Dating scans during pregnancy

If you do know the conception date, this is classed as day 14 and not day one.If you have an irregular cycle, or if you've recently been taking the contraceptive pill, working out the date from your LMP isn't a very accurate method.

Should a problem be found, we will make all the necessary arrangements for follow-up care at a suitable time and location of your preference.Having an ultrasound in the first trimester of pregnancy can be a thrilling experience. Bear in mind that you may need a second ultrasound before you know for certain if all is well.The length of your pregnancy is calculated from the first day of your last menstrual period (LMP), even though you don't actually conceive until 14 days after your LMP, and later than this if your cycle is longer than 28 days.The LMP is used because most women know when their last period was, but may not know when they actually conceived.Closer to 7 weeks a fetal pole, the visual start of seeing a baby(s) but still measuring only a few millimetre (the size of a grain of rice) with a heartbeat the chances of pregnancy continuing 78%.

The baby usually measures 10 – 20 mm and a heartbeat can be seen clearly Baby now measures 20 – 30 mm and again a heartbeat is clearly visible.

Ultrasounds are more accurate than using the LMP and, if the ultrasound date differs from your period dates, the ultrasound date will be used.

The ultrasound date is usually later than the period date, so accurate dating has been found to reduce the number of women having labour induced because their babies are overdue The ultrasound can check that your baby has a heartbeat and is developing normally.

It's wonderful to see a little blob with a heartbeat that will become your baby. If you are unsure of the first day of your last period you will be offered a dating ultrasound when you are between 10 and 14 weeks pregnant.

But ultrasounds can also lift the lid on a few worries you might be having. The main reason for the ultrasound is to work out how many weeks pregnant you are, and to estimate your due date.

The heart can be seen beating in the chest area and the stomach, bladder and cord insertion are visible.