Showing papers on "Amniocentesis published in 1976"

Studies on Human Sexual Development. III. Fetal Pituitary and Serum, and Amniotic Fluid Concentrations of LH, CG, and FSH

Abstract: Fetal sera (9-20 weeks fetal age, n = 80) and pituitary glands (9.5-20 weeks, n = 36) obtained from hysterotomy specimens, and amniotic fluids (amniocentesis; 8-40 weeks, n = 123) were assayed for FSH, LH (βLH assay) and CG (βCG assay). Results are expressed as mass of pure hormone. Prior to 12 weeks fetal age, pituitary, serum and amniotic fluid concentrations of LH and FSH were low or unmeasurable. In contrast, levels of CG in serum and in amniotic fluid were clearly measurable prior to 12 weeks. There was a definite CG peak at 11-14 weeks with levels up to 550 ng/ml in serum and 7400 ng/ml in amniotic fluid. Although LH levels began to rise at 12 weeks, when CG levels started to decline, serum levels of LH from 14-20 weeks in males (2-13 ng/ml) were still lower than the majority of CG levels at this time (6-115 ng/ml). These observations suggest that CG is the primary stimulus to the fetal Leydig cell which results in testosterone secretion (peak 11-17 weeks) and masculine differentiation of the genital tract. Significantly lower concentrations of both FSH and LH were observed in pituitary, serum and amniotic fluid between 12-20 weeks fetal age in males compared to females. This may be a result of feedback inhibition by the higher concentrations of testosterone in males at this time. Amniotic fluid FSH and LH concentrations correlated with their respective serum and pituitary values (P less than 0.01) indicating that amniotic fluid may provide a convenient index of fetal serum concentrations.

Prenatal diagnosis of genetic disease in Canada: report of a collaborative study

Abstract: A study of 1223 amniocenteses carried out during 1020 pregnancies in 990 women showed that 2nd-trimester amniocentesis at about 16 weeks' gestation is a safe, accurate and reliable procedure for the diagnosis of certain classes of genetic disease when it is monitored by ultrasound, performed by a trained obstetrician and carried out in a major health sciences centre. The percentage of fetal losses (4.7%) and neonatal deaths (0.5%) during the study was not greater than in control samples for women 35 years of age and older. The best results were obtained when needles of gauge 20 or 21 were used. The use of needles of gauge 19 or larger and more than two insertions during a single amniocentesis were associated with a significantly greater frequency of fetal loss than a second or even a third amniocentesis during the same pregnancy. For 39 fetuses (3.8%) a diagnosis of a genetic abnormality was made and 23 male fetuses were found to be potentially hemizygous for an X-linked gene. There were 51 therapeutic abortions as a result of the diagnosis. Sixty-six tests (5.4%) gave an inconclusive result and seven (0.6%) gave an erroneous diagnosis; five of the latter (two false-positives and three false-negatives) resulted from the alpha1-fetoprotein test for neural-tube defects and in two cases the sex was incorrectly determined. The frequency of all chromosome abnormalities was 1:20 when the mother's age was 40 years or more and 1:60 when the mother's age was between 35 and 39 years. When a mother had previously had a child with a chromosome abnormality the risk of recurrence of such an abnormality was 1:100 when the age of the mother was 35 years or more.

Prenatal diagnosis of genetic disorders.

Abstract: Three hundred and fifty pregnancies were monitored by transabdominal amniocentesis in the fourteenth to sixteenth week of gestation followed by karyotyping or biochemica assays of cultured amniotic fluid cells and analysis of alpha-fetoprotein in the amniotic fluid supernatant. The pregnancy was interrupted in 36 cases (10%) either becasue of a fetal abnormality or the presence of a male fetus in pregnancies at risk for an X-linked disease. Four chromosomal aberrations were found in 87 pregnancies tested because of advanced maternal age. In 101 pregnancies with a recurrence risk of Down's syndrome, 2 fetuses with an abnormal karyotype were detected. In 11 cases, in which 1 parent was a carrier of a balanced translocation, 2 unbalanced fetal karyotypes were found. Fetal chromosome studies in 43 pregancies at risk for an X-linked disease indicated the presence of a male fetus in 21 cases. Prenatal diagnosis of 11 different metabolic diseases was performed in a total of 34 cases. Microchemical techniques were used to allow completion of the diagnosis of seven different enzyme deficiencies within 9 to 22 days after amniocentesis. Alpha-fetoprotein assay in the amniotic fluid supernatant of 47 pregnancies at risk for an open neural tube defect resulted in the detection of 3 anencephalic fetuses during the second half of pregnancy. The safety and reliability of amniocentesis and the possible effects on the outcome of pregnancy are evaluated. Prenatal diagnosis offers a promising alternative for parents who are at risk of having a child with a genetic disease which can be detected in amniotic fluid or in cultured amniotic fluid cells.

