Investigation of confined placental mosaicism (CPM) at multiple sites in post‐delivery placentas derived through intracytoplasmic sperm injection (ICSI)

Abstract

Although earlier studies on pregnancies derived through intracytoplasmic sperm injection (ICSI) reported increased non-mosaic aneuploidy among ICSI children, undetected mosaicism, such as confined placental mosaicism (CPM) has not been evaluated. We investigated the incidence of CPM in post-delivery placentas derived from ICSI, evaluated whether CPM was increased and whether it was a contributing factor to negative pregnancy outcome. [Fifty-one post-delivery placentas were collected from patients who underwent ICSI with a normal or negative pregnancy outcome]. Trophoblast and chorionic stroma from three sites were analyzed by comparative genomic hybridization (CGH) and flow cytometry. Detected abnormalities were confirmed by fluorescence in situ hybridization (FISH). The incidence of CPM in the ICSI population was compared to the general population from published data. We detected three cases of CPM in our study. One abnormality was found by CGH analysis; partial trisomy 7q and a partial monosomy Xp limited to the trophoblast at two sites. The abnormality was associated with a child affected by spina bifida. Two cases of mosaic tetraploidy were observed by flow cytometry in pregnancies with a normal outcome. All three abnormalities were confirmed by FISH analysis. The incidence of CPM in the ICSI study population was 5.88% (3/51), which was not statistically different from published reports in the general population (5.88% (42/714), Chi square, P > 0.05). The post-ICSI population was not at risk for CPM in this study.