Follow‐up and pregnancy outcome after a diagnosis of mosaicism in CVS

Abstract

In 2103 consecutive diagnostic chorionic villus samples, examined in a 4-year period in our clinical genetics unit, 26 samples (1.2 per cent) presented chromosomal mosaicism in the direct and/or long-term culture preparations. Only once (46,XX/47,XX,+9) was the mosaicism confirmed in the fetus. In the cytogenetic follow-up studies of the remaining 25 pregnancies, in no cases could the aberration be confirmed in amniotic fluid or fetal tissue. One patient requested a termination after the CVS result. Of the remaining 24 pregnancies, four (16.7 per cent) ended in a spontaneous abortion. These findings suggest an association between placental mosaicism and fetal loss.

Abnormal karyotypes in semi-direct chorionic villus preparations of women with different cytogenetic risks

“…An increased risk of intra-uterine growth retardation (IUGR), fetal loss and poor pregnancy outcome has been reported in association with CPM (Schwinger et al, 1989;Johnson et al, 1990;Goldberg et al, 1990;Kalousek et al, 1991;Breed et al, 1991;Wapner et al, 1992;Brandenburg et al, 1996). The prevalence of 13 per cent congenital malformations in our CPM group is in agreement with these reports.…”

Four years' cytogenetic experience with the culture of chorionic villi

“…This result con®rms the increased risk of poor pregnancy outcome described in the literature. Breed et al (1991) reported 16.6% IUD and Wapner et al (1992) 8.6% IUD. However, Goldberg and Wohlferd (1997) were unable to correlate CPM with poor pregnancy outcome.…”

PLACENTAL MOSAICISM IS ASSOCIATED WITH UNEXPLAINED SECOND-TRIMESTER ELEVATION OF MShCG LEVELS, BUT NOT WITH ELEVATION OF MSAFP LEVELS

“…In UPD, the two chromosomes in a pair are inherited from the same parent, instead of one chromosome being inherited from each parent. Several authors found a relationship between CPM and adverse pregnancy outcome, such as perinatal loss (Johnson et al, 1990;Breed et al, 1991;Wapner et al, 1992) and fetal growth retardation (Kalousek ef al., 1991;Wolstenholme et al, 1994;Wilkins-Haug et al, 1995), whereas others failed to find such an association (Leschot and Wolf, 1991). The majority of these reports suggest that placental mosaicism has a biological influence on intrauterine fetal development.…”

“…In 1-2 per cent of all pregnancies, aneuploidy or mosaicism in the placenta with normoploidy in the fetus can be found; this is called confined placental mosaicism (CPM) (Kalousek, 1994). CPM, detected after the introduction of chorionic villus sampling (CVS) for prenatal cytogenetic diagnosis, is known to interfere with normal fetal development (Breed et al, 1991;Wapner et al, 1992;Wilkins-Haug et al, 1995). In particular, CPM that involves trisomy 16 is frequently associated with pregnancy complications (Kalousek et al, 1993;Vaughan et al, 1994).…”