“I hate being around my lady when her period is about to arrive; she is so moody and miserable. She has bad PMS.” This cry may resonate with many men. In fact, many women may actually believe they suffer from the condition called PMS — Premenstrual Syndrome. But is this really so?

To understand PMS we first have to understand the menstrual cycle: the series of changes a woman’s body undergoes in preparation for the possibility of pregnancy. Each month, one of the ovaries releases an egg — a process called ovulation. At the same time, hormonal changes prepare the uterus for pregnancy. If the egg is not fertilised, the lining of the uterus sheds through the vagina, resulting in a woman seeing an outflow of blood and tissue. This outflow is known as the menses or the period. Most women have a 28-day menstrual cycle which is divided into two. The first half is called the follicular phase and the second half is called the luteal phase.

Most women know when their period is about to occur as they tend to have various premenstrual symptoms: bloatedness, breast tenderness and irritability, which occur two to three days before the onset of the menses. This is normal.

What then is the difference between normal premenstrual signs/symptoms and PMS?

The difference here is the timing of these symptoms. By definition, premenstrual syndrome is a distressing physical, behavioural and psychological condition with no known organic cause, which occurs in the luteal phase (last two weeks before the menses versus two to three days before the menses for normal premenstrual symptoms) and improves with the onset of menstruation. Physical symptoms include breast tenderness and bloating. Psychological symptoms include irritability, mood swings and even depression, while behavioural symptoms include a decrease in concentration and an increased risk of accidents.

PMS can be mild, moderate or severe. Mild PMS has little or no effect on a woman’s social, behavioural or professional capacity. Moderate PMS affects some women, but they are still able to function. Severe PMS is a debilitating condition where the woman is unable to function in any capacity.

What causes PMS and how common is it? The truth is, we do not know. Other causes such as underlying medical conditions like thyroid disease or mental disorders have to be ruled out, as these conditions can mimic PMS. What is thought to be a cause is the relationship between hormones in the menstrual cycle and brain receptors. PMS affects 20-30 per cent of women.

Since we have a basic understanding of PMS, next week we will discuss how to diagnose PMS and how to treat it.

Dr Daryl Daley is a consultant OBGYN at Gynae Associates, 23 Tangerine place, Kingston 10, and Shops 46-50, Portmore Town Centre, Portmore. He can be contacted at 929-5038-9 and 939-2859, or drdaryldaley@gmail.com.