Table 4 Implementation characteristics of studies
Characteristics | n | % |
|---|---|---|
Time of sampling | ||
At the time of delivery | 82 | 91.1 |
Before delivery | 13 | 14.4 |
After delivery | 5 | 5.5 |
At the time of abortion | 7 | 7.8 |
Not reported | 7 | 7.8 |
Sample | ||
Placenta | 75 | 83.3 |
Maternal peripheral blood | ||
Plasma | 9 | 10.0 |
Serum | 2 | 2.2 |
White blood cells (WBC) | 9 | 10.0 |
Lymphocytes | 1 | 1.1 |
Whole maternal blood | 1 | 1.1 |
Umbilical cord blood | 7 | 7.8 |
Omental fat arteries | 3 | 3.3 |
Placental vessels | 1 | 1.1 |
Umbilical vein | 1 | 1.1 |
Targeted genetic locations | ||
Global DNA-methylation | 5 | 5.5 |
Genome-wide | 4 | 4.5 |
Genome-wide, selected genes for replication | 25 | 27.8 |
Candidate gene(s) | 58 | 64.4 |
DNA methylation method (most frequent) | ||
Illumina27+Illumina450 | 21 | 23.3 |
Bisulfite sequencing | 23 | 25.5 |
Bisulfite pyrosequencing | 19 | 21.1 |
Methylation specific PCR | 11 | 12.2 |
Purification of DNA extraction | 33 | 36.7 |
Validation of methylation | 30 | 33.3 |