A lot of women who suffer from period pain every month rely on prescription drugs.
There are a lot of women who rely on prescription drugs when they have monthly menstrual pain.
この場合、次のような言い方ができますよ。
ーA lot of women who suffer from period pain every month rely on prescription drugs.
「毎月生理痛に悩まされる多くの女性は、処方薬に頼ります」
to suffer from period pain every month で「毎月生理痛に苦しむ・悩む」
ーThere are a lot of women who rely on prescription drugs when they have monthly menstrual pain.
「毎月の生理痛があると処方薬に頼る女性がたくさんいる」
to have monthly menstrual pain で「毎月の生理痛がある」
ご参考まで！
Many women suffer from period pains every month and rely on prescription medication.
Many women suffer from period pains every month and rely on prescription medication.
Especially for women, monthly menstrual cramps lead many to depend on prescribed medicine.
「多くの女性が毎月の生理痛に苦しんでおり、処方薬に頼っています」
・period pains / menstrual cramps
「生理痛」を表す一般的な言葉です。cramps は「（筋肉の）けいれん、差し込むような痛み」を指します。
カナダ 
アメリカ合衆国 
