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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. 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.

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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.

RIE parenting

Tue Jul 28 10:46 PM by ladyhawk in Pregnancy & Parenting

Like soacefem, I did some googling to figure out what it was.

The first part, anout talking to your child, made me ho, "Okay, yeah. S'cool." I think most people (that I know) do that anyway, and communicating with your child, at every stage of life, is important.

Then, I ran across this gem in the Huffington Post:

Bouncers are discouraged on the principle that they are disrespectful to a baby’s true emotions, as the object is to make him zone out and stop annoying you. RIE is philosophically opposed to anything that disrespects a baby, including not only sippy cups and high chairs but also baby gyms, baby carriers like Björns, baby swaddles, and baby walkers, which Gerber, who had quite a way with words, called “a moving prison.”

At this point, my eyes rolled so hard they almost fell out of my head.

If you can make oarenting like that work for you, nifty! But, in my experience, that would just be impractical nonsense. At no point do I think swaddling my children was "disrrspectful." Mostly because, you know, it soothed them. And that's what most people try to do -- soothe their babies, not try to "make him zone out and stop annoying them." Same thing with swings and bouncers. They were only in strollers/baby carriers until the started to walk, for practicality sake since neither my husband or I could hold them all the time since, you know, we needed our hands to do other things.


do you have a parenting goal?

Sun Jul 26 5:16 PM by rosefox in Pregnancy & Parenting

I'm definitely in the "happy healthy child is my only goal" camp. I know some people who are superstars in their chosen fields. From what I can tell, being a superstar is completely exhausting and often really psychologically taxing. So if my kid isn't naturally inclined that way, I certainly don't intend to push them.

If I'm hoping for anything, I hope they'll end up being a quirky artsy/techy type like just about everyone else in the family. But my brother's a corporate lawyer and I love him anyway, so even if our kid turns out to be a white sheep, they'll just bond with Uncle A and it'll all be fine. :)


Newborns are difficult!

Fri Jul 17 2:41 PM by robichek in Pregnancy & Parenting

I hated breastfeeding, couldn't seem to make "enough" while pumping (looking back on it I think there may have been something wrong with the pump parts), and by the time it was a year I was done. And then by the time he was 16 months I tried to coax him back on because I missed it so much and loved him so much. But, although curious at first, he literally shook his head at me. :-(


Spacefem's homemade playdoh recipe

Mon Jul 13 3:01 AM by Zeph in Pregnancy & Parenting

A parent in my Kindergarten class would bring us homemade purple play dough that smelled like grape!


cosleeping

Fri Jun 12 4:01 PM by spacefem in Pregnancy & Parenting

Thanks! I was going to put my labor story in Random but never got around to it. I can try to do it soon - it's written out already so just a matter of editing.

Yes you must! I'm happy to hear from you, hope everything went and is going well :)


What new thing did your baby do this week?

Tue Jul 28 7:24 PM by ladyhawk in Pregnancy & Parenting

Mine started walking. :( SO not ready for two kids running around getting into things.

Stay little longer!


for all you moms and future moms

Tue Jul 21 2:28 AM by DarkOne in Pregnancy & Parenting

Eek and here I was about to say this felt like a tame version of Mother Lover.


Diaper bags

Wed Jul 15 3:46 AM by geerlady in Pregnancy & Parenting

We used/still use our diaper bag quite a lot.

For our little guy's first year of life we were urban dwellers and I would often go out for half a day at a time. I would take a diaper for every hour I planned to be out of the house plus one, which was too much for the clutch. I needed a change pad, since he was often changed in nasty places, wipes, hand sanitizer (for changes away from running water), Kleenex, and disposal bags. He needed spare clothes, I needed a spare shirt (discovered after an emergency, useful many times afterwards), and it was useful to have a plastic bag for clothes which were victims of a diaper explosion. For longer days out I would bring two spares for him (and did have days where I used both). I would also have a nursing cover and a blanket in there. We also had a stroller cover for napping which was quite handy when we were taking the stroller as opposed to a carrier. And then there was my stuff, like my wallet, phone, lip balm, keys, granola bar, etc... I did pack the camera, and was often glad for it. Nearly all of our first year pics were from our little excursions.


