The tightness, the puffiness, the waistband that fit fine a week ago. Bloating before your period is one of the more physically uncomfortable parts of the luteal phase. It comes up often as part of premenstrual syndrome (PMS), and it has a clear hormonal cause. Bloating can also point to other conditions though, so if yours is severe, sticks around, or comes with other symptoms you are not sure about, it is worth raising with your GP.1
Why does bloating happen in the luteal phase?
The luteal phase is the stretch of your cycle between ovulation and the start of your period. Through this window, progesterone rises. Progesterone relaxes smooth muscle across your body, including the muscle lining your intestines. That can slow the movement of food through your gut.2
When digestion slows, food sits in your gut longer, which gives the bacteria there more time to ferment it. That fermentation makes gas, and the gas is part of the bloated, heavy feeling you may notice. Slower gut movement can also make constipation more likely in the days before your period.3
Something else runs alongside this. Shifts in oestrogen and progesterone through the luteal phase can lead your body to hold onto more salt and water, which adds that puffy, heavy feeling that sits apart from ordinary digestive discomfort. Slowed digestion and fluid retention often happen at once, and that is why bloating before your period can feel so pronounced.4
What tends to make luteal phase bloating worse?
Some foods and drinks can add to the bloating your hormones are already driving. Salty foods, including a lot of processed and packaged ones, can make your body hold onto more water and leave you puffier. Fizzy drinks send extra gas straight into your digestive system, which adds to the discomfort.5

Large meals ask more of a digestive system that is already moving more slowly than usual through the luteal phase. You may find that smaller, more frequent meals, rather than three big ones, ease the feeling of fullness and pressure.6
What can ease bloating before your period?
Keeping your fluids up helps your body flush out excess fluid and may ease water retention. Cutting back on salt in the days before your period is a practical step that goes straight at one of the main drivers of fluid retention.7
Foods rich in potassium, like bananas, dark leafy greens, and sweet potatoes, may help your fluid balance by offsetting some of what sodium does. Working these into a balanced diet through the luteal phase is an easy change to make.8
Regular, gentle movement can help your digestion along and may ease bloating. Walking, stretching, or light movement can make a difference. Gentle movement is also one of the more consistently useful approaches for PMS more broadly, and the way it keeps your gut moving makes it especially handy for bloating.9