A big part of any natural birth control method is learning about your menstrual cycle—how long it typically lasts, the length of time between your period and ovulation, and the specific ways that your body changes around the time of ovulation. However, when you start perimenopause, things begin to get a lot less predictable. In this post, we’ll take a look at how perimenopause affects your menstrual cycle and whether you’ll be able to continue using natural birth control to prevent pregnancy during this time.
Perimenopause happens when your body starts making the transition from fertility towards menopause (technically, menopause is the point when you reach twelve consecutive months without having a menstrual period) (1). The length of this transition is different for everyone, but it can start as early as 10 years before menopause. Women typically experience menopause between the ages of 45 and 55 (2).
During your menstrual cycle each month, the levels of the hormones estrogen and progesterone in your body rise and fall in a regular pattern (2). These hormonal fluctuations are behind the changes that your body goes through during each cycle as it gets ready for a possible pregnancy (3). When perimenopause starts, your hormone levels start to deviate from that pattern, causing your ovulation and menstruation to happen with more irregularity. This can make the length and heaviness of your periods unpredictable as well (1).
The hormonal changes that you go through during perimenopause can cause other noticeable symptoms as well, such as hot flashes, problems sleeping, changes in your mood, urinary incontinence, and vaginal dryness (1). The type and severity of perimenopause symptoms vary from woman to woman, but a 2016 review published in the Journal of Women’s Health found that up to one-third of women experience vaginal dryness, and up to 70% experience hot flashes (4). If you have had experience using fertility awareness-based methods for natural birth control before perimenopause, you may have an easier time spotting some symptoms, like shifts in your period length or vaginal dryness, because you’re used to tracking your body’s changes throughout your menstrual cycle.
Perimenopause happens gradually, and there’s no single test or indicator that can definitively determine whether it’s happening to you. Typically, your doctor will consider several factors, such as your age, symptoms, and menstrual history, to help you figure out whether you’re going through this transition (5).
During perimenopause, ovulation becomes more unpredictable, but it doesn’t stop completely. Your fertility may decrease as you approach menopause. However, until you’ve gone twelve full months without having a period (meaning that your ovaries have completely stopped releasing eggs), you’re still ovulating, and it’s still possible for you to get pregnant. If you wish to avoid getting pregnant, you’ll need to use a form of birth control throughout perimenopause (more on this in a moment) (1).
When you’re deciding whether to continue using birth control during perimenopause, it’s important to consider the additional risk factors that come with getting pregnant later in life. A 2018 study published in Obstetrics & Gynecology found that women who get pregnant over the age of 40 were at a greater risk for chromosomal abnormalities, miscarriage, and birth before 34 weeks of gestation, compared to younger women. About 11% of women aged 40 or older who get pregnant experience some form of adverse pregnancy outcome, compared with 5% to 6% of women who get pregnant between the ages of 20 and 34 (6).
If you have been using natural birth control before entering perimenopause, you probably know how changes in your cervical mucus, cervical position, and basal body temperature (BBT) change around the time that you ovulate. While you’re going through perimenopause, you’ll notice that these markers start to get more and more unpredictable as the hormone levels in your body start fluctuating with irregularity.
As is the case with many women’s health issues, there haven’t been many studies done about using fertility awareness-based methods (FABMs) of birth control during perimenopause. A 2014 study published in the Journal of Obstetric, Gynecologic & Neonatal Nursing looked at 160 couples that used natural birth control methods to avoid pregnancy during a twelve-month period. The perimenopausal women in the study used the Marquette Method of birth control, meaning that they track their BBT and cervical mucus, as well as use an electronic hormone fertility monitor (a device that measures estrogen and luteinizing hormone in urine to determine fertility) (7, 8).
The study found that the unintended pregnancy rate was 1.5% with completely correct use of the Marquette Method and 6% with typical use over the course of one year. Those numbers are promising, especially when you compare them to the unintended pregnancy rate for typical use of hormonal birth control of 8%. However, the study’s authors point out that it can be challenging to track and interpret your body’s changes during perimenopause accurately, and that the low unintended pregnancy rates may be partly because of a decrease in fertility during this time (7).
If you’re used to your menstrual cycle following the same schedule, more or less, every month, then tracking your cycle during perimenopause may be a bit of an adjustment. Most women are only fertile for six days out of each cycle—the day that you ovulate and the five days preceding it, depending on your cervical mucus (9).
However, even women with irregular periods will notice their cervical mucus getting more watery as they approach ovulation and their BBT spike at the time of ovulation, according to the American Pregnancy Association (10). This means that, even though your menstrual cycles won’t stick to their usual schedule, your body will still undergo the same changes as it prepares for ovulation. If you’re using an FABM that involves tracking your cervical mucus—like the TwoDay Method®, which says that if you didn’t have any cervical mucus today and you didn’t have any yesterday, then you can have unprotected sex without getting pregnant (11)—then you can still get an idea of when you’re fertile and when you’re not (and plan your sex life accordingly).
If you think there’s a chance that you may be in your fertile window, and you absolutely want to avoid pregnancy, it’s best to either abstain from sex altogether, use an additional barrier method for contraception, or find other ways to be intimate with your partner without having penis-in-vagina sex.
Regardless of whether it’s your only—or even your main—method of preventing pregnancy during menopause, natural birth control can be an incredibly valuable source of information as your body goes through this transition. By paying close attention to your cycles (and all of the accompanying bodily changes), you’ll have an easier time talking to your doctor about the symptoms you’re experiencing. You’ll be able to notice the changes in how often you ovulate, and make informed decisions about your health as you approach menopause.
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