Thursday Aug 7, 2014 (foodconsumer.org) -- A new study published in Cancer Causes and Control suggests that induced abortion can increase risk of breast cancer, at least among Chinese women.  

Induced abortion is voluntary termination of a pregnancy with medications or by surgery.  This is compared to spontaneous abortion or miscarriage, which occurs without medical intervention.

The study shows that Chinese women who ever induced abortion or at least once were at 44% increased risk of developing breast cancer, compared with those who never had induced abortion.

The study is a meta-analysis of data from 36 studies covering 14 provinces in China published prior to Dec 12 in PubMed, ScienceDirect and Wiley and three Chinese databases (CNKI, WanFang and VIP) intended to reveal how induced abortion may affect the risk of breast cancer.

The study also found women who had two or three induced abortions at 76% or 89% increased risk for breast cancer, respectively, compared with women who never induced any abortion.

The study concludes "IA (induced abortion) is significantly associated with an increased risk of breast cancer among Chinese females, and the risk of breast cancer increases as the number of IA increases. If IA were to be confirmed as a risk factor for breast cancer, high rates of IA in China may contribute to increasing breast cancer rates."

Induced abortion leaves pregnant women at higher risk of breast cancer as the breast tissue of pregnant women who have not completed at least one full term pregnancy is not mature and their hormone levels are high during pregnancy, making them susceptible to carcinogenesis.  This explains why induced abortion increases risk of breast cancer.

Induced abortion is commonly performed in many countries including China and the United States.  In the U.S., nearly one-third of pregnancies end up being voluntarily terminated.

Huang Y, Zhang X, Li W, Song F, Dai H, Wang J, Gao Y, Liu X, Chen C, Yan Y, Wang Y, Chen K.  A meta-analysis of the association between induced abortion and breast cancer risk among Chinese females.  Cancer Causes Control. 2014 Feb;25(2):227-36.