How Your Menstrual Cycle Influences Your Chances of Getting Pregnant

Periods are a hassle. But when they come early and you’re trying to get pregnant, it’s even more of a hassle. If you’ve ruled out the possibility that your early period is implantation bleeding, you might be frustrated wondering what’s going on. Well, one way to look at it is that your period is your body’s way of communicating with you.

Yes, what many people don’t realize is that your menstrual cycle can provide clues about your health and fertility. Tracking your cycle can help you understand (roughly) when you’re most fertile and uncover clues about your chances of conceiving.

If your menstrual cycle is regular and you are not yet pregnant, factors like the length of your menstrual cycle and menstrual flow can affect your ability to conceive. This is because your menstrual cycle is influenced by the hormones that regulate your menstrual cycle, help you conceive, and maintain a healthy pregnancy. So if your hormone levels are out of balance due to underlying illness, stress, or extreme dietary changes, your menstrual cycle is likely to be disrupted as well.

Read on to learn about common concerns people have about their periods and how they may affect your fertility. This information can help you know when to talk to your doctor about how your menstrual cycle may affect your chances of getting pregnant.

Missing your period

If you’re not pregnant but your period isn’t coming on time, consult a doctor to get to the root of the problem, as an irregular menstrual cycle can have a two-way effect on your fertility.

First, it is much harder to pinpoint the key days before (and including) ovulation when conception is most likely; ovulation calculators don’t work well in these cases. Second, and more importantly, prolonged periods often indicate underlying issues that may be affecting fertility, such as limited or absent ovulation (oligozoospermia or azoospermia). Some are more complicated, while others are relatively easy to solve.

If you’re wondering what could be causing your period to miss a day other than pregnancy, there are a number of possible reasons. They include:

• Breastfeeding
• menopause
• Some contraceptive methods
• Some medicines, such as antidepressants and blood pressure lowering drugs
• Scar tissue from previous procedures (such as treatment for endometriosis, cesarean section, or uterine fibroids)
• Underweight
• Inadequate calorie intake
• Emphasize
• Burning more calories than you take in (due to excessive exercise)
• Polycystic ovary syndrome (PCOS)
• Thyroid problems
• Pituitary tumors
• Premenopausal
• Premature ovarian failure

“PCOS is probably the most well-known cause of menstrual irregularities,” says Lauren Deville, PhD, a naturopathic doctor at Nature Cure Family Health in Tucson, Ariz. “Hypothyroidism can also cause amenorrhea. Elevated prolactin levels, zinc deficiency, extreme dieting or weight loss, and excessive exercise can also cause amenorrhea.”

Many of these concerns can be easily addressed or corrected with the help of your OB-GYN, who can also refer you to a fertility specialist if needed.

Abnormal flow

If you have a period every month, you’re more likely to get pregnant. But your menstrual flow can also give you clues about your fertility. An abnormally heavy or light period could indicate a problem that needs to be addressed before you can conceive.

So if you’re having regular periods but not pregnant, the amount of bleeding may indicate the cause.

Heavy menstrual periods

According to the Centers for Disease Control and Prevention (CDC), signs of a heavy period include:

• Feminine hygiene products need to be changed within 2 hours
• Passing out blood clots larger than the size of a U.S. quarter
• Bleeding lasting more than 7 days

Extremely heavy menstrual bleeding is called menorrhagia, says Jessica Shepherd, M.D., an obstetrician-gynecologist at the University of Illinois at Chicago. In addition to the symptoms mentioned above, women with menorrhagia may also experience symptoms like dizziness, fainting, anemia, and shortness of breath during their period. In severe cases, blood transfusions may be required due to blood loss.

Even if your period is regular, abnormally heavy periods can affect your ability to become pregnant. Many underlying causes can cause very heavy periods that can make it impossible to conceive or maintain a healthy pregnancy. According to ACOG, some causes of very heavy periods include:

• Uterine fibroids or polyps
• Endometriosis
• Adenomyosis (uterine tissue grows into the muscular wall of the uterus)
• Irregular ovulation
• Polycystic ovary syndrome
• Hypothyroidism
• Bleeding disorders
• Certain medications, particularly anticoagulants and aspirin
• Copper IUD
• Endometrial cancer
• Pelvic inflammatory disease
• Ectopic pregnancy or miscarriage

The Age of Light

If you’re having trouble getting pregnant, a light period can be a sign of underlying infertility issues. Light periods can be caused by being underweight, stress or menopause.

