Pregnancy should always be considered in a sexually active woman who misses her period. A urine pregnancy test is easy to do and available in most drugstores. However, there are other possibilities a missed period could signal that are important to understand.
First, missed or irregular menstrual cycles may be related to a woman's method of birth control. A menstrual cycle occurs when a woman ovulates but does not get pregnant that month. The lining inside the uterus that was built up to support a pregnancy is then shed off when no pregnancy occurs. Oral contraceptives (birth control pills) suppress ovulation and can cause missed or irregular cycles because they are low dose (20-35 micrograms of estrogen per pill per day) and may not build up much lining. If the lining in the uterus is thin, there is not much to shed off during her period, so it may only look like spotting or no bleeding at all. The blood is not left inside -- it was never produced.
But if the birth control pills are taken correctly -- every day approximately the same time, don't double them if you forget one -- then pregnancy should not result. There is a 1% failure rate if used correctly. Spotting does not mean they are not working to prevent a pregnancy, it just means they aren't holding up the lining very well. If the birth control pills are not taken properly, spotting may occur and there is a risk of pregnancy with only one or two missed pills per cycle.
Missed or irregular periods can also be the symptoms of several gynecological conditions. Let's review two of them. Polycystic Ovaries (PCO) occurs in approximately 5% of women. Missed or irregular menstrual cycles are the first clue. Other symptoms may be overweight/obesity, acne and hirsuitism (a lot of hair-body, facial or both).
Blood tests and a pelvic sonogram can confirm the diagnosis. Some women have no symptoms other than missed or irregular periods. A normal menstrual cycle represents normal hormone levels of estrogen and progesterone-necessary for a woman's body.
Women with PCO have the normal number of follicles to ovulate every month, but their hormone levels are imbalanced with low levels of estrogen so no follicle matures enough to ovulate and therefore no period. Without ovulation, there is no progesterone. Many women like not having a period with the pain, bleeding and the expense of pads or tampons, but constant low levels of estrogen without progesterone can cause bone loss and the chance of endometrial (uterine) cancer over time. Treatment is necessary. Birth control pills and metformin are the best treatment, giving a woman the estrogen and progesterone she needs every day. These two hormones protect a woman from bone loss and endometrial cancer.
Polycystic Ovarian Syndrome (PCOS) is a more advanced condition which includes cardiovascular disease and insulin resistance/diabetes.
When birth control pills are discontinued in order to conceive it may be necessary to add another medication (Clomid) to encourage ovulation.
Another GYN condition that causes missed or irregular periods is Premature Ovarian Failure, sometimes referred to as premature menopause. For mostly unknown reasons, the ovaries stop producing estrogen and effectively shut down before the age of 40. Although this is usually a permanent condition the woman may occasionally ovulate and conceive. Premature ovarian failure is easily diagnosed by taking a careful history (few or no periods, hot flashes, vaginal discomfort), a pelvic sonogram and blood tests which should include Fragile X (genetic screen) and a karyotype (chromosomal analysis). Although this occurs in less than 1% of women, it is a devastating diagnosis. Treatment may be hormone replacement or birth control pills. These hormones are necessary to prevent bone loss as well as quality of life issues such as hot flashes and vaginal discomfort. Pregnancy may occur in up to 10% of women, including those women using birth control pills. More common than a spontaneous pregnancy is the need to use assisted reproductive technologies such as in-vitro and donor eggs.
To review, missed periods can signal a variety of women's health conditions or issues related to your birth control. Being empowered with information concerning some of these possible women's health conditions is a good first step. If you are experiencing missed periods, it is important to consult with your midwife or physician.