From:  Pregnancy depends on a delicate balance of immune activation and regulation

 Epidemiological risk factors in PE and miscarriage

PEMiscarriage
Inadequate induction of tolerance
  First pregnancy○×
  The second pregnancy reduces the risk, even if the first pregnancy is a miscarriage○×
  First pregnancy with a new partner in multiparous women○×
  More than 10 years after the last delivery, the risk increases even if adjusted by age○×
  IVF-ET○×
Low or lack of semen exposure
  Condom use○×
  Short cohabitation○×
  Sperm donation pregnancy○×
  Egg donation pregnancy○○
  Embryo donation pregnancy○○
Fetus is a complete allograft to maternal host
  Egg donation pregnancy○○
  Embryo donation pregnancy○○
  Hydatidiform mole○○
○:

risk factor; ×: not risk factor