Maternal cell contamination in amniotic fluid samples as a consequence of the sampling technique

Maternal cell contamination in amniotic fluid samples is easily detected by in situ hybridization if the karyotype of the fetus differs from the karyotype of the mother. One out of two amniotic fluid samples appears to contain more than 20% maternal cells. Bloody samples often contain even more than 50% maternal cells. Maternal cells can also be identified on the basis of their nuclear morphology. Maternal cell contamination is regularly observed in pregnancies with an anterior placenta, whereas it is rare in posterior placenta pregnancies. The maternal cells are therefore thought to be artificially introduced into the amniotic fluid sample, as a result of placental bleeding during amniocentesis. The implications of maternal cell contamination for prenatal diagnosis using uncultured amniotic fluid samples are discussed.     

Prenatal fetal karyotyping and maternal serum alpha-fetoprotein screening.

Prenatal karyotyping was undertaken in 569 consecutive amniotic fluid samples where the indication for amniocentesis was two sequential raised maternal serum alpha-fetoprotein concentrations. In 475 successful cultures five chromosome abnormalities were found--four constitutional anomalies (47,XXY; 47,XYY; an inherited inv(8) (p23q11); and a de-novo translocation t(6;7) (p11;p22) and a culture-derived anomaly (trisomy 2) found in amniotic fluid cells but not in the fetus aborted because it had spina bifida. Of the pregnancies complicated by constitutional abnormalities, only the pregnancy in which the de-novo translocation was detected was terminated. No chromosome abnormalities were detected in the 17 pregnancies which miscarried after amniocentesis. These results provide little justification for including fetal karyotyping as an essential part of maternal serum alpha-fetoprotein screening programmes.     

Chorionic villi sampling: cytogenetic and clinical findings in 500 pregnancies.

The cytogenetic findings were analysed in a series of 500 pregnancies in which chorionic villi sampling was performed. In all cases a direct method was used, karyotyping being successful in 481 cases (96.2%). The main indication for sampling was maternal age over 36 (412 cases; 82.4%). Abnormal laboratory findings resulted in 24 terminations of pregnancy (4.8%); in addition five unexpected balanced chromosome rearrangements were detected. Twelve of 15 cytogenetic discrepancies were detected at amniocentesis, two after termination, and one at spontaneous abortion. Complete follow up data were available for the first 250 patients, among whom nine pregnancies (3.6%) ended in spontaneous abortion before the 20th week. There were no false negative findings. Seventy additional chromosome studies were performed because of failure of chorionic villi sampling or equivocal results, or for confirmation. Counselling before chorionic villi sampling should include the possibility that subsequent amniocentesis may be needed should mosaicism or other unexpected abnormalities be found. The success rate and accuracy of karyotyping chorionic villi samples by the direct method are acceptable but distinctly less than those of karyotyping cultured amniotic fluid cells.     

Influence of Amniotic Fluid Volume on Lecithin Estimation in Prediction of Respiratory Distress

One hundred samples of amniotic fluid were obtained by amniocentesis from 82 patients at different stages of normal and abnormal pregnancies. The concentration of lecithin was estimated together with the volume of the amniotic fluid, using the dilution technique. Thus the total quantity of lecithin in any amniotic sac could be calculated. While confirming the findings of others that concentrations of lecithin below 3·5 mg/100 ml in the liquor immediately before delivery suggested that the baby was likely to develop respiratory distress syndrome, we found that in borderline cases the total amount of lecithin in the sac was of greater prognostic significance than the lecithin concentration.     

Antenatal diagnosis of glutaric acidemia

Two pregnancies at risk for glutaric acidemia were monitored. In one, in which the fetus was not affected, glutaric acid was not detected in the amniotic fluid at amniocentesis (15 weeks) and the glutaryl-CoA dehydrogenase activity of cultured amniotic cells was normal. In the other, a marked elevation of glutaric acid in the amniotic fluid, together with deficiency of glutaryl-CoA dehydrogenase in amniotic cells, prompted termination of the pregnancy, and studies on the abortus confirmed the diagnosis of glutaric acidemia. Glutaric acidemia, is, thus, another inborn error of metabolism which can be diagnosed in utero.     

