In ancient Egypt women used to urinate on to the leaves of the papyrus plant. If the plant died they weren’t pregnant, if it lived they were.

A general shortage of papyrus plants has led to the development of a number of less colourful ways of diagnosing pregnancy. Most of these depend on levels of specific hormones in the urine. There are two things to be remembered about all pregnancy tests: firstly, they cannot be used until a number of days after conception (the actual number of days depends on the test) and secondly, they may on occasion be wrong, producing both false positives and false negatives.

The best-known home test method is probably the Predictor test which can be used by a potential mother nine days after her period should have started. It seems simple to use. A few drops of urine are added to the test tube provided. The tube is then shaken and left for two hours. If the woman is pregnant a brown ring appears – if she isn’t it doesn’t. Discover 2 is a similar test kit.

Almost every woman who has been pregnant will know that there are certain signs which tell her that she’s expecting: she may feel sick, have enlarged, tender, tingling breasts and feel a need to pass urine more frequently than usual. A woman who has been pregnant in the past and who feels that she is pregnant again usually is.

Any woman who misses a period and does a pregnancy test which turns out negative should visit her doctor if she misses another period.