European experience with prenatal diagnosis of congenital disease: a survey of 6121 cases

Abstract: The results of 6121 prenatal diagnoses established by 46 centers in eight West-European countries are reported. The percentage of "spontaneous" abortions following early amniocentesis (1.4%) does not seem to exceed the normal rate of spontaneous abortion in this period of pregnancy. A total of nearly 300 affected fetuses was detected, and in all but 5 instances the parents asked for interruption of the pregnancy. The majority of prenatal monitoring (75%) was carried out because of an increased risk of chromosomal aberration. In the group with higher maternal age 2.8% of the fetuses were affected; this figure was 4.6% for mothers older than 38 years. Monitoring because of an earlier child with trisomy 21 showed 1.3% fetuses with a chromosomal aberration, and 1.7% abnormal karyotypes were detected in the group where amniocentesis was performed for "miscellaneous reasons." In pregnancies where a parental translocation has been demonstrated, 6.7% of the fetuses showed an unbalanced karyotype and 25% were balanced carriers. Also discussed are results and organizatioal problems of prenatal monitoring for inherited metabolic disorders (206 analyses for 23 different enzyme defects) and for neural tube defects (about 2700 cases).

Current concepts in genetics: prenatal diagnosis of genetic disorders.

Abstract: The current status of amniocentesis and the problems surrounding it are assessed. The safety of the procedure is supported by a 4-year study by the National Institute of Child Health and Human Development. Fetal loss was actually lower in 1040 cases of amniocentesis than in 992 matched controls and there was no evidence of an increase in major maternal complications or in frequency or type of congenital malformations or psychomotor malformation in the infants at 1 year. Indications for prenatal genetic studies are 1) chromosomal disorders 2) sex-linked disorders 3) hereditary biochemical disorders and 4) congenital malformation. The list of metabolic disorders subject to pre natal diagnosis numbers more than 70. Despite the availability and success of prenatal diagnostic procedures however there has been poor utilization of facilities to date. It is assumed that these techniques will find increasing application among women 35 years of age or older but the prohibitive cost of the studies calls for government participation in a prenatal diagnostic program.

Evaluation of amniotic fluid for aerobic and anaerobic bacteria.

Abstract: Lewis, Jay F., Johnson, Peggy, and Miller, Phyllis: Evaluation of amniotic fluid for aerobic and anaerobic bacteria. Studies of 117 pregnant women, 83 at term, were instituted to determine the bacteriologic state of amniotic fluid, utilizing both standard aerobic and anaerobic technics. A high association of postpartum infection was found in women who had long periods of premature ruptured membranes and many vaginal examinations. Significant organisms including anaerobes, were isolated in many of these instances. Based on the findings of these studies, it is recommended that amniocentesis for aerobic and anaerobic cultures be done when membranes have been ruptured for 8 hours or more, and when the patient has had seven or more vaginal examinations during the course of labor.

Changes of biochemical constituents in bovine fetal fluids with gestational age.

Abstract: Serum, amniotic fluid, allantoic fluid, stomach contents, and urine were taken from 141 bovine fetuses 120 to 245 days old. The concentrations of the biochemical constituents were examined in tests to ascertain systematic changes with increasing crown-rump length, i.e., gestational age. As the crown-rump length increased, glucose concentrations decreased in allantoic fluid, amniotic fluid, and stomach contents; creatinine and uric acid concentrations increased in serum, allantoic fluid, and stomach contents; thyroxine concentrations increased in serum and allantoic fluid; potassium decreased in amniotic fluid and stomach contents; and total iron-binding capacity increased in amniotic fluid. The data in the present report can be used to identify the fetal fluid obtained by amniocentesis, to estimate the age of the fetus, and to aid the diagnosis of nutritional or infective processes that might affect the fetus.