Contribution of amniocentesis to prenatal screening of neural tube closing defects: evaluation of 10 years of a center's experience

The authors report retrospective data on analysis of amniotic fluid DFTN markers (AFP and AChE) from 306 cases. Data were obtained from 261 amniocentesis done because there was a recurrence risk of DFTN and from 45 amniocentesis done because an anomaly as DFTN was diagnosed with ultrasonography. Results first show that the risk of recurrence is 3.03% in Rh?ne-Alpes area. In utero exposure to valproate appears as new indication for amniocentesis, in view of the possible association between Spina-Bifida and prenatal-valproate exposure (1/8 in the study). In contrast to anencephaly, Spina Bifida can be difficult to diagnose with ultrasonography before 20 weeks and require amniocentesis with AFP and AChE study.     

Antenatal diagnosis of neural tube defects in Canada: extension of a collaborative study.

Experience with the diagnosis of neural tube defects from alpha1-fetoprotein (AFP) concentrations in amniotic fluid is reported from a prospective study of five laboratories testing for 13 Canadian genetic centres. The results of the study indicate that antenatal diagnosis of open neural tube defects is being carried out effectively in Canada (in 99.2% of cases the AFP measurements were interpreted correctly). Amniocentesis should be recommended to women at high risk for having a child with a neural tube defect (i.e., those who have a child, a parent or a sibling with a neural tube defect). The rate of neural tube defects in 182 high-risk pregnancies was 2.2% for an open defect and 1.1% for a closed defect, whereas the rate in 673 pregnancies in which amniocentesis was being performed for other reasons was 0.3%. This suggests that the AFP concentration should be measured in any sample of amniotic fluid collected for other reasons (usually fetal karyotyping). There were three instances of false-negative results, for a rate of 0.4%. Two closed neural tube defects were not detected; this limitation of the test has also been found by others. One of the six fetuses with an open neural tube defect, who died in utero, had a large myelocele in the neck that was not recognized. There were also four instances of false-positive results, for a rate of 0.5%. The findings suggest that AFP values that are more than 2 but less than 7 standard deviations (SDs) above the mean may indicate a neural tube defect, and that values 7 or more SDs above the mean very likely indicate such a defect, although other reasons for such high values (e.g., fetal erythrocytes in the amniotic fluid, intrauterine death and mistaken gestational age) must be ruled out by other methods.     

Prenatal diagnosis of sex in bovine fetuses by amniocentesis

The sex of 1, 056 bovine fetuses was diagnosed by cytogenetic analysis of amniotic cells collected surgically from cows made pregnant as a result of embryo transfer. The fetuses ranged in gestational age from 7 to 22 wk at the time of amniocentesis. Amniotic cells were cultured for 5 to 30 d to obtain a sufficient number of cells for cytogenetic analysis. The growth rate of 819 samples was examined in detail. On average, amniotic cells from pregnancies that were 7 or 8 wks old required about 13 d to reach a cell concentration sufficient for analysis, whereas those from pregnancies that were 10 wk old or more required only 10 d or less to reach that concentration. Final disposition of 325 pregnancies subjected to amniocentesis was unequivocally confirmed. Of these, the sex of 302 fetuses (93%) was determined with a male: female ratio of 51:49. The gender of 213 of 220 fetuses (96.8%) was correctly dignosed, as verified by examination of either 33 intentionally induced abortuses or of 187 live calves. Thirteen percent (29) of 216 pregnancies that were allowed to proceed to term ended in spontaneous abortion, a rate only about 5% higher than that reported to occur normally in embryo transfer pregnancies. The remaining 53 pregnancies were induced to abort, but it was not possible to recover and verify the sex of those fetuses. The capability to diagnose fetal sex in utero yielded other useful information as well. For example, the sex ratio of 1,056 fetuses during development from 7 to 15+ wk of gestation was found to be the same (51:49) as it was at calving. Finally, amniocentesis to determine prenatal sex provides time to alter the sex ratio of a calf crop. It may ultimately prove valuable as an adjunct to genetic engineering of cattle to identify presumptive transgenic calves in utero.     

