From a medical standpoint, I think it is very difficult, if not arbitrary to determine which hormonal contraception is an abortifacient. The uterus is the best abortifacient around, with 25-50 percent of conceived "human beings" being flushed down due to poor implantation. (I put it in "" to designate controversy, but I am not trying to take a stance on that point in this post). With a series of menstruations, any sexually active, fertile woman (let's say happily married, heterosexual and monogamous) is likely to have several "aborted conceptions" without even knowing. A woman's uterus is a very dangerous, unforgiving place statistically speaking.
Another note...many, many normally perscribed drugs are, in fact, great abortifacients. From acne medication to anti-epilepsy drugs. Can hobby lobby determine not to cover these medications because they will harm a fetus? Medical professionals warn, strongly, when any of these medications are given to not get pregnant but things happen. In fact, this is a very good reason to put someone on an IUD or other "fool proof" contraception, so they can take their necessary medication without worrying about harming a fetus. It is dangerous giving a person insurance to cover their anti-epilepsy medication but deny them coverage to avoid damaging a potential fetus.
My understanding is that Hobby Lobby objects to Plan B and both hormonal and copper IUDs, but not the majority of "contraception pills." I have no idea why they would think hormonal IUDs are any different than hormonal contraception pills when it comes to implantation. Both, in theory, are supposed to prevent ovulation. That means there is nothing to implant. The mechanism of action of a copper IUD is not perfectly understood but it is primarily thought to act through inhibition of sperm. I find it concerning when religious beliefs that seem to have no solid knowledge of what they oppose pick and choose arbitrarily.
If anything, most literature I have read have found (through population studies, mind you) that those individuals who have the highest rate of IUD implantation have the lowest abortion rates. I, personally, love IUDs. They are low risk, very easy to use and work in a wide population. I would gladly (if I were an OB/GYN) spend a day a week volunteering to place IUDs in any women of reproduction age who would like one.
Do you have anything to back-up the notion that cheap access to birth control leads to an unhealthier lifestyle compared to those without access?