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Pregnancy Due Date Ranges

This table attempts to estimate your probability of going into labor on different individual days based on your estimated due date. If you don't know your due date, or just want a handy daily page to tell you where you're at, use the pregnancy calendar.

It's based on the idea that the average pregnancy lasts 40 weeks with a standard deviation of about 10 days. This means you're more likely to go into labor on one of the days close to your due date. For instance, about half of all babies are born within a week of their date. Scroll to the bottom of this page if you want to know more about where I got these numbers.

The following dates are based on an estimated due date of January 15th, 2014.

Change due date:
Month Day Year
Date Progress Overall probability of
spontaneous labor
Current probability of
spontaneous labor
probability of a pregnant woman at this stage going into labor
On this date By this date On this date By this date On this date Within 3 days Within 5 days Within 7 days
Wednesday December 11th, 2013 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Thursday December 12th, 2013 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Friday December 13th, 2013 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Saturday December 14th, 2013 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Sunday December 15th, 2013 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Monday December 16th, 2013 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Tuesday December 17th, 2013 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Wednesday December 18th, 2013 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Thursday December 19th, 2013 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Friday December 20th, 2013 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Saturday December 21st, 2013 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Sunday December 22nd, 2013 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Monday December 23rd, 2013 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Tuesday December 24th, 2013 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Wednesday December 25th, 2013 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Thursday December 26th, 2013 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Friday December 27th, 2013 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Saturday December 28th, 2013 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Sunday December 29th, 2013 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Monday December 30th, 2013 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Tuesday December 31st, 2013 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Wednesday January 1st, 2014 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Thursday January 2nd, 2014 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Friday January 3rd, 2014 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Saturday January 4th, 2014 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Sunday January 5th, 2014 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Monday January 6th, 2014 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Tuesday January 7th, 2014 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Wednesday January 8th, 2014 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Thursday January 9th, 2014 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Friday January 10th, 2014 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Saturday January 11th, 2014 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Sunday January 12th, 2014 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Monday January 13th, 2014 39W, 5D 3.91% 42.07% -% -% 6.7% 20.6% 34% 46.7%
Tuesday January 14th, 2014 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Wednesday January 15th, 2014 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Thursday January 16th, 2014 40W, 1D 3.97% 53.98% -% -% 8.6% 25.1% 40.4% 54%
Friday January 17th, 2014 40W, 2D 3.91% 57.93% -% -% 9.3% 26.7% 42.5% 56.2%
Saturday January 18th, 2014 40W, 3D 3.81% 61.79% -% -% 10% 28.2% 44.5% 58.5%
Sunday January 19th, 2014 40W, 4D 3.68% 65.54% -% -% 10.7% 29.8% 46.6% 60.6%
Monday January 20th, 2014 40W, 5D 3.52% 69.15% -% -% 11.4% 31.3% 48.6% 62.7%
Tuesday January 21st, 2014 40W, 6D 3.33% 72.57% -% -% 12.1% 32.9% 50.5% 64.7%
Wednesday January 22nd, 2014 41W, 0D 3.12% 75.8% -% -% 12.9% 34.4% 52.4% 66.6%
Thursday January 23rd, 2014 41W, 1D 2.9% 78.81% -% -% 13.7% 36% 54.3% 68.5%
Friday January 24th, 2014 41W, 2D 2.66% 81.59% -% -% 14.4% 37.5% 56.1% 70.2%
Saturday January 25th, 2014 41W, 3D 2.42% 84.13% -% -% 15.2% 39% 57.9% 71.9%
Sunday January 26th, 2014 41W, 4D 2.18% 86.43% -% -% 16.1% 40.5% 59.6% 73.5%
Monday January 27th, 2014 41W, 5D 1.94% 88.49% -% -% 16.9% 42% 61.3% 75.1%
Tuesday January 28th, 2014 41W, 6D 1.71% 90.32% -% -% 17.7% 43.4% 62.9% 76.4%
Wednesday January 29th, 2014 42W, 0D 1.5% 91.92% -% -% 18.6% 44.8% 64.5% 77.8%
Thursday January 30th, 2014 42W, 1D 1.3% 93.32% -% -% 19.5% 46.3% 65.9% 79.2%
Friday January 31st, 2014 42W, 2D 1.11% 94.52% -% -% 20.3% 47.6% 67.3% 80.5%
Saturday February 1st, 2014 42W, 3D 0.94% 95.54% -% -% 21.1% 48.9% 68.8% 81.6%
Sunday February 2nd, 2014 42W, 4D 0.79% 96.41% -% -% 22% 50.1% 70.2% 82.7%
Monday February 3rd, 2014 42W, 5D 0.66% 97.13% -% -% 23% 51.6% 71.4% 83.6%
Tuesday February 4th, 2014 42W, 6D 0.54% 97.72% -% -% 23.7% 53.1% 72.8% 84.6%
Wednesday February 5th, 2014 43W, 0D 0.44% 98.21% -% -% 24.6% 54.2% 73.7% 85.5%
Thursday February 6th, 2014 43W, 1D 0.35% 98.61% -% -% 25.2% 55.4% 74.8% 86.3%
Friday February 7th, 2014 43W, 2D 0.28% 98.93% -% -% 26.2% 56.1% 75.7% 87.9%
Saturday February 8th, 2014 43W, 3D 0.22% 99.18% -% -% 26.8% 57.3% 76.8% -%
Sunday February 9th, 2014 43W, 4D 0.18% 99.38% -% -% 29% 58.1% 79% -%
Monday February 10th, 2014 43W, 5D 0.14% 99.53% -% -% 29.8% 59.6% -% -%
Tuesday February 11th, 2014 43W, 6D 0.1% 99.65% -% -% 28.6% 62.9% -% -%
Wednesday February 12th, 2014 44W, 0D 0.08% 99.74% -% -% 30.8% -% -% -%
Thursday February 13th, 2014 44W, 1D 0.06% 99.81% -% -% 31.6% -% -% -%
Friday February 14th, 2014 44W, 2D 0.04% 99.87% -% -% 30.8% -% -% -%

