What Causes a Woman to Menstruate Twice in a Month?

Noticing two periods in the same month (AKA metrorrhagia or intermenstrual bleeding) can be confusing, stressful, and sometimes downright alarming. It’s natural to wonder if something’s wrong or if it signals a bigger issue.

The truth is, there are several possible reasons why someone might bleed twice in one month — and many of them are harmless or temporary. Whether it’s due to hormonal shifts, birth control changes, or life stress, your body’s cycle can sometimes act in ways that aren’t perfectly predictable.

Let’s break down the possible causes of double periods, when to be concerned, and how to support your physical and mental health through it all.

Why am I suddenly getting my period twice a month?

The menstrual cycle is often described as a predictable 28-day loop — but real bodies don’t follow textbook rules. Many people have cycles that range anywhere from 21 to 35 days, and sometimes things shift. The majority of our Rescripted community (44%) have periods that last between 21 to 27 days, with 13% having periods lasting 28 to 35 days.

If you normally have a shorter cycle (like 21-24 days), you might occasionally bleed twice in one calendar month simply because your body’s natural rhythm falls that way. But if you’re noticing this as a new pattern, or if your periods have suddenly become irregular, it’s worth paying attention.

Some common (and not-so-common) causes include:

• Hormonal changes: Shifts in estrogen and progesterone levels can throw off the timing of your cycle.
• Ovulation spotting: Light bleeding mid-cycle when an egg is released.
• Perimenopause: The years leading up to menopause often bring unpredictable cycles.
• Stress or lifestyle changes: Intense stress, weight changes, or travel can impact hormones, and therefore your bleeding pattern.
• Polycystic ovary syndrome (PCOS): A hormonal disorder that can cause irregular or absent periods, as well as mid-cycle spotting.
• Breakthrough bleeding: Especially if you’re on birth control or just switched methods.
• An infection or irritation: Such as bacterial vaginosis, a yeast infection, STI, or cervical inflammation.
• Pelvic inflammatory disease (PID): An infection of the reproductive organs that can cause irregular bleeding.
• Thyroid disorders: Both hypothyroidism and hyperthyroidism can mess with your menstrual cycle.
• Bleeding disorders: Like von Willebrand disease, which affects the blood’s ability to clot.
• Fibroids or polyps: Benign growths in the uterus or cervix.

Sometimes, the bleeding you’re seeing isn’t technically a “period” but breakthrough bleeding or spotting. This is why tracking the flow, timing, and any additional symptoms can help you and your doctor figure out what’s up.

If you’re experiencing other symptoms — such as severe cramps, very heavy bleeding (soaking through pads or tampons in an hour), dizziness, fevers, chills, body aches, or pain during sex — don’t wait. Reach out to a healthcare provider. As Dr. Caledonia Buckheit explains, “PID [Pelvic Inflammatory Disease] can show up with irregular bleeding and systemic symptoms.”

Am I pregnant if I got my period twice this month?

This is a common worry — but here’s the deal: true menstrual bleeding cannot physically happen during pregnancy. However, some people experience implantation bleeding (light spotting) when a fertilized egg attaches to the uterine wall, usually just before the time a period would normally be due.

Dr. Buckheit explains: “Bleeding in early pregnancy can also be a sign of impending miscarriage, threatened miscarriage or even an ectopic pregnancy. If you are bleeding in early pregnancy, especially if it is heavy, keeps happening, or is associated with pelvic pain, seek care.”

If you’re sexually active and not using contraception, it’s a good idea to take a pregnancy test if you’ve noticed unusual bleeding.

Is it normal to have a period twice a month during perimenopause?

Yes — and it’s one of the most common times for cycle changes. Perimenopause usually starts in your 40s, though it can begin earlier, and lasts until menopause (when periods stop altogether).

During this transitional phase, your ovaries produce less estrogen and progesterone, which can lead to shorter cycles, heavier or lighter periods, missed periods, and random spotting.

It’s all part of your body’s natural winding down of reproductive hormones. If bleeding is unusually heavy, prolonged, or accompanied by pain, check in with a healthcare provider.

Can stress cause periods twice a month?

Stress messes with more than just your mood — it can disrupt your menstrual cycle, too.

When the body is under significant stress, whether from emotional strain, intense exercise, illness, or even travel, it produces more cortisol. This hormone can suppress your body's normal reproductive hormones, sometimes causing irregular bleeding or missed periods altogether.

But as for causing two periods in one cycle, that might not be down to stress. As Dr. Buckheit says, “Stress generally has more of a suppressive effect, [it’s] less likely to provoke a period.”

Mind-body practices like mindfulness, yoga, or therapy can help lower stress levels. Studies have shown that stress reduction can improve menstrual regularity.

Why am I having two periods a month on birth control?

If you’ve recently started or switched birth control, especially hormonal methods like the pill, patch, or IUD, your body may need time to adjust. Breakthrough bleeding or spotting is common in the first few months.

Other possible reasons:

• Missed pills or inconsistent use: Which can lead to withdrawal bleeding.
• Lower-dose pills: Sometimes these don’t fully suppress the uterine lining, causing spotting.
• Prolonged use of hormonal birth control: The endometrial lining can become excessively thin, leading to “atrophy bleeding.”
• Hormonal IUDs: Some users experience irregular bleeding in the first 3-6 months.

If irregular bleeding persists beyond the adjustment period, talk to your provider about possibly changing methods or dosages.

When do you ovulate if you have two periods a month?

Ovulation typically happens about 14 days before your next period. But if your cycles are very short (say, 21 days), you might ovulate soon after your period ends — or sometimes not at all, depending on whether the bleeding is true menstruation or another type of bleeding.

Tracking your ovulation with tools like basal body temperature charts, ovulation predictor kits, or cervical mucus monitoring can help clarify your personal pattern. Keep in mind that just because you bleed doesn’t always mean you ovulated that cycle, especially if other factors (like stress or hormonal imbalance) are in play.

When to see a doctor if you’re bleeding twice in one month

While occasional irregular bleeding can be a normal part of life, it’s time to check in with a provider if:

• You’re soaking through one or more pads or tampons every hour for several hours.
• Bleeding lasts longer than 7-10 days.
• You have severe pelvic pain or pressure.
• You’re feeling dizzy, faint, or weak.
• You’re concerned about pregnancy or fertility.

Remember: menstrual health is whole-body health. It’s not just about your uterus — it’s about your hormones, stress levels, nutrition, and overall well-being.

What’s really going on with double periods

Our bodies are complex, and our menstrual cycles don't always follow the rules we expect them to. Having two periods in one month can be alarming, but in most cases, it’s not an emergency. Your body might be responding to stress, hormonal shifts, life transitions, or even just the natural ebb and flow of your cycle.

If you’re concerned or notice a persistent change in your bleeding patterns, check in with a healthcare professional. You deserve answers, support, and care that takes your physical and emotional health seriously.

Tassia O'Callaghan is an experienced content writer and strategist, having written about a vast range of topics from chemical regulations to parenting, for brands like Peanut App Ltd, Scary Mommy, Tally Workspace, and Fertility Mapper. She's an advocate for realistic sustainable living, supporting small businesses (author of A-Z of Marketing for Small Businesses), and equity across all walks of life. Follow her on LinkedIn or TikTok, or see more of her work on Authory or her website.