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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 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% -% -% 6.7% 20.6% 34% 46.7%
Friday December 19th, 2014 39W, 6D 3.97% 46.02% -% -% 7.4% 22.1% 36.2% 49.2%
Saturday December 20th, 2014 40W, 0D 3.99% 50% -% -% 8% 23.6% 38.3% 51.6%
Sunday December 21st, 2014 40W, 1D 3.97% 53.98% -% -% 8.6% 25.1% 40.4% 54%
Monday December 22nd, 2014 40W, 2D 3.91% 57.93% -% -% 9.3% 26.7% 42.5% 56.2%
Tuesday December 23rd, 2014 40W, 3D 3.81% 61.79% -% -% 10% 28.2% 44.5% 58.5%
Wednesday December 24th, 2014 40W, 4D 3.68% 65.54% -% -% 10.7% 29.8% 46.6% 60.6%
Thursday December 25th, 2014 40W, 5D 3.52% 69.15% -% -% 11.4% 31.3% 48.6% 62.7%
Friday December 26th, 2014 40W, 6D 3.33% 72.57% -% -% 12.1% 32.9% 50.5% 64.7%
Saturday December 27th, 2014 41W, 0D 3.12% 75.8% -% -% 12.9% 34.4% 52.4% 66.6%
Sunday December 28th, 2014 41W, 1D 2.9% 78.81% -% -% 13.7% 36% 54.3% 68.5%
Monday December 29th, 2014 41W, 2D 2.66% 81.59% -% -% 14.4% 37.5% 56.1% 70.2%
Tuesday December 30th, 2014 41W, 3D 2.42% 84.13% -% -% 15.2% 39% 57.9% 71.9%
Wednesday December 31st, 2014 41W, 4D 2.18% 86.43% -% -% 16.1% 40.5% 59.6% 73.5%
Thursday January 1st, 2015 41W, 5D 1.94% 88.49% -% -% 16.9% 42% 61.3% 75.1%
Friday January 2nd, 2015 41W, 6D 1.71% 90.32% -% -% 17.7% 43.4% 62.9% 76.4%
Saturday January 3rd, 2015 42W, 0D 1.5% 91.92% -% -% 18.6% 44.8% 64.5% 77.8%
Sunday January 4th, 2015 42W, 1D 1.3% 93.32% -% -% 19.5% 46.3% 65.9% 79.2%
Monday January 5th, 2015 42W, 2D 1.11% 94.52% -% -% 20.3% 47.6% 67.3% 80.5%
Tuesday January 6th, 2015 42W, 3D 0.94% 95.54% -% -% 21.1% 48.9% 68.8% 81.6%
Wednesday January 7th, 2015 42W, 4D 0.79% 96.41% -% -% 22% 50.1% 70.2% 82.7%
Thursday January 8th, 2015 42W, 5D 0.66% 97.13% -% -% 23% 51.6% 71.4% 83.6%
Friday January 9th, 2015 42W, 6D 0.54% 97.72% -% -% 23.7% 53.1% 72.8% 84.6%
Saturday January 10th, 2015 43W, 0D 0.44% 98.21% -% -% 24.6% 54.2% 73.7% 85.5%
Sunday January 11th, 2015 43W, 1D 0.35% 98.61% -% -% 25.2% 55.4% 74.8% 86.3%
Monday January 12th, 2015 43W, 2D 0.28% 98.93% -% -% 26.2% 56.1% 75.7% 87.9%
Tuesday January 13th, 2015 43W, 3D 0.22% 99.18% -% -% 26.8% 57.3% 76.8% -%
Wednesday January 14th, 2015 43W, 4D 0.18% 99.38% -% -% 29% 58.1% 79% -%
Thursday January 15th, 2015 43W, 5D 0.14% 99.53% -% -% 29.8% 59.6% -% -%
Friday January 16th, 2015 43W, 6D 0.1% 99.65% -% -% 28.6% 62.9% -% -%
Saturday January 17th, 2015 44W, 0D 0.08% 99.74% -% -% 30.8% -% -% -%
Sunday January 18th, 2015 44W, 1D 0.06% 99.81% -% -% 31.6% -% -% -%
Monday January 19th, 2015 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.

Bilingual Babies

Mon Mar 2 7:38 PM by Nachos in Pregnancy & Parenting

I am/was a bilingual kid. I am now a bilingual (in another language though) adult. My mother is Dutch and I was born in England so I grew up speaking and understanding English and Dutch. I don't believe I had any problems up until my first day at school when apparently I came home saying "I don't want to speak that funny language any more!" and since my mother was told my doctors and teachers to only speak one language to your kid, I ended up forgetting it all.

Later on (when I was 11) we ended up moving to a Dutch speaking country and even though I was immersed in school I had to learn it all over again. Funnily enough, after about 7 months something clicked and the language started to come back.

Next problem was then we moved to Germany and even though the languages are similar, they are not the same. It took me about three years (immersed again) while learning German too for something to click and I started to also dream in German.

My Dutch teacher in the Dutch country had a grandson who spoke 4 languages fluently at the age of 6. He could differentiate between them too.


Breastfeeding & accoutrements thereof

Thu Feb 26 5:28 PM by rowan in Pregnancy & Parenting

My boobs are small, and this is important for a couple of reasons: At any one time I can only produce a max of about 6 oz.
Actually, the physical size of your boobs doesn't have much to do with how much you produce. There are lots of small-breasted women who produce a lot and lots of large-breasted women who don't. It's mostly genetic and some other variables thrown in (e.g. if there was a lot of BPA in your mom when you were in utero can affect it, we're finding out).


Keeping your pre-pregnancy/parenthood identity

Thu Jan 29 4:36 PM by rowan in Pregnancy & Parenting

You don't have to post at all if you don't want to! But we're here to offer support if you do want to.

