The effective strategies go beyond the contraceptive devices themselves to include better counseling, more dignity for women in clinics, a greater choice of methods that are completely free — and a broad effort to raise the status of women.
The best way to elevate women, by far, is to educate girls and to give them opportunities to earn income through micro-loans, factory jobs or vocational training. It is sometimes said that the best contraceptive isn’t the pill or the IUD, but education for girls.
(A side note: Whenever I write about efforts to save children from malaria or diarrhea, I get cynical letters from neo-Malthusians who argue that saving children’s lives is pointless until birthrates drop. That’s incorrect. There’s abundant evidence that when parents are confident that their children will live, they will have fewer and invest more in each of them.)