Pregnancy: The roles of oligomenorrhoea and fetal chromosomal abnormalities in spontaneous abortions

The pathogenesis of spontaneous abortions, other than fetalchromosomal abnormalities, is not fully understood. We examinedthe incidence of oligomenorrhoea in relation to fetal chromosomalanalyses and ultrasonographic examination in women who abortedspontaneously. The data demonstrated that the incidence of oligomenorrhoeawas higher in women with normal fetal karyotyped abortions,especially normal karyotyped anembryonic pregnancies, than inthose with abnormal karyotyped abortions (34.0 versus 12.5%,<italic>P</italic> <0.01). Furthermore, the incidenceof oligomenorrhoea was inversely correlated with fetal sizeexclusively in abortions with normal fetal karyotypes. It issuggested that oligomenorrhoea, i.e. delayed ovulation, itselfmay be closely associated with sporadic spontaneous abortion.     

Fetal loss in the first trimester after demonstration of cardiac activity: relation of cytogenetic and ultrasound findings

A retrospective comparison of cytogenetic and ultrasound findingsin first trimester spontaneous fetal loss after demonstrationof cardiac activity was made. The crownrump length (CRL) wasmeasured twice for each fetus resulting in spontaneous abortion:(i) CRL was measured in the viable state while demonstratingcardiac activity, and the growth deviation was expressed asthe measured/ expected CRL ratio (M/E CRL ratio); (ii) in thesame fetus, CRL was measured after confirmation of fetal death,and designated as the post-mortem CRL. The chorionic tissuesof these abortuses were karyotyped. The CRL of fetuses whichresulted in normal deliveries were also measured as controls.As a result, 16 of 24 abortuses displayed an abnormal chromosomalanalysis (67%). Themean M/E CRL ratio of still-viable fetuseswas smaller than that of control fetuses (0.74 ± 0.20versus 0.98 ± 0.13 respectively, P < 0.01). The differencesin ratio between karyotypically normal and abnormal abortuseswere not statistically significant. The post-mortem CRL of deadfetuses was >20 mm in four of five monosomy X, two of three21-trisomy, one of three triploidy and none of eight embryoswith normal karyotype and five other trisomies. In conclusion,our study demonstrated that the M/E CRL ratio could be usedas a predictor of spontaneous abortions, although it does notdiscriminate abnormal karyotypes from normal ones. The embryoswith a post-mortem CRL more than 20 mm have a higher likelihoodof suffering monosomy X or 21-trisomy. The ultrasonographicfindings might offer a cytogenetic clue as to a possible causeto the developmental arrest.     

Telomerase activity in gestational trophoblastic disease and placental tissue from early and late human pregnancies

BACKGROUND: The aim of this study was to evaluate telomerase activity in tissue from cases of gestational trophoblastic disease (GTD) and in placental tissue from early and late human pregnancies. METHODS: We used a telomeric repeat amplification protocol assay to measure telomerase activity in 132 tissue samples from normal early pregnancies, spontaneous abortions, normal late pregnancies, cases of late-pregnancy intrauterine fetal death, and GTD. RESULTS: Telomerase activity was detected more often in normal early pregnancies and cases of GTD than in spontaneous abortions and normal late pregnancies (P < 0.001). During early gestation, no significant difference in detection rates was found between normal pregnancies and complete hydatidiform mole. As gestational age increased, detection rates for normal pregnancies decreased significantly (P = 0.0001), while for complete hydatidiform mole no significant changes occurred. CONCLUSIONS: Our findings indicate that placental tissue from normal early pregnancies and neoplastic tissue from GTD possess similar levels of telomerase activity. Decreasing regulation of telomerase activity is present in normal pregnancies but not in complete hydatidiform mole. The fact that telomerase activity decreases in cases of fetal demise, and as pregnancy progresses, also suggests that placental senescence may play a role in the development and ageing of the placenta.     

