Do you experience pain in one side of your tummy area about two weeks before your period? Congratulations – you are one of about 20 per cent of women who experience mittelschmerz.

Mittelschmerz is one-sided, lower abdominal pain associated with ovulation. The word is German for ‘middle pain’, so-called because it happens mid cycle, which is generally about 14 days before your period. The pain can be dull and cramp-like or sharp and sudden, and it lasts from just a few minutes to a day or two. It can sometimes (not often) be accompanied by a bit of blood spotting. You may feel it some months and not others.

The discomfort is so localised that most people who experience it can tell which of their two ovaries has just popped out an egg. The pain may switch sides from month to month, or it may happen on one side for months at a time. (Studies have shown that in the majority of women, the right ovary is more likely to produce the ‘queen’ egg - the one that gets released for potential baby making.)

It’s not known precisely what causes some women to feel mittelschmerz, when others don’t. But it’s thought to be caused by the swelling and retracting in the follicle that releases the egg, or the egg bursting through at the point of ovulation. Because of this, it's a handy sign that you are at your most fertile, and more likely to get pregnant. So if you’re planning to have a baby, it can be handy. But using it as a time to avoid pregnancy isn’t reliable, so don’t abandon the contraception!

In most cases, mittelschmerz doesn't require medical attention. Once you’ve identified it you can work out when it’s likely to happen and have Panadol at the ready. If the pain gets intense, or if you experience pain at other times of your cycle, see your GP.