Anovulatory drug and Preventative

Anovulatory drug noun - A contraceptive in the form of a pill containing estrogen and progestin to inhibit ovulation and so prevent conception.

Preventative and anovulatory drug are semantically related. In some cases you can use "Preventative" instead a noun phrase "Anovulatory drug".

Preventative noun - Any obstruction that impedes or is burdensome.

Anovulatory drug and preventative are semantically related. Sometimes you can replace phrase "Anovulatory drug" with "Preventative", this terms are similar.