Please choose the correct ending to complete the given sentence: Health: [header] How to know if menstrual periods have stopped [title] Evaluate the contraceptives you're taking. [step] If you missed a period while on birth control pills, your period may be irregular or absent longterm depending on how you use the medication and your body's reaction to it. [substeps] Oral contraceptives typically come in 21 day packs with 7 days worth of inactive placebo pills.

Ending1: Expect menstrual periods to last between 30 and 90 days. While they're not foolproof, you may still notice changes after they have stopped. Ending2: While taking these pills, you should have your period. If you skip the placebo pills and go straight into the next pack, you will probably miss your period. Ending3: Penile prolapse may interfere with the process of getting pregnant for some women. ( but it is a relatively universal problem. Ending4: These include some containing other active post-menstrual hormones that help many women get pregnant. [title] Ask your doctor about the due date.

Answer format: ending1/ending2/ending3/ending4