If you’re trying to get pregnant, then anything that can give you an insight into when you’re ovulating, or better yet, can predict when you’re going to ovulate, is worth a look. An accurate prediction of the days in each cycle when you’re fertile let you know you’re trying to get pregnant at the time when it’s most likely to succeed.

One of the most common ways to check if you’re ovulating are OPKs. That’s an abbreviation of ‘Ovulation Predictor Kits’, they’re available from chemists and supermarkets, and work like pregnancy tests. They test your urine for a particular hormone that’s associated with ovulation (Luteinising Hormone, or LH, which spikes to stimulate your ovaries to release an egg, or, to be technical, ovulate). When they detect a surge in that hormone they tell you you’re ovulating and now is the time to try and conceive!

They’re similar to pregnancy tests, so the extent to which you’re going to find them convenient to use will depend on how comfortable you are peeing onto a stick or into a cup. The kit itself does all the hard of testing for you: you don’t need to plot numbers on a graph or count the days since your last period, just wait and look for the result.

But are they worth it? If they can’t give you a good prediction then you’re spending money and enduring minor indignities for nothing.

The short answer is: sometimes. That’s not very comprehensive but a longer answer is available.

OPKs work by testing your urine, but they compare your very specific hormone levels with a standard result. For the average woman, with a regular cycle and no major health issues the comparison is easy and the result is clear and helpful. If you depart from the average in any way, the results get less clear, the predictive power wanes, and it is easy to depart from the average.

The Luteinising Hormone is produced in the brain, and ‘ordered’ by the hypothalamus. The hypothalamus is the same region of brain impacted by stress. That means stress can affect the hormones in your body, or to put it another way, a tough day at work could mean your ovulation test gives you a false positive.

Medical conditions like Polycystic Ovary Syndrome are caused by a hormonal imbalance, which means that OPKs simply aren’t useful at all – and considering PCOS means ovulation is rarer, an accurate result is even more important!

With some debate over the best time to take an ovulation test even for people without health issues, it’s hard to give them a ringing endorsement, but fortunately there are plenty of options still available.