Luteal phase

After an egg is released from the ovary at ovulation, the empty follicle becomes a structure called the corpus luteum. The corpus luteum produces progesterone for around 12 to 14 days. Progesterone prepares the uterine lining for a possible pregnancy. If pregnancy does not happen, progesterone falls, the lining sheds as a period, and the cycle resets. The luteal phase is the predictable hormonal half of the cycle. The follicular phase (the first half) varies more between people and from month to month.

• Bloating: progesterone slows gut motility, so more gas builds up; fluid shifts add to the feeling of puffiness (measured retention actually peaks around day one of the period, White 2011).
• Constipation: same mechanism, gut transit slows by about a day on average.
• Cravings: small but real increase in appetite, often peaking in the last week.
• Body temperature: rises by about 0.3 to 0.5 degrees Celsius after ovulation. The basis for fertility tracking by basal body temperature.
• Sleep: progesterone is mildly sedating early in the phase but can fragment sleep in the last week.
• Mood: more variability, more sensitivity. Premenstrual syndrome (PMS) sits in the last 5 to 7 days for around 75% of women.

12 to 14 days is the typical range. A luteal phase shorter than 10 days, called a short luteal phase, is associated with a modestly lower chance of conceiving in the next cycle and over the first few months, though by a year pregnancy rates tend to even out. It is common and is not a proven independent cause of infertility, and fertility specialists no longer routinely investigate it as an isolated diagnosis. A luteal phase longer than 16 days without a period usually means pregnancy or a hormonal shift worth asking your doctor about.

1. Track your cycle. Most people are surprised how predictable their luteal-phase patterns are once they have 2 or 3 months of data.
2. Lower-sodium evenings in the last week of the phase. Reduces water bloat noticeably.
3. More fibre and water across the phase to offset slower gut transit.
4. Walk daily. Movement counters the gut slowdown and stabilises mood.
5. Magnesium is often suggested for this phase. The trial evidence is modest, mainly for cramps, sleep and fluid-retention symptoms (Parazzini 2017 review; the Walker 1998 trial used 200 mg daily). If you try it, ask a pharmacist and keep supplemental magnesium within the UK guidance level of 400 mg a day; the glycinate form is the usual evening choice and has no laxative effect, so it will not help the luteal constipation.
6. Caffeine and alcohol are felt more strongly in the luteal phase. Cutting back the last 7 days often helps mood and sleep more than expected.

Bloating that is there most days and does not settle deserves a doctor's check whatever your age, and there is no age cut-off on that advice. A luteal phase stretching past 16 days usually means pregnancy or a hormonal shift worth asking your doctor about, monthly patterns severe enough to disrupt work or relationships are treatable rather than endurable, and anything that does not lift when the period arrives deserves looking at in its own right.

Bloating, cramping or constipation that recurs in the luteal phase is often hormonally driven rather than triggered by food. Many women spend years cutting foods chasing a pattern that turns out to be cyclical. A 3-month cycle log alongside symptom tracking usually reveals the pattern, and then the relationship to food becomes clearer because hormones are no longer a hidden variable.