FEMAILE HEALTH
CONTRACEPTION
CONTRACEPTION IS THE PROCESS OF PREVENTING PREGNANCY THROUGH PHYSICAL OR PHARMACOLOGICAL MEANS. FEMALE CONTRACEPTION IS PRIMARILY PHARMACOLOGICAL AND IS THE PROCESS OF MANIPULATING THE NATURAL RELEASE OF HORMONES DURING THE MENSTRUAL CYCLE.
T
he menstrual cycle is usually a 28 day cycle. The process of the cycle involves follicle stimulating hormone (FSH), oestrogen and luteinising hormone (LH), which are released at different times throughout the cycle.1
The three main methods of contraception are hormonal pills, intrauterine devices and barrier methods.
HORMONAL
The hormonal method of contraception is the most effective way to prevent pregnancy2
. The
most common of these is: Combined Oral
Contraceptives (COCs)
COCs contain an oestrogen and a progestogen in both fi xed and varying amounts. Those that have a fi xed amount are known as ‘monophasic’ and those with a varying amount are known as ‘phasic’.
58 - PHARMACY IN FOCUS
They work mainly through inhibiting ovulation. This occurs through action on the Hypothalamus and the Pituitary gland to reduce LH and FSH. This reduction in hormones leads to a stop in the maturation of the egg in the ovary and its subsequent release. They also exhibit an action on the mucus in the neck of the womb, increasing its viscosity to make it more diffi cult for sperm to reach an egg, and on the lining of the womb (endometrium), thinning it to ensure there is less chance of an egg attaching successfully3
.
The lowest content of oestrogen and progestogen which gives good cycle control with a minimum risk of side effects should be chosen2
.
There is low strength and standard strength COC’s available.
Low strength COC contain 20mcg of oestrogen and standard strength COC contain between 30-40mcg of oestrogen. Most COCs are
• Whether the patient is 50yrs or older: COCs can be used up to the age of 50 if there are no other risk factors
• The smoking status of the patient: it is not recommended to prescribe the use of COC in women 35 or older and who smoke
• The patient’s BMI, should be determined at initial consultation:
taken daily for 21days followed by a 7day pill free period. They are packaged in strips of 21 active pills.
There is every day (ED) COCs that contain 21 active pills followed by 7 inert pills. These are taken every day without a pill free interval. These ED tablets help encourage compliance in those patients that have struggled with the 21 day cycle4
The main issues that need to be determined before commencing COCs are5
:
those who have a BMI of 35 and over are at an increased risk of myocardial infarction(MI) and venous thromboembolism (VTE) when used with COCs
• Blood pressure readings: if the patient’s BP readings are above 140mmHg systolic and/ or above 90mmHg diastolic then COC use is not recommended.
As with all medication COCs carry with them a series of advantages and disadvantages.
.
The advantages of COCs are that when menstruation occurs the bleeding is usually lighter and less painful plus it will occur more regularly than if contraception wasn’t being taken. Use of COCs reduces the risk of cancer of the ovaries, uterus and colon. They also decrease the risk of functional ovarian cysts and in some women the severity of acne is reduced. Normal fertility resumes once the patient stops taking their medication.
The disadvantages of COCs are that there may be temporary adverse
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