That '70s Show S01 E17 The Pill

"Be groovy... be very groovy!"

Since no one else is around, Jackie confides in Eric that she thinks she might be pregnant. Eric passes the news on to Donna, who tries to get Jackie to tell Kelso. The incident inspires Donna to go on birth control pills. Her decision inadvertantly causes Eric a lot of grief when Bob and the Formans find out.