Gaining weight is common with premenstrual syndrome (PMS), symptoms people who menstruate experience before and during their periods.
Around 70-90% of people have PMS symptoms at one time or another. Besides weight gain, PMS can cause other discomforts like cramps, sleep issues, fatigue, headaches, stomach issues, and back aches.
You may also experience symptoms such as swelling, water retention, bloating, gas, breast swelling, and soreness.
In the week before and during the first few days of your period, it’s common to feel heavier and more bloated and to notice an increase in weight. This is due to various factors, such as hormonal changes, water retention, gastrointestinal (GI) changes, food cravings, and eating patterns.
Research has found that up to 65% of people experience swelling before and during their periods. This is known as PMS-H (hyperhydration), another form of PMS defined by specific features like water retention, bloating, breast soreness, and weight gain.
Swelling can make you feel like you’ve gained weight and can cause temporary weight gain. It may occur in your face, breasts, belly, arms, thighs, and legs.
Gastrointestinal (GI) issues are a very common symptom of PMS. Some studies find that over 70% of people who menstruate experience this.
Common symptoms include stomach pain, diarrhea, bloating, and gas. Bloating and gas, in particular, can make you feel as if you’ve gained weight and make your stomach area look and feel larger.
GI symptoms can make you uncomfortable and make you feel heavy in combination with menstrual cramps, overall swelling, and water retention.
If you have a period, it’s common to feel hungrier and consume more calories during the second half of your cycle (the luteal phase) and when you experience PMS. This may be due to an increase in progesterone during this phase.
Your food cravings may also change. One study found that people tend to crave more protein (animal protein in particular), sweets, and salty foods before their periods.
Some of the physical changes that happen in your reproductive organs during PMS may make you feel heavier. It’s not known exactly how much larger your uterus becomes right before your period, but your uterine lining does build up and thicken during PMS, and it’s at its thickest right before your period.
Due to progesterone, the milk ducts in your breasts also widen, causing them to swell, feel heavier, and become larger during the second half of your period.
Your menstrual cycle includes four distinct phases: menstruation, the follicular phase, ovulation, and the luteal phase. The luteal phase is roughly the two weeks between ovulation and when you get your period. It’s when PMS symptoms are most likely, especially during the second week of the luteal phase. During this phase, estrogen and progesterone are high.
Progesterone is particularly involved in the symptoms of weight gain. High progesterone can make the walls of your veins sag, which can trigger swelling. It can also prevent your body from draining water, leading to water retention. Progesterone can also increase appetite and cause your breasts to swell.
The important thing to remember is that gaining weight during your period is temporary. These symptoms can start up to two weeks before your period, but they typically start about five days to one week before your period.
You may experience weight gain during the first 3-4 days of your period, which should end when your period is over. That said, it’s normal to have small weight fluctuations throughout the day, even when you don’t have PMS or your period.
It’s not always possible to prevent gaining weight during your period, but there are things you can try to lessen the weight gain, swelling, and water retention.
Here are some tips from the American College of Obstetricians and Gynecologists (ACOG):
- Add exercise to your daily routine
- If you crave carbohydrates, try to eat complex carbohydrates, like whole-grain bread, pasta, and cereal, as well as beans, lentils, and brown rice
- Reduce unhealthy fats, salt, and sugar before your period
- Under a doctor’s supervision, consider magnesium supplements, which may help with bloating and water retention
- Under a doctor’s supervision, consider using diuretics to minimize fluid retention
It’s also important to remember that certain conditions may cause weight gain—not just during PMS and your period—but throughout the month. For instance, people with polycystic ovarian syndrome (PCOS) may see weight gain as a symptom.
Anyone with irregular periods may have underlying conditions or hormonal imbalances that can also cause weight gain. Addressing the underlying cause may be the best way to prevent menstruation-related weight gain in these cases.
Gaining weight before and during your period is usually normal and should pass once it’s over. If you notice weight gain that doesn’t go away or weight gain accompanied by other concerning symptoms, talk to a healthcare provider.
Most PMS symptoms aren’t serious, but severe PMS symptoms sometimes indicate an underlying condition, such as:
- PCOS
- Hormonal imbalances
- Perimenopause or menopause
- Irritable bowel syndrome (IBS) or other GI conditions
- Thyroid disease
- Anxiety or depression
Weight gain during periods isn’t typically a concern, but if you have any concerns, contact a healthcare provider.
It’s very common to experience weight gain before and during your period. This is due to the physical and hormonal changes that occur during this time, including bloating, water retention, swelling, and changes in eating patterns.
The good news is that weight gain is not dangerous and typically goes away after your period is over.
If your weight gain doesn’t go away once your period comes, or if you are experiencing other concerning symptoms, you should reach out to a healthcare provider.
