spacefem.com

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 December 20th, 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
Saturday November 15th, 2014 35W, 0D 0.01% 0.02% -% -% -% 0.1% 0.1% 0.2%
Sunday November 16th, 2014 35W, 1D 0.01% 0.03% -% -% -% 0.1% 0.2% 0.3%
Monday November 17th, 2014 35W, 2D 0.02% 0.05% -% -% -% 0.1% 0.2% 0.4%
Tuesday November 18th, 2014 35W, 3D 0.02% 0.07% -% -% -% 0.1% 0.3% 0.6%
Wednesday November 19th, 2014 35W, 4D 0.03% 0.1% -% -% -% 0.2% 0.4% 0.7%
Thursday November 20th, 2014 35W, 5D 0.04% 0.13% -% -% -% 0.2% 0.5% 0.9%
Friday November 21st, 2014 35W, 6D 0.06% 0.19% -% -% 0.1% 0.3% 0.6% 1.2%
Saturday November 22nd, 2014 36W, 0D 0.08% 0.26% -% -% 0.1% 0.4% 0.8% 1.5%
Sunday November 23rd, 2014 36W, 1D 0.1% 0.35% -% -% 0.1% 0.5% 1% 1.9%
Monday November 24th, 2014 36W, 2D 0.14% 0.47% -% -% 0.1% 0.6% 1.3% 2.4%
Tuesday November 25th, 2014 36W, 3D 0.18% 0.62% -% -% 0.2% 0.8% 1.7% 3%
Wednesday November 26th, 2014 36W, 4D 0.22% 0.82% -% -% 0.2% 1% 2.1% 3.7%
Thursday November 27th, 2014 36W, 5D 0.28% 1.07% -% -% 0.3% 1.2% 2.5% 4.5%
Friday November 28th, 2014 36W, 6D 0.35% 1.39% -% -% 0.4% 1.5% 3.1% 5.4%
Saturday November 29th, 2014 37W, 0D 0.44% 1.79% -% -% 0.4% 1.8% 3.8% 6.4%
Sunday November 30th, 2014 37W, 1D 0.54% 2.28% -% -% 0.6% 2.2% 4.5% 7.6%
Monday December 1st, 2014 37W, 2D 0.66% 2.87% -% -% 0.7% 2.7% 5.4% 8.9%
Tuesday December 2nd, 2014 37W, 3D 0.79% 3.59% -% -% 0.8% 3.2% 6.3% 10.4%
Wednesday December 3rd, 2014 37W, 4D 0.94% 4.46% -% -% 1% 3.8% 7.4% 11.9%
Thursday December 4th, 2014 37W, 5D 1.11% 5.48% -% -% 1.2% 4.4% 8.6% 13.7%
Friday December 5th, 2014 37W, 6D 1.3% 6.68% -% -% 1.4% 5.2% 9.8% 15.5%
Saturday December 6th, 2014 38W, 0D 1.5% 8.08% -% -% 1.6% 6% 11.2% 17.5%
Sunday December 7th, 2014 38W, 1D 1.71% 9.68% -% -% 1.9% 6.9% 12.7% 19.7%
Monday December 8th, 2014 38W, 2D 1.94% 11.51% -% -% 2.2% 7.8% 14.3% 21.9%
Tuesday December 9th, 2014 38W, 3D 2.18% 13.57% -% -% 2.5% 8.8% 16% 24.2%
Wednesday December 10th, 2014 38W, 4D 2.42% 15.87% -% -% 2.9% 9.9% 17.8% 26.6%
Thursday December 11th, 2014 38W, 5D 2.66% 18.41% -% -% 3.3% 11.1% 19.7% 29%
Friday December 12th, 2014 38W, 6D 2.9% 21.19% -% -% 3.7% 12.3% 21.6% 31.5%
Saturday December 13th, 2014 39W, 0D 3.12% 24.2% -% -% 4.1% 13.5% 23.6% 34%
Sunday December 14th, 2014 39W, 1D 3.33% 27.43% -% -% 4.6% 14.9% 25.6% 36.6%
Monday December 15th, 2014 39W, 2D 3.52% 30.85% -% -% 5.1% 16.2% 27.7% 39.2%
Tuesday December 16th, 2014 39W, 3D 3.68% 34.46% -% -% 5.6% 17.6% 29.8% 41.7%
Wednesday December 17th, 2014 39W, 4D 3.81% 38.21% -% -% 6.2% 19.1% 31.9% 44.2%
Thursday December 18th, 2014 39W, 5D 3.91% 42.07% 6.3% 6.2% 6.7% 20.6% 34% 46.7%
Friday December 19th, 2014 39W, 6D 3.97% 46.02% 6.4% 12.6% 7.4% 22.1% 36.2% 49.2%
Saturday December 20th, 2014 40W, 0D 3.99% 50% 6.5% 19.1% 8% 23.6% 38.3% 51.6%
Sunday December 21st, 2014 40W, 1D 3.97% 53.98% 6.4% 25.5% 8.6% 25.1% 40.4% 54%
Monday December 22nd, 2014 40W, 2D 3.91% 57.93% 6.3% 31.9% 9.3% 26.7% 42.5% 56.2%
Tuesday December 23rd, 2014 40W, 3D 3.81% 61.79% 6.2% 38.2% 10% 28.2% 44.5% 58.5%
Wednesday December 24th, 2014 40W, 4D 3.68% 65.54% 6% 44.2% 10.7% 29.8% 46.6% 60.6%
Thursday December 25th, 2014 40W, 5D 3.52% 69.15% 5.7% 50.1% 11.4% 31.3% 48.6% 62.7%
Friday December 26th, 2014 40W, 6D 3.33% 72.57% 5.4% 55.6% 12.1% 32.9% 50.5% 64.7%
Saturday December 27th, 2014 41W, 0D 3.12% 75.8% 5% 60.8% 12.9% 34.4% 52.4% 66.6%
