Why Do Period Cramps Hurt So Bad the First Day? Science Weighs In

There’s a certain day or two every month when you just know you won’t be at your best. So much so that you’ve taken to blocking out that time on your calendar to spend on the couch with your heating pad.

Yep, we’re talking about first-day period cramps.

And no, you’re not being a wuss who needs to buck up and push through: That pain is very, very real, and there’s even a scientific explanation for why those first-day period cramps are so debilitating.

Read on to unpack not only the reasons behind your painful periods, but also physician-recommended relief strategies.

The science behind first-day period cramps

“Cramps are usually most painful at the start of your period because your body releases chemicals called prostaglandins,” explains Jessica Ryniec, M.D., a double-board-certified reproductive endocrinologist and infertility specialist at CCRM Fertility in Boston. The intense pain occurs because the prostaglandins “cause the uterus to contract to help shed its lining.”

Okay, that tracks, but what is it about those first-day cramps that makes them so intense?

According to Dr. Ryniec, “the highest levels of prostaglandins are present at the beginning of menstruation.”

However, pain tolerance and prostaglandin sensitivity vary by individual; some people may have mild or no cramps, while others may have severe pain. Dr. Ryniec says that period pain can depend on factors like family history, your age when you got your first period, stress, sleep, and lifestyle habits. In addition, she mentions that “drinking cold drinks, high caffeine intake, and irregular cycles can make cramps worse,” so you may want to lay off the coffee and the ice cubes around your period.

When first-day cramps need medical attention

While first-day period cramps are quite common and “usually not a sign of a serious problem,” Dr. Ryniec says that pain that doesn’t improve or is associated with other concerning symptoms is a sign that it’s time to consult your doctor.

Make an appointment with your healthcare provider if you're experiencing any of these symptoms—they could point to endometriosis or fibroids:

• Pain that gets worse over time or lasts longer than your period
• Heavy bleeding or bleeding between periods
• Pain with intercourse/penetration
• Foul-smelling vaginal discharge
• Cramps that don't get better with medicine
• Severe GI symptoms
• Painful bloating or rectal pain with menses

“Early treatment can prevent pain from becoming a long-term problem,” advises Dr. Ryniec.

Why first-day cramps feel different (and worse)

If you’re someone who experiences intense first-day period cramps, then you only have hormone surges to blame. As Dr. Ryniec mentioned, prostaglandin levels are at their highest on the first day of menstruation. But, according to the American College of Obstetricians & Gynecologists, the prostaglandin levels decline as the bleeding continues and your uterus lining sheds. This is why period pain tends to decrease after the first couple of days.

This is not to dismiss any level of period pain, however. Remember, period cramps result from your uterus contracting, and the same thing happens to your uterus when you’re in labor.

Pain is pain. Period.

How long do period cramps last on the first day?

“Cramps usually start just before or when bleeding begins and last for one to three days,” says Dr. Ryneic. “Most people feel better by the third day of their period (even if their periods are longer than three days).”

According to the Mayo Clinic, period cramps tend to peak about 24 hours after the pain’s onset.

But if the cramps are so debilitating that they’re affecting your daily functioning, and they’re not alleviated by pain medication, then you should call your doctor.

Bad cramps during first day of period: What's normal vs. concerning

There are two different kinds of painful menstrual cramps: primary dysmenorrhea and secondary dysmenorrhea. It’s important to know the distinction, as secondary dysmenorrhea can be a warning sign of another medical condition.

Primary dysmenorrhea (normal cramps)

“Primary dysmenorrhea is period pain without any other medical problem or underlying cause,” explains Dr. Ryniec. “It usually starts in the teen years and gets better with age or after childbirth.”

In short, primary dysmenorrhea is regular, run-of-the-mill period cramps that can be annoying, but shouldn’t cause any long-term damage. This type of dysmenorrhea lasts approximately one to three days at the start of menstruation.

Secondary dysmenorrhea (when something else is going on)

The major difference between primary and secondary dysmenorrhea is that the latter is the result of a disorder in the reproductive organs: “Secondary dysmenorrhea is caused by another condition, like endometriosis or fibroids,” says Dr. Ryniec. “It often starts later in life and may come with other symptoms like heavy bleeding or pain outside of your period.”

Since, according to ACOG, pain from conditions like endometriosis, fibroids, and adenomyosis can exacerbate menstrual discomfort, these debilitating cramps may serve as a signal that it’s time for a medical evaluation.

First day of period, cramps but no blood: What's happening?

There are several reasons you may experience cramps without blood flow, even around the time of your period. First of all, “it’s possible to have cramps before your period starts,” Dr. Ryniec assures. But your cramps without menstruation could be due to any number of other issues, including gastrointestinal concerns, pelvic inflammatory disease, ovarian cysts, stress, musculoskeletal causes, anovulation (meaning you’re not ovulating), or pregnancy.

Cramping first day of missed period: Could you be pregnant?

“If you have cramps but your period doesn’t come on time, and you’re sexually active, it is worth taking a pregnancy test right then,” advises Dr. Ryniec. But while it’s better to be safe than sorry, remember that there are several key differences between implantation cramping (aka cramping associated with the early stages of pregnancy) and period cramps.

Generally speaking, implantation cramps occur about 6 to 12 days before a missed period, while period cramps appear right before and during menstruation. In addition, implantation cramping is usually less painful than menstrual cramps and is typically confined to the lower abdomen. Period pain can be felt in the back and thighs as well.

