Once your body starts producing the pregnancy hormone, human chorionic gonadotropin (HCG), your normal periods will stop. Bleeding in pregnancy is surprisingly common. It may look like a period which is known as a breakthrough bleeding. It happens when the hormones that control your menstrual cycle break through the pregnancy hormones that are flooding your body. Bleeding could happen when the fertilised egg implants into the lining of your uterus (womb), where it will grow and form. This usually happens at about the time your period would have been due, and is called the implantation bleeding. if you are pregnant Any blood you notice around this time is more likely to be because of breakthrough bleeding than implantation bleeding. It’s only natural to be worried if you have any bleeding or spotting at this time. It’s a good idea to tell your doctor or midwife about any bleeding that you may notice, because it can occasionally be a cause for concern. Unfortunately, sometimes bleeding may be the first sign of a miscarriage. If so, it probably won’t feel like a normal period. You are likely to have stronger tummy cramps and much heavier bleeding You should call your doctor straight away if you have dark, or watery bleeding, together with sharp pains in your lower tummy, especially on one side. You could have be experiencing an ectopic pregnancy and you’ll need swift treatment. It’s much more likely that your bleeding is nothing to worry about. A midwife may look into why you’ve had the bleeding. If you’re only just pregnant, she may suggest that you have a blood test to check your hormone levels or she may refer you for an early scan just to ensure everything is fine. Another thing your midwife will want to find out is when your baby is likely to be born. Bleeding during early pregnancy can make it hard to predict your due date Midwives and doctors often use the first day of your last period to estimate when your baby is due to be born. If that’s in any doubt, measuring your uterus may help to work out how far along you are. You may also be offered a dating scan which is booked about the time you are 12 weeks pregnant.