What is Due Date?
Due date is the estimated date of delivery calculated by two methods, using the last menstrual period and the other one is using the conception date.
LMP Method: Using LMP method, you can calculate the due date by adding 40 weeks to the first day of your last menstrual period. i.e (Due Date = LMP* + 280 days)
*LMP - First day of last menstrual period.
Conception Date Method: This method is based upon the date you conceive a child, for which wwomen need to keep track of ovulation date and estimate the date of conception. Using this method, the due date is 38 weeks from the conception date.
It is difficult to track conception dates and this is why the LMP method could be more suitable to calculate the estimated due date. The actual delivery date may be the same or different due to many other factors related to pregnancy.
What Is Pregnancy Calculator And How Does It Calculate Your Due Date?
Pregnancy calculator determines the date of your baby's birth. It gives an approximate date helping you to prepare for the big day.
You can calculate the due date by entering the first day of your last menstrual period and the average length of your cycle in the pregnancy calculator. The due date is calculated by adding 280 days, i.e., 40 weeks to the first day of your last period (if it is a 28-day cycle). The menstrual period and ovulation are the first two weeks of pregnancy. If you are delivering your baby on the due date, your baby will be 38 weeks, and not 40. This method is known as Dr. Nagele's rule.
How Do You Estimate Baby Due Date Using Conception Date Calculator?
If you are keeping a track on your ovulation and know the fertilization date, you can estimate the due date based on the date of conception. The estimated due date, in this case, will be 38 weeks (266 days) from the date of conception. Only a few women can accurately track the ovulation days and can guess when they have conceived. But, the calculations can go wrong as you may not conceive on the same day of the intercourse. The sperm can live up to five days, and the ovum for up to 24 hours after being released. In short, there is only a six-day fertile window where you can get pregnant.
In cases of in-vitro fertilization, the date of conception would be precise.
What Is The Date Of Conception?
Conception occurs after ovulation, when the sperm meets the egg. For instance, if you had intercourse on the 5th of the month, and you did not ovulate until the 8th of the month, the conception will occur on or just after the 8th. If you have a 28 day-cycle, conception is known to occur between 11 and 21 days after the first day of your LMP. As most of us do not know the date of conception, it is taken as an estimate based on the LMP method.
What Is An EDD (Estimated Due Date)?
An estimated due date (EDD) is the best guess for a spontaneous onset of labor. Your due date is estimated by adding 280 days (i.e., nine months and seven days) to the first day of your LMP.
By How Many Weeks Are You Pregnant?
There is no exact way to determine when you have ovulated and conceived. Therefore, health professionals date the pregnancy considering the last menstrual period.
To know your pregnancy weeks with this calculation, remember the first day of your last period. This is counted as day one of pregnancy. If you have a 28-day menstrual cycle, and find out that you have not had your periods on the expected date, then you are considered four weeks pregnant.
Some women prefer calculating their pregnancy weeks from the day of ovulation. This would be the estimated date of conception, which is about two weeks after the first day of your LMP. In this case, you are known to be two weeks pregnant, and you are likely to have your periods.
Division of Pregnancy Trimesters:
| Trimester | Duration |
|---|
| First trimester | LMP to end of week 12 |
| Second trimester | Week 13 to end of week 26 |
| Third trimester | Week 27 until childbirth |
Some Facts About MomJunction Pregnancy Due Date Calculator
- Your due date is estimated to last 40 weeks post the first day of your last period.
- Your menstrual cycle is presumed to be 28 days with ovulation taking place on the 14th day.
- Thus, the calculator adds 40 weeks (280 days) to the first day of your LMP.
Disclaimer: While our tool gives you a tentative due date and other details, it cannot replace a medical consultation. Visit a physician for confirming your EDD based on your complete medical history.
Our calculations are only an indication. MomJunction is not liable for any related issues, consequences or damages.
References:
- 1. Baskett TF, et al. Naegele's rule: A reappraisal. BJOG: An International Journal of Obstetrics and Gynaecology. 2000;107:1433.
- 2. American College of Obstetricians and Gynecologists. Your Pregnancy and Childbirth Month to Month. 5th ed. Washington, D.C.: American College of Obstetricians and Gynecologists; 2010:13.
- 3. MacKenzie AP, et al. Prenatal assessment of gestational age. Accessed Apr. 15, 2016.
- 4. Cunningham FG, et al. Williams Obstetrics. 23rd ed. New York, N.Y.: The McGraw-Hill Companies; 2010. Accessed Apr. 15, 2016.
- 5. American College of Obstetricians and Gynecologists Committee on Obstetric Practice. Committee Opinion No. 579: Method for estimating due date. Obstetrics & Gynecology. 2014;124:863.
Have you tried a due date calculator during pregnancy? How accurate was the prediction? Let our readers know by commenting below!
