Follow your baby's development week by week in our article series.We have created a slew of pregnancy calculators and tools to help you through your pregnancy.Gestational age is calculated from the first day of the mother’s last menstrual period and not from the date of conception.The baby can be measured as early as 5 or 6 weeks after the mother’s last menstrual period.Your due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (assuming a 28 day cycle).
Consult a doctor or other health care professional for diagnosis and treatment of medical conditions.
Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines.
They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Every pregnancy is unique and your baby will come when it's ready.
Be sure to talk to your health care provider about your due date.