Probability of labor on a given day

Probability of labor by a given day

Notes and disclaimers

All percentages are estimates based on mathematical averages and should not be taken terribly seriously... just because you only have 5% chance of going into labor two weeks early, that doesn't mean you should schedule a trip to the bahamas that weekend (see xkcd to get what I mean here).

You should (obviously) listen to your doctor or midwife on all matters related to pregnancy and childbirth. Just because this chart tells you that a 42W pregnant woman has a high chance of delivering in the next seven days, it doesn't mean it's healthy for her to be pregnant for seven more days. If your doctor wants to increase probability of delivery by inducing labor, there's probably a good reason.

Finding good distribution statistics on spontaneous labor is interesting. I have not found a study with an exact daily breakdown of when babies are born. However I have read way too much on this topic, so I can tell you that my favorite published research is The length of human pregnancy as calculated by ultrasonographic measurement of the fetal biparietal diameter (H. Kieler, O. Axelsson, S. Nilsson, U. Waldenstrรถ) which a very nice table of 10 published studies, which found various means between 272-283 days. The study contributes their own results as well, analyzing nearly 2000 mothers who went into labor spontaneously, and there's graphs of what they found. They found a mean around 280 days, and standard deviations between 8-11 days. There's a big list of other studies and answers in the Introduction to my due date survey results.

Which leads to this topic... I am also in the process of collecting my own statistics. If you have had a baby, please take my due date survey. Oddly enough, the numbers I've collected so far support my messy hunch that pregnancy length has a 40-week mean and 9-10 day standard deviation. So go me.

Anyway if you have better research, drop me an e-mail (spacefem@spacefem.com).

Charts are generated by flot.

