One of the first things you may wonder after finding out you are pregnant is when will your baby make her arrival. Predicting your baby's due date is a matter of knowing a few important facts about your menstrual cycle and the typical length of a full-term pregnancy. Because the exact date of conception is difficult to determine, the baby's gestational age and due date are determined by the first day of the woman's last menstrual period. Knowing your due date will help you to properly plan and monitor the health of your growing baby.
Step 1
Use a calendar to mark the first day of your last menstrual period. This would be the first day that menstrual flow began.
Step 2
Count forward 280 days, or 40 weeks, from the first day of your last period. This is your estimated due date.
Step 3
Use an online due date calculator to verify the date that you have determined using your own calendar.
Tips and Warnings
- Because full-term pregnancies can vary from 37 to 42 weeks, it is important to remember that your baby may not arrive on his predicted due date. If you are unsure of the first day of your last menstrual period, request a dating ultrasound from your caregiver, which can be completed as early as 5 to 6 weeks into a pregnancy to verify gestational age.
