I was sent this link by Everydayhealth.com and thought it was worth sharing. A straightforward experiment where birth control / contraception was provided free of charge in St. Louis, under the ‘Contraceptive Choice’ project, showed that these women had much lower birth rates and abortion rates than the national (US) average. Everydayhealth.com have published this nice and simple infographic:

Obviously you’d hope the lower abortion rate and lower birth rate was due to the free contraception, and that would be a great message to send, which I agree with. The scientist in me though, wants to know – how many people took part in the study? Did the participants represent a variety of ages and backgrounds to be representative of the national distribution of diversity of ages and backgrounds? How were participants selected? Because, if it was highly educated, self selecting women of a particular privileged background, then the study would be biased as they would probably be less likely to be getting accidentally pregnant anyway (because due to a combination of these factors and others, they might have better sex education and more access to information and healthcare to avoid accidental pregnancy, possibly more agency to avoid being pressured into unprotected sex etc. etc. than the national average).

So I checked the comments thread on Everydayhealth.com and found the source of the research: The Choice Project http://www.choiceproject.wustl.edu/. So that’s 10,000 women. Sounds like a reasonable sample. The Choice Project site is great as it shows the demographic breakdown of the participants. But I don’t know anything about the St. Louis birth or abortion rates before the project started. So seems weird to compare project data from one city to national data.

I haven’t read the Choice Project in detail but it seems weird it doesn’t seem to have offered condoms which makes me suspicious. Was the project sponsored by any drug companies? I can’t find details of how it was funded. A publication by the project on ePub says the project’s objective was, “To promote the use of long-acting reversible contraceptive (LARC) methods (intrauterine devices [IUDs] and implants)”.

Actually I’m going to quote the whole study abstract from ePub because that has much more useful info:

OBJECTIVE:: To promote the use of long-acting reversible contraceptive (LARC) methods (intrauterine devices [IUDs] and implants) and provide contraception at no cost to a large cohort of participants in an effort to reduce unintended pregnancies in our region. METHODS:: We enrolled 9,256 adolescents and women at risk for unintended pregnancy into the Contraceptive CHOICE Project, a prospective cohort study of adolescents and women desiring reversible contraceptive methods. Participants were recruited from the two abortion facilities in the St. Louis region and through provider referral, advertisements, and word of mouth. Contraceptive counseling included all reversible methods but emphasized the superior effectiveness of LARC methods (IUDs and implants). All participants received the reversible contraceptive method of their choice at no cost. We analyzed abortion rates, the percentage of abortions that were repeat abortions, and teenage births. RESULTS:: We observed a significant reduction in the percentage of abortions that were repeat abortions in the St. Louis region compared with Kansas City and nonmetropolitan Missouri (P<.001). Abortion rates in the CHOICE cohort were less than half the regional and national rates (P<.001). The rate of teenage birth within the CHOICE cohort was 6.3 per 1,000, compared with the U.S. rate of 34.3 per 1,000. CONCLUSION:: We noted a clinically and statistically significant reduction in abortion rates, repeat abortions, and teenage birth rates. Unintended pregnancies may be reduced by providing no-cost contraception and promoting the most effective contraceptive methods. LEVEL OF EVIDENCE:: II.

The recruitment of participants is not particularly random, it seems quite self selecting, so I’m not sure how this might have affected the results. i.e. people less likely to participate in this study are more likely to have an unplanned pregnancy and abortion, whether or not they actually did participate in the study.

Still, these are all criticisms of a study claiming to show proof of causation, when of course I agree that everyone should get free contraception, and I am also sure that more contraception use leads to fewer unplanned pregnancies which leads to fewer abortions. I just don’t think people should be encouraged so strongly to use chemical contraception methods over and above promoting condoms – it doesn’t sound like all their options were fairly offered to them. Although the infographic above mentions condoms, the Choice Project site itself does not (in its data on the homepage – condoms are mentioned in a list of methods but not in the choices given to women in the project).

Do let me know if I’ve misunderstood as I have written the above quite quickly and may have missed some detail. Also I haven’t read the full research paper only the abstract and the project website.