First day of period cramps and diarrhea: The gut connection

You may have noticed that, along with menstrual pain, you’re pooping a lot more during those first couple of days of your period. Once again, you can thank those good ol’ prostaglandins for your extra time on the toilet.

“Prostaglandins can also affect your stomach and bowel because they act on smooth muscle,” explains Dr. Ryniec. “This can cause diarrhea, nausea, or upset stomach during your period.”

Just as prostaglandins cause your uterus to contract, they can also stimulate your intestines, leading to more bowel movements and/or diarrhea during menstruation. This also occurs because both the uterus and intestines share similar prostaglandin receptors. So when the release of prostaglandins activates the monthly shedding of your uterine lining, your intestinal muscles are similarly stimulated, resulting in more trips to the bathroom.

(But if you are experiencing more intense gastrointestinal issues, however, call your healthcare provider. “Severe GI symptoms would not be expected to be related to prostaglandins alone,” says Dr. Ryniec.)

Extra “period poops” cramping your style? Keep your gut health in check by staying extra hydrated, getting enough sleep and exercise, and laying off the caffeine. You may even find that those lifestyle changes ease your period pain too!

How to get rid of first-day period cramps

So you’ve tried the extra sleep/less coffee/more water routine, and you’re still in pain those first couple of days of your period. Don’t worry, it’s completely normal, and there are plenty of medicinal and natural remedies to try.

Fast-acting relief methods

Dr. Ryniec recommends nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen: “They are very effective,” because “they directly lower prostaglandins, going right to the cause of period cramps.” She advises taking these pain meds either at the first sign of cramps or even right before your period starts.

“If you have a regular period and can predict when it is coming, it can be helpful to start NSAIDs and continue them on a schedule starting the day before the anticipated period through the first one to three days or whenever your cramps usually improve,” says Dr. Ryniec.

She also suggests trying heat therapy (e.g., heating pads, hot water bottles) or a transcutaneous electrical nerve stimulation (TENS) unit, a device that uses a low-voltage electrical current to block pain.

Natural and alternative remedies

For those interested in exploring more natural and alternative remedies to ease their period pain, Dr. Ryniec recommends Traditional Chinese medicine techniques such as acupuncture or acupressure.

As for supplements and herbal remedies, a 2025 article from the Cleveland Clinic says that while magnesium supplements are safe to use to relieve menstrual cramps, the effect may be minimal.

According to a March 2021 study published in the Cureus Journal of Medical Science, ginger was found to be “useful and effective” along the lines of NSAIDs. However, the study also “strongly” recommended further research regarding ginger’s effectiveness as a form of pain relief.

Anti-inflammatory foods, specifically ones rich in omega-3 fatty acids, can also help reduce menstrual cramps. A 2023 article published by the NewYork-Presbyterian Hospital recommends adding fresh fruits and vegetables, nuts and seeds, and lean meats and fish to your diet.

You can even try some specific yoga poses to alleviate your period pain:

• Cat/Cow
• Cobra
• Downward Dog
• Happy Baby
• Legs Up the Wall

Lifestyle modifications for long-term relief

As previously mentioned, it can never hurt to adopt some lifestyle modifications, like adding anti-inflammatory foods to your diet, that may ultimately reduce your period pain in the long term.

Dr. Ryniec also recommends maintaining your exercise routine during your cycle, reducing your caffeine intake, lowering your stress levels, and ensuring you get enough sleep.

Medical interventions for severe cramps

If you find that none of the above suggestions are alleviating your period pain, then it’s probably time to talk to your healthcare provider.

One option is to discuss hormonal birth control (pills or IUDs) with your doctor, as it can make periods lighter and less painful. Keep in mind that this is “a more long-term option,” says Dr. Ryniec.

“Unfortunately, there are not many other effective medical interventions for severe cramps if the above are not effective,” continues Dr. Ryniec. While she says you could consider “adding Tylenol or narcotic/opioid pain medications,” such severe pain would warrant investigation. At that point, “surgical evaluation and management may be considered.”

Prevention strategies: Preparing for day one

Now let’s turn your newfound knowledge into action! One of the best ways to conquer your menstrual cramps is to anticipate their arrival, and that starts with cycle tracking (while apps exist, you can totally kick it old school and use pen and paper!).

Once you have a general idea of when your period will appear, the next step is to stock up on your preferred pain relief (NSAIDs, heating pad, creating a playlist of your favorite yoga videos, etc.). Depending on the severity of your cramps, now is also the time to talk with school/work administrators about any possible accommodations.

Finally, remember that it is perfectly safe to take pain relief meds right before your period begins. “This prevents prostaglandin release,” explains Dr. Ryniec, and [doing so] stops the pain before it starts, so you don't have to play catch-up.”

First-day cramps don’t have to control the month

Although severe first-day menstrual cramps are common, that doesn’t mean you’re supposed to just “tough it out.” Cramps are common because your body is doing what it’s supposed to do; prostaglandins help the uterus contract and ultimately shed its lining. At the same time, there are several effective solutions (both medical and natural) that can alleviate these pesky cramps.

No one deserves to be in agony every month, which is why we’ve provided the tools you need to advocate for yourself in this article. If you’re suffering from intense menstrual pain, our expert recommendations can help you take charge of period cramps.

Above all, track your symptoms and talk to your doctor if pain is interfering with your life.