I have very little time sans baby anymore
This does get a little better over time, when they're a little more autonomous. Though I still long for the day when I can just freaking go to the bathroom all by myself. (I seriously spent like 20 minutes in the bathroom the other day while the hubby was watching the kid @ a birthday party, just for that reason. I mean how sad does that sound?)

I know he requires more alone time than I do, and I know he isn't getting any more than I am.
Any chance of arranging a tag-team schedule?


sleep humor

Fri Jan 23 7:13 PM by rowan in Pregnancy & Parenting

Here's a really funny humor bit about sleep, but the same general idea can apply to pretty much any "advice" given to new parents.

"I bought all the top books on baby sleep and development. I read through them all, as well as several blogs and sleep websites. I gathered lots of advice:"

https://chimericalcapuchin.wordpress.co ... babybooks/


Why Pocket Diapers Are Better Than Disposables

Sun Jan 11 3:31 PM by Nancy Erick in Pregnancy & Parenting

Hi everyone

A Beautiful article by writer Kathryn McDowell recently I read liked to share with you

Why Pocket Diapers Are Better Than Disposables :


As a young parent, you've no doubt heard of pocket diapers. Perhaps a neighbor or a co-worker told you about them. Or it was your babysitter, who asked you to get them soon. Well, so many families in America are today turning to pocket diapers for their little ones. But a majority still holds on to disposable diapers, while being curious about pocket diapers at the same time.

Why are diapers so great? For a start, pocket diapers come with brand new fabrics and super absorbent pads, are easy to put on, simple to take off, easy to wash and quick to dry. And they are better than disposable diapers.

They are Cheaper
Until your child is potty trained, you'd probably spend something close to $2500 to $3000 on diapers - which is quite a lot. Biodegradable disposable diapers are even costlier. But with pocket ones, you won't have to spend anything more than $350 to $400, till your child is potty trained.


10 things you can leave off the baby registry

Sat Feb 28 7:48 AM by Gnarlbanya in Pregnancy & Parenting

I really want one of those baby boxes and would jump at it if not for $69.95 shipping. Will keep thinking about it, I suspect my resolve will crumble eventually.


Bonding

Fri Feb 6 4:35 AM by Zeph in Pregnancy & Parenting

Bonding with my future infant is a concern of mine, because my depression is debilitating. I'm relieved to know that normally functioning women don't feel that head-over-heels mushy baby love.


name trends

Wed Jan 28 8:58 AM by Lemon in Pregnancy & Parenting

Some of my family members who work in the healthcare system have overheard some doozies.

I work in healthcare, so I can relate. I think my favourite was a kid called "Abcde" which we were assured was pronounced "Abasidee". Mirena was a cute choice, named after the contraceptive device. Then there have been some good narrative names including places of birth - e.g. "Shell" (after the baby born in a petrol station carpark) - and places of conception - e.g. "...(a suburb which I'll keep secret - just in case this somehow breaches some poor kid's privacy) bus stop."


It takes 13 million calories to raise a child!

Wed Jan 21 4:32 AM by textualorientation in Pregnancy & Parenting

Recently found out how much energy it takes to raise a child. Woah.

I'm pretty infuriated that in Canada it can cost $1,676/month for daycare, when science actually tells us we evolved to help each other raise children. I wrote a blog about this in case anyone is interested! I would really like to see this change for mothers all over Canada.

https://textualorientation.wordpress.co ... ledaycare/


some quotes recently I read

Sat Jan 10 4:50 PM by Nancy Erick in Pregnancy & Parenting

i search about these quotes in google


How did you decide how many kids to have?

Fri Feb 27 2:42 AM by MFS in Pregnancy & Parenting

First 2 were on purpose, 3rd kinda not so much, 4th was totally an oops (when you think things are broken, they have this habit of fixing themselves). Made sure we were done after that. Aside from that, we knew we'd have at least 2, likely 3, but the timing was not at all what we thought we were "planning". Such is life.


Because judging other parents is absurd.

Tue Feb 3 7:05 AM by Zeph in Pregnancy & Parenting

It's alright to discuss these topics, but there needs to be boundaries. I would use the following, personally:

1. Don't insert yourself into a stranger's situation or bring up the topic yourself to a stranger.
2. It's probably not your business if you're not a parent yourself.
3. Ask the person why they are making these choices, don't assume.
4. Try to end on a positive note.

I don't feel right bringing up to my sister that I don't agree that she spanks my nephew, but after being a teacher, I am pretty forgiving of parents' choices. It's the hardest role there is. Even though I want to raise my children on nutritious meals, cloth diapers, and museum passes, I know I'm going to slip up and give them fries, Huggies, and Disney DVD's.

I also feel that home birth is a fine option for low-risk births, where the mother is well coached and the midwife is reputable. If you live near a hospital and your midwife is highly qualified, why not? They have equipment. I won't be choosing this option, but with any birth plan there needs to be a series of precautions taken.


34 Weeks

Fri Jan 23 11:57 PM by Sonic# in Pregnancy & Parenting

Probably not. As we pointed out in the other topic, 34 weeks isn't even on the chart because it's so rare:
http://spacefem.com/pregnant/charts/duedate1.php

You'd be better off worrying over a car accident.


Work

Thu Jan 15 9:17 PM by bigdaddy in Pregnancy & Parenting

I will do cheers but in people's experiences and options I should be ok


Working as due date approaches

Mon Jan 5 6:18 AM by Bork in Pregnancy & Parenting

However long you end up staying at work, once you're in labor, PLEASE GO HOME. Or to the hospital. Because staying at work while you're in labor is hella awkward for everyone involved.