Operational Obstetrics & Gynecology
Birth Control Pills
Benefits of BCPs
BCPs provide highly reliable contraceptive protection, exceeding 99%. Even when imperfect use (skipping an occasional pill) is considered, the BCPs are still very effective in preventing pregnancy.
In addition to their contraceptive benefits, the BCPs have a number of other benefits. BCPs generally:
Risks of BCPs
Aside from a number of minor, but annoying, side effects, serious risks of BCPs are limited, for the most part, to cardiovascular problems, including stroke, heart attack, thrombophlebitis and thromboembolism.
There is also a very small, but measurable increase in the risk of liver tumors and cysts. The incidence of such problems in the population is so small and the added risk so marginal that only rarely will this risk play a role in the clinical decision for or against BCPs .
Which Pill to Start
Pick any standard, low-dose birth control pill that is readily available.
Most women (90%) will do well on any low-dose BCP. A few will do well only on certain BCPs, but there is no way to predict in advance which pill will work best for any individual woman.
Historically, as the hormone dose of birth control pills was lowered, the risk of serious complications such as blood clots was also reduced. For that reason, starting a low-dose pill (30-35 mcg of estrogen) is preferable to starting medium dose (50 mcg) or high dose BCPs. Lowering the dose below the 30-35 mcg dose has not, however, led to any additional clinical benefits but has made some of the very-low-dose pills more "unforgiving" than the standard low-dose BCPs.
Starting the Pill
Take the first pill on the first Sunday following the beginning of the menstrual flow.
This means that if a period starts on a Tuesday, you should wait all the way through the week until Sunday, and then start taking the BCPs. If the period starts on a Saturday, then the first BCP would be taken the next day, Sunday. If the period starts on a Sunday, take the BCPs the same day. This method is called a "Sunday Start" and has a number of advantages. Because a fresh pill pack is always started on Sunday, it is easier for some people to remember. Using a "Sunday Start" means that the pill-induced periods will usually begin early in the week (Monday or Tuesday) and will be over before the weekend. Many women find this timing convenient and desirable.
An alternative method ("5th Day") is to always start the BCP pack on day #5 of the menstrual cycle. Day #1 is the first day of flow. This method is very effective but requires counting and recalculations each month.
When are the Pills Effective?
The pills are reasonably effective right away.
Some physicians recommend that women use a back-up method of contraception (such as condoms) during the first month of BCP use.This is based on the observation that BCPs probably do not achieve their 99.9% effectiveness until after the first month of use.
It is also true that the BCPs are pretty effective, even starting with the first BCP. Many BCP manufacturers suggest that the BCP is effective after 7 days of continuous use. Even before 7 days of BCPs have been taken, considering that phase of the menstrual cycle, pregnancy is not very likely. For these reasons, the BCPs are probably about as effective as using a diaphragm (~85%-95% effective) as soon as they are started. For women seeking a higher level of protection against pregnancy (99.9%), using a backup method of contraception during the first month of BCP use may be considered.
Skipped a Pill
If she just skipped one pill, she should take it as soon as she remembers, then continue the rest of the pills at the normal time.
If she didn't remember until the next day, take both the current day's pill and yesterday's pill together. Then continue with the rest of the pills in the usual way.
If she's forgotten two pills or more, stop the BCPs, wait a few days for a "withdrawal" menstrual flow, and then restart a fresh package of BCPs 5 days after the onset of flow. Use backup contraception during this time and for the first month after restarting the BCPs.
History of Migraine Headaches
A history of migraine headaches is not a contra-indication to taking birth control pills.
Some women with migraine headaches find they have fewer headaches while taking BCPs. This is particularly true for those women whose headaches primarily occur with ovulation or around the time of the menstrual flow. Other women with migraine headaches find the BCPs have no noticeable effect on their headache frequency or severity. These women may safely take BCPs.
Those women who experience worsening of their migraine headaches should not be continue the same BCP. Switching to a different pill, with different content, from a different manufacturer, may solve the problem. If not, it will generally be necessary to stop the BCP completely.
