I have been on Micronor birth control pills for a little over a month. My last period was December 6 and I started Micronor the following Sunday. My husband and I had sex on the 4th and the 18th. I had some spotting and a discharge on the 19th. I was on the antibiotic ampicillin the last week of December and the anti-infective macrobid during the week of the 15th. Could I be pregnant? Could it be implantation spotting? How long should I wait to test?
Micronor is a progestin-only type of oral contraceptive. The majority of birth control pills contain both female sex hormones, estrogen and a progestin.
Progestin-only pills work similarly to both: Depo-Provera (Depo), a contraceptive injection given once every three months and Norplant, a formulation of progestin in slow release tubes which are implanted under the skin, and work for five years.
Depo-Provera and Norplant are often used for women who don’t want to, or can’t reliably take a daily pill. Once the medication is in, no further action is necessary. A monthly combination estrogen/progestin shot is now also available for women who don’t want to take pills.
Progestin only pills are generally used only for women who shouldn’t be taking the estrogen component of the combination pills. Some contraindications include: being over 35 and a smoker, having fibroids, having migraine headaches, being predisposed to cardiovascular disease and several others.
All of the progestin-only methods, including the pills, suffer from one major drawback or side effect — irregular bleeding. With the combination pills, the estrogen component stabilizes the endometrium, the lining of the uterus, and tend to prevent irregular bleeding. If sotting does occur on a combination pill, it will usually stop after two to three cycles. If it doesn’t, a pill with a slightly higher estrogen dose, or an additional estrogen pill on certain days of the cycle, will usually take care of it.
With progestin-only methods, this stabilizing effect is not present, and irregular bleeding is common. With Depo-Provera irregular bleeding will usually diminish, and about 75 percent of women will stop having periods entirely after a year on Depo.
With Norplant, the progestin dose is lower, and fewer women stop bleeding completely, although frequent irregular bleeding does diminish.
Micronor, which has quite a low dose of progestin, seldom stops menses completely, and although excessive bleeding may diminish, it will remain irregular. Because Micronor pills are taken every day, the endometrium bleeding cycle is confused. The seven hormone-free days of combination birth control pills allow for a more normal bleeding cycle.
All the combination estrogen/progestin pills have failure rates of about 0.75 pregnancies per 100 woman years of use. Progestin-only pills have a failure rate of about 2 pregnancies per 100 woman years, or slightly more than twice the rate of the combination pills. Pregnancy may be occuring more often with these pills because woman may be more likely to skip doses of the progestin-only pill due to the irregular bleeding pattern.
By contrast, Depo-Provera has a failure rate of just 0.5 pregnancies per 100 woman years.
In terms of other side effects, the progestin-only pills do not tend to cause blood clotting as do pills containing estrogen, nor will they usually increase migraines. Like Depo, large doses of progestin-only pills can lead to unfavorable changes in cholesterol, but the low dose Micronor appears to have no effect on cholesterol.
All birth control pills reduce the long-term risk of getting ovarian or endometrial cancer, as well as ovarian cysts, endometriosis, and pelvic inflammatory disease.
Contrary to widespread popular opinion, there is no proven relationship between the use of oral contraceptives (OC) and breast cancer. Dickey, in Managing Contraceptive Pill Patients states, “After adjustment for other risk factors, newer reports show either a slight increase in or a possible protective effect against breast cancer for OC users. A review of 22 epidemiological studies found no increased risk in OC users.”
Your concern about spotting after you started the pill is probably unnecessary — you may be simply having the irregular bleeding which one would expect with Micronor. I would be more concerned about pregnancy if you failed to bleed at all after a month or so on the pill. The fact that you took ampicillin during the last week of December is somewhat troubling. Antibiotics in general, including ampicillin, cause the hormones in OCs to be less effective, and it is generally advised that women taking the pill use another form of contraception, either condoms or a diaphragm, while on the antibiotic and for at least a week after.
I also want to make readers aware that the common practice which our writer followed of starting the pill on the Sunday after the start of a menstrual period is being modified by many providers. This was originally done to make it less likely for pill users to miss pills, by printing the days of the week above each pill. Sunday was picked as the standard start day. However, it did leave some women susceptible to getting pregnant during the first month of use, and using condoms along with the pill was usually recommended during that month.
Many providers now tell their patients to take the first pill on the first day of their period, whatever day that might be. This makes it much less likely that they will become pregnant during that first month, and pill manufacturers have responded by designing the pill packs so that any day can be set as the first day.