Amniotic Fluid Cells; Prenatal Sex Prediction and Culture

Sex chromatin studies were carried out on small amounts of amniotic fluid obtained by amniocentesis or from intact amniotic sacs removed at hysterotomy. Provided that satisfactory preparations were obtained the accuracy of fetal sexing was 87%. Nevertheless, in the management of a pregnancy in which there is a risk of a serious X-linked recessive disorder, repeat amniocentesis may be necessary to ensure satisfactory specimens.Of 90 samples of fluid cultured, satisfactory growth was obtained in 49; the success rate was not increased by the addition of stimulants to the culture medium. It is suggested that between the 13th and the 16th week of pregnancy is the optimum time for amniocentesis to obtain cells for culture, since sufficient cells are then present in a small volume of fluid and therapeutic abortion would still be possible once the results were available.     

High amniotic fluid alpha-1-fetoprotein in a case of fetal sacrococcygeal teratoma.

Amniocentesis was performed in a pregnancy of 26 weeks because of hydramnios. The amniotic fluid was examined for fetal karyotype and AFP content. The latter was elevated to 300 mug/ml. Fetal death occurred shortly after amniocentesis and a malformed male fetus with a large sacrococcygeal teratoma was stillborn 3 days later.     

Birth weight and non-insulin dependent diabetes: thrifty genotype,thrifty phenotype,or surviving small baby genotype?

OBJECTIVE--To determine the prevalence of diabetes in relation to birth weight in Pima Indians. DESIGN--Follow up study of infants born during 1940-72 who had undergone a glucose tolerance test at ages 20-39 years. SETTING--Gila River Indian community, Arizona. SUBJECTS--1179 American Indians. MAIN OUTCOME MEASURE--Prevalence of non-insulin dependent diabetes mellitus (plasma glucose concentration > or = 11.1 mmol/l two hours after ingestion of carbohydrate). RESULTS--The prevalence was greatest in those with the lowest and highest birth weights. The age adjusted prevalences for birth weights < 2500 g, 2500-4499 g, and > or = 4500 g were 30%, 17%, and 32%, respectively. When age, sex, body mass index, maternal diabetes during pregnancy, and birth year were controlled for, subjects with birth weights < 2500 g had a higher rate than those with weights 2500-4499 g (odds ratio 3.81; 95% confidence interval 1.70 to 8.52). The risk for subsequent diabetes among higher birthweight infants (> or = 4500 g) was associated with maternal diabetes during pregnancy. Most diabetes, however, occurred in subjects with intermediate birth weights (2500-4500 g). CONCLUSIONS--The relation of the prevalence of diabetes to birth weight in the Pima Indians is U shaped and is related to parental diabetes. Low birth weight is associated with non-insulin dependent diabetes. Given the high mortality of low birthweight infants selective survival in infancy of those genetically predisposed to insulin resistance and diabetes provides an explanation for the observed relation between low birth weight and diabetes and the high prevalence of diabetes in many populations.     

