In most cases, a simple urine test can detect pregnancy. These are available from supermarkets, chemists and online pharmacies. Your doctor can also do a test if you request this. Pregnancy tests are usually accurate from the first day of your missed period. Some brands can detect HCG five days earlier and some very sensitive tests have been known to detect pregnancy even earlier than that.
If you are having IVF treatment you may get a false positive result as the hormone HCG is used in the IVF process. Some weight loss programs also use HCG and could give a false pregnancy result.
If you are having assisted reproduction technology (ART), then your fertility specialist will normally give you a blood test two weeks after your embryos have been implanted to see if they have "taken".