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 23rd, 2021.
| 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 December 19th, 2020 | 35W, 0D | 0.01% | 0.02% | -% | -% | -% | 0.1% | 0.1% | 0.2% |
| Sunday December 20th, 2020 | 35W, 1D | 0.01% | 0.03% | -% | -% | -% | 0.1% | 0.2% | 0.3% |
| Monday December 21st, 2020 | 35W, 2D | 0.02% | 0.05% | -% | -% | -% | 0.1% | 0.2% | 0.4% |
| Tuesday December 22nd, 2020 | 35W, 3D | 0.02% | 0.07% | -% | -% | -% | 0.1% | 0.3% | 0.6% |
| Wednesday December 23rd, 2020 | 35W, 4D | 0.03% | 0.1% | -% | -% | -% | 0.2% | 0.4% | 0.7% |
| Thursday December 24th, 2020 | 35W, 5D | 0.04% | 0.13% | -% | -% | -% | 0.2% | 0.5% | 0.9% |
| Friday December 25th, 2020 | 35W, 6D | 0.06% | 0.19% | -% | -% | 0.1% | 0.3% | 0.6% | 1.2% |
| Saturday December 26th, 2020 | 36W, 0D | 0.08% | 0.26% | -% | -% | 0.1% | 0.4% | 0.8% | 1.5% |
| Sunday December 27th, 2020 | 36W, 1D | 0.1% | 0.35% | -% | -% | 0.1% | 0.5% | 1% | 1.9% |
| Monday December 28th, 2020 | 36W, 2D | 0.14% | 0.47% | -% | -% | 0.1% | 0.6% | 1.3% | 2.4% |
| Tuesday December 29th, 2020 | 36W, 3D | 0.18% | 0.62% | -% | -% | 0.2% | 0.8% | 1.7% | 3% |
| Wednesday December 30th, 2020 | 36W, 4D | 0.22% | 0.82% | -% | -% | 0.2% | 1% | 2.1% | 3.7% |
| Thursday December 31st, 2020 | 36W, 5D | 0.28% | 1.07% | -% | -% | 0.3% | 1.2% | 2.5% | 4.5% |
| Friday January 1st, 2021 | 36W, 6D | 0.35% | 1.39% | -% | -% | 0.4% | 1.5% | 3.1% | 5.4% |
| Saturday January 2nd, 2021 | 37W, 0D | 0.44% | 1.79% | -% | -% | 0.4% | 1.8% | 3.8% | 6.4% |
| Sunday January 3rd, 2021 | 37W, 1D | 0.54% | 2.28% | -% | -% | 0.6% | 2.2% | 4.5% | 7.6% |
| Monday January 4th, 2021 | 37W, 2D | 0.66% | 2.87% | -% | -% | 0.7% | 2.7% | 5.4% | 8.9% |
| Tuesday January 5th, 2021 | 37W, 3D | 0.79% | 3.59% | -% | -% | 0.8% | 3.2% | 6.3% | 10.4% |
| Wednesday January 6th, 2021 | 37W, 4D | 0.94% | 4.46% | -% | -% | 1% | 3.8% | 7.4% | 11.9% |
| Thursday January 7th, 2021 | 37W, 5D | 1.11% | 5.48% | -% | -% | 1.2% | 4.4% | 8.6% | 13.7% |
| Friday January 8th, 2021 | 37W, 6D | 1.3% | 6.68% | -% | -% | 1.4% | 5.2% | 9.8% | 15.5% |
| Saturday January 9th, 2021 | 38W, 0D | 1.5% | 8.08% | -% | -% | 1.6% | 6% | 11.2% | 17.5% |
| Sunday January 10th, 2021 | 38W, 1D