How to Calculate the Due Date Based on the Ovulation Date

The gestational age of the baby is calculated by the first day of the mother's last period. An average menstrual cycle is 28 to 32 days. Ovulation normally occurs the second week after your period or the eleventh through twentieth days of a 28 to 32-day cycle. Ovulation is the specific phase in your menstrual cycle when your body releases an egg. It is difficult to pinpoint the exact day because each month your menstrual cycle can be different. The average pregnancy is 38 weeks or 266 days. You would calculate your due date by starting with your estimated day of ovulation.

Things You'll Need

• Ovulation predictor kit

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Instructions

• 1

  Track your menstruation cycle. Count the number of days between cycles each month. Ovulation normally occurs two weeks before your next period. If your menstrual cycles run 28 days, then you are likely to be ovulating on the 14th day of each cycle. You would calculate your due date starting with the 14th day in your ovulation phase. If your cycle is longer some months and shorter other months, your ovulation phase is anywhere between day 8 and 20 of your cycle.

• 2

  Look for the signs of ovulation. Breasts will become more tender as the hormones increase in your body during this phase. You might experience cramping in your lower abdomen. Some women experience these cramps on the side that the egg is released. If you experience these symptoms, keep track of the days by documenting them on a calendar. You would calculate your due date based on the time you experience these symptoms.

• 3

  Chart your body temperature. It will rise slightly during the ovulation phase. Called the Basal Body Temperature (BBT), a normal body temperature is 98.7. During this phase your temperature might elevate .4 degrees higher than normal. Take your temperature every day at the same time. When you see a temperature elevation, chart the temperature and the date. You are looking for an elevated temperature for a period of 48 hours. When this happens, document the date as your ovulation phase.

• 4

  Conduct a cervical check. During the ovulation phase, the mucus in the cervix will increase. Most women will feel the need to put on a panty liner during this phase. Take some of the mucus between two fingers and pull your fingers apart. If the mucus stretches between your fingers about an inch without breaking, you are ovulating and at your most fertile. Keeping track of when this happens each month will give you an idea of when you are ovulating. Chart your due date calculation based on this.

• 5

  Purchase an ovulation predictor kit. These tests allow you to measure the level of LH in your urine. LH (Luteinizing hormone) is a hormone that is produced in the anterior pituitary gland. When your body gets an LH surge, it triggers ovulation. The ovulation predictor kit lets you know when this happens. You will get an accurate reading confirming when your body is ovulating. Chart the date for your ovulation phase.