The relationship of initial embryo crown-rump length to pregnancy outcome and abortus karyotype based on new growth curves for the 2-31 mm embryo

The objective of this study was to determine if measurementof initial crown-rump length (CRL) is helpful in predictinglow birth weight, newborn length, spontaneous abortions, orabortus karyotype. We measured CRL prospectively in 837 consecutivesingleton pregnancies at the time a heart rate was first detectablewith transvaginal ultrasonography and compared these measurementsto normal values for the 10th through 90th centiles determinedfrom 227 transvaginal ultrasound measurements in in-vitro fertilizationand gamete intra-Fallopian transfer pregnancies with known ovulationdates. The relationship of initial CRL to birth weight and lengthand to abortion and abortus karyotype was analysed after allpregnancies had delivered. Initial CRL measured after the 28thpost-ovulation day was predictive of subsequent abortion, butnot of low birth weight or length. The abortion rate was 3.3%[95% confidence interval (CI) 1.5%, 5.1%] when initial CRL50thcentile, compared to 19.4% (95% CI 15.4%, 23.4%) when <50thcentile. Initial CRL was <50th centile in 13 out of 14 trisomicand in eight out of 10 other karyotypically abnormal aborti.These results indicate that initial CRL measured after the 28thpost-ovulation day may help to identify pregnancies at increasedrisk of abortion due to abnormal karyotypes.     

Materno-fetal ABO incompatibility as a cause of spontaneous abortion

In a series of 288 spontaneous abortions occurring during the first 16 weeks of gestation, simultaneous karyotyping and ABO blood grouping of 555 of the parents were carried out. In 74 of the 288 chromosome-analyzed abortuses, the ABO blood group of the fetus was determined by the immuno-fluorescence technique and the mixed cell agglutinating reaction in fetal tissue. The results of the blood grouping were compared with the ABO blood group frequencies of 8818 blood donors from the same area.
Among abortuses with normal karyotype, a significantly higher frequency of ABO incompatibility was found between mother and fetus ( P < 0.005) and also between mother and father (P < 0.01) in comparison with abortuses with abnormal karyotype. Furthermore, the ABO blood group frequencies of the karyotypically normal fetuses deviated significantly from those of fetuses with abnormal karyotypes ( P < 0.001). No significant difference was found when the total ABO frequencies of the abortuses and of their parents were compared with the frequencies in the control group.
It is concluded that the ABO incompatibility between mother and fetus is likely to be a cause of early spontaneous abortions, but almost exclusively in chromosomally normal abortuses. In the present series of cases, the maximum fraction of abortions caused by materno-fetal ABO incompatibility is estimated to be 18 %.     

徐州地区57对复发性流产夫妇的染色体核型分析

目的探讨复发性自然流产与外周血染色体异常核型之间的关系。方法采用外周血淋巴细胞培养,常规G显带技术行染色体核型检查,后结合临床资料对其进行分析。结果57对复发性自然流产夫妇中,检出异常染色体核型20例,检出率17.54%。结论染色体核型异常是导致复发性自然流产的重要原因之一,对复发性流产患者进行染色体检查及遗传咨询具有一定的临床意义。     

The "vanishing embryo" phenomenon in an oocyte donation programme

BACKGROUND: We studied the incidence of vanishing embryos (VE) in pregnancies achieved by oocyte donation and evaluated the obstetric and perinatal complications. METHOD: A retrospective study was carried out based on a chart review of 399 patients with multiple pregnancies from our oocyte donation programme. We defined vanishing phenomenon as the early resorption, in the first trimester, of one or more embryos in a multiple gestation, after confirming embryonic heart activity by transvaginal ultrasound. RESULTS: Vanishing embryo was observed in 75 patients (18.8%). In 60 patients (80%) this phenomenon occurred before the ninth gestational week. A higher incidence of VE was observed in patients who initially showed a higher number of gestational sacs (P < 0.03). Vaginal bleeding in the first trimester was significantly higher in patients with VE (P < 0.005). Miscarriage rate was similar in pregnancies with and without VE (P = NS). The incidence of pregnancy induced hypertension was decreased in the group with VE (P < 0.03). Preterm spontaneous rupture of membranes occurred more frequently in pregnancies with VE (P < 0.05). However, gestational age at delivery was similar in the group with VE and the controls. CONCLUSIONS: The high incidence of VE in pregnancies achieved by oocyte donation should be considered when counselling patients with high order multiple gestations.     

