Due Date

What is my due date based on?

Your due date, or estimated date of delivery (EDD), is the estimated calendar date when your baby will be born. Because prenatal tests and fetal development are affected by your due date, having an accurate date is important.

How does a doctor determine your due date? Your healthcare provider can give an estimated due date based on your last period or by performing an early ultrasound examination.

When determining your due date, your healthcare provider will need to know the first day of your last menstrual period (LMP). Based on the first day of your last menstrual cycle, your due date will be 280 days away!

If you are unsure of the first date of your last menstrual period or you have irregular periods, an early ultrasound will be the next best tool for obtaining an accurate due date. Because of the timing of fetal development, early ultrasounds are the most accurate at determining a precise due date. As pregnancy progresses, ultrasounds are not as reliable at determining accurate due dates.

Doctors don’t generally use the date of conception as an accurate reference for pregnancy dating purposes. You might think that you know exactly when you conceived based on the timing of sexual intercourse, but fertilization may not have taken place exactly at that time. Sperm can survive in the uterus for three days, allowing conception to take place anytime during intercourse and up to three days after. Based on the date of conception (if it could be pin-pointed), your due date will be 266 days later.

Based on ultrasounds, fetal growth, uterine development and other factors, your due date could be changed during your pregnancy. Due dates are only an estimation of when your baby is expected to be fully developed and ready for birth. Your baby could come before, on or even after your due date. Research shows that less than 5% of babies arrive on their actual due date, so don’t expect your little one to make his/her grand appearance on the EDD that your caregiver provides. Most babies will be born within 2 weeks of their estimated due date.

Comments: Due Date

Comments 1 to 14 of about 14.
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cerjks - 97 days ago.
hi folks, pls help me, i had my last period on may 13, next mnth i had a +ve pregnancy test, bt unfortunately on june 23 i had bleeding lasted for 3-4 days, on june 30 my gynec gave antibiotics for 4 days to clean uterus,as no d&c was required, and i had bleeding with clots upto july 4. after that i didnt had periods, by gods grace im conceiving, which will be my LMP????. doctors have confusion in my due date, pls help me?? am in tension......plsss

bribri1616 - 698 days ago.
Confused...HELP!! SO, mt LMP was on 25MAR2011 . and I do not know my average cycle length, tends to be longer I think bc I was on the DEPO shot a year ago.... I THINK CONCEPTION date was 16APR2011 which means I would be about 11w3d and EDD of 1/6/2012 my first ultrasound said I was 12w1d and EDD of 1/1/2012 based on my LMP I would be 12w3d and EDD of 12/30/2011 I know its not a diff of very many days (6) but Is this all accurate??

nawis1 - 698 days ago.
Very interesting way to calculate due date is http://calcduedate.com

ksimonne - 746 days ago.
Just found out last week, by a blood test, that I'm pregnant. I felt that I was but the home tests kept coming out negative. According to my last cycle, I should be due Dec 13th. I'm on a 35 day cycle. This will be my 4th child!! I'm so excited.

ohgoodnessbaby - 746 days ago.
So I have to wait 'til June 8th to see what's going on in my tummy but according to my last menstrual I am seven weeks today :)

mommy2BApril26th - 843 days ago.
well im 27 weeks and 2 days :) me and my boyfriend are expecting her on April 26th 2011 :)

flossy05 - 846 days ago.
Im having a csection on the 14th of feb 2011,im so excited to meet my new wee boy! :0)

hug0056 - 880 days ago.
My due date is 6th june 2011, my daughter's birthday is 20th may and the midwife said due to my age i will prob have baby early...... my daughter is praying bubs doesnt come on her birthday x legs crossed lol

little-angel-to-be - 918 days ago.
I'm due june 20th, 2011. says my 6w 1 d ultrasound. I had no period in september, but my doctors made one up for me. Make sense? I am so confused on this whole thing. Can't wait for my little angel to be born. :))

gamermommy - 1003 days ago.
when i went for a u/s at 11w6d, they said i was 11w3d... then the u/s at 19w2d they said i was 18w1d... i've been confused ever since! but i read somewhere that the dating at 18wks isn't as accurate as earlier (like my 11wks one) so i'm gonna stick to that, the baby will come whenever he/she feels like :D

parsons04 - 1003 days ago.
So according to my ultrasounds, I am one week further ahead than I should be. According to my period, I should be 19 weeks, but my ultrasounds are showing 20 weeks. I thought today at my appointment, the doctor would say I was 19w5d, but he said I was 20w6d. Apparently my baby is a big baby for how far I am along. Anyone else have an issue with being confused about how far along they actually are??

jsalmon - 1043 days ago.
I'm due 11/01/11, we would love baby to come on this date as we love our numbers, we chose to get married on 07/08/09! No pressure then....!!

EllisJayne - 1076 days ago.
Aaww congratss :)' my brothers girlfreind is due 16.12.2O1O! im due 29.O8.2O1O idont want too carry herr longer than 4O week although iwould really love herr birthday to be in september near herr daddies good luck with your pregnancy!

nikkii b - 1103 days ago.
Im due 12/25/2010 woo hoo.....(if all goes well)