One of the potential medical issues doctors look for that are associated with light periods is PCOS (polycystic ovary syndrome), a condition in which a person produces higher than average levels of androgen hormones. PCOS is one of the leading causes of infertility. But the good news is that with the right treatment to maintain proper hormones, many people with PCOS are able to have a healthy pregnancy and carry their baby to term.

But in most cases, a light period isn’t something to worry about. If you’ve always had light or short periods, it’s unlikely to affect your chances of getting pregnant. However, if your light period is a sudden change that can’t be explained by increased stress or sudden weight loss, it may be time to find out what’s causing your light period.

Cycle Length

Having an abnormally long or short menstrual cycle can affect your fertility, and large variations in cycle length could indicate a hormone imbalance or other underlying medical problem.

The average cycle is 28 days. But, of course, we’re all different, so there will always be some variation in cycle length. In fact, a 2020 study of 1.5 million people who menstruate found that only 16% of participants had a 28-day cycle.

Cycle length is important because it can indicate whether ovulation is occurring regularly, and can also give you clues about when you are ovulating.

Long cycle

Longer periods between periods could mean that your ovulation isn’t regular. Longer cycles usually mean that you’re having an anovulatory cycle, meaning that your egg isn’t released. As you might imagine, not ovulating can make it harder to get pregnant.

When you’re trying to conceive, a 30-day cycle can feel like a century, but a longer-than-average cycle usually isn’t a problem if it’s only a few days longer than average: Cycles that last up to 38 days are still within the “normal” range, according to the Office on Women’s Health.

And don’t worry, a longer-than-normal cycle every now and then is perfectly normal. Little things like travel, stress, or illness can cause your period to be a few days late. But if it goes on for more than 45 days, or if a longer-than-average cycle becomes the norm, you need to figure out what’s going on.

Many of the same causes of amenorrhea and other abnormalities can also cause a prolonged menstrual cycle, including thyroid or adrenal hormone imbalances, uterine polyps or fibroids, Polycystic Ovary Syndrome (PCOS), and obesity.

Short cycle

On the other hand, if your period comes early or occurs more than once a month, you may have an abnormally short cycle. If you think this means your chances of getting pregnant are increased, unfortunately, this is not always the case. An abnormally short cycle can indicate a defect in the luteal phase, among other complications.

“The luteal phase is the second half of your cycle after ovulation. During this time, progesterone increases to nourish the uterine lining in preparation for implantation. Implantation takes about seven days after ovulation to occur, so a shorter luteal phase than this makes conception less likely. Ideally, you want a luteal phase of around 14 days,” says Dr DeVille.

According to the American Society for Reproductive Medicine, the luteal phase usually lasts 12 to 14 days, but can range from 11 to 17 days. Clinically detected luteal phase deficiency is defined as a luteal phase lasting less than 10 days.

Other signs of luteal phase defect include repeated bleeding and early miscarriages. The solution often lies in fertility medications such as Clomid (clomiphene) or progesterone suppositories. So if you’ve been diagnosed with luteal phase defect, know that it’s usually a treatable problem and once fixed, you’ll have little to no trouble getting pregnant.

Interestingly, studies have shown that although short-term fertility may be reduced for those with a short luteal phase, pregnancy rates after 12 months of trying to conceive are generally similar to those of those with a longer menstrual cycle.

Detect

Sometimes bleeding can occur outside of your period. But if you regularly have a light shedding before your period starts each month, or suddenly have heavy bleeding between periods, your hormone levels may be a little out of balance. Bleeding is more common during the first few years of menstruation and as you approach menopause.

“Bleeding usually occurs when progesterone levels are too low to hold the uterine lining in place, or estrogen levels are too high,” explains Dr. DeVille.

If you’re experiencing heavy bleeding outside of your period, consider trying a home hormone test first. But ultimately, you’ll need to undergo a physical exam, which may include an ultrasound and lab tests. From there, your healthcare provider can determine what treatments you need to improve your chances of conceiving.