High Blood Pressure
The birth control pill may be safely prescribed to women with pre-existing high blood pressure, but it is important for many reasons that the blood pressure be monitored and well-controlled.
BCPs occasionally aggravate pre-existing high blood pressure. If this happens, switching to a different pill will sometimes solve the problem. If switching fails to resolve the problem, then usually the BCP will need to be stopped.
BCPs will rarely cause a woman with normal blood pressure to become hypertensive. If this happens, switching to a different pill manufacturer will often solve the problem, but if not, the BCP is usually stopped.
The birth control pill may be safely taken by women with either a personal history or family history of diabetes melitus.
Women who have diabetes often find taking BCPs has either no effect on their diabetic control or else improves their control. Some women find they need more insulin while taking BCPs, but are otherwise satisfied with the pill and these women may safely take it. A few women find their diabetic control is adversely affected by the BCP. For those women, changing the pill may be tried, but often the BCP must be discontinued.
Women with a family history of diabetes generally have no trouble taking BCPs. Very rarely, the BCPs may provoke diabetes (or unmask it). If this happens, alternative BCPs may be tried but usually the BCPs will be discontinued.
Blood Clot History
Women who have personally experienced such blood clot problems as deep-vein thrombophlebitis, pulmonary embolism, cerebrovascular accident (stroke) or heart attack should not, under ordinary circumstances, take birth control pills.
Women who have a family history of such problems but who have not, personally, experienced the problems, may safely take BCPs.
The Particular Pill She's Using is not Available
Switch her to a BCP that is available.
This is frequently an issue in operational settings. Because medical resources are not unlimited in these situations, it is often necessary to switch to a different pill. Since most women (90%) will tolerate any BCP without difficulty, making a switch is usually uneventful and most women will not notice any difference. It is best to make the switch at the time the old pills would have been started (after the "off" week), but they can be switched at any time during the cycle.
It is possible but not common that they will experience some of the side-effects of nausea, spotting or breast tenderness during the first month of the switch. After the first month of the switch, these symptoms generally disappear.
Anticipate that some of these women will be reluctant to change pills, particularly if they have had good success with one pill for a long time or if they had difficulty finding a pill that worked well for them.
If a woman is expected to have a menstrual period at a time that is inconvenient or troublesome from an operational standpoint, it is often possible to postpone the menstrual flow using BCPs.
Usually, BCPs inhibit ovulation and menstrual periods occur among women taking BCPs only because the user stops taking the BCPs for a few days. The fall in hormone levels triggers an apparently "normal" menstrual flow.
With that principle in mind, a woman's normal menstrual flow can often be postponed by starting BCPs within 5 days of the beginning of her last menstrual flow. When she comes to the end of a 21-day pack of BCPs, she goes immediately into the next pack of BCPs (skipping the "week off.") She then continues with the second pack until such time as it becomes convenient to have a menstrual flow. Stopping the pills at this time will provoke a normal flow about 3 days after stopping the pills.
This use of pills will usually keep her from ovulating (and keep her from having a period at the normal time). It is safe and will not cause any other disruption to the menstrual flow.
Postponing menstrual periods is a technique often used by women entering short-term operational settings when they do not wish to have a menstrual flow while operationally deployed. There are drawbacks, however, to this approach. While most women tolerate BCPs without side-effects, some women (~20%) will experience such side effects as breast tenderness, nausea and spotting. Most of these side effects will occur during the first month of BCP usage. So a woman who takes BCPs for 6 weeks to postpone a menstrual period may be substituting one nuisance (menses at an inopportune time) for another nuisance (nausea, breast tenderness, spotting). One way to avoid these problems is to begin the BCPs well enough in advance of the operational commitment that any minor side effects have worn off.
Another issue to consider is that while BCPs usually inhibit ovulation, they don't always inhibit ovulation. In other words, this menstrual-flow-postponing-protocol may not work, although it usually does.
