Pro-life reaction to free contraception study

A recent article, from LifeSiteNews is a perfect representative of the more-contraception-leads-to-more-abortions perspective.

The author is specifically reacting to a recent study published in the journal Obstetrics & Gynecology that showed a strong correlation between the provision of free and highly effective contraceptives to women and a drop in unplanned pregnancies (including teen pregnancies) and abortions.

The LifeSiteNews article includes the following assertions:

1. Inter-uterine devices (IUDs) can cause abortions by preventing the implantation of an already-fertilized egg; therefore, more IUD use leads to more abortions. 
2. Making contraception more widely available will lead to more sexual behavior.
3. Given the error rates of contraceptive methods, more sexual behavior that relies on contraception will lead to more unplanned pregnancies, which will lead to more abortions
4. One contraception method, the 'rhythm' method, is more effective than 'artificial' contraceptive methods. 

Some perspective here:

1. The claim about IUDs is tenuous. One common misunderstanding about IUDs is that they primarily work by preventing fertilized eggs from attaching to the uterine wall. In fact, their primary effect is to prevent fertilization. There is also little evidence to suggest that, while some eggs are fertilized in IUD-fitted women, the failure rate of implantation is statistically higher than the 'natural' non-implantation rate. Furthermore, to claim that more IUD use would lead to more abortions could be true only if the percentage of times the IUD worked by preventing an egg from implanting was relatively high (which it is not), and higher than the number of unplanned pregnancies avoided by women using this more effective contraception method. 
2. There is little evidence to suggest that contraception increases sexual behavior. Consider third-world countries where the birth rate has been roughly halved in recent decades by the introduction of birth control and family planning programming. People in those countries were not having less sex before birth control, and the introduction of birth control clearly reduced the number of unplanned pregnancies (not that access to effective birth control does not have a long way to go in the third world). Consider also, for example, young people in the United States who are transitioning into sexual behavior. Studies of abstinence-only vs. abstinence-preferred sexual educational programs demonstrate that providing information on birth control (and making people comfortable with its use) does not lead to more sexual behavior.
3. The too-high error rate of many methods of contraception is real, but is not evenly applied across methods. Some contraceptive methods are more effective than others. The authors of the study in Obstetrics & Gynecology likely had such a dramatic result precisely because the women in the study asked for and received highly effective but more expensive contraception methods, for free. 
4. The 'rhythm' method does not appear to have a lower error rate than other methods of contraception, certainly not lower than the methods used in the study (LARCs, or long-acting reversible contraceptives-- hormonal implants and IUDs). 

Links:

LifeSiteNews (October 8, 2012): Study claiming Obamacare would reduce abortions debunked

Abstract to article about IUDs and implantation in Studies in Family Planning: IUDs are contraceptives, not abortifacients: a comment on research and belief

From the authors of the textbook Contraceptive Technology: A table comparing the effectiveness of different methods of contraceptives