A team of Canadian researchers undertook a study to examine the risk factors of placenta previa and placental abruption incidence. They found a link between development of these disorders in subsequent pregnancies and previously undergone cesarean sections.

Placental previa is a disorder defined as the implantation of the placenta over or near the internal opening of the cervix while placenta abruption represents premature separation of the placenta from the uterus. Both disorders cause bleeding during the pregnancy, which could represent danger for both mother and baby.

Study results showed that women who previously delivered by caesarean section had a 47% increased risk of developing placenta praevia and a 40% increased risk of placental abruption in the following pregnancy.

It is thought that cesarean sections could cause scarring inside the womb and affect placental attachment in future pregnancies. Cesarean also causes ligation of the uterine vessels that could also damage the lining of the womb and end up with low implantation of the placenta in the next pregnancy.

In practice, over 1% of pregnancies with a prior Cesarean section had one of these events which represent a 50% increase compared to women without previous Cesarean section. This has important implications on the management of these pregnancies.

Women should be informed of the possible risks that can happen throughout the pregnancy as well as risks associated with C-section.