Choose a monophasic, standard low-dose BCP, such as LoOvral, Ortho Novum 1+35, LoEstrin 1.5/30 or similar pill when using it for this purpose. Avoid multiphasic pills and extremely low dose pills as their inhibition of ovulation is less reliable although they certainly are effective as far as contraception is concerned.
Most women (about 80%) experience no side effects while taking BCPs.
The rest experience generally minor side-effects during the first month of BCPs. These side-effects might include breast tenderness, nausea, spotting or headaches, and generally disappear after the first month. If they persist, changing to a different pill, from a different manufacturer, with different hormonal content, will usually eliminate the problem.
Occasionally, several pills will need to be tried before the best (least side effect for that individual person) is found. Very rarely, no satisfactory BCP can be found and those women will need to make a judgment whether they would rather continue the BCPs (with the side effect but with the BCP benefits) or to use an alternative method of contraception.
Breast tenderness is relatively common during the first month of BCPs and uncommon thereafter.
Persistent breast tenderness is most often associated with fibrocystic breasts. Typically, women with this condition notice the breast tenderness getting much worse just before menses and much better after the onset of flow. BCPs are a reasonably effective treatment for fibrocystic breasts so subsequent development of significant breast pain should be viewed as unusual.
A careful breast exam should be done to rule out newly-developed breast disease. A recent onset of significant breast tenderness should raise your suspicions about a possible unsuspected pregnancy.
Nausea occurring after the 1st month or severe nausea at any time should make you suspicious of pregnancy, and this is usually ruled out by a negative pregnancy test or convincing patient history.
As individuals age, there is a tendency to gain weight, with or without BCPs. It is difficult to show any significant additional weight gain in groups of women taking low-dose BCPs compared to groups of women (of the same age) not taking BCPs.
That said, there are certainly individual women who gain weight when they take BCPs and lose the weight when they stop taking the BCPs. Similarly, there are individual women who lose weight while taking the BCPs and gain it back when they stop.
While headaches can have many different causes, it is uncommon for the birth control pill to provoke headaches.
Migraine headaches generally improve or stay the same on BCPs, but occasionally get worse.
Premenstrual or menstrual headaches generally improve on BCPs, but occasionally get worse. If a woman complains of headaches only during the "off week" of BCPs, you can frequently resolve her headaches by modifying the way in which she takes her BCPs. These menstrual headaches are often provoked by the withdrawal of estrogen and progestin that accompanies the stopping of the BCPs at the end of each cycle.
If headaches persist on the BCPs and alternative formulations or dosage schedules fail to resolve the problem, the BCPs will generally be stopped.
Moodiness or Depression
Most cases of mood change are unrelated to the BCP use, but mood changes are a recognized potential side effect.
In these cases, switching to a different BCP from a different manufacturer, with a different hormone formulation, will often resolve this problem. If the mood changes persist, it may be worthwhile to stop the BCPs for a month or two to see if this resolves the problem.
Women with pre-existing depression, with or without anti-depression medication, can safely take BCPs, but should be monitored for signs of worsening of their depression.
It is not healthy to remain moody or depressed for long periods of time, so this is an issue that clearly will need resolution one way or another.
Vaginal dryness or decreased lubrication during sexual activities is an uncommon but not rare side effect.
This occurs when the BCP suppresses ovarian function (and natural estrogen production) but does not replace enough estrogen (from the BCP) to fully stimulate the vaginal and vulvar tissues. Women with this problem complain of vaginal dryness, irritation, sometimes painful intercourse and diminished lubrication during sex.
Stopping the BCP will resolve this problem, but switching to a different pill from a different manufacturer may also resolve the problem. Adding additional estrogen (such as Premarin 0.625 daily) can also be effective, but long-term use may pose added cardiovascular risks such as is seen in the medium-dose or high-dose BCPs. "Personal Lubricants" can be used to overcome the problem, such as Lubrin, Replense, or KY Jelly.