Cytogenetic Studies in Reproductive Loss

Abstract: Cytogenetic studies were performed on 57 families with pregnancy wastage (eg, two or more spontaneous abortions or stillbirths). Chromosomal abnormalities were ascertained in 17 couples, through offspring with congenital malformations. Seven families had children with neural tube defects, and five families also had a previous child with Down syndrome. One mother had mosaic Turner syndrome; two additional mothers and one father had balanced chromosome translocations. These findings indicate that chromosome analyses should be performed on every couple with repeated miscarriages or malformed children, and subsequent pregnancies at risk should be monitored by amniocentesis. ( JAMA 236:369-373, 1976)

The prenatal diagnosis of neural tube defects.

Abstract: This review concentrates on the current status of alpha fetoprotein (AFP) measurement in the early prenatal diagnosis of spina bifida and anencephaly. High incidence rates are found in Britain and Ireland intermediate ones in Europe North America and Israel and low ones in Africa Asia and South America. Risk of recurrence for each pregnancy subsequent to the birth of a neural tube defective child is 1/20. Amniotic fluid AFP in normal pregnancies parallel the fetal serum levels with a concentration gradient of about 150:1 so the highest concentration of about 40 mcg/ml is found at 13-14 weeks gestation. Immunodiffusion techniques are adequate for qualitating levels above 1 mcg/ml. As a diagnositc test applied before 20 weeks of pregnancy amniotic fluid AFP is very specific. Elevated levels have also been associated with twin pregnancy severe RH immunization and in third trimester fetal distress. Other possible abnormalities for which AFP may be diagnostic include Turners syndrome and various other chromosomal and congenital abnormalities. In addition increased bilirubin beta-trace protein and macroglobuins may indicate early neural tube defects. Ultrasonography has also been proved useful for prenatal diagnosis of neural tube defects. For measuring maternal serum AFP immunodiffusion techniques are not sensitive enough and specific radioimmunoassays must be employed. 80-90% of anencephalic and 40-50% of open spina bifida defects may be determined by maternal serum screening.

Prenatal diagnosis of Wolman's disease.

Abstract: Amniocentesis was performed in the 15th week of a pregnancy at risk for Wolman's disease. The cultured amniotic fluid cells were found to have a severe deficiency of acid esterase activity consistent with homozygosity of the fetus. The pregnancy was terminated in the 19th week and the prenatal diagnosis confirmed by enzymic and chemical evaluation of the fetal tissues.

Rapid prenatal diagnosis of gm1-gangliosidosis using microchemical methods

Abstract: Prenatal diagnoses were established in 3 pregnancies at risk for GM1-gangliosidosis at 9, 10, and 12 days after amniocentesis. Beta-galactosidase activities in cultured amniotic fluid cells were determined by microchemical assays in cell homogenates and in isolated groups of 10--30 freeze-dried cells. The latter method requires only a few hundred cells growing in one or more clones and will usually allow a diagnosis within 9--12 days after amniocentesis.

Prenatal Diagnosis of Neural Tube Defects

Abstract: A prospective program for the prenatal detection of neural tube defects in a high-risk pregnancy group has been under way for one year. Twenty high-risk mothers have undergone a complete prenatal work-up, including sonography, amniocentesis, and amniotic fluid and maternal serum α-fetoprotein quantitation. Within this group, two cases were prospectively diagnosed and were later confirmed. ( JAMA 236:1251-1254, 1976)

Antenatal diagnosis of trisomy 13 with unexpected increase in alpha-feto protein.

Abstract: A 24-year-old woman who had previously given birth to an infant with Down's syndrome was shown by chromosomal analysis of the liquor amnii to be carrying an infant with trisomy D. Routine examination of serum and liquor alpha-feto protein (AFP) in the antenatal period showed unexpected high levels of both, consistent with a neural tube defect. The fetus, however, did not have evidence of a neural tube defect but had scalp defects which were presumed to have allowed the leakage of AFP from the fetus into the liquor amnii and hance into the maternal serum.

Biochemical characteristics of collagen produced by long term cultivated amniotic fluid cells.

Abstract: The synthesis of the most common type I of collagen was proven in human amniotic fluid cell culture with fibroblast morphology in the cells as well as in the culture medium. Mesenchymal origin of long term cultivated amniotic fluid cells is indicated and the possibility of prenatal investigation of hereditary disorders of connective tissue is pointed out.