Amniotic Fluid Karyotype Research Articles

Androgen insensitivity syndrome: in utero diagnosis by four‐dimensional sonography and amniotic fluid karyotype

We describe a fetus with androgen insensitivity syndrome diagnosed at 16 weeks' gestation with two-dimensional (2D) and four-dimensional (4D) sonography and karyotype analysis in a 37-year-old pregnant woman. Two-dimensional (2D) sonography revealed a female phenotype. Karyotype analysis revealed an unremarkable 46,XY chromosomal complement. Repeat 4D sonography confirmed a female phenotype with edematous labia majora, consistent with androgen insensitivity syndrome.

Jejunal atresia in an infant with triple-X syndrome

A 33-year-old woman presented at 31 weeks' gestation with polyhydramnios that required repeated amniodrainage. An antenatal scan at 32 weeks showed dilated fetal bowel loops, which were not confirmed on subsequent scans. The amniotic fluid karyotype confirmed 47,XXX. After birth, jejunal obstruction was confirmed. To our knowledge, this is the first report of an association of triple-X syndrome and jejunal atresia.

Jejunal atresia in an infant with triple-X syndrome

A 33-year-old woman presented at 31 weeks' gestation with polyhydramnios that required repeated amniodrainage. An antenatal scan at 32 weeks showed dilated fetal bowel loops, which were not confirmed on subsequent scans. The amniotic fluid karyotype confirmed 47,XXX. After birth, jejunal obstruction was confirmed. To our knowledge, this is the first report of an association of triple-X syndrome and jejunal atresia.

Intraamniotic infection in the very early phase of the second trimester

A total of 157 consecutive patients were studied in an effort to examine prospectively the incidence of asymptomatic intraamniotic infection in the early phase of the second trimester. All patients were referred for amniotic fluid karyotyping. In addition, the amniotic fluids were examined for Gram stain and were directly cultured on blood agar and MacConkey agar as well as in thioglycollate broth. We found positive amniotic fluid cultures in eight cases (5.09%); however, results of Gram stain examinations were negative in all amniotic fluid samples. The data indicate that there is no correlation between white blood cells in the amniotic fluid and positive amniotic fluid culture results. Only one pregnancy with positive amniotic fluid culture resulted in a septic abortion. Therefore we can suggest that intraamniotic infection can exist early in pregnancy, even with intact membranes, and in most cases without any clinical symptoms.

Prenatal diagnosis—amniotic fluid chromosome studies in 1000 cases

Over a 6-yr period (1974-80) 1000 samples of amniotic fluid were referred for chromosome analysis. Five hundred and thirty-six patients (53.6%) were referred because of advanced maternal age, 105 (10.5%) because of the birth of a previous child with Down's syndrome or a family history of Down's syndrome, 7 (0.7%) were translocation carriers and 17 (1.7%,) had a previous child with a chromosome abnormality other than Down's syndrome. The husbands of 3 patients had chromosome abnormalities and there were 3 referrals from families with sex linked disorders. Thirty-three per cent of the sample (329 cases) comprised a miscellaneous group including those referred primarily for α-feto protein estimation and maternal anxiety. Sixteen major chromosome abnormalities were detected and of these, 12 pregnancies were terminated, one-pregnancy miscarried, one resulted in a stillbirth and 2 continued to term. Foetal loss occurred in 19 pregnancies (1.9%). Twenty-six specimens failed to grow (2.6%) but 19 of these were considered unsuitable for culture on arrival at the laboratory. Of 783 births to date, one case of unconfirmed mosaicism was the only discrepancy between the amniotic fluid karyotype and the foetal karyotype. Results were available on most cases within 14 d of amniocentesis.

Amniotic fluid testosterone concentration as an index of fetal sex.

Summary: Testosterone concentrations were measured by radioimmunoassay in 57 amniotic fluid samples obtained from 43 women whose gestational ages varied from 14–40 weeks. These women were grouped according to the sex of the fetus and the gestational age at the time of amniocentesis: group I, less than 20 weeks; group II, 21–30 weeks; group III, 31–40 weeks. In each gestational age group, mean testosterone concentrations were significantly higher in women bearing male fetuses. Of the 14 patients comprising group I, 8 bore male fetuses. The mean testosterone concentration for male fetuses in this group was 198.7 pg/ml (range 93–319.8 pg/ml) and 74.1 pg/ml for female fetuses (range 39–122.8 pg/ml). Group II was comprised of 23 patients, 13 of whom bore male fetuses. The mean testosterone concentration for male fetuses was 221.5 pg/ml (range 133.6–395.0 pg/ml), and for female fetuses it was 67.7 pg/ml (range 35.6–103.0 pg/ml). Group III consisted of 20 patients of whom 10 bore male fetuses. The mean testosterone concentration for the male fetuses was 149.1 pg/ml (range 99.2–262.0 pg/ml), and for female fetuses it was 60.2 pg/ml (range 39.5–96.7 pg/ml). Some overlapping of individual testosterone values was observed in fluid from male and female fetuses; however, the percentage of women bearing males and having amniotic fluid testosterone concentrations greater than 100 pg/ml was 93.5% (29/31). The percentage of women bearing females with testosterone concentrations less than 100 pg/ml was 88.5% (23/26).Speculation: Amniotic fluid testosterone concentrations have proven useful for the antenatal diagnosis of fetal sex. Correlation between the fetal sex based upon testosterone analysis and the amniotic fluid karyotype increases the probability that the cultured cells are of fetal origin. Certainty of diagnosis could be increased even further by combining antenatal sex diagnosis with fluorescent Y-chromatin screening of uncultured amniotic fluid. A combination of these techniques should aid in the elimination of diagnostic errors arising from contamination by maternal cells.

A case of trisomy 18 diagnosed before birth

Abstract In polyhydramnios, fetography together with amniotic fluid cell cultures and karyotyping are helpful in diagnosing serious chromosomal defects, such as trisomy 18.