Hello and welcome to the zero to finals podcast.

My name is Tom and in this episode I'm going to be talking to you about the progestogen

only pill.

And you can find written notes on this topic at zero to finals.com slash p o'p or in the

contraception section of the zero to finals obstetrics and gynecology book.

So let's get straight into it.

The progestogen-only pill or POP is a type of contraceptive pill that only contains progesterone.

The POP is taken continuously unlike the cyclical combined pills.

This means there's no pill-free period. It's more than 99% effective with perfect use, but less

effective with typical use, at 91%. Thegestergent-only pill has far fewer contraindications and risks compared with the combined

pill. The only UK-MEC-4 criteria for the POP is active breast cancer.

Let's talk about the types. There are two types of progestogen-only pill

to remember. Traditional progestogen-only pills, for example, norgesten and noraday, and desogestrel-only

pills, for example, Sarazette.

The traditional progestergent-only pill cannot be delayed for more than three hours.

Taking the pill more than three hours late is considered a missed pill.

The desogestrel-only pill can be taken up to 12 hours late and still be effective.

Taking the pill more than 12 hours late is considered a missed pill.

Let's talk about the mechanism of action.

Traditional progestogen-only pills work mainly by thickening the cervical mucus,

altering the endometrium and making it less accepting of implantation, and reducing ciliary action in the fallopian tubes.

Dezogestrel has an additional mechanism of action which is to inhibit ovulation.

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