Survival rates during the first trimester of multiple gestations achieved by ICSI: a report of 1448 consecutive multiples

BACKGROUND: The purpose of this study was to determine the rate of spontaneous gestational sac loss during the first trimester in women achieving multiple pregnancies by ICSI. METHODS: A retrospective analysis was performed of 1448 consecutive multiple pregnancies conceived by ICSI. RESULTS: Of the cohort of 1448 pregnancies, twin gestations constituted 59.6% (864), triplets 30.2% (438) and quadruplets 10.0% (146). During the first trimester, 69 (4.7%) patients miscarried, while 179 (12.3%) continued their pregnancies and had fewer gestational sacs at the end of the first trimester than at the beginning. The overall loss rate of any gestational sac during the first trimester in these multiple pregnancies was 10.1%. There was a significant difference in the frequency of spontaneous reduction to twin or singleton pregnancies in the first trimester between women carrying triplets (11.7%) and those carrying quadruplets (3.5%) [P = 0.004; odds ratio (OR) 3.5; 95% confidence interval (CI) 1.3-9.1]. The frequency of gestational sac loss was significantly greater among women >35 years old (20.9%) than in women less than 35 years old (15.9%) (P = 0.03; OR 1.4; 95% CI 1.0-1.9). CONCLUSION: In multiple pregnancies there is a significant risk of spontaneous loss of any embryo during the first trimester. These findings should be considered prior to any decision about selective embryo reduction.     

Development of the secondary human yolk sac: correlation of sonographic and anatomical features.

Transvaginal ultrasound examination of the secondary yolk sac was performed in 145 first trimester pregnancies with a normal outcome (Group A), in 10 normal pregnancies undergoing artificial termination (Group B) and in 25 pregnancies that subsequently failed (Group C) due to embryonic death (n = 17) or to spontaneous abortion of a live embryo (n = 8). The yolk sac structure of all cases from Group B and from 12 cases of Group C were examined morphologically, in order to investigate the changes secondary to normal yolk sac senescence or to pregnancy complication and to evaluate the relationship existing between these changes and ultrasound features. The yolk sac diameter measured in vivo increased significantly between 6 and 10 weeks of gestation and then decreased significantly. Morphologically, the yolk sac showed degenerative changes after 9 weeks of gestation suggesting that the disappearance of the yolk sac in normal pregnancies was a spontaneous event of embryonic development rather than the result of mechanical compression by the expanding amniotic cavity. Yolk sac measurements in complicated pregnancies were not predictive of pregnancy outcome. Irrespective of gestational age, important degenerative changes were found in pregnancies complicated by embryonic death or disappearance, suggesting that variation of yolk sac size and appearance in these cases is the consequence of abnormal embryonic development of death rather than being the primary cause of early pregnancy failure.     

Teratogenic IgG From Sera of Women With Spontaneous Abortions Seem to Induce Anomalies and Yolk Sac Damage in Rat Embryos. A Possible Method to Detect Abortions of Immunologic Origin

PROBLEM: Spontaneous abortions due to immunological rejection of the embryo may be avoided by immunotherapy with paternal allogeneic leukocytes but there is no appropriate method to detect and differentiate this group of aborters from other groups. METHODS: In previous studies we have demonstrated that in about two-thirds of sera from women with spontaneous abortions the IgG antibodies are responsible (alone or in combination with other factors) for the embryotoxic effects of these sera on cultured rat embryos. We presently cultured 10.5-day-old rat embryos on highly teratogenic serum (“high risk” serum that induced anomalies in more than 50% of the embryos) from women with spontaneous abortions, where the IgG fraction was exchanged with IgG from control sera and vice-versa. We studied by Transmission Electron Microscopy (TEM) the extent of yolk sac damage in comparison to the rate of embryonic anomalies. RESULTS: In cases where IgG antibodies were teratogenic, embryos cultured in control sera with IgG from “high risk” sera exhibited ultrastructural yolk sac damage as well as embryonic anomalies, and the yolk sacs cultured in “high risk” sera with control IgG were normal. In cases in which the IgG exchange did not change the rate of anomalies, as IgG was not teratogenic, yolk sacs from embryos cultured in “high risk” sera remained damaged, while yolk sacs from embryos cultured in control sera after IgG exchange stayed normal. Although no significant difference in total IgG levels was found between the groups, a higher IgG1 level in sera from women with teratogenic IgG was observed in comparison to control women's sera. The obstetrical history of the women with two or more abortions who took part in our study showed that there were more cases of unknown etiology of the abortion in the women from the “high risk” group. CONCLUSIONS: The serum and the IgG fraction from women with habitual abortions can be tested in whole embryo culture to evaluate the embryonic and yolk sac damage. On this basis it may be possible to detect the women in whom the habitual abortions result from immunological rejection.     

