Daily odds of pregnancy miscarriage

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This can be an upsetting topic, but after passing a pregnancy test and facing so much uncertainty about my future I just wanted something to make me feel a little more... in control. For me, that's statistics. So based on some human embryo survival rates - overall and at 6, 8, and 10 weeks, I did some curve matching to calculate the risk of miscarriage at each day of an early pregnancy. The data here is based on a study of 600 women who were tested daily for pregnancy while trying to conceive, so early pregnancies were all evaluated for survival rate. The numbers are an estimate, but they're something.

The following dates are based on an estimated LMP of August 10th, 2012.

Change LMP:
Month Day Year
Date Progress Overall probability of miscarriage
Friday August 31st, 2012 3W, 0D 33%
Saturday September 1st, 2012 3W, 1D 32.9%
Sunday September 2nd, 2012 3W, 2D 32.6%
Monday September 3rd, 2012 3W, 3D 32%
Tuesday September 4th, 2012 3W, 4D 31.3%
Wednesday September 5th, 2012 3W, 5D 30.3%
Thursday September 6th, 2012 3W, 6D 29.2%
Friday September 7th, 2012 4W, 0D 28%
Saturday September 8th, 2012 4W, 1D 26.6%
Sunday September 9th, 2012 4W, 2D 25.2%
Monday September 10th, 2012 4W, 3D 23.6%
Tuesday September 11th, 2012 4W, 4D 22.1%
Wednesday September 12th, 2012 4W, 5D 20.5%
Thursday September 13th, 2012 4W, 6D 18.9%
Friday September 14th, 2012 5W, 0D 17.3%
Saturday September 15th, 2012 5W, 1D 15.8%
Sunday September 16th, 2012 5W, 2D 14.4%
Monday September 17th, 2012 5W, 3D 13%
Tuesday September 18th, 2012 5W, 4D 11.7%
Wednesday September 19th, 2012 5W, 5D 10.5%
Thursday September 20th, 2012 5W, 6D 9.4%
Friday September 21st, 2012 6W, 0D 8.4%
Saturday September 22nd, 2012 6W, 1D 7.5%
Sunday September 23rd, 2012 6W, 2D 6.6%
Monday September 24th, 2012 6W, 3D 5.9%
Tuesday September 25th, 2012 6W, 4D 5.3%
Wednesday September 26th, 2012 6W, 5D 4.7%
Thursday September 27th, 2012 6W, 6D 4.3%
Friday September 28th, 2012 7W, 0D 3.9%
Saturday September 29th, 2012 7W, 1D 3.5%
Sunday September 30th, 2012 7W, 2D 3.2%
Monday October 1st, 2012 7W, 3D 3%
Tuesday October 2nd, 2012 7W, 4D 2.8%
Wednesday October 3rd, 2012 7W, 5D 2.6%
Thursday October 4th, 2012 7W, 6D 2.5%
Friday October 5th, 2012 8W, 0D 2.4%
Saturday October 6th, 2012 8W, 1D 2.3%
Sunday October 7th, 2012 8W, 2D 2.2%
Monday October 8th, 2012 8W, 3D 2.2%
Tuesday October 9th, 2012 8W, 4D 2.1%
Wednesday October 10th, 2012 8W, 5D 2.1%
Thursday October 11th, 2012 8W, 6D 2.1%
Friday October 12th, 2012 9W, 0D 2.1%
Saturday October 13th, 2012 9W, 1D 2%
Sunday October 14th, 2012 9W, 2D 2%
Monday October 15th, 2012 9W, 3D 2%
Tuesday October 16th, 2012 9W, 4D 2%
Wednesday October 17th, 2012 9W, 5D 2%
Thursday October 18th, 2012 9W, 6D 2%
Friday October 19th, 2012 10W, 0D 2%
Saturday October 20th, 2012 10W, 1D 2%
Sunday October 21st, 2012 10W, 2D 2%
Monday October 22nd, 2012 10W, 3D 2%
Tuesday October 23rd, 2012 10W, 4D 2%
Wednesday October 24th, 2012 10W, 5D 2%
Thursday October 25th, 2012 10W, 6D 2%
Friday October 26th, 2012 11W, 0D 2%
Saturday October 27th, 2012 11W, 1D 2%
Sunday October 28th, 2012 11W, 2D 2%
Monday October 29th, 2012 11W, 3D 2%
Tuesday October 30th, 2012 11W, 4D 2%
Wednesday October 31st, 2012 11W, 5D 2%
Thursday November 1st, 2012 11W, 6D 2%
Friday November 2nd, 2012 12W, 0D 2%
Saturday November 3rd, 2012 12W, 1D 2%
Sunday November 4th, 2012 12W, 2D 2%
Monday November 5th, 2012 12W, 3D 2%
Tuesday November 6th, 2012 12W, 4D 2%
Wednesday November 7th, 2012 12W, 5D 2%
Thursday November 8th, 2012 12W, 6D 2%

Future probability of miscarriage at a given day

Notes and disclaimers

All numbers are estimates. If you have better research, drop me an e-mail (

I used information from two studies to make my assumptions: Wilcox AJ, Baird DD, Weinberg CR (1999). "Time of implantation of the conceptus and loss of pregnancy." and Wang X, Chen C, Wang L, Chen D, Guang W, French J (2003). "Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study.". I was not able to obtain full access to the second one, but based on citations I believe I had the numbers I needed for this.

The studies analyzed women who were trying to conceive for the first time.

There is a page of good studies here: that compares risks based on age, whether you've heard a heartbeat, previous miscarriage, and hosts of other factors.

Charts are generated by flot.

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?

Sat Dec 20 4:29 PM by Zoraptera in Pregnancy & Parenting

The second someone starts feeling contractions on TV, they have to be raced to the hospital immediately! You almost never see people saying, "Okay, let's get out the timing app!" and waiting until the contractions are five minutes apart.

And so many people end up being delivered by a random dude they know. There's an episode of Fresh Prince where Will delivers a baby. In Star Trek:TNG, Worf delivers Keiko O'Brien's baby. And on and on...

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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.

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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.

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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.

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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?

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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).

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