Chromosome Studies in Investigation of Stillbirths and Neonatal Deaths

A selective clinical cytogenetic study in prenatal and pediatric pathology: A comparison with unselected studies

“…If we consider only the perinatal deaths, the frequency was 2.9% (24/835), compared with 13.5% if only the cases of congenital anomalies are considered (70/517). This frequency of 4.5% is very similar to that obtained in unselected studies [Bauld et al, 1974;Machin and Crolla, 1974;Kuleshov, 1976;Sutherland et al, 1978;Sutherland and Carter, 1983;Angell et al, 1984;Baena et al, 2001], ranging from 3.5% [Angell et al, 1984] to 4.4% [Kuleshov, 1976] ( Table III). However, if we consider only perinatal deaths our frequency was low (2.9%; 24/835) when compared to other unselected studies (5.9%; 113/ 1914).…”

“…The lack of detection of sex chromosomes aneuploidies in our selected sample could be explained by the fact that, in cases of stillbirth or early neonatal death of individuals with sex chromosome anomalies, there are no clear dysmorphologic/ ectoscopic signs to indicate the need for karyotyping (and that the clinical severity of the complete 45, X fetus would cause death before 20 weeks of pregnancy?). Other observation that reinforce this suggestion was the study of Bauld et al [1974] who karyotyped 91 cases died in perinatal period without congenital malformations, being able to detect chromosomal anomalies in four (4.4%). Another factor for underestimation of chromosomal anomaly frequency in our sample could be that we had eleven (Table I) whose karyotypes were not obtained due to unsuccessful cultures and seven of these were selected for cytogenetic studies by clinical criteria.…”

Frequency of chromosomal abnormalities in miscarriages and perinatal deaths.

“…Prevalence of chromosomal anomalies Table 1 shows the prevalence of chromosome abnormalities in spontaneously aborted fetuses (Creasy et al, 1976) in infants dying during the perinatal period (Bauld et al, 1974;Machin and Crolla, 1974;Kuleshov, 1976) and in liveborn infants (Ratcliffe, 1975). There has been a considerable variation between the prevalence of abnormal karyotypes reported by different studies: the major factor influencing the proportion of abnormalities being the gestational age of the abortuses.…”

Meiotic spindle checkpoints for assessment of aneuploid oocytes

“…If chromosome separation goes awry, aneuploid cells and gametes will likely be produced. While genetic instability is associated with cancer progression (Hartwell, 1992), the incidence of aneuploidy in gametes is thought to contribute to birth defects and pregnancy loss (Bauld et al, 1974). It is generally accepted that nondisjunction of bivalent chromosomes during oogenesis increases significantly with increasing maternal age (Dailey et al, 1996;Hassold and Sherman, 2000).…”