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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.

Flying during third trimester

Sun May 24 2:46 PM by rowan in Pregnancy & Parenting

That would probably apply at 36+ weeks but then nothing will be comfortable. :P
(though really it was 38 weeks I was super uncomfortable, ymmv)


The responsibility of choosing a name

Wed Apr 29 8:02 PM by melsbells in Pregnancy & Parenting

I fretted way too much about this.

Finland is one of the countries in the world with an approved name list. People can deviate from the list, but then they need to participate in bureacracy. Foreigners often get approval for names from their home culture, but as someone from the U.S., I'm not sure how straightforward it is to say "this cultural name appropriately represents my culture". Do I pick the cultures of my ancestors or modern U.S. conglomeration?

We went with approved names, but not the Swedish ones because my spouse felt weird giving a Swedish name without Swedish heritage. The Swedish names would have been most easily recognizable for my family.

Our main criteria ended up including:
Finnish
I could pronounce it
we didn't hate the way Americans would pronounce it

We had to eliminate one contender because I sometimes mispronounced it, turning the name into a word that meant "failure".


Advice for non-parents?

Tue Apr 7 8:56 PM by Nedra in Pregnancy & Parenting

I definitely agree on the flexibility of where to meet. It makes a huge difference when you aren't stressed about your kid in a public place. Recently, I went to a tea shop with my daughter. Not only was the layout of the seating area very conducive to letting a toddler walk around a bit while still keeping a close eye on her, but there was plenty of room for my stroller and plenty of available tables. That is rare! It wasn't a huge space, but it was just laid out well for what we needed. I will definitely be suggesting it the next time a friend asks if we can get together. Let your parent friends choose the location! They know which places have changing tables and room to park a stroller.


How Good Parents Miss Child Sexual Abuse and 5 Questions to Change That

Tue Mar 24 3:20 AM by rowan in Pregnancy & Parenting

And that includes parents too - I try to always ask "can I have a hug/kiss" rather than "give me a hug/kiss" and that she can always always say no if she doesn't want to, even with me. (She's old enough now that I've had enough practice that even writing "give me a hug" sounds weird to me)

Also I think on a more general level it's good to practice asking these kinds of questions anyway. Not just for abuse, but in general if you want to know what's going on in their life. Asking "how was school" gets an "I dunno" even now, but asking more specific things like "What was something funny that happened today" or "What did you do at recess?" really gets her talking more. Not sure where I read that, but the kinds of questions above made me think that sometimes just asking a better question will help get at what you want to know more than asking generalities.

The other thing is definitely definitely not making judgment on those things that they're saying. Instead try "What did you think about that ?" or "What did you do when happened?" "What would make you feel safe?" "What could you try if that happens again?" "Is there anything you'd like me to do?" These are things that I've asked wrt other kids on the playground (pushing etc) but I think it's the same idea in terms of empowering the child to talk about things that happen and letting them help come to the conclusions. Which isn't to say you can't help them get there by suggesting actions they could do, etc, just that if you get them talking about things that happen on a daily basis then if something weird happens then they'll likely be more comfortable telling you, especially if you've already shown them what boundaries there are and respecting those boundaries (like not tickling if they say they don't want to be tickled etc).


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.


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.


the worst first birthday invite ever

Wed Apr 29 7:52 PM by melsbells in Pregnancy & Parenting

the understanding that when people buy gifts, it's their way of saying "hey, this says something about me, I want your kid to have it because we have a relationship." two ways.

Except sometimes those gifts are inappropriate. Part of me feels a lot of sympathy for these parents because what can I do with gifted clothing that is already too small for my kid except pass them on? What can I do with gifts that conflict with my personal beliefs, like a racist book that I don't want to inflict on anyone else either?


Tips and pitfalls for gender-neutral parenting

Mon Mar 30 9:25 PM by rowan in Pregnancy & Parenting

^I agree with that! :)

Part of "gender neutral" parenting is supplying the side of things that doesn't get given by other people.


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.


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.


Can't find my tribe

Sat May 9 9:25 PM by Nedra in Pregnancy & Parenting

We've found relatively like-minded parents in the following ways:

-We went to undergrad at a liberal arts college and most of our alumni friends live in town still.
-I worked for 5 years at a charter school that was "girl-focused" (meaning, it was a girls school and any student who identified as a girl -- either biologically or socially -- could attend as long as they were cool with being part of a community of girls). Deconstructing sexism, heterosexism and racism was part of our mission and so the staff was very like-minded in this regard.

That's where virtually all my local, like-minded parents came from. Our church is pretty open-minded too. I don't know that I've ever seen a boy in a dress there, but I can't really imagine anyone batting an eye if we did. Certainly lots of boys playing with dolls and girls with trucks in the nursery.

When my own parents were in this position, they started a "non-sexist parenting group." Basically, they found ONE family who felt the same way, that family knew another, etc. They built a community intentionally by voicing out loud that that was what they wanted and spreading the word. They also found a lot of like-minded people through church. We are hippy-church and hippy-daycare/school people, so that helps.


Bilingual Babies

Mon Apr 13 11:41 AM by sakooon in Pregnancy & Parenting

Spacefem's husband no longer speaking Spanish and Nachos no longer speaking Dutch, I think are great examples of lacking motivation. Likewise, I had mentioned that my kid is unlikely to pick up Swedish, despite 10% of the population being native Swedish speakers, Swedish being one of the offical languages and therefore alongside Finnish everywhere, and having a Swedish speaking uncle.???


Interacting with parents whose choices you don't trust

Thu Mar 26 3:08 PM by rowan in Pregnancy & Parenting

How can you tell who has been vaccinated or not?
That's the tricky part, you can't really. So unless the parents say something you never actually know.


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.


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/