Decreased Libido (Sex-Drive)
Some women notice diminished interest in sex while taking BCPs.
Changing to a different BCP from a different manufacturer may resolve this problem, but some of these women find that no matter what brand of BCP they take, they experience this problem.
There are many possible causes of decreased libido, including stress and relationship problems. To be certain the cause is the BCPs requires stopping the BCPs for a reasonable period of time (1-3 months) and seeing if the libido returns. Then, the BCPs are restarted to see if libido again changes.
Painful Menstrual Cramps
This is an unusual complaint for someone taking the birth control pill.
Usually, BCPs make menstrual cramps better and many women find they have no cramps at all while taking BCPs. For someone to notice worsening of menstrual cramps while taking BCPs suggests that some other medical problem has developed, such as pelvic infection or endometriosis.
In an operational environment, it is may be worthwhile to obtain cervical cultures for chlamydia and gonorrhea, but many physicians would give a course of antibiotics considering the varying degrees of reliability of such cultures and unusual nature of the symptoms in such circumstances. Good choices for antibiotics in this situation would include any of the following:
The symptoms of menstrual cramps (dysmenorrhea) on BCPs can usually be relieved by taking the BCPs continuously, without stopping for the "off week." Whenever the operational commitment is complete, gynecologic consultation can be very useful to look for the many causes of cyclic pelvic pain.
Continuous Birth Control Pills
In some operational settings, it may be desirable to avoid menstrual flows completely. Depending on the tactical situation, changing sanitary pads or tampons can be difficult, distracting or dangerous. Women with significant menstrual symptoms (cramps, malaise, depression) may find it easier to complete their mission if menstruation is avoided altogether.
Normally, women take BCPs for 3 weeks and then stop the BCPs for a week. During the "off week," they have their menstrual period. The reason they have a menstrual flow at that particular time is because they stopped taking the BCPs. In other words, the menstrual flow is really a hormone withdrawal bleed. If they didn't stop taking their BCPs, they wouldn't have a period.
Using this principle, a woman can go directly from one pack of pills into the next, skipping the "week off." She won't have a period. At the end of the second pack of pills, she can again go directly into the third pack, skipping the "week off' and skipping a menstrual flow.
This way of taking BCPs is safe and just as effective in preventing pregnancy as taking them the normal way. The only drawback is that she loses the regular, monthly feedback of a menstrual flow, reassuring her that she is not pregnant. In practice, the BCPs are so powerfully effective that effectiveness is not really an issue. Should a woman become pregnant despite the use of BCPs (very, very rare), she will have other symptoms suggesting the pregnancy, including breast tenderness, fatigue, nausea and bloating.
In theory, women could use continuous BCPs indefinitely and never have a period so long as she continued taking the pills. Actually, there are two limiting factors to this approach. First, most women taking continuous BCPs will eventually experience some spotting or breakthrough bleeding. If it is mild and occasional, it is generally ignored. If it is daily or heavy, you can:
Second, some women will occasionally experience a break-through ovulation, followed two weeks later by a menstrual flow. BCPs normally suppress ovulation, but their contraceptive effectiveness does not depend totally on ovulation inhibition. BCPs also change cervical mucous, fallopian tube motility, endometrial receptivity and doubtlessly has other effects. Particularly with low-dose BCPs, some women will ovulate anyway, although it is usually not noticed (when it occurs in phase with the BCP's), and pregnancy does not occur. For women taking continuous BCPs, any ovulation will inevitably be followed 2 weeks later by a full menstrual flow (whether she's taking BCPs or not), and such an event will certainly be noticed. If the woman taking continuous BCPs has a full-blown period, then it is wise to change to a different pill from a different manufacturer. Monophasic pills work better for this purpose than multiphasic pills.
No Period or Very Light Period
The heaviness of a menstrual flow depends on the thickness of the lining of the uterus just before the onset of menses. The thicker the lining, the heavier the flow. In women using low-dose BCPs (for example: Ortho Novum, LoOvral, Ovcon, etc.), there is a tendency for the uterine lining to become very thin, over the course of many months.
