Accuracy of ultrasound dating
Here are some helpful facts: The temperature shift occurs because of an increase in progesterone production after ovulation.
Keeping track of cervical mucus changes within a menstrual cycle can help narrow down the day of ovulation.
It is important to remember the lifespan of the egg and sperm can influence the date of conception.
By these facts: A conception date calculator can make it easier to figure out your date.
The calculator below works for you if your menstrual cycles are regular and are between 24 and 38 days long.
If your cycle lengths vary a lot, your results might not be accurate.
The calculator assumes ovulation occurs 14 days before the date of an expected period as explained in the section on 'Calculation by Menstrual Cycle Length' above.