11 reasons why your period might be late—that aren’t related to pregnancy

Late periods can be stressful, whether or not you’re trying to conceive. But a late period with a negative pregnancy test can be a source of confusion as well. We spoke with experts to find out why your period might be late that isn’t related to pregnancy.

Symptoms of a late period that aren’t pregnancy-related

The first symptom of a late period is, well, the late period. However, given that the menstrual cycle can vary from 21 to 35 days, it’s possible for your period to be later than normal (for you) but still within the normal range. So at what point should you reach out to your health care provider?

“It is recommended to call a doctor if a woman has missed a period and has a negative pregnancy test or if her period is significantly late or lighter or heavier than usual and is accompanied by other symptoms such as severe cramping, pain or discomfort,” says Dr. Alex Polyakov, associate professor and gynecologist at The University of Melbourne.

Related: 6 signs it’s time to talk to your doctor about your period symptoms 

“It is also essential to see a doctor if a woman has not had a period for three or more months, as this can be a sign of a medical issue,” he says.

Each person knows their own body, so if you’re concerned about a late period and a negative pregnancy test, consider calling your doctor to check in.

7 common causes of late periods when you’re not pregnant

There are many reasons your period might be late that aren’t related to pregnancy, from stress to birth control to illnesses. 

Here are some of the most likely causes of late periods:

1. Stress or travel

Thanks to an increase in the hormone cortisol, stress can delay the menstrual cycle. Similarly, travel causes stress on the body and can affect the circadian rhythm, which can lead to a late period.

2. Significant weight loss or gain

Researchers have found fluctuations in weight can lead to “menstrual irregularity.”

3. Polycystic ovary syndrome (PCOS)

“This hormonal disorder can cause irregular or absent periods,” says Dr. Polyakov. However, if you’re trying to conceive, know that it’s possible to get pregnant with PCOS.

4. Thyroid disorders

“An underactive or overactive thyroid gland can cause changes in menstrual cycles, as well as other symptoms such as fatigue, weight changes and mood swings,” he says.

Related: How to talk to kids about periods: An age-by-age guide

5. Perimenopause or menopause

“As a woman approaches menopause, her periods may become less frequent and eventually stop,” says Dr. Polyakov. During early perimenopause, often in one’s early 40s, cycles might become shorter. However, during late perimenopause, they can stretch to 60 days or longer.

6. Medications

“Certain medications, such as hormonal birth control and antipsychotics, can affect the menstrual cycle and cause periods to be late or absent,” he says.

7. Other health conditions

Polyps, uterine fibroids and endometriosis can cause pain in addition to irregular periods. 

4 less common causes of late periods

1. Intense exercise

While intense exercise can cause late periods, it’s still important to check in with your healthcare provider if you think your workouts are interfering with your period.

2. Breastfeeding

Nursing can lead to a period that’s harder to predict than normal or even missing until the end of the time that you’re exclusively breastfeeding.

3. Changing forms of contraception

Switching up your birth control might affect your menstrual cycle. “If you are switching from pill to pill, then there should be no effect if you go from active pill to active pill or from placebo week and start a new active pill,” says Sophia Yen, MD, MPH, the co-founder and CEO of Pandia Health, a telehealth and birth control delivery service. “However, if the pill is lower dose than the previous pill, there can be some breakthrough bleeding.”

Similarly, changing forms of contraception can also change your cycle. “If you are going from IUD with hormone, implant or shot to the pill then there might be bleeding where there was not bleeding before,” says Dr. Yen. “If you are going from pill to IUD with hormone, implant, or shot, then your ‘periods’, which are actually withdrawal bleeds, might go away.”

Related: How likely is it to get a blood clot from birth control? Here’s what we know

4. Covid-related issues

While the Covid vaccine is safe and recommended, some people have reported irregular periods after receiving the second dose in the series, and menstrual changes have also been seen as a post-Covid side effect after contracting the virus itself. However, both effects should be temporary, Dr. Yen says. “Covid’s effect on periods should only affect the next period. It should not affect anything greater than 6 weeks.” Still, consider checking in with your healthcare provider if you’ve had Covid and your period is unusually late.

Related: Here’s how to tell if you’re in perimenopause

Talking with your doctor about regularly late periods

If you’re not trying to conceive and aren’t breastfeeding or in perimenopause, a period that’s consistently late might not seem like a big deal. However, it’s still good to check in with your health professional if your cycle has become unpredictable.  

“Regularly late periods can signify a medical issue such as hormonal imbalances, thyroid problems, polycystic ovary syndrome [PCOS], or other conditions,” says Dr. Polyakov. “The doctor may perform a physical exam, ask about symptoms and perform tests to determine the cause of the irregular periods. The doctor may recommend further testing or treatment if necessary based on the evaluation results.”

A note from Motherly on late periods when you’re not pregnant

A late period and negative pregnancy test can be crushing if you’re trying to conceive. Some people start to question the pregnancy test itself.

“… it is not uncommon for people trying to conceive to question the accuracy of a negative pregnancy test, especially if they have a late period,” says Dr. Polyakov. “This can be a difficult and emotional time, as the wait for a positive test result can be stressful and disappointing.”

However, there are ways to help manage the stress and cope with the uncertainty. He suggests engaging in self-care (especially activities like meditation, hobbies or exercise), seeking a support group for people trying to conceive or talking to a counselor about how you’re feeling.

“Remember that every person’s journey to conception is unique, and it’s important to seek support and care as needed,” says Dr. Polyakov. “Your doctor can also provide guidance and resources to help manage the emotional aspects of trying to conceive and address any medical issues that may be affecting fertility.”

Sources

Al-Najjar MAA, Al-Alwany RR, Al-Rshoud FM, Abu-Farha RK, Zawiah M. Menstrual changes following COVID-19 infection: A cross-sectional study from Jordan and Iraq. PLoS One. 2022;17(6):e0270537. Published 2022 Jun 29. doi:10.1371/journal.pone.0270537.

Ko KM, Han K, Chung YJ, Yoon KH, Park YG, Lee SH. Association between Body Weight Changes and Menstrual Irregularity: The Korea National Health and Nutrition Examination Survey 2010 to 2012. Endocrinol Metab (Seoul). 2017;32(2):248-256. doi:10.3803/EnM.2017.32.2.248