Why was the abortion legalization wave so short?

[buritobr]

Most of the countries which legalized abortion did it between 1965 and 1975. The countries which didn't legalize abortion until 1975, kept the abortion ilegal until today. The few exceptions are Portugal, Uruguay and Spain, which legalized abortion at the beggining of the 21th century.

[True Federalist (진정한 연방 주의자)]

If I had to guess, it was because The Pill made family planning respectable.  Back when abortion was the only means a female had to ensure birth control, it simply would not have been acceptable.  Once abortion became a backstop to other means of feminine birth control, there was less demand to restrict it.