This study shows that assisted reproductive technology pregnancies were associated with increased risks such as preterm birth, placenta previa, and low birthweight infants.

In this Japanese study of 242,715 pregnancies published in Fertility & Sterility the authors reviewed pregnancy outcomes after 3 types of assisted reproductive technology pregnancies:

1. ovarian hyperstimulation
2. insemination without stimulation
3. In vitro fertilization (IVF)

They showed that all three ART pregnancies were associated with risks such as preterm birth, placenta previa, and low weight newborns.

They came to the following conclusions:

"Among singleton pregnancies, patients conceived with ART procedures were at increased risk for several adverse obstetric and perinatal outcomes, regardless of the type of ART procedure used. These results suggest that maternal factors associated with infertility may contribute to the adverse outcomes rather than the ART procedures themselves."

Hayashi et al  Fertil Steril 2012; 98:922-928'