Menstrual cycle influences blood sugar levels more than previously understood, particularly in women with insulin resistance

New research highlights how hormonal shifts during the menstrual cycle can impact blood sugar regulation, especially in women with prediabetes, diabetes, or PCOS, prompting calls for cycle-aware monitoring.

For many women, the days before a period bring a familiar mix of sweet cravings, low energy, irritability and a sense that the body is running on empty. While these symptoms are often dismissed as premenstrual syndrome, there is also a blood sugar angle to consider, according to the Deccan Chronicle and related medical research.

The menstrual cycle does more than regulate bleeding. Hormonal shifts can change appetite, insulin sensitivity, energy levels and the way the body handles glucose. During the first half of the cycle, when oestrogen rises, the body tends to be more responsive to insulin. In the second half, known as the luteal phase, progesterone becomes dominant and can temporarily increase insulin resistance, which may nudge blood sugar higher in some women.

That change is usually modest, but it can be more noticeable in women who already have insulin resistance, prediabetes, diabetes or polycystic ovary syndrome. Dr Meenakshi Ahuja, Principal Director of Obstetrics and Gynaecology at Fortis La Femme, told Deccan Chronicle that these hormonal shifts are temporary but can still cause visible swings in blood sugar, particularly in women already prone to glucose regulation problems.

The craving for chocolate or other sugary foods is not just a matter of willpower. Hormonal changes in the premenstrual phase can affect serotonin, appetite control and the brain’s reward system, making refined carbohydrates especially tempting. That can create a short-lived cycle: a sugary snack raises blood glucose quickly, then it falls again, leaving a person hungry, tired or unfocused soon after.

Symptoms often associated with PMS can overlap with the effects of fluctuating blood sugar. Fatigue, headaches, mood changes, difficulty concentrating and increased hunger may all appear when glucose levels swing. Lifestyle factors can intensify the pattern too. Poor sleep, less exercise and higher stress can all affect blood sugar, making the pre-period week feel more difficult.

The effect may be stronger for women with PCOS, which is commonly linked to insulin resistance. Research cited by Harvard T.H. Chan School of Public Health and older studies indexed on PubMed and in the International Journal of Reproduction, Contraception, Obstetrics and Gynaecology all point in the same direction: glucose handling can vary across the menstrual cycle, with the luteal phase often associated with less efficient control. That does not mean every symptom is caused by blood sugar, but it does suggest that recurring monthly patterns should not be ignored.

Doctors quoted in Deccan Chronicle also said there is no special day in the cycle for a fasting glucose test, and HbA1c, which reflects average blood sugar over roughly two to three months, is not tied to menstrual timing either. For women who suspect a pattern, keeping a simple record of period dates, glucose readings, sleep, activity, cravings and energy levels may help reveal whether the cycle is influencing the numbers. Persistent abnormal readings, however, should not be written off as hormones alone.