Early pregnancy loss, premature and low birth weight delivery, and increased maternal lymphocyte cytotoxicity

Lymphocytes of 628 pregnant women were tested for natural cytotoxic activity to human embryonic fibroblast cells. The data were analyzed with regard to previous obstetric history, symptoms occurring during the present gestation, and the outcome of pregnancy. The normal rate of cytotoxicity during pregnancy was established by determining cytotoxic activity of the lymphocytes from 56 healthy pregnant women. The values higher than the mean + 2 SD of the "normal" (greater than or equal to 40%) were considered as high. Increased cytotoxicity was associated with the occurrence of previous spontaneous and missed abortions, as well as with bleeding and uterine contractions during the present pregnancy observed at the time of the test. In 15 out of 35 cases resulting in spontaneous abortion and 15 out of the 34 pregnancies resulting in missed abortion, cytotoxic activity of the lymphocytes during pregnancy was higher than normal. Similarly, in 38 and 32.7% of the pregnancies resulting in preterm (n = 121) or low birth-weight deliveries (n = 101) respectively, we found increased lymphocyte cytotoxicity, in contrast to that being found in 5.4% of uncomplicated normal pregnancies. These data suggest that at least some pregnancy failures might be immunologically mediated.     

Systemic CD56+ Cells Can Predict Pregnancy Outcome

PROBLEM: To evaluate differences in circulating CD56+ cells between successful and unsuccessful pregnancies, 114 pregnant women were studied prospectively. METHOD: Seventy women had a history of infertility (INF) and 44 had two or more previous spontaneous abortions (RSA). Among the infertile women, 12 were donor egg recipients (DER) and 15 underwent intracytoplasmic sperm injection (ICSI) for treatment of male factor infertility. Nineteen women were carrying multiple gestations (MG) and 55 had singleton gestations (SG). Thirteen additional women were receiving intravenous immunoglobulin (IVIg). RESULTS: The percentage of CD56+ cells was determined in 310 blood samples from 114 pregnant women by flow cytometry. The prevalence of women with persistent elevation of percent of 56+ cells (>12%) was 58% among DER, 73% among ICSI, 37% among MG, 22% among SG, 18% among RSA, and 39% among INF. Thirteen women with SG received IVIG, 10 had CD56+ cells greater than 12% and all 13 experienced live births. Women with percentage CD56+ cells persistently greater than 12% who were not DER, not ICSI, not receiving IVIg, and not carrying MG had a live birth rate of 11%. Women with greater than 12% CD56+ cells had normal karyotype in 78% of concepti studied in contrast to women less than 12% CD56+ cells who had 68% abnormal karyotypes (P=0.04). CONCLUSION: Elevated CD56+ cells in pregnant women who are not DER, not ICSI, not receiving IVIg, and not carrying MG predicts loss of a karyotypically normal conceptus with a specificity of 87% and positive predictive value of 78%. While the specificity value of this test is high in both infertile and RSA populations, the sensitivity is 86% in RSA and only 54% in INF suggesting this test does not identify all losses among INF. It may identify a subset of pregnancies at risk for loss of a karyotypically normal embryo that may respond to treatment with IVIg.     

Congenital malformations of the central nervous system in spontaneous abortions.

