploidy mechanisms are different in two situations of increased chromosomal risk: older patients and patients with recurrent implantation failure after in vitro fertilization.

OBJECTIVE: To clarify the mechanisms underlying oocyte abnormalities in meiosis: meiotic nondisjunction of a whole chromosome or premature separation of sister chromatids in two situations of increased chromosomal risk. DESIGN: Preconception diagnosis by first polar-body analysis in two situations of increased chromosomal risk. SETTING: Departments of reproductive biology, cytogenetics, gynecology, and obstetrics. PATIENT(S): First polar body analysis was proposed to 76 patients (91 cycles) for advanced age (AMA; n = 30, 36 cycles), recurrent implantation failure (RIF; >10 embryos transferred without implantation; n = 32, 36 cycles), or both (AMA + RIF; n = 14, 19 cycles), before their intracytoplasmic sperm injection procedure. INTERVENTION(S): First polar-body analysis using fluorescence in situ hybridization. MAIN OUTCOME MEASURE(S): Mechanisms and frequency of aneuploidy. RESULT(S): Three hundred eighty-four oocytes were analyzed by fluorescence in situ hybridization, 130 from women >38 years of age, 171 from women with RIF, and 83 from women with both indications. The oocyte abnormality rate was similar in the three groups, respectively, 38.5%, 40.4%, and 45.8%. The aneuploidy mechanisms were different for women >38 years of age who had no previous implantation failure (AMA) compared with women of whatever age who had implantation failure (P<.05 vs. RIF; P<.001 vs. AMA+RIF), with, respectively, for the AMA, RIF, and AMA+RIF groups, 72.2%, 56.6%, and 49.2% premature separation of sister chromatids and 27.8%, 43.4%, and 50.8% meiotic nondisjunction. In the two implantation-failure groups, we distinguished a subgroup (22% in the RIF group and 33% in AMA+RIF group) of patients with >2/3 abnormal oocytes, suggesting a meiosis alteration. CONCLUSION(S): The mechanisms accounting for oocyte aneuploidy differed in the two clinical situations of advanced maternal age and RIF. Advanced maternal-age aneuploidy was linked to a loss of sister chromatid cohesion that led to one single chromatid abnormality, whereas implantation failure is a much more heterogeneous situation.

Evidence of a high proportion of premature unbalanced separation of sister chromatids in the first polar bodies of women of advanced age.

BACKGROUND: Maternal ageing is the only aetiological factor unequivocally linked to aneuploidy. Two mechanisms seem to explain these abnormalities in oocytes: non-disjunction and premature unbalanced separation of sister chromatids (PSSC). Previous studies of unfertilized oocytes argue for a major role of PSSC in the aetiology of aneuploidy for women of advanced age, but in vitro ageing of the oocytes could influence the results. METHODS: Owing to the high prevalence of aneuploidy in women of advanced age, chromosomal screening of the first polar body just before ICSI was offered to women (from 38 years of age) included in an assisted reproduction programme. RESULTS: Among 141 oocytes from 29 women (mean age 40 years and 2 months), 43 (30.5%) were abnormal. Sixty-five abnormalities were found and PSSC was involved in 80% of cases. CONCLUSION: These results are in accordance with previous studies and confirm, in 'fresh' oocytes, the major role of PSSC in the aetiology of aneuploidy in women of advanced age.

Fetal karyotyping after 28 weeks of gestation for late ultrasound findings in a low risk population.

OBJECTIVE: To analyze the indications and the results of invasive testing for fetal karyotyping for ultrasound abnormality in the third trimester of pregnancy, when first- and second-trimester screening tests were negative. METHODS: Retrospective study of 171 consecutive pregnancies that underwent invasive testing after 28 weeks of gestation in 2 institutions between January 1999 and December 2001. Forty-one patients did not have any form of screening for fetal aneuploidy beforehand. One hundred and thirty of them had a normal first-trimester scan and a low risk of fetal aneuploidy by nuchal translucency and/or maternal serum screening and were included in the statistical analysis. RESULTS: Mean maternal age, gestational age at diagnosis and at invasive testing were 30.5 years; 29.3 weeks and 32.5 weeks respectively. Amniocentesis and fetal blood sampling were performed in 97 and 33 cases respectively. The most frequent indications for invasive testing in the third trimester were major fetal malformations (51%) and intrauterine growth restriction (19%) detected on routine second- or third-trimester ultrasound examination. Ultrasound markers of aneuploidy and polyhydramnios accounted for 17 and 11% of the indications respectively. Fetal karyotype was normal in 121/130 cases. A gene mutation was found in one case. The karyotype was abnormal in nine cases, including seven cases of aneuploidy (one Turner syndrome, three trisomy 18, and three trisomy 21) and two cases of structural chromosomal abnormalities (46,XX, del 4 p16.1 and 46,XX, dup1). One hundred cases resulted in the delivery of a normal baby. Thirty cases led to termination of pregnancy or intrauterine death due to major fetal malformations (N = 25), abnormal karyotype in six of these, and severe IUGR (N = 5) with normal karyotype. Fetal US markers of aneuploidy and isolated polyhydramnios were associated with a favorable outcome in all cases.A significant increase in the risk of chromosomal anomaly was seen when two or more anomalies were found, rising from 2% with one anomaly to 21% when two or more anomalies were present. CONCLUSION: In low risk patients, fetal karyotyping in the third trimester may be justified when the diagnosis of fetal malformation is made in the third trimester of pregnancy. Two or more anomalies increase the risk of fetal aneuploidy even with a negative-screening test in the first and second trimester of pregnancy.