Investigation of confined placental mosaicism by CGH in IVF and ICSI pregnancies.

BACKGROUND

Assisted reproductive technologies include in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). It has been shown that embryos derived from ART have higher rates of aneuploidy. Although the majority of ART pregnancies are genetically normal, it is suspected that aneuploid embryos may persist as mosaics and lead to confined placental mosaicism (CPM). Due to the greater risks of sperm aneuploidy in infertile men, CPM may be more prevalent in ICSI than IVF pregnancies. In this report, we investigated the prevalence of CPM in IVF and ICSI pregnancies using comparative genomic hybridization and flow cytometry.

METHODS

The placenta and umbilical cord blood were collected after birth. To determine the presence of CPM, karyotypes of umbilical cord blood were compared to the results of placental analyses. For each placenta, multiple villous sites were investigated for DNA gains/losses and polyploidy using comparative genomic hybridization and flow cytometry. Detected abnormalities were further confirmed by fluorescent in-situ hybridization (FISH).

RESULTS

In total, 134 IVF/ICSI cases were investigated. CPM was detected in five of these cases (5/134) giving an overall rate of 3.73%. CPM was detected in one IVF case (1/31; 3.23%) and four ICSI cases (4/103; 3.88%). The prevalence of CPM in IVF and ICSI pregnancies was not statistically different from each other. CPM was not observed in 13 ICSI and 6 IVF cases that were determined to be small for gestational age (SGA).

CONCLUSIONS

The prevalence of CPM in ICSI pregnancies is not greater than IVF pregnancies. In addition, the overall prevalence of CPM in ART pregnancies (IVF and ICSI) is similar to that of the general population. CPM was not observed in the limited cases that were affected by small for gestational age. Our results suggest that ART pregnancies are not at a greater risk for CPM.