INDUCED ABORTION AND BREAST CANCER: 
A Meta Analysis

Karthikbajalee Raghuraman

Advisor: Tilahun Adera, Ph.D.

OBJECTIVES:
To review from published reports to date, the relationship between Induced Abortion and Breast Cancer and the magnitude of such an association, independent of spontaneous abortion. And also to look at the risk of Induced abortion in subgroups of nulliparous and parous women who were exposed to the risk factor before and after first full term pregnancy.

METHODS:
Systematic search for published studies using Medline (Pub med) databases from 1966 to 01/2002 was conducted. Out of a total 52 studies, (n = 31) studies which reported specific data on Induced abortion and Breast cancer were included in the analysis and the remaining studies which did not specify the type of abortion or which did not report specific details about Induced Abortion and Breast cancer were excluded from the analysis. Over all Odds ratio and its corresponding 95% Confidence Interval(C.I ) was calculated by the Fixed effects(Wolf) model and over all odds ratio using Random effects model was also computed for comparison using SAS software. And also Case-Control studies and Cohort studies were separately analyzed.

RESULTS:
The overall odds ratio for any Induced Abortion; n = 29 studies was 1.12 and the 95% C.I (1.07 – 1.16) by the Fixed effects Model and 1.26 and 95% C.I (1.13 – 1.42) by the Random effects model. The over all odds ratio for nulliparous women was 1.26 and 95% C.I of (1.11 – 1.43), for parous women who had Induced Abortion before their first full term pregnancy was 1.16 (1.03– 1.30) and for Parous women after first full term pregnancy the risk of Induced Abortion was 1.15 (1.05 – 1.25).

CONCLUSION:
The results show that the risk of Induced Abortion to Breast cancer 1.26 (1.11- 1.43) remains higher in the Nulliparous women.