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Recent Comments

For more support, encouragement, Q&A, you are invited to join our pregnancy forum. We are dedicated to answering complicated questions as logically as we possibly can.

How is pregnancy different from when it's shown in TV?

Thu Dec 18 10:19 PM by Sonic# in Pregnancy & Parenting

^ In one of the last Frasier episodes, this happens: the couple are visiting a veterinarian to get a ring out of a dog when her water breaks. In what could plausibly be only an hour or so, she has delivered her baby and it's all cleaned up and wrapped up. Of course this is also the show that covered up Jane Leeves's pregnancy by making her character Daphne become fat and have to go to fat camp - an example of how pregnancy is hidden on TV.


Visitors soon after birth

Sat Dec 13 6:21 PM by monk in Pregnancy & Parenting

My sister and her husband were glad for mine and our mothers help for limited periods when she just wanted to sleep but we both understood "the look" that said we should go away without her having to actually throw us out. If you don't have that relationship with "S" and can't establish it before the babies born don't guest her at your house.

But it is a really kind offer. Maybe she doesn't know you already have a support system? let her know.


Confessions of an Evil Stepmother

Thu Dec 11 1:15 PM by Nachos in Pregnancy & Parenting

I have no help, but I can offer hugs. *hugs*


Finding out baby's sex before birth

Wed Dec 3 3:54 AM by aka_laura in Pregnancy & Parenting

We found out, it was a fun detail to learn about our baby, it inspired the Wonder Woman nursery theme. My friends and family didn't go too nuts on the pink. There were a number of weird conversations with people who assumed I would oppose pink. I think pink is a lovely color for a baby to wear, alongside all the others, but people associated feminism with some kind of anti-pink venom that I just don't feel. I guess I feel like eventually, my family and friends are going to know the kid's sex. Our culture will ascribe gender roles to her far before she's conscious of them herself, so she'll have to be taught from a very young age that such things are bullshit. Wether she starts being gendered at 3 months or 3 days doesn't stand to change things significantly, in my view, we still have a long road on that one.


Pregnancy Books

Sun Nov 30 2:38 PM by Metcodon1 in Pregnancy & Parenting

For a good pre-conception book with a lot of science in it, I really enjoyed "The Impatient Woman's Guide to Getting Pregnant". All the science is cited and it's an easy read.

I really liked the book "Origins: How the Nine Months Before Birth Shape the Rest of Our Lives". It contained a lot of information a lot of other books didn't and was fun to read.

For a good reference book, I love the 411 series (Expecting 411, Baby 411, Toddler 411). It has really helpful information in an easy to look up format.

I also have enjoyed reading some essays about motherhood including "Waiting for Birdy" about a woman's second pregnancy while raising a toddler, "The Good Mother Myth: Redefining Motherhood to Fit Reality" which is a collection of essays about motherhood, and "Bringing Up Bebe" for a travelogue while parenting.


Keeping calm in new pregnancy after a loss

Sun Dec 14 4:25 AM by ladyhawk in Pregnancy & Parenting

I haven't had to go through anything that is this (I imagine) traumatic. However, I have been pregnant five times, and I do only have two children. During my two successful pregnancies (I miscarried very early in the other three) I pretty much had to just stop reading anything at all, because, for me personally, it wasn't reassuring. It just made it worse. No news, baby books, articles, no online communities, nothing. Just made me more paranoid.

After the 3rd miscarriage, I went to grief counseling, and I continued therapy through my pregnancy with my second child, which seemed to help a lot.

I will tell you, if it gives you any peace of mind whatsoever, that I was told after my second miscarriage, when I was only 20 years old, that I would need a hysterectomy and probably never have children. Five years later, I have all my reproductive organs and have two healthy children.

I know what works for me won't for everyone, but you could maybe try some of these things?


