Studies on post-abortion trauma are methodologically flawed due to denial, high attrition rates, delayed reactions, and inadequate research tools. A correlational study done in Denmark is one of the methodologically best studies completed to date. However, many studies cannot obtain accurate data because cooperation of the study population is inconsistent and unreliable. Women often do not return to the clinic to complete the study which results in high sample attrition rates. Denial can also distort the results of a study.
Women also conceal their past abortions in longitudinal and retrospective studies.
This is due partly to the emotional numbness experienced directly after an abortion. Many women cannot objectively report what they feel following an abortion because they do not necessarily know their true emotions or understand their source. Delayed reactions suppress the reported rate of negative reaction and may be due to repression, societal denial, or both. Those who support abortion often partially cite questionnaire studies, and therefore only report that the immediate reaction is one of relief. Pro-choice researchers, in an attempt to minimize the mental health risk of abortion, fail to mention that these same questionnaire studies find abortion to be traumatic.