The detection of neural tube closure defects by exfoliative cytology of amniotic fluid

Cytospin preparations of amniotic fluid samples from 200 pregnancies, taken between 16 and 20 weeks' gestation, were examined without knowledge of the fluid alpha-fetoprotein (AFP) level. The specimens were taken because of the possibility of neural tube closure defect. All but eight cases showed predominantly squamous cells, amnion cells, macrophages and blood cells. AFP levels in these fluids were within the normal range in 178 cases, unequivocal in 11, undetectable in 2 and raised in 1; none of the babies in these cases had a neural tube closure defect. In eight cases a large population of small cells with dark nuclei and a population of large, foamy macrophages were present in addition to the other cell types; all of these babies had a neural tube closure defect (five anencephaly and three anencephaly with spina bifida). This technique may provide a useful additional method of diagnosis of neural tube closure defects.     

Outcome of pregnancy after amniocentesis for chromosome analysis.

A consecutive series of 1177 pregnant women examined by amniocentesis for chromosomal abnormalities delivered 1039 live-born babies weighing over 2500 g and 79 live-born babies weighing under 2500 g. Twenty-six abortions were induced (2.2%)--13 (1.1%) because of chromosomal abnormalities--and 28 women (2.4%) aborted spontaneously; in these cases chromosomes were normal. Analysis of all spontaneous abortions in the series suggested that 0.3-0.7% might have resulted from amniocentesis.     

Recurrent nonimmune hydrops fetalis: a rare presentation of sialic acid storage disease.

A case of recurrent hydrops fetalis, diagnosed on second trimester's ultrasonography, has led to the diagnosis of sialic acid storage disease. No classic etiology was found after the first accident. The recurrence in subsequent pregnancy raised the possibility of a storage disease that was confirmed by amniocentesis. The diagnosis of Salla's disease was based on high levels of free sialic acid in amniotic fluid and fetal cells culture and by specific histologic features on fetopathologic examination. Diagnosis of inherited diseases is important because it implies a high risk of recurrence which makes mandatory genetic counseling and prenatal care in subsequent pregnancies.     

过期妊娠并发羊水过少70例分析

目的 探讨过期妊娠合并羊水对围产儿的影响。方法 将２３３例过期妊娠的孕妇分为羊水过少组７０例及不适量组１５３例,动态观察两 组４０￣４３孕周１２ｈ尿Ｅ／Ｃ值、Ｂ超检测羊水量,产后胎盘检查,胎儿宫内窘迫,新生儿窒息剖宫产及围产儿死亡发生率,两组进行分析比较。结果 不过少组４０￣４１孕周即开始出现不量减少及胎盘功能下降,产时胎儿窘迫,羊水杂,Ａｐｇａｒ评分以及剖宫产率均地羊水适量组（Ｐ〈０．０５,Ｐ〈     

Characteristics of Human Amniotic Fluid Mesenchymal Stem Cells and Their Tropism to Human Ovarian Cancer

The mesenchymal stem cells (MSCs) derived from amniotic fluid (AF) have become an attractive stem cells source for cell-based therapy because they can be harvested at low cost and avoid ethical disputes. In human research, stem cells derived from AF gradually became a hot research direction for disease treatment, specifically for their plasticity, their reduced immunogenicity and their tumor tropism regardless of the tumor size, location and source. Our work aimed to obtain and characterize human amniotic fluid mesenchymal stem cells (AFMSCs) and detect their ovarian cancer tropsim in nude mice model. Ten milliliters of twenty independent amniotic fluid samples were collected from 16-20 week pregnant women who underwent amniocentesis for fetal genetic determination in routine prenatal diagnosis in the first affiliated hospital of Harbin medical university. We successfully isolated the AFMSCs from thirteen of twenty amniotic fluid samples. AFMSCs presented a fibroblastic-like morphology during the culture. Flow cytometry analyses showed that the cells were positive for specific stem cell markers CD73,CD90, CD105, CD166 and HLA-ABC (MHC class I), but negative for CD 45,CD40, CD34, CD14 and HLA-DR (MHC class II). RT-PCR results showed that the AFMSCs expressed stem cell marker OCT4. AFMSCs could differentiate into bone cells, fat cells and chondrocytes under certain conditions. AFMSCs had the high motility to migrate to ovarian cancer site but didn’t have the tumorigenicity. This study enhances the possibility of AFMSCs as drug carrier in human cell-based therapy. Meanwhile, the research emphasis in the future can also put in targeting therapy of ovarian cancer.     