Sunday December 28th, 2014 41W, 1D 2.9% 78.81% 4.7% 65.7% 13.7% 36% 54.3% 68.5%
Monday December 29th, 2014 41W, 2D 2.66% 81.59% 4.3% 70.2% 14.4% 37.5% 56.1% 70.2%
Tuesday December 30th, 2014 41W, 3D 2.42% 84.13% 3.9% 74.3% 15.2% 39% 57.9% 71.9%
Wednesday December 31st, 2014 41W, 4D 2.18% 86.43% 3.5% 78% 16.1% 40.5% 59.6% 73.5%
Thursday January 1st, 2015 41W, 5D 1.94% 88.49% 3.1% 81.4% 16.9% 42% 61.3% 75.1%
Friday January 2nd, 2015 41W, 6D 1.71% 90.32% 2.8% 84.3% 17.7% 43.4% 62.9% 76.4%
Saturday January 3rd, 2015 42W, 0D 1.5% 91.92% 2.4% 86.9% 18.6% 44.8% 64.5% 77.8%
Sunday January 4th, 2015 42W, 1D 1.3% 93.32% 2.1% 89.2% 19.5% 46.3% 65.9% 79.2%
Monday January 5th, 2015 42W, 2D 1.11% 94.52% 1.8% 91.1% 20.3% 47.6% 67.3% 80.5%
Tuesday January 6th, 2015 42W, 3D 0.94% 95.54% 1.5% 92.8% 21.1% 48.9% 68.8% 81.6%
Wednesday January 7th, 2015 42W, 4D 0.79% 96.41% 1.3% 94.2% 22% 50.1% 70.2% 82.7%
Thursday January 8th, 2015 42W, 5D 0.66% 97.13% 1.1% 95.4% 23% 51.6% 71.4% 83.6%
Friday January 9th, 2015 42W, 6D 0.54% 97.72% 0.9% 96.3% 23.7% 53.1% 72.8% 84.6%
Saturday January 10th, 2015 43W, 0D 0.44% 98.21% 0.7% 97.1% 24.6% 54.2% 73.7% 85.5%
Sunday January 11th, 2015 43W, 1D 0.35% 98.61% 0.6% 97.8% 25.2% 55.4% 74.8% 86.3%
Monday January 12th, 2015 43W, 2D 0.28% 98.93% 0.5% 98.3% 26.2% 56.1% 75.7% 87.9%
Tuesday January 13th, 2015 43W, 3D 0.22% 99.18% 0.4% 98.7% 26.8% 57.3% 76.8% -%
Wednesday January 14th, 2015 43W, 4D 0.18% 99.38% 0.3% 99% 29% 58.1% 79% -%
Thursday January 15th, 2015 43W, 5D 0.14% 99.53% 0.2% 99.2% 29.8% 59.6% -% -%
Friday January 16th, 2015 43W, 6D 0.1% 99.65% 0.2% 99.4% 28.6% 62.9% -% -%
Saturday January 17th, 2015 44W, 0D 0.08% 99.74% 0.1% 99.6% 30.8% -% -% -%
Sunday January 18th, 2015 44W, 1D 0.06% 99.81% 0.1% 99.7% 31.6% -% -% -%
Monday January 19th, 2015 44W, 2D 0.04% 99.87% 0.1% 99.8% 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. Waldenströ) 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.

More tools

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?

Wed Dec 17 6:35 PM by spacefem in Pregnancy & Parenting

I remember joking with someone that I wanted one of those three-episode pregnancies like they have on sitcoms. Seriously this is how they all are:

First episode: Pregnancy test passed in very obvious way, those who know are unsure how to tell those who don't know, hilarity ensues.

Second episode: Pregnancy person is fat and hungry, insert cute funny morning sickness scene.

Third episde: Water breaks in inconvenient time, lots of screaming at people in hilarious ways, end shot of happy new parents holding baby waxing philosophically about the meaning of life.

So that's television.

In reality, pregnancy takes nine months. You aren't instantly big and pregnant the day after you pass the test, in fact you might not feel pregnant at all. Labor & delivery go at very odd paces. Women give birth in many different positions and are definitely not always fully clothed, yes even in hospitals.

I just watched an episode of Grey's Anatomy... which as medical staff as writers I'm sure! That shows Dr. Grey, a few months pregnant, feeling "flutters" and realizing it's her baby moving. She goes home that very night and there's a scene with her husband with his hand on her stomach feeling the baby kick, making soccer jokes. Uh, what? It takes forever before someone else can feel that baby move and tell you you're not crazy! Amiright?


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!