Clinically, this is reflected as lighter and lighter periods which may even stop completely.
This is not a dangerous condition and will resolve if the BCPs are stopped. Stopping the BCPs is not necessary, however, because there are other safe alternatives. If the periods are simply very light (1-2 days), you can ignore the problem because this situation poses no threat to the patient.
If periods have totally stopped:
Spotting Between Periods
This symptom is common during the first month of BCPs, particularly with some of the multiphasic BCPs.
This is not a dangerous condition, but may be a nuisance to the patient. In the presence of a normal Pap smear, this symptom can be safely ignored for two months and more likely than not, it will go away.
If spotting persists, changing to fixed-dose, mono-phasic BCP (such as Ortho Novum 1/35 or LoOvral) will usually solve the problem, particularly if you switch to a different manufacturer.
Occasionally, women spot even following this change and these women should stop the BCP briefly to make sure this symptom goes away. So long as the spotting disappears with discontinuation of the BCP, you can safely conclude that the spotting was due to the BCP and you may resume the BCP if you like. The spotting may return, but poses no threat.
Other benign conditions can cause spotting, such as endocervical or endometrial polyps, cervical irritation, and uterine fibroid tumors, but none of these pose an immediate threat and can reasonably be ignored for months if necessary until definitive gynecologic consultation can be obtained.
Uterine malignancy in a woman under 35 is extremely rare, particularly if that woman has been on BCPs. Spotting caused by uterine malignancy won't go away if BCPs are discontinued. Cervical malignancy can be reasonably excluded by a recent (within 1 year) normal Pap smear and the absence of a visible lesion on the cervix. Vaginal cancer (extremely rare) is ruled out by a normal vaginal exam.
Periods at the Wrong Time
If a full menstrual flow occurs while the woman is taking her pills, this usually means she has ovulated despite the BCPs.
This doesn't mean she will become pregnant, since the BCP has a number of ways of preventing pregnancy in addition to inhibiting ovulation, but it may increase slightly the statistical chance of pregnancy.
If she continues to take the same BCP according to her usual routine, the BCP may, over the next month or two, achieve reasonable control over the menstrual cycle. Backup methods of contraception should be employed during this time.
Alternatively, many gynecologists will stop the BCPs for 1-2 months to allow the woman's normal cycle to re-assert itself, and then resume BCPs (but from a different manufacturer, often using monophasic rather than multi-phasic BCPs) in step with the woman's own cycle. This means starting the BCP the 5th day after the beginning of flow, or alternatively, the first Sunday after the onset of the flow.
Pregnancy may also cause bleeding during the pill cycle.
Other causes for episodic abnormal bleeding include uterine fibroid tumors, uterine polyps, trauma and malignancy. A physical exam will reveal some of these but others will require more sophisticated gynecologic evaluation. Remember, uterine malignancy under age 35 is very rare and vaginal malignancy is extraordinarily rare. Cervical malignancy in the presence of a normal Pap smear is also very uncommon.
If abnormal bleeding persists, gynecologic consultation will be necessary, but this can be safely accomplished within weeks to months so long as the:
When taking Birth Control Pills and antibiotics, it is generally not necessary to use any form of back-up contraception.
Taking antibiotics may lead to altered intestinal flora and ultimately to changed levels of hormone in the patient's blood stream. This observation has led some authorities to suggest the use of back-up contraception, believing that the changed levels of hormone might diminish the effectiveness of the BCP.
In controlled studies, this theory has not been proven, and in the case of tetracycline and chlortetracycline, no increased risk of pregnancy was found.
If taking antibiotics has any effect at all on pregnancy rates, the effect must be very small and is not likely to have much clinical relevance in an operational setting.
Thinks She May be Pregnant
You should find out.
BCPs are the most effective reversible method of contraception and failures are uncommon. Factors which increase the likelihood of failure would include skipping BCPs or taking an interfering drug. Pregnancies may rarely occur in women taking the BCP correctly.
