The Outcome of Pregnancies With Confined Placental Chromosome Mosaicism in Cytotrophoblast Cells

Abstract

Cytogenetic findings and outcome of pregnancy are reported in 108 cases in which confined placental mosaicism (CPM, n=101) or generalized mosaicism (n=7) was found at or after first‐trimester chorionic villus sampling. In all samples, a (semi)direct cytogenetic analysis of cytotrophoblast cells was performed. Two pregnancies with CPM ended in a spontaneous abortion before 28 weeks (1·9 per cent). In 15 cases the pregnancy was terminated: eight cases were shown to be examples of CPM; seven cases can be considered as examples of generalized mosaicism. A normal cytogenetic result was obtained after follow‐up amniocentesis in 88 of the remaining 91 cases. In three cases, no amniocentesis was performed but confirmation of a normal karyotype was obtained in other cells. One of the 91 pregnancies was nevertheless terminated for psychosocial reasons. One child died perinatally and another on the seventh day after birth. The birth weight is known for 89 children; the curve shows a normal distribution. In 11 of these children (12·3 per cent), the birth weight was found to be below the tenth centile. The outcome in a subgroup of eight pregnancies with CPM and involvement of chromosome 13, 16, or 22, however, revealed two fetal losses and four children with a birth weight below the tenth centile (75 per cent).

Genetic analysis of first‐trimester miscarriages with a combination of cytogenetic karyotyping, microsatellite genotyping and arrayCGH

“…It is most likely to occur as the result of the unequal distribution of the embryonic and placental progenitor cells in a mosaic blastocyst (40). Recently, CPM has been considered more related to intrauterine growth restriction (41)(42)(43). In this study, we found two cases of mosaicism that accounted for 2.9%.…”

Influence of O2‐carrying plasma hemoprotein “albumin‐heme” on complement system and platelet activation in vitro and physiological responses to exchange transfusion

“…We were surprised to find a relatively high incidence of tetraploidy in our study population (3.92%, 2/51) compared to the general population (0.56%, 4/714 (Table IV), Chi square, P < 0.01). The presence of tetraploidy in term placentas in the general population is most often associated with a negative pregnancy outcome, such as IUGR, primarily when a large proportion of trophoblast cells are affected [Wilkins‐Haug et al, 1995; Cowles et al, 1996; Leschot et al, 1996]. Complications were not observed in the two tetraploid cases detected in the current experiment, indicating that the presence of chromosomal abnormality in the placenta does not always affect pregnancy outcome.…”

“…The chromosomal abnormality can be confined to the trophoblast (type I), the chorionic stroma (type II) or both cell lineages (type III), while the fetal cells remain normal [Kalousek and Vekemans, 1996]. CPM may be associated with a negative pregnancy outcome, including congenital abnormalities [Leschot et al, 1996; Farra et al, 2000] and intrauterine growth restriction (IUGR) [Lestou and Kalousek, 1998]. Complications most often occur when mosaicism persists to term [Henderson et al, 1996] and affects a large proportion of cells [Wolstenholme, 1996].…”

Preimplantation Genetic Testing for Chromosomal Abnormalities: Aneuploidy, Mosaicism, and Structural Rearrangements

“…In gestation, mosaicism is implicated in confined placental mosaicism (CPM), where cells with different ploidy are present specifically in the placenta and fetal cells are normal. The majority of pregnancies diagnosed with CPM continue to term with no complications [61], but some result in intrauterine growth retardation (IUGR), placental insufficiency, and potentially miscarriage [62,63]. The real medical meaning of mosaicism in newborns and adults remains elusive.…”