Period Power & Blood Sugar

It starts innocently enough. A few days before your period, you suddenly want something sweet. Then comes the constant hunger, the 4 pm energy crash, the irritability and that familiar feeling of being completely drained. Most of us simply file these symptoms under PMS. But there could be another piece to the puzzle: blood sugar.

The menstrual cycle does more than determine when your period arrives. The hormonal shifts that happen throughout the month can influence appetite, insulin sensitivity, energy levels and the way the body processes glucose. For some women, this can mean subtle changes in blood sugar that become particularly noticeable in the days leading up to menstruation. For women with PCOS, prediabetes, insulin resistance or diabetes, these fluctuations can be even more apparent.

The Hormonal Connection

The menstrual cycle is broadly divided into two phases. During the first half, known as the follicular phase, oestrogen levels rise. The body is generally more sensitive to insulin during this time, allowing glucose to be used more efficiently.

After ovulation comes the luteal phase — the period between ovulation and the start of menstruation. This is when progesterone becomes the dominant hormone. According to Dr Meenakshi Ahuja, Principal Director, Obstetrics & Gynaecology, Fortis La Femme, progesterone can temporarily increase insulin resistance.

This means that the body may need more insulin to achieve the same level of blood sugar control. The liver may also produce more glucose, while muscles may not take up glucose as efficiently. The result? Some women may notice slightly higher blood sugar readings in the days before their period. “These hormonal shifts are temporary but can cause noticeable fluctuations in blood sugar, especially in women who already have insulin resistance, prediabetes or diabetes,” says Dr Ahuja.

The Sweet Craving

There is a reason the cookie jar can suddenly become far more interesting before your period. Hormonal changes during the premenstrual phase can affect serotonin, appetite regulation and the brain’s reward pathways. This can make sweet and refined carbohydrate-rich foods particularly tempting.

And once the craving hits, it can become a cycle. You reach for something sugary, your blood sugar rises quickly and then drops, and you may find yourself hungry or exhausted again soon afterwards. Dr Ahuja suggests, building meals around protein, fibre and low-glycaemic-index carbohydrates. Think vegetables, pulses, whole grains, millets, fruits and lean protein. These foods release glucose more gradually and can help keep energy levels steadier.

PMS & Blood Sugar

Fatigue, headaches, irritability, difficulty concentrating, in-creased hunger and cravings are all common PMS symptoms. But some of these can also occur when blood sugar fluctuates. Hormonal changes can increase insulin resistance and lead to greater glucose variability. At the same time, cravings for sugary foods can cause significant rises and falls in blood sugar, potentially contributing to fatigue, shakiness, mood changes and what many women describe as “brain fog”.

Then there are the lifestyle changes that often come with PMS. You may sleep poorly, exercise less or feel more stressed — all factors that can influence blood sugar. PMS has many causes, and these symptoms are extremely common. But if you notice the same pattern month after month, it may be worth paying attention.

PCOS Fluctuations

PCOS is frequently associated with insulin resistance, meaning the body does not respond to insulin as efficiently as it should. When the natural hormonal changes of the menstrual cycle are added to this, some women may notice more pronounced fluctuations. “Women with PCOS, prediabetes or

diabetes are more likely to experience noticeable blood sugar fluctuations during different phases of the menstrual cycle because their glucose metabolism is already impaired,” says Dr Ahuja.

This can sometimes coincide with stronger cravings, mood changes, fatigue and irritability. A balanced diet, regular physical activity and consistent meals can help support steadier blood sugar and overall metabolic health.

Blood Test Timing

If you’re scheduling a fasting blood glucose test, you don’t need to wait for a particular day of your cycle. Dr Rashmi Rasi Datta, Consultant Biochemist and Section Head, Agilus Diagnostics, says there is no strict time during the menstrual cycle when fasting glucose needs to be tested. “Fasting glucose can be checked on any day,” she says.

The same applies to HbA1c, with even less reason to worry about cycle timing. HbA1c gives an estimate of average blood sugar levels over approximately the previous two to three months, rather than measuring your glucose at one particular moment. So, whether you’re on your period, approaching it or somewhere in the middle of your cycle generally doesn’t determine the accuracy of an HbA1c test. If you’re repeating blood tests, however, keeping conditions as consistent as possible can make it easier to compare results.

Reading Obsession

A single high or low blood sugar reading doesn’t necessarily tell the whole story. Your glucose levels can change because of what you ate, how much you slept, your stress levels, physical activity, illness and hormonal fluctuations. “Don’t look for one high or one low; look for trends that repeat,” says Dr Datta. If you suspect your menstrual cycle is affecting your blood sugar. Try keeping a simple record for a few months. Note the first day of your period, fasting glucose readings if you monitor them, cravings, energy levels, sleep and physical activity.

For women with PCOS, prediabetes or diabetes, this information can also give doctors a clearer picture of what is happening.

Matter Of Concern

Persistent abnormal blood sugar readings should not be dismissed as “just hormones”. Understanding the relationship between your menstrual cycle and blood sugar isn’t about micromanaging every bite of food or worrying about every reading. It’s about recognising that your body is constantly responding to hormonal changes.

So the next time the week before your period brings an inexplicable craving for chocolate, a mid-afternoon slump or a sudden increase in hunger, remember: your hormones may be part of the story.