Historically patients need to be counselled to determine their suitability for a Progesterone Only Pill (POP) because the original brands have to be taken within 3 hours of the same time, every day. With its slightly increased failure rate than the combined pill, it was felt that ladies with a stable lifestyle would be more suited to this regime, especially if this was combined with the reduction in fertility found with ladies aged over 30 and/or breast feeding. However, the introduction of the newer POP Cerazette, with its up to12 hour delay in pill taking has made the POP a useful option as a method of contraception, particularly if the Combined pill is contraindicated. The use of progesterone only products have a reduced risk of venous embolism compared with combined contraceptive pills. Counselling re sexual health and the prevention of STIs should also be included in the consultation. All available methods of contraception should be discussed, to give the patient a wide choice of options.
Types of progesterone only pills
There are 6 brands of old POPs eg Femulen, which must be taken every day and within 3 hours of the same time of day. The newer POP, Cerazette, can have a delay of up to 12 hours before adding in precautions.
Other progesterone only products include
- Injections (eg depo provera)
- implants (implanon)
- IUD (Mirena)
- vaginal rings
Risks, advantages and disadvantages
- Effective and reversible (failure rate 0.5% in original POPs but 0.17% with Cerazette)
- Decreased risk of venous embolism (suitable for certain WHO contraindications)
- Decreased risk of endometrial cancer, PID, PMS, mastalgia and thrush.
- Does not interfere with breast-feeding.
- Not affected by antibiotics, sodium valproate or clonazepam.
- Causes fewer metabolic changes does not raise BP or increase cholesterol levels. Minimal effects on clotting mechanism and glucose metabolism.
- Not known to increase risks of IHD, stroke or venous thromboembolic disease.
- Need to be taken daily, and if using any POP other than Cerazette, must take the pill at the same time every day or at least within 3 hours.
- Irregular periods, heavy periods or no periods, can occur.
- Interactions with enzyme inducing drugs can occur (rifampicin and some anti-epileptics.
- May worsen acne. Side effects headaches, dizziness, nausea, bloating, breast tenderness, moodiness and loss of libido.
- Ovarian cysts may occasionally develop.
History is patient suitable for a POP?
- Weight (if over 70kg, needs double dose of original POP such as Femulen, or normal dose of cerazette.)
- BP if hypertensive, control first.
- Age and lifestyle
- General Health and Past History
- Menstrual History & Obstetric History
- Altered cervical mucous preventing sperm penetration.
- Altered endometrium preventing implantation.
- Suppresses FSH and LH and therefore ovulation (not absolute in old POP)
Pill Taking Education
- The POP should be started on the first day of a period, if any later than this, additional contraception must be used for 7 days.
- If changing from a COC, start the POP at the end of the COC pack, without having a pill free week. After pregnancy, 3 4 weeks, once lactation is established.
- Must be taken every day and at the same time of day or within 3 hours. Preferably at the time of day when intercourse usually takes place. EXCEPT Cerazette, where a delay of up to 12 hours will not affect the efficacy of the pill.
- If a pill is delayed by more than 3 hours (or 12 hours with Cerazette) but no missed pills, then added precautions (eg condoms) should be used for 48 hours.
- If a pill is missed, then the due pill should be taken and any others discarded and added precautions taken for 7 days. However, if missed POP and intercourse has taken place, then emergency contraception should be given as well, and POP restarted the next day.
- If vomited with 3 hours of pill taking, another pill should be taken. If further vomiting occurs, then continue with daily pill, and added precautions should be taken till illness resolved plus 7 days.
- If severe diarrhoea occurs, continue taking pill but use added precautions until illness resolved plus 7 days.
- Added precautions may be needed for short-term interactions.
- Sexual health use of condoms reduces the risks of STIs. Give PAL. Check smear status.
Choice of POP
The older POPs are cheaper than Cerazette and with reduced fertility found with lactating mothers and ladies over 45, could still be first choice. However with Cerazettes lower failure rate and greater effectiveness, especially if overweight, then serious consideration should be given to prescribing Cerazette as the POP of choice.
- Known or suspected pregnancy.
- Menstrual disturbance of unknown cause.
- Breast cancer unless in remission and with permission from consultant.
- Current history of serious cardiovascular disease.
- Hydatidiform mole not fully resolved
- Hepatic adenoma. Severe active hepatitis or cirrhosis.
- On medication that may interact enzyme inducers.
- Severe allergy to constituent.
- Caution with those who would not take pills regularly or would not tolerate irregular periods and patients with ovarian cysts.
- BP check at 6 months and if stable, review annually.
- Menstrual disturbance.
- Education and pill taking. Knowledge re when needs to take extra precautions.
- Wt if weight 70kg or more, needs to double dose if on old POP or use Cerazette.
- Side effects or any new risk factors. Stop POP if develops a contraindication and refer to GP.
- Aware of STIs and use of condoms.
- Smear status.
- If wanting to conceive, pre-natal advice re smoking, diet and exercise. Also to take folic acid and check rubella status. POPs not known to be teratogenic.
- If menopause check FSH and LH, two weeks apart and discuss with GP.
- Glasier,A Bebbie,A Family Planning and Reproductive Health Churchill Livingstone
- Guillebaud,J Contraception Today. Taylor and Francis