A study of 2620 pregnancies ending in spontaneous abortion revealed a CNS defect in 3.6% of embryos and fetuses, and 3% of all complete conceptuses. The type of malformation observed varied with the gestational age at expulsion, encephaloceles being predominant in earlier specimens, while more typical anencephalus and spina bifida were more common among later abortions. Chromosome abnormalities were found in 40% of abortuses with CNS defects, but were almost entirely confined to those which were still at the embryonic stage of development. 53% of the latter were chromosomally abnormal, which is the same as the proportion found among embryos without a CNS malformation. Using published life-tables of recognized pregnancies it was estimated that the prevalence of anencephalus, spina bifida, or related malformation (other than hydrocephalus), without a chromosome anomaly, is 5.3 per thousand conceptuses at the beginning of the eighth week of gestation. By comparing this with the prevalence in total births, it was further estimated that only 24% of these are born alive, with 54% aborting spontaneously and 22% being stillborn.     

Relationship of initial chorionic sac diameter to abortion and abortus karyotype based on new growth curves for the 16th to 49th post-ovulation day

In order to determine whether initial chorionic sac diameteris related to subsequent abortion, abortus karyotype, or birthweight and length, chorionic sac diameter was prospectivelymeasured by transvaginal ultrasound in 700 singleton pregnanciesbefore post-ovulation day 31, the latest day cardiac activitybecomes detectable in normal pregnancy. Results were comparedto values for the 10th to the 90th centiles, determined from227 measurements of in-vitro fertilization and gamete intra-Fallopiantransfer pregnancies. The abortion rate was 23.9% [95% confidenceinterval (CI) 19.2%, 28.6%] when initial chorionic sac diameterwas below the 50th centile, compared to 6.9% (95% CI 4.9%, 9.4%)when equal to or above the 50th centile. Chorionic sac diameterwas below the 50th centile in all anembryonic abortions andin 62% of embryonic abortions. Triploidy, trisomy 47 + 16, ortrisomy 16 and the presence of satellite bodies on chromosome22 were the only abortus karyotypes significantly associatedwith small chorionic sac diameter. Initial chorionic sac diameterwas not associated with birth weight or length. We concludethat chorionic sac diameter is decreased in anembryonic andembryonic abortion and that normal pregnancy outcome may beexpected in 90–95% of pregnancies in which initial chorionicsac diameter is equal to or above average     

The Effects of Sera From Women With Spontaneous Abortions on the In Vitro Development of Early Somite Stage Rat Embryos

PROBLEM: Spontaneous abortions occur in 40 to 50% of pregnancies, but the causes for some abortions, especially those that are recurrent (spontaneous), are still unknown. METHOD: Following previous studies that demonstrated embryotoxic effects of sera from women with spontaneous abortions in preimplantation mouse embryos, we cultured 10.5-day-old rat embryos in sera from women after spontaneous abortions to look for specific teratogenic effects. RESULTS: About 50% of the embryos cultured in sera from women after spontaneous abortions were malformed, as compared to 19.1 and 27.1% malformations in embryos cultured in sera from women after a normal delivery and during a normal second trimester of pregnancy, respectively. We divided the sera from women who had spontaneous abortions into high-risk, and low-risk sera. In the high-risk sera from one abortion, we found 74.2% malformed embryos and in the high-risk group from two or more abortions this rate was 81.0%. This is compared to a rate of 17.1 and 10.3% in the low-risk sera, respectively. We have also found lower DNA and protein synthesis in the embryos cultured in high-risk sera compared to those cultured in low-risk and control sera. Transmission electron microscopy examination of yolk sacs cultured in high risk sera showed ultrastructural damage as represented by a lower number of microvilli and a higher number of inclusions in the entodermal cells when compared to controls. Amino acid chromatography of the serum and the concentrations of folic acid and zinc were similar in control and high-risk sera. CONCLUSION: It seems that the majority of sera from women with unexplained spontaneous abortions are teratogenic to rat embryos in culture. In about two-thirds of these sera the teratogenic factor(s) seem to be present in the IgG fraction.     