Pregnancy insomnia

Thu Jun 25 9:05 AM by Gnarlbanya in Pregnancy & Parenting

Thanks for the tips. It's not so much getting to sleep that's the problem, it's staying that way that is causing the issue - too many things waking me up. I seem to be in a bit of a pattern now of alternating good and bad nights, which I guess I can live with. Meanwhile, Netflix is getting a damn good workout in the early hours.


Flying during third trimester

Wed May 27 2:03 AM by ablotial in Pregnancy & Parenting

Thanks, I love the part about not being able to lower the tray table all the way :) I never would have thought of that.

Normally, my doctor said not to do aspirin or ibuprofen for pain relief, but only tylenol (acetemenophen) and even that only if -absolutely- needed after trying other remedies (like heat pack, cold pack, resting with lights closed eyes shut, etc). But the directions for flying specifically say to take one baby aspirin (81mg) a day for three days before the flight as well as the day of the flight to prevent blood clots. My guess is the risk of such a small dose is outweighed by the benefit of not getting blood clots for this particular situation.


Braxton Hicks questions

Mon Jul 27 2:13 PM by Metcodon1 in Pregnancy & Parenting

In my experience "real" contractions are pretty much the whole uterus (top, bottom and lower back). I remember reading somewhere that the ones that get you dilated from 0-7/8 cm are largely the muscles pulling up, trying to stretch the cervix out. As a result many people largely do feel them most strongly at the top of their belly. Whether you feel them strongly in your back or not depends on how the baby is positioned. If you've heard the term "back labor" that usually happens if the back of the baby's head is pressed up against your spine (less common than when the baby's face is on the spine). The contractions that take you from 7 or 8 cm to 10 - i.e. the ones in the part of labor known as "transition" - do tend to be lower down (and also more painful). That said, I think there is A LOT of variation in experience...


the wonder weeks: practical help for parents or self-fulfilling quackery?

Mon Jul 20 2:29 AM by geerlady in Pregnancy & Parenting

I am actually a big fan of the wonder weeks. I found it better than most popular level books looking at infant development. My son was right on the clock for the fussy/happy times, and it was interesting to look for the new skills that I might not have noticed if I hadn't been watching for them.

On the other hand, I stumbled upon this accidentally, so didn't have any hype surrounding it. I also read the author biographies before picking up the book, so took everything with a grain of salt knowing that 1) the authors specialized in chimpanzees, not humans, and developed their theories based on chimps; 2) the bulk of the research is greater than 20 years old and so much of the book is out-dated; and 3) given #'s 1&2, incidental parenting advice had to be filtered.

That said, I still found the book useful and regularly recommend it to people.


if you need to breastfeed, please cover yourself

Mon Jul 13 12:32 PM by DarkOne in Pregnancy & Parenting

Sorry to CPR a dying thread, but I came across this, and thought I'd share.

LURZqBig734


Antidepressants during pregnancy

Thu Jun 25 1:03 AM by Aum in Pregnancy & Parenting

http://www.henriettes-herb.com/blog/pos ... ssion.html

Pre and post-partum depression have similar reasons, physically speaking. Check nutrition first.


getting along while doing things differently

Wed May 20 9:11 AM by Gnarlbanya in Pregnancy & Parenting

I'm finding it interesting that some people I've encountered (online) presume that if they know one of your pregnancy or parenting preferences or opinions, they can extrapolate them all. For example, in discussing pain relief options recently, after expressing my desire not to have an epidural it was also assumed that I would forego vaccinations for my child and would be automatically pro home VBAC. When I made it clear that this wasn't the case, people were more annoyed than they would have been had I just said I wanted an epidural. There seems to be a really odd sort of tribalism around many of these choices, and a strange playground mentality whereby you can't deviate from the 'norm' (made harder to navigate because different groups have very different norms). For me, my preference to go without an epidural is not out of any desire to have a more natural experience but more because I want to be able to walk around and I find the idea of having a catheter just horrible. That doesn't mean that I judge anyone else's choices or motives that differ from mine, though. I do think it's worth remembering that people may make identical choices for very different reasons.