The purpose of the gestation wheel is to determine how far along you are in your pregnancy; all you need to do is turn the wheel to point at the date of the first day of your last monthly period or use the calendar to insert this date and the gestational age will be calculated for you along with the estimated date of delivery.

In women who have regular menstrual cycles the average cycle generally lasts 28 days, ovulation occurs on or around day 14 and the menstruation occurs 12-14 later.  However if an egg is fertilised in due course then menstruation does not occur.  Nägele’s Rule is used to calculate gestational age, which is based on the average human pregnancy lasting 280 days from the first day of the last monthly period.  This involves adding 7 days and subtracting 3 months to give the expected date of delivery.

This calculation is based on ovulation occurring approximately two weeks into your menstrual cycle therefore the gestation of your baby is calculated from the dates you have input.  However, in women who have irregular menstrual cycles or women who have recently been on the pill then this method can be inaccurate, it is therefore recommended that an ultrasound scan is performed as a more accurate means to date your pregnancy. Please visit our Packages and Fees Page to see all of our available packages and our Special Offers Page for up to date offers on our 3D and 4D ultrasound scans.