The Oft Forgotten Minipill (POP)
There seems to be a slow resurgence in the use of the minipill (or progestin only pill POP) as a form of birth control for women. This POP has been around for some time but is rarely used in the United States whereas 10-15% of women in Great Britain and Sweden are on the POP.
What Is the POP?
Unlike the normal birth control pill that has both estrogen and a progesterone component, the POP has solely a progestin agent. There are commercially three available brands of the POP. Two have the same hormone known as norenthindrone and are called Nor QD and Micronor. A third variety has the hormone norgestrel and is known by the name of Ovrett. Each one containing a progestin in a dose lower than even the low dose estrogen/progesterone pills.
How do POP Work?
Unlike the regular pills the POP have an active hormonal agent all 28 days of a cycle. This mimics the effect of the injectable Depoprovera or the subdermal Norplant. These are two similar progesterone only contraceptive methods that last 3 months to 5 years. The POP is just taken daily to reach the same effect. But because of the very low dose of the pill the contraceptive efficacy is slightly less then the injectable or subdermal route.
The mechanism action is on (1) decreasing the chance of ovulation, (2) altering the endometrial lining where if fertilization did occur then implantation is less likely and (3) thickening the cervical mucus making sperm penetration less likely.
POP Precautions
POP users need to be meticulous about taking the pill the same time each day. Because of a short half life of the progestin agent the miss timing of taking the pill by just 3 hours may decrease the pill effectiveness and thus require a backup birth control method. For example, if a woman normally takes the pill each morning and forgets to take such by lunch time then she should take the pill immediately and use back up the rest of the month.
POP Success Rates
If the POP is taken in a timely fashion the failure rates are similar to the regular birth control pill; between 1-3 per 100 users. The side effects are minimal with the most common one being irregular bleeding or spotting and even lack of periods all together; otherwise there are not really any other reportable side effects of POP.
The Benefits of the POP
The POP is of particular benefit for women who cannot use the regular birth control pill. Most commonly these are women who cannot tolerate the estrogen or have a medical condition that contraindicates its use. These are those who may get nausea from the estrogen pill, headaches, blood pressure elevation, breast tenderness and decreased libido.
Some women can’t use the estrogen pill because of a history of blood clots, diabetes or lipid disorders. The POP is of benefit to nursing women since it does not effect mild breast production. In fact some studies have shown an improvement in mild production for women on the POP. This is one of my preferred choices for my postpartum patients because it gives good birth control without any unwanted side effects and can be used while breast-feeding.
Women who smoke will be able to use POP with less risk then the estrogen pill. Those women who use anticonvulsant medication though should realize that their medicine will decrease the effectiveness of the POP.
The POP, when taken meticulously, can offer women a new option for an effective and low hormonal dose of birth control. Particularly those women who are breastfeeding, cannot tolerate the estrogen pill or have medical conditions contraindicated to using estrogen.
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