Familial Down's syndrome.

A family is reported in which the same mother conceived two children with trisomy 21. The pregnancy with the second affected child was interrupted after diagnostic amniocentesis. Maternal chromosome analysis was normal. This family and those previously reported suggest that there is an increased recurrence risk of trisomy 21 after the birth of an affected individual, possibly caused by a genetic tendency for non-disjunction. After the birth of a child with Down's syndrome, amniocentesis and chromosome analysis of cultured amniotic fluid cells is indicated in each further pregnancy, irrespective of maternal age.     

Epidemiology of spontaneous premature rupture of membranes: factors in pre-term births

The frequency of spontaneous premature rupture of membranes (PROM) was determined in the pregnancies of 1,848 white mothers and their singleton infants, born at the University of Kansas Medical Center between April 1975 and April 1978. The frequency of PROM increased significantly from a low of 34/707 (4.8 percent) among low-risk mothers, to 40/444 (9.0 percent) among mothers smoking one to 60 cigarettes a day, to 21/204 (10.3 percent) among mothers with multiple adverse maternal practices, and to 12/46 (26 percent) among mothers with selected complications of their pregnancies. The proportion of low birth weight (LBW) (less than 2,500 g) pre-term infants born to PROM mothers increased among the risk factor groups in a similar manner, from a low of 2/34 (6 percent) in low-risk pregnancies to 8/40 (20 percent) among mothers smoking one to 60 cigarettes a day, to 7/21 (33 percent) among mothers with multiple adverse practices, and to 7/12 (58 percent) among mothers with selected complications of pregnancy. The increased incidence of low birth weight pre-term infants born to mothers with PROM was associated with evidence of growth retardation among full-term infants in the high-risk groups. This finding was manifested by reductions in mean birth weights of full-term infants born to high-risk mothers but not observed in full-term infants born to low-risk mothers. The attained growth at birth of low birth weight pre-term infants could not be determined, because appropriate birth weight standards for pre-term infants born to mothers with low-risk pregnancies are not available. These results suggest that growth retardation in fetuses increased the probability of the mothers having PROM prior to the onset of labor, and, if PROM did occur, of having a premature delivery. We hypothesize that the tensile strength of the amnion and chorion is diminished by the same conditions that retard fetal growth, and that this reduction in strength of the fetal membranes contributes to premature rupture of membranes and pre-term delivery.     

Garlic Ingestion by Pregnant Women Alters the Odor of Amniotic Fluid

Amniotic fluid samples were obtained from 10 pregnant womenundergoing routine amniocentesis procedure. Approximately 45min prior to the procedure, five of the women ingested placebocapsules, whereas the remaining five ingested capsules containingthe essential oil of garlic. Randomly selected pairs of samples,one from a woman who ingested garlic and the other from a womanwho ingested placebo capsules, were then evaluated by a sensorypanel of adults. The odor of the amniotic fluid obtained fromfour of the five women who had ingested the garlic capsuleswas judged to be stronger or more like garlic than the pairedsamples collected from the women consuming placebo capsules.Thus, garlic ingestion by pregnant women significantly altersthe odor of their amniotic fluid.     

Biochemical markers of neural tube closure defects during the second half of pregnancy

Increasing number of amniocentesis done during the second half of gestation with indication "signe d'appel" made necessary for authors to study amniotic fluid markers in late pregnancy. Normal evolution curve must be established with samples obtained after 20 weeks gestation. Study reveals more false-negative results with AFP than before 20 weeks. AChE remains constantly positive in cases with NTD, band aspect being specific. For other malformations, AChE positivity seems inconstant, with a different aspect. Some normal gestation cases can be associated with faint AChE band.