Sandra G. Marchese

Etiology of Recurrent Pregnancy Losses and Outcome of Subsequent Pregnancies

Prospective evaluation of 155 couples with two or more consecutive pregnancy losses disclosed uterine morphologic abnormalities in 27%, chromosomal abnormalities in 21 individuals (7.7%, or 15.4% of the couples), and at least one abnormal diagnostic test suggestive of a cause for recurrent pregnancy losses in 106 (68%). A positive test for antinuclear antibody was found in 7.5% of the women, whereas the expected rate in a population of this age is less than 2%. Cervical cultures for Ureaplasma urealyticum (T-strain my-coplasma) were positive in 48% of the women, and 28% of these women had a genetic or uterine abnormality to explain their pregnancy losses. Thyroid function profiles and cervical cultures for Mycoplasma hominis provided no significant information in the evaluation in these couples. With the exception of women with a positive antinuclear antibody, the overall prognosis for later pregnancies was quite good whether the diagnostic evaluation of the couple was normal (77% subsequent live births) or abnormal (71% subsequent live births). The significance of the positive antinuclear antibody in these women is unclear, but further studies and long-term evaluation are necessary to determine the relationship between recurrent pregnancy losses and later development of collagen-vascular diseases.

The transverse cerebellar diameter in the second trimester is unaffected by Down syndrome

Cerebellar hypoplasia is a consistent finding in necropsy studies of children and adults affected by Down syndrome. The transverse cerebellar diameter was measured in 23 second-trimester fetuses with Down syndrome. All the measurements were within the normal range for gestational age.

The effect of trisomy 18 on transverse cerebellar diameter

The transverse cerebellar diameter was measured in 19 fetuses with trisomy 18. Eleven of the cerebellar measurements (57.9%) were greater than 2 SD below the mean for the patients gestational age. If fetal biometry rather than last menstrual period were used to determine gestational age, four of the 19 (21.0%) cerebellar measurements were greater than 2 SD below the mean. Both intrauterine growth retardation and intrinsic central nervous system abnormalities associated with trisomy 18 appeared to affect cerebellar size.

Increased amnionic fluid alpha-fetoprotein due to a holoacardium amorphous twin

Amnionic fluid alpha‐fetoprotein measurement was employed as a screening test for neural tube defects in a pregnancy only at risk due to advanced maternal age. The alpha‐fetoprotein concentration was elevated more than 10 standard deviations above the mean and was found to be caused by a holoacardium amorphous twin. A normal female fetus was also present. Various causes of elevated alpha‐fetoprotein concentration in amnionic fluid are discussed.

Origin of Lactate Dehydrogenase in Amniotic Fluid

The origin of protein including enzymes in amniotic fluid is of clinical and research interest. 8 patients were evaluated, with their informed consent, prior to therapeutic abortion. Amniotic fluid, placentas and blood were obtained and lactate dehydrogenase (LDH) isozyme patterns of cell-free amniotic fluid was compared to the LDH patterns of uncultured amniotic fluid cells, maternal serum and RBC, placentas and placental membranes. The LDH isozyme pattern of amnion closely corresponded to that of cell-free amniotic fluid and represents the major source of this enzyme in amniotic fluid.

Mosaicism or Pseudomosaicism: The Problem of Hypermodal Cells in Amniotic Fluid Cell Culture

A series of 2029 consecutive amniotic fluid specimens studied for prenatal genetic diagnosis were reviewed and reassessed so as to evaluate the frequency and clinical significance of hypermodal cells in amniotic fluid cell cultures. Hypermodal cells were defined as those with more than 46 chromosomes, and were characterized by an additional structurally normal or structurally abnormal chromosome. Of 2029 specimens, 47 (2.31 per cent) contained a total of 167 hypermodal cells. True fetal mosaicism was detected in three cases (0.14 per cent). All had hypermodal cells in more than one culture flask or colony which contained the same aberrant chromosome complement. In all but one case the babies were normal when only one cell was hypermodal, or when several cells were hypermodal but present in only one colony or one culture vessel. One case had an extra No. 20 chromosome in one cell. Although the child had multiple anomalies, they were not characteristic of trisomy 20, and subsequent chromosomal study on the baby postnatally revealed a 46,XX karyotype. The in situ coverslip technique is recommended as the preferred method for prenatal diagnosis, and it is useful as an aid in differentiating true mosaicism from pseudomosaicism.