Finding out you are pregnant

Some women are convinced that they are pregnant from the moment of conception; others have such irregular periods that a long gap in between does not alert them to the possibility of pregnancy. But for most women the first sign of pregnancy is a missed period.

Perhaps it is five days since the day when you expected it, but then you start wondering if your dates were wrong. Perhaps you usually make a note in your diary, but last time you forgot. You lie in bed, unable to sleep, trying to fix dates firmly in your mind by finding some useful landmark, like your mother's visit or the end of a particular work assignment. Still another three days go by and the reality gradually dawns: you might be pregnant. You might not be, but it does seem quite possible that you are. When is it sensible to go to the doctor, and how early can you know for certain?

When to diagnose

There is a strong case for finding out if you are pregnant before two periods have been missed. It is during these few weeks, while the embryo is still no larger than a hazelnut, that the major organs of the body and the brain itself are being formed; the sooner you know that you are pregnant the sooner you can start caring for yourself and for the baby.

How to diagnose

Pregnancy can now be diagnosed about two weeks after conception, on the day your period should have started if you have a regular menstrual cycle, although you are likely to get more accurate results if you wait at least another four days - which can be difficult if you are feeling anxious or excited. When you are pregnant, the embryo releases a hormone called human chorionic gonadotrophin (HCG) into your bloodstream. Minute traces of HCG will be present in your urine approximately six days after conception, but then the level builds up quite rapidly, doubling every two or three days until it reaches a peak about 60 days after conception - approximately 74 days after your last period started - when it begins to decrease. It is possible to detect the presence of this hormone in your urine or blood. Your doctor or midwife will take a urine or blood sample for analysis at a laboratory.

You may prefer to use one of the do-it-yourself pregnancy kits that are widely available. Whichever method you choose, if at all possible, test urine passed first thing in the morning, when you have not drunk anything during the night, since it is at this time that urine contains the highest concentration of pregnancy hormone.