The most obvious symptom is missing a period, although stress or anxiety can delay this too. By far the most accurate way to confirm this is to perform a pregnancy test. Nowadays, home pregnancy tests can be used as early as the day your period is due and are approximately 97-99% accurate, if used correctly. Your GP can also offer a pregnancy testing service.
Non - confirming signs include feeling tired and bloated however, many women experience this when their period is due. This may also be confusing if a lighter period is then experienced, as this could be a small bleed that occurs when the fertilised egg implants in to the wall of the uterus (womb). Tender breasts, an increase in needing to pass urine and a greater or lesser sex drive can also be mistaken for symptoms of pregnancy, when in fact it is because the period is due. Some women report having a metallic taste in their mouths, feel nauseous or experience vomiting generally described as morning sickness but can occur at any time, however, as each pregnancy is different, it is difficult to know exactly which symptoms a woman will experience, if any. Some women ‘just know’ instinctively.
For further information, see ‘I feel pregnant – how early can I test?’, ‘Are home pregnancy tests reliable?’ and ‘My pregnancy test was negative but I’m sure I’m pregnant – can they be wrong?’
Kitzinger, S. (2003) The New Pregnancy and Childbirth: Choices and Challenges. Dorling Kindersley.