POP acts by thickening the mucous in the cervix, thereby preventing sperm from entering the uterus. It also makes the lining of the uterus thin, thereby making it less receptive to implantation of a fertilised egg on it.

Progestogen only Pill (POP) can be used at any age, even if the user is aged 35 years and above and/or is a smoker. It can also be used if there are health conditions that make the users unsuitable for the oestrogen found in the combined Pill.

THE length of time between the birth of a child and the conception of the next (inter-pregnancy interval) is associated with problems for both mother and the next child.

There is increased risk of pre-term birth (less than 37 weeks), low birth weight (less than 2.50kg) and intrauterine growth restriction (less than the 10th percentile of weight for gestational age), with the highest risk for those with an IPI of less than six months, the least risk between 18 and 23 month, and an increasing risk thereafter.

Those with an IPI of less than six months or more than 60 months also have an increased risk of the next baby having a birth defect.

Women who have had a previous Caesarean section have double to treble the risks of uterine rupture, blood transfusion or major morbidity when the IPI is less than six months.

These facts make it advisable for women to play an active role in contraception, which is a shared responsibility.

The progestogen only pill (POP) contains only progestogens which are similar to the hormone progesterone that is produced by the ovaries. It is different from the combined oral contraceptive (COC) pill, which contains both oestrogen and progestogen.

The POP acts by thickening the mucous in the cervix, thereby preventing sperm from entering the uterus. It also makes the lining of the uterus thin, thereby making it less receptive to implantation of a fertilised egg on it.

The POP may also prevent the release of an egg from the ovaries (ovulation).

They are a reliable and reversible contraceptive method that is suitable for women who want to use hormonal contraception but do not want to take oestrogens, or who have conditions which make them unsuitable for the COC.

POPs are very effective. When used correctly and consistently, less than one in 100 women will get pregnant in one year of use. When commonly used, about five in 100 women will get pregnant in a year of use.

Different POPs

There are various progestogens in POP, i.e. norethisterone, levonorgestrel, desogestrel and etynodiol diacetate.

For practical purposes, there are two different types of POP – one must be taken within three hours of the same time daily and another which must be taken within twelve hours of the same time daily.

Each pack contains 28 tablets, one of which has to be taken daily. There is no pill free interval.

POP can be used at any age, even if the user is aged 35 years and above and/or is a smoker. It can be used if there are health conditions that make the users unsuitable for the oestrogen found in the combined Pill, contraceptive patch or vaginal ring.

POP can be used when breastfeeding as it does not affect milk production, unlike the COC.

Its use is convenient and unrelated to sexual intercourse. It reduces the symptoms of premenstrual syndrome and painful periods.

If one is healthy and there are no medical reasons for not taking POP, it can be taken until menopause or the age of 55 years, when natural loss of fertility is assumed.

As soon as the POP has been stopped, one can try to get pregnant. However, it is advisable to wait for one period before trying, as it will permit more accurate dating of the pregnancy.

POPs are generally well tolerated and side effects are uncommon.

However, menstruation may be irregular, light, more frequent, or could stop altogether. In general, about four in 10 users will have regular bleeding; four in 10 users erratic bleeding; and two in 10 users will have no periods.

Other temporary side effects include breast tenderness, nausea or acne. Some women may find these side effects annoying. However, they usually settle down with time.

Mood change can occur with POP, but there is no evidence of a causal association for depression.

The use of POP is associated with a 30% increased risk of developing ovarian retention cysts, which usually disappear without treatment. Most women do not have symptoms, but some may have pelvic pain.

If one gets pregnant while on POP, there is a rare chance of having an ectopic pregnancy, ie a pregnancy that develops outside the uterus, usually in the fallopian tube. This is a potentially life threatening condition and immediate medical attention should be sought if there is sudden abdominal and/or shoulder tip pain, slight vaginal bleeding or fainting.

POP does not provide protection against sexually transmitted infections.

There is no causal relation between POP and headache. POP may be used by women of any age with a history of migraine. Users of POP who develop migraine are advised to seek medical attention.

POP is not suitable if the potential user has ischaemic heart disease, stroke, migraine with aura, breast cancer, gestational trophoblastic disease, unexplained vaginal bleeding, viral hepatitis, severe liver cirrhosis, liver tumours or is taking liver enzyme-inducing medicines.

Taking POP

The POP can be started at any time of the menstrual cycle. If started on the first day of the period, or up to, and including, the fifth day of the period, there will be immediate protection against pregnancy unless the menstrual cycle is short – 23 days or less.

If the POP is started later or the menstrual cycle is short, there will not be immediate protection against pregnancy and either abstinence or additional contraception, like condoms, is required until after it has been taken for two days.

When changing to a POP from a combined oral contraceptive (COC), the pill free interval should be omitted and the POP started at the end of the pack of COC. In the case of daily COC, the POP should be started after the last active tablet, omitting the inactive tablets.

POP can be started up to and including 21 days after giving birth without any additional contraception required. If POP is started after this time, abstinence or additional contraception is required until after the POP has been taken for two days.

POP can be taken immediately after a miscarriage without any additional contraception required. If a POP is started more than seven days after a miscarriage, then abstinence or additional contraception is required until after the POP has been taken for two days.

It is advisable to choose a convenient time to take the POP, a time that can be adhered to consistently for the maintenance of contraceptive cover. One should continue taking the POP daily within either three or twelve hours of the same time daily, depending on the type of POP. When the pack is finished, the next pack has to be started immediately. There is no break between packs of POP.

Missed pills

If the POP is taken less than three or twelve hours late, depending on the type of POP, the missed pill should be taken immediately and subsequent pills taken at the usual time even if it means taking two pills at the same time. As contraceptive protection is unaffected, additional or emergency contraception is not required.

If the POP is taken more than three or twelve hours late, depending on the type of POP, the missed pill should be taken immediately and subsequent pills taken at the usual time even if it means taking two pills at the same time. Abstinence or another contraceptive method has to be used for 48 hours after the pill is taken.

If there is sexual intercourse when one or more POP are taken more than three hours or twelve hours, depending on the type of POP, emergency contraception is required.

If there is vomiting within two hours of taking a POP, then another pill has to be taken as soon as possible. If vomiting continues or there is severe diarrhoea, the above rules have to be adhered to.

The effectiveness of POP is affected by antibiotics like rifampicin and medicines that hasten the breakdown of progestogen by the liver (enzyme inducers) like anti-epileptics, St John’s wort and antiretroviral medicines used to treat HIV.

The doctor will advise alternative or additional contraception while taking any of these medicines.

Bleeding problems are not uncommon with POP. Should there be a change in bleeding pattern when using a POP, assessment by a doctor is advisable and the risk of pregnancy, sexually transmitted infections or gynaecological pathology have to be considered.

There is no evidence that changing the progestogen type or dose will improve bleeding but this may be helpful in some individuals. If bleeding patterns are still unacceptable after other causes have been excluded, alternative contraception may need to be considered.

It is advisable to take POP under medical supervision. A clinical history and physical examination is necessary at the initial consultation to identify conditions which render a person unsuitable for POP. Follow-up appointments are tailored to the individual woman, who would be advised to return at any time if problems arise.

In the absence of any problems, women may be prescribed up to 12 months supply of POP.

Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation the writer is associated with. For further information, e-mail starhealth@thestar.com.my. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.

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