Random urinary pregnanediol glucuronide measurements in pregnancy: lack of utility for evaluation of first-trimester vaginal bleeding

Progesterone and its urinary metabolite pregnanediol-3 alpha-glucuronide (PDG) are generally lower in women with abnormal pregnancies compared to those with normal intrauterine gestations. We evaluated the ability of random urinary PDG measurements determined by enzyme immunoassay (EIA) to differentiate normal from abnormal pregnancies. Patients with first-trimester vaginal bleeding (n = 104) were evaluated. Eventual outcomes indicated 39 women had viable intrauterine pregnancies (IUPs), 54 had spontaneous abortions (SABs) and 11 had ectopic pregnancies (EPs). Urinary PDG was significantly lower in SAB and EP compared to IUP patients. However, a wide range of values in IUP patients was noted (3.2-93.3 micrograms/ml), due to varying degrees of patient hydration at presentation. Hence, random measures of urinary PDG demonstrated poor specificity (32.8%) in correctly differentiating normal from abnormal gestations, thus limiting its clinical usefulness.     

Familial occurrence of chromosome 7/12 translocation

A new balanced autosomal translocation, t(7;12) (p12;p13), was found in a high genetic risk family in which the mother is a translocation carrier. She had 12 pregnancies, six of which were terminated during the first trimester by spontaneous abortions. Among the six live births, three children inherited the translocation from their mother and were phenotypically normal. The father and three other children had normal karyotypes.     

Cytogenetic study of spontaneous abortions using semi-direct analysis of chorionic villi samples detects the broadest spectrum of chromosome abnormalities

Conventional tissue culturing and karyotyping of spontaneous abortions has limitations such as culture failure, external contamination and selective growth of maternal cells. Molecular cytogenetic techniques such as FISH, QF-PCR, and CGH allow diagnosis on uncultured cells but are also limited as to the spectrum of cytogenetic abnormalities detected. We describe the cytogenetic findings in a series of 116 first trimester arrested pregnancies, obtained through chorionic villi sampling (CVS) and semi-direct analysis that avoids some of the long-culture pitfalls such as maternal contamination, and compare our results with those that would have been obtained theoretically using molecular cytogenetic techniques. Samples were obtained by transcervical CVS from women with a diagnosis of missed abortion, most of them referred for cytogenetic prenatal diagnosis. Cytogenetic analysis was performed using semi-direct technique. A karyotype was obtained in 103 cases. Eighty-two abnormal karyotypes were found (80%), including 12 triploidies, 10 monosomies, 61 trisomies, and 9 structural abnormalities; a double abnormality being present in 10 cases. Between 10% and 50% of our abnormal results would have been missed using the most common molecular cytogenetic techniques. Semi-direct analysis of CVS may still be considered as a comprehensive, reasonably rapid, cost-effective and reliable method for detecting the broadest spectrum of chromosome abnormalities in missed abortions.     

Predictable ultrasonographic findings of early abortion.

Early fetal growth delay and early oligohydramnios have been suspected as signs of embryonal jeopardy. However, little information is available for the prediction of early abortion. Sonographic examination of 111 early pregnancies between the sixth and ninth gestational week with regular, 28 day menstrual cycles was performed to investigate predictable sonographic findings of early abortion. Sonographic measurements of the gestational sac (G-SAC), crown-rump length (CRL) and fetal heart rate (FHR) were performed using a linear array real time transducer with Doppler. All measurements of 17 early abortions were compared to those of 94 normal pregnancies to investigate the objective rules for the screening of early abortion. Most of the early aborted pregnancies were classified correctly by discriminant analysis with G-SAC and CRL (G-SAC = 0.5222 CRL + 14.6673 = 0.5 CRL + 15, sensitivity 76.5% specificity 96.8%). With the addition of FHR, 94.1% of early abortions could be predicted. In conclusion, sonographic findings of early intrauterine growth retardation, early oligohydromnios and bradycardia can be predictable signs for the poor prognosis of early pregnancies.     

Sex ratio and absence of uniparental disomy in spontaneous abortions with a normal karyotype

A series of spontaneous abortions collected in the South Wales region over a period of 18 months was karyotyped to identify those with a normal chromosome complement. Microsatellite polymorphisms distributed throughout all autosomes were typed by the polymerase chain reaction to determine the parental origin of each autosome pair in karyotypically normal spontaneous abortions. In 35 cases biparental inheritance of every autosome pair was demonstrated. The sex ratio of the normal spontaneous abortions of proven biparental origin was 0.77, but this was not significantly different from 1.00.