Comments on Brown JS, Adera T and Masho SW, “Previous abortion and the risk of low birth weight and preterm births,” Journal of Epidemiology and Community Health, 2008, 62: 16–22
Comments on Brown JS, Adera T and Masho SW, “Previous abortion and the risk of low birth weight and preterm births,” Journal of Epidemiology and Community Health, 2008, 62: 16–22 Prepared by the Guttmacher Institute, December 2007 The 2008 study by Brown, Adera and Masho purports to show a causal connection between abortion and subsequent premature births. In reality, the study does not even show an association between induced abortion and premature birth. The study suffers from several fundamental flaws: 1. The study does not distinguish between spontaneous abortions (i.e., miscarriages) and induced abortions (commonly known as “abortions”). It is well known that miscarriages are associated with low birthweight and prematurity because the physiological conditions responsible for some miscarriages can also cause prematurity and low birthweight. Thus, a study that does not distinguish spontaneous from induced abortion says nothing about the effect of induced abortion. (Although the term “spontaneous abortion” as a synonym for miscarriage is well understood in the medical community, the general public equates “abortion” with induced abortion, a fact that makes this study’s title and content prone to misinterpretation.) 2. Abortion is dramatically underreported by women in surveys. Even today, many women do not report their prior induced abortions, and even fewer would have done so at the time these data were collected (1959–1966), when abortion was generally illegal. We can tell that abortion was underreported in this study because the number of miscarriages plus abortions reported in the study was about 13% of the number of births; this is fewer than the number of miscarriages alone that one would expect given the number of births that occurred. Therefore, it is likely that very few of the “abortions” reported in the study were in fact induced abortions. 3. The Brown study looks at preterm births that occurred more than 40 years ago, before induced abortion was legal nationwide. At that time, most abortions were performed by dilation and curettage; even if these abortions (many illegal) were associated with later reproductive problems, this has no bearing on the effect of induced abortions as performed today, most of which are performed by vacuum aspiration. Several reviews of the available scientific literature affirm that vacuum aspiration — the modern method most commonly used during first-trimester abortions — poses virtually no long-term risks of future fertility-related problems, such as infertility, ectopic pregnancy, spontaneous abortion or congenital malformation.
| 