Any time any woman taking BCPs thinks she might be pregnant, get a sensitive pregnancy test. Usually, she'll be wrong and not pregnant, but occasionally, she'll be right and in such cases the BCP should be immediately stopped.
Emergency Contraception ("Morning After" Contraception)
Within 72 hours of unprotected intercourse, birth control pills can be taken in such a way as to reduce the likelihood of pregnancy occurring.
Two Ovral (not Lo-Ovral) are taken, followed 12 hours later by two more Ovral pills. No additional pills are taken. Should Ovral not be available, good alternatives include:
If none of these pills are available, it is likely that any standard low-dose BCP (four pills initially, followed by four more, 12 hours later) will have similar effects. These other preparations have not been studied in as much depth, however, so it is certainly preferable to use one of the listed BCPs.
With the use of emergency contraception, the risk of a pregnancy occurring is reduced by about 75%. If 100 women have a single episode of unprotected intercourse during the middle two weeks of their menstrual cycle, normally about 8 of them will conceive. If they all use emergency contraception, only about 2 of them will conceive, a 75% reduction in risk of pregnancy.
The greatest experience with emergency contraception has been within the 72-hour window. Some studies find emergency contraception is most effective the sooner it is initiated within that 72 hours. Other studies find no difference in pregnancy rates. A few studies have looked at the use of emergency contraception for up to 120 hours after unprotected intercourse and find that it can still be effective in some cases, even after 72 hours.
The menstrual cycle is usually unaffected by the use of emergency contraception. Breast tenderness is variable. Significant nausea occurs in about half of women and vomiting affects in about one in 6 women. These symptoms generally disappear within a day or two and can be moderated by using any standard anti-emetic or anti-nausea drug starting an hour before the BCPs are taken. If started after the onset of symptoms, these medications are not likely to be effective.
The mechanisms by which this contraceptive effect occurs have not been established, but should a pregnancy occur despite the use of these BCPs, there is no evidence of harm to the fetus from having been exposed.
Contraindications to use of emergency contraception are essentially the same as those for use of the birth control pill in general. Previous stroke, undiagnosed uterine bleeding, heart attack, deep vein thrombophlebitis and cancer of the breast or uterus are all contraindications to sustained pill use. The extent to which they represent risks in the context of emergency contraception is not known, but should be weighed in evaluating a patient for emergency contraceptive use.
A single overdose of BCPs is not likely to cause any serious harm. Nausea, breast tenderness, and possibly a BCP withdrawal bleed (menstrual flow or spotting) are possibilities if large numbers of BCPs are taken all at once. Gastric lavage or induced vomiting are unnecessary.
If the overdose was accidental, consideration of alternative methods of contraception can be explored, particularly those requiring less individual attention to detail.
If the overdose was intentional, psychiatric evaluation is important as other, more threatening attempts at self-harm may follow.
Home · Introduction · Medical Support of Women in Field Environments · The Prisoner of War Experience · Routine Care · Pap Smears · Human Papilloma Virus · Contraception · Birth Control Pills · Vulvar Disease · Vaginal Discharge · Abnormal Bleeding · Menstrual Problems · Abdominal Pain · Urination Problems · Menopause · Breast Problems · Sexual Assault · Normal Pregnancy · Abnormal Pregnancy · Normal Labor and Delivery · Problems During Labor and Delivery · Care of the Newborn
This web version of Operational Obstetrics & Gynecology is provided by The Brookside Associates Medical Education Division. It contains original contents from the official US Navy NAVMEDPUB 6300-2C, but has been reformatted for web access and includes advertising and links that were not present in the original version. This web version has not been approved by the Department of the Navy or the Department of Defense. The presence of any advertising on these pages does not constitute an endorsement of that product or service by either the Department of Defense or the Brookside Associates. The Brookside Associates is a private organization, not affiliated with the United States Department of Defense. All material in this version is unclassified.
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