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 combined

oral contraceptive pill.

And you can find written notes on this topic at zero to finals.com slash C OCP

or in the contraception section of the zero-definals, obstetrics and gynecology book.

So let's get straight into it.

The combined oral contraceptive pill, or COCP, contains a combination of estrogen and

progesterone.

The combined pill is more than 99% effective

with perfect use, but less effective with typical use at around 91%. The pill is licensed

for use up to the age of 50 years. Let's start by talking about the mechanism of action. The combined pill prevents pregnancy in three years. Let's start by talking about the mechanism of action. The combined pill prevents

pregnancy in three ways. It prevents ovulation, and this is the primary mechanism of action.

The progesterone in the pill thickens the cervical mucus, making it difficult for sperm to get

through, and the progesterone

also inhibits the proliferation of the endometrium, which reduces the chances of successful

implantation if fertilization occurs. Estrogen and progesterone have a negative feedback effect

on the hypothalamus and the anterior pituitary,

which suppresses the release of GnRH, LH and FSAH.

Without the effects of LH and FSAH, ovulation does not occur.

Pregnancy cannot happen without ovulation.

The lining of the endometrium is maintained in a stable state whilst taking

the combined pill. When the pill is stopped, the lining of the uterus breaks down and sheds. This leads

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