Objective To investigate the correlation between CpG island methylation levels of human placental genes and spontaneous abortion in pregnant women.

Methods A total of 55 pregnant women who underwent routine prenatal examination were selected as the study subjects, including 25 cases of spontaneous abortion (abortion group) and 30 cases of normal delivery (control group). Clinical data and human placental tissue samples were collected from the enrolled pregnant women. Clinical general data of the two groups were compared. The predictive value of methylation levels of related placental genes on the outcome of spontaneous abortion in pregnant women was analyzed. Logistic regression analysis was used to analyze the influencing factors of spontaneous abortion in pregnant women.

Results There were statistically significant differences in maternal age, birth weight of aborted fetuses/neonates, days of pregnancy, and gender of aborted fetuses/neonates between the two groups (P < 0.05). Methylation of MECP2-1, MECP2-4, HSD11B2, MECP2-3 and MECP2-2 genes was associated with spontaneous abortion. The methylation rates of MECP2-1, MECP2-4, HSD11B2 and MECP2-3 genes in the abortion group were higher than those in the control group, with statistically significant differences (P < 0.05). The area under the curve (AUC) of MECP2-1, MECP2-4, HSD11B2, MECP2-3 and MECP2-2 was 0.773, 0.737, 0.700, 0.663, and 0.627, respectively. Logistic regression analysis showed that MECP2-1 was an independent influencing factor for miscarriage in pregnant women (P < 0.05).

Conclusion The methylation levels of MECP2-1, MECP2-4, HSD11B2, MECP2-3 and MECP2-2 genes are related to the outcome of spontaneous abortion in pregnant women. The MECP2-1 gene is an independent influencing factor for spontaneous abortion.