Can You Actually Get Pregnant With Irregular Periods?

The internet thinks this question is only asked by teens afraid of unplanned pregnancy. From there, you’ll get the short answer: “Yes! You can get pregnant anytime you have unprotected sex!” followed by advice to always use a condom, to prevent both pregnancy and STIs.

While this is always a helpful reminder (STIs are no joke — they may actually cause fertility problems), if you’re struggling with infertility, this is probably far too incomplete an answer.

If your period feels untrackable, we're here to not only break down the potential causes of irregularity and when to seek medical attention, but also to provide some tips for keeping your cycle healthy and regular.

How to know if your period is irregular (and when to see a doctor)

For many women, irregular periods make it difficult to get pregnant. Ovulation may happen less frequently, less predictably, or potentially not at all. Around 14 days before your period, the ovaries release the egg, and it’s advised to have sex in the surrounding days when trying for a baby.

A regular cycle lasts 21-35 days. This means that if your period begins between 21-35 days from the beginning of your last period (give or take a few days), your period is considered regular. If it’s falling outside this range, or happening less than eight times per year, your period is considered irregular and may contribute to difficulties conceiving.

Dr. Adriana Wong, a Reproductive Endocrinology and Infertility fellow at USC, notes irregular cycles and subsequent issues with ovulation contribute to about 25% of infertility. She recommends seeing a fertility doctor if you are trying for a baby and notice your periods are irregular. “There is no need to wait 6 to 12 months of trying on your own. Time is fertility. We can take a look at your medical history, do an evaluation, and discuss options,” Dr. Wong says.

Potential causes of irregular periods

Dr. Wong says irregular periods could be caused by anything that impacts ovulation or hormones. These might include:

• PCOS: PCOS is a hormonal disorder that affects each person differently and often causes irregular periods. In certain cases, women struggling with PCOS don’t produce enough hormones to ovulate, or ovulation may happen irregularly.
• Thyroid conditions: Your thyroid, found at the front of your neck, controls your body’s metabolism and creates hormones that can affect your reproductive system. Thyroid conditions may cause imbalances in hormone levels, causing irregular or sometimes even absent periods, and also affecting ovulation.
• Hyperprolactinemia: The pituitary gland, located at the base of your brain, produces hormones your body uses for reproduction, including prolactin, which stimulates milk production during and after pregnancy. If you have hyperprolactinemia, you have abnormally high levels of prolactin, and it may affect the regularity of your period.
• Perimenopause: During this period before menopause, your body starts producing less estrogen as your reproductive system winds down for menopause. Ovulation will likely occur less often or not at all, and your period might become more irregular. (While pregnancy is still possible during this period, ovulation typically happens in only about 20-23% of perimenopausal women.)
• Cushing’s syndrome: Sometimes called hypercortisolism, Cushing’s syndrome is caused by high cortisol levels over a long period of time, and symptoms can include irregular or absent menstrual cycles.
• Birth control methods: Most birth control methods, including pills, injections, implants, and IUDs, use the hormone progestin or estrogen to block ovulation and can often cause irregular periods.

While Dr. Wong recommends seeing a fertility doctor immediately if you notice irregular periods and you’re trying to conceive, she also says maintaining a healthy lifestyle can help with fertility and regaining a regular period. “In general, things that are good for your overall health and better for your fertility," Dr. Wong says.

She recommends at least 150 minutes of moderate intensity exercise every week, keeping a well-balanced diet full of whole foods and high fiber, and maintaining a healthy weight.

If overweight, some cases show that losing 5% of your body weight may correct an irregular period. A 2022 study found that obesity in childhood increased the likelihood of irregular periods and the development of PCOS later in life. But losing or gaining weight may not be easy for everyone. “It’s important to note that even people in perfectly good shape may have irregular cycles because of underlying health conditions,” Dr. Wong adds. “This is not your fault at all.”

How can you fuel your body for regular menstruation?

What you eat is important for maintaining regular periods — your reproductive system needs energy to menstruate, just as your brain needs energy to think, and your body needs energy to move. Anna Bohnengel, MS, RD, LD (The Fertility Nutritionist), says energy availability, or calories eaten minus calories burned, is one of the biggest drivers of hormone balances, and therefore reproductive hormone production and ovulation.

A study from 1992 found an association between weight loss and less regular menstrual cycles — Bohnengel explains potential causes. Undereating may affect ovulation because restricting certain macronutrients, like proteins, fats, or carbs, may disrupt brain-ovary connections, specifically the release of “luteinizing hormone” which triggers the ovaries to release eggs.

Bohnengel says fats and proteins are essential for hormone health, regular cycles, and, therefore, ovulation. Estrogen and progesterone, some of our most important reproductive hormones, are made of cholesterol, which comes from fats. Protein also helps signal the hormones governing your menstrual cycle, including follicle-stimulating hormone, which, in women, stimulates estrogen production and the maturation of ovarian follicles (where eggs are released during ovulation).


She suggests including more monounsaturated fats (found in avocados, olive oil, and nuts), omega-3s (found in salmon and sardines), and moderate amounts of saturated fats (preferably from whole-food sources) if your period is irregular. For proteins, she recommends high-quality sources like eggs, Greek yogurt, cottage cheese, chicken, tofu, lentils, or fish.

Some of her other suggestions include:

• Ensure you’re eating enough (health is not simply eating less, no matter what social media tells you!).
• Eat balanced meals — include protein sources, healthy fats, fiber-rich carbs, and colorful produce. This supports egg quality and can help keep blood sugar stable, which supports hormone levels.
• Limit ultra-processed foods and added sugars, and focus on nutrient-dense foods. Nutrients like iron and vitamin B12 (seen in grass-fed meat), folate (present in avocado and dark leafy greens), zinc (found in shellfish and pumpkin seeds), and antioxidants all support ovulation and hormone production.
• Support your gut and digestion — keeping your gut healthy can help with estrogen metabolism and nutrient absorption. Try including some fermented foods like yogurt and sauerkraut, and eat plenty of fiber.

This may feel like a lot of information, but you should also “give yourself grace,” Bohnengel says importantly. “Diet is a powerful tool, but it’s not about perfection — it’s about creating a supportive environment for your body to thrive and feel safe enough to prioritize reproduction.”

So... can you get pregnant with irregular periods?

Yes — but it might take a little more planning, support, and self-compassion. Irregular periods can make it harder to track ovulation and time sex effectively, but they don’t mean pregnancy is impossible. Understanding your cycle, fueling your body well, and getting the right medical support can all make a difference. Whether you’re just starting to try or you’ve been at it a while, irregular periods are a clue worth listening to — not a full stop.

Eliza Mattson is a journalism student at Northwestern University and a Rescripted editorial intern. She is primarily interested in health and science writing, but she also studies history and economics. When she’s not writing or studying, you can find her rewatching Speed for the millionth time or baking cookies.