Contraception and Sterilization
By Date of Release Topic April 30, 2000 Drugs Affecting Birth Control Pills December 12, 1999 Menstrual Seizures and Progestin Only Contraceptives September 26, 1999 Pregnancy During and After Taking Oral Contraceptives July 25, 1999 IUCD - A Forgotten Contraception Method April 25, 1999 Post Tubal Ligation Syndrome Review February 28, 1999 Bleeding Expectations on Oral Contraceptives January 10, 1999 Timing Advice for Contraceptives August 16, 1998 Hereditary Ovarian Cancer Reduced by Oral Contraceptives July 5, 1998 Self-administered Emergency Contraception February 8, 1998 Oral Contraceptives and Cancer Risks November 30, 1997 Side effects of Depoprovera® in teens
Menstrual Seizures and Progestin Only Contraceptives
Frederick R. Jelovsek MD
How do reproductive hormones affect epileptic seizures?
Taking estrogen medications may cause an increase is seizure activity in some women prone to this and taking progesterone may lessen seizures. It is interesting that at the time of menses there is a decrease in both estrogen AND progesterone. Therefore it is the lack of progesterone that was preventing some seizures that is the primary force leading to increased seizures in catamenial epilepsy. And since progesterone is only naturally secreted in the last two weeks of the menstrual cycle, there may be a decrease in seizures at that time but the "decrease" disappears at the time of menses just as progesterone also disappears.
How does the seizure frequency vary with a menstrual cycle?
There can be several different effects of the normally cycling reproductive hormones on seizure frequency in women with epilepsy. In women with ovulatory cycles, there can be an increase in seizures right around ovulation at midcycle when estrogen levels spike higher. There also can be an increase during menses when progesterone (and estrogen levels) decrease. Finally, in women who are anovulatory, there seems to be a lower seizure incidence in the first two weeks of the cycle and an increased incidence after the first two weeks when there should be progesterone around but it is not present because ovulation did not occur.
Is there a birth control pill consisting of only natural progesterone, not synthetic progestins?
No, not at the current time. It sounds enticing to take a progesterone only birth control pill which should keep constant progesterone levels throughout the entire cycle. Thus seizure activity should be decreased all of the time and not vary in frequency throughout the days of a menstrual cycle. In fact progesterone supplements have been shown to reduce catamenial epileptic seizures on the average by about 55%. The main problem is that natural progesterone alone is not a contraceptive. Synthetic progestins like medroxyprogesterone acetate (Provera®, DepoProvera®) can also reduce seizure activity but not as effectively as natural progesterone.
Would a natural progesterone pill or the natural progesterone cremes for that matter, protect you against getting pregnant?
There are no natural progesterone containing birth control pills that I know of at the present time. Historically when researchers first developed oral contraceptives, they were looking for a way to manufacture progesterone from Mexican yams and when they first discovered the contraceptive effects of their manufactured progestins, they were very excited. As they purified the compounds to contain only progestins and not the contaminant estrogen (specifically mestranol) they lost the contraceptive effect of the pills. Thus the discovery that you needed both progestin and estrogen to have an effective contraceptive pill by mouth.
Now we know that progestin only pills can function as contraceptives, not by inhibiting ovulation but by making the cervical mucous hostile to sperm penetration and the endometrium hostile to fertilized egg implantation. But they are not as effective as combined oral contraceptives in preventing pregnancy. The typical use failure rate of progestin only pills is about 5%.
What would be the best birth control for a woman with catamenial epilepsy?
There is no best answer for this. I could not find studies of DepoProvera® used for contraception in women with epilepsy, nor with just progestin only pills. It is not even clear that regular oral contraceptives containing estrogens worsen seizure activity; they may not. In the absence of clinical trials and data, we need to reason using the studies and physiology that we do know about.
