Due date is the estimated date of delivery calculated by two methods, using last menstrual period and other one is using conception date.
LMP Method: Using LMP method, you can calculate the due date by adding 40 weeks to 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 woman need to keep track of ovulation date and estimate the date of conception. Using this method due date is 38 weeks from the conception date.
It is difficult to track conception date and this is why 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.
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.
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.
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.
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.
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.
|First trimester||LMP to end of week 12|
|Second trimester||Week 13 to end of week 26|
|Third trimester||Week 27 until childbirth|
Sperms can live up to five days in the female body. For instance, if you had sex on Sunday, your chances of conception last till the following Thursday. To determine the date of conception, add two days to the day you had intercourse. It might not be an actual figure, but is a fair estimate.
A due date is an estimated time frame when you can expect the baby. Only 4% babies are likely to be born on the expected date. About 80% deliver between two weeks before or after the due date. Thus, the term “due date” is used.
To calculate the due month, subtract two weeks from the estimated date of delivery and add another two weeks to your EDD. This time frame will be your due month.
Gestational age (GA) refers to the length of your pregnancy calculated from the first day of your LMP. It is expressed in weeks and days and is also known as menstrual age.
Conceptional age (CA) refers to the age of the baby from the time of conception.
LMP stands for last menstrual period. It is the last period you got before conception. The LMP date is the first day of your pregnancy. This date is useful for calculating your due date (by adding 280 days or 40 weeks).
There is no difference between the two calculators. In both the calculators, the first day of your LMP is used to determine the estimated due date and conception day.
All you need to know is the accurate first day of your LMP to achieve the reliable results.
Ultrasound scan, clinical examination of pelvic supported by accurate menstrual records in the first trimester, Doppler ultrasonography after 10 to 12 weeks, and human chorionic gonadotropin (hCG) pregnancy test are some scientific methods to calculate due dates.
Yes, due date can change due to a few reasons. If you have irregular periods, your dates change. There would also be no confirmation on your pregnancy as the ultrasound would be called off due to irregular periods. Abnormal fundal height (distance from the top of the pubic bone to top of the uterus) or abnormal AFP (alpha-fetoprotein) levels also affect the due date.
Due date calculation is not completely accurate. Only 4% of babies are known to be born on the EDD. And, 80% of them are born between the two weeks before or after the EDD.
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.
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