First trimester nausea and keeping it together at work

Sat Dec 13 3:00 PM by aka_laura in Pregnancy & Parenting

Ladies, I am so sorry you're feeling so awful. Do talk to your doctors about this, and expect them to take is seriously. I delayed getting help for way too long because I thought I was just having normal morning sickness and it was NOT normal morning sickness. Once you've tried the usual round of crackers, ginger everything, sea bands, teas, etc. there are prescriptions that can help you stay healthy so you can nurture your growing baby. I had to take enough Zofran and Phenergan to put a horse to sleep and had a healthy, happy baby born to a healthy, happy momma. If things really persist check out http://beyondmorningsickness.com for more options.


The madness of modern parenting

Sat Dec 6 2:27 PM by spacefem in Pregnancy & Parenting

kaybee that is a great write-up, thank you for sharing! do you mind if I split this off to its own topic? because it's worth it!

I especially admired the conclusion:

There is no broad responsibility to create a healthy environment for children (because mothers who were concerned would live in some other environment), and no social imperative to look after children who were born in ill-health or some other misfortune (because mothers who behaved responsibly would have prevented this outcome).


Food restrictions in pregnancy

Wed Dec 3 3:44 AM by aka_laura in Pregnancy & Parenting

Pretty much the only helpful comment I got from a member of the general public while I was pregnant was this super sweet woman at a lecture. We were chatting, I told her I was expecting my first baby, and a few minutes later I mentioned my friends and I had just gone out to a local sushi place. She got this big smile and said "I didn't have sushi until my third kid, GOOD FOR YOU! You'll be a great mom!"

Bless that wonderful woman.


favorite movie about anyone having a baby

Sat Nov 29 4:31 AM by Sonic# in Pregnancy & Parenting

When I was little I was wild about Look Who's Talking. I think the novelty of a narrating baby wore off sometime after I saw Milo and Otis.


pregnancy and anxiety

Sat Dec 13 6:54 PM by Wilde83 in Pregnancy & Parenting

This is my second pregnancy, with unfortunately no children. This statistics page has given me comfort both times even though no one could have predicted the oddball birth defect that ended my last pregnancy in the second trimester. I suppose I was just one of the unlucky 1% last time, and am so hopeful this time. Thank you for posting it!


fired pregnant worker takes it to the supreme court

Thu Dec 11 7:03 PM by jen4knits in Pregnancy & Parenting

The place I work at did the same thing to a temporary type employee when she was pregnant. She had let them know when she was hired that she was pregnant and would be needing a c-secition. But then when the time came she hadn't been at the job for a full year so they said she didn't qualify for FMLA (family medical leave something) and emailed her... (email yes) to say her options were: 1) resign and reapply or 2) call off and get fired after missing work for 4 days.

Needless to say it worries me about my options even though I'm in a different department, with different job type. It will be interesting to see what the ruling is for this and how it affects current policy.


pin it: pocket guide to fish

Sat Dec 6 10:27 AM by spacefem in Pregnancy & Parenting

I have a whole big pregnancy board on pinterest that's kinda fun. There's an infographic version of my due date statistics that a lot of folks have appreciated. So today I added this pocket guide to fish recommendations:

http://www.pinterest.com/pin/135671007500096368/

Totally grabbed from other sources (http://www.fda.gov/Food/FoodborneIllnes ... 393070.htm & http://www.nrdc.org/oceans/seafoodguide/page4.asp) but it mimics a little card that I literally printed out and folded up in my wallet while I was pregnant.


Babyproofing the House

Mon Dec 1 4:16 AM by MFS in Pregnancy & Parenting

We locked down the universe with the first, still pretty tight with the 2nd, but by the time we had #3 and 4, things got a lot looser. We also had so much more stuff that certain areas that were "dangerous" were now totally inaccessible and irrelevant (yay piles of blankies?)


going public with the new pregnancy & parenting forum

Fri Nov 28 7:03 PM by rowan in Pregnancy & Parenting

OMG AKA_LAURA CONGRATULATIONS!