I think in the next patient I see who describes catamenial epilepsy, I might suggest one of several approaches:
- if a woman has had one or more children, the use of a progesterone IUCD and continuous oral micronized progesterone at about 100mg or 200 mg twice a day should provide birth control as well as decrease the seizures as much as reproductive hormones can.
- The above is also an option for a woman who has not had any children but if tolerating the IUCD was a problem, then using a very low dose estrogen containing oral contraceptive (20 mcg dose) with a supplement of oral micronized progesterone at about 100-200 mg twice a day could be tried.
The twice a day dose of oral progesterone should be better to lower neuron sensitivity since the blood level of progesterone from an oral dose peaks at about 3 hours with therapeutic levels for 6 hours and clearing by 24 hours. I do not know if the current non prescription progesterone creams(25 mg/tsp) would provide this level of progesterone unless you used at least 1-2 teaspoons a day. No woman should used the progesterone cream as a contraceptive.
Pregnancy During and After Taking Oral Contraceptives
Frederick R. Jelovsek MD
Will taking birth control pills make a pregnancy test inaccurate?
No. Pregnancy tests are NOT interfered with by the hormones of oral contraceptives. You are correct that estrogens are elevated in pregnancy and birth control pills contain estrogens, but that is not the hormone that is measured to determine pregnancy. All pregnancy tests measure the beta subunit of a placental hormone called human chorionic gonadotropin (HCG). You will often see it abbreviated as beta HCG. It can be measured in the urine
or blood. While it depends upon the sensitivity of the specific test, most home urine pregnancy tests (sensitive to 25 mIU) will turn positive about 13-16 days after conception. If you were not on oral contraceptives, this would mean about the time of the first missed menses. When you are on oral contraceptives, ovulation could have occurred at more irregular times so that all you can say is if the pregnancy test is negative, you are either not pregnant or are less than about 14 days pregnant from ovulation.
How likely is it to get pregnant with missing pills or being late in taking them?
There are many reasons why women may not take their birth control pill on time or even miss them entirely. Such reasons for missing pills include disruptions in their daily routines, their husband's absence, spotting, and just trouble remembering to take them each day. If you are missing pills, you are not alone. One study shows 47% of women missing >=1 pill per cycle and almost a quarter (22%) missing >=2 pills per cycle. Even though this rate of missing pills commonly happens, it is still unlikely to get pregnant. In women off pills for 10 days, only about one in ten will ovulate.
While it is normal to be concerned about possible pregnancy when missing pills, most women can be reassured that they will not get pregnant as long as they do not continue to stay off of the pills.
If I miss some pills in a cycle, should I take them or just stop and wait for my menses?
Ovulation does not usually occur within the first 4 days of missing pills. For many women, however, by the third day of missing pills a menses will usually have started. If you have just missed one pill, take that pill (yesterday's) and today's pill both together and just continue on as per your normal schedule. If you have missed 2-4 pills and just have spotting, you should go ahead and resume taking the pills you are supposed to be on and finish out the pack. Even though the odds are still in your favor not to get pregnant, most doctors would advise you to use back up contraception (condoms/foam) over the next seven days or abstain from further intercourse until that cycle is over.
If your menses has fully started, just stay off of the pills until you have been off for seven days and then start a new birth control pill pack.
What happens if I was taking oral contraceptives when I was already pregnant?
While no one would intentionally take oral contraceptives if they knew they were pregnant, many women each year inadvertently take pills being un
aware they are already pregnant. In the U.S. and Europe, in approximately 2-5% of all pregnancies mothers have a history of having taken birth control pills without realizing they were pregnant. Many years ago, with higher dose contraceptive pills, there were concerns that the hormones in pills could produce genital changes in both male and female babies. Subsequent studies have failed to confirm this. At the Hospital for Sick Children in Toronto, Canada, the Motherisk program which tracks various birth defects, there is a good article on oral contraceptives and their effect on pregnancy. This article suggests that there is no need to be concerned about the pills causing birth defects any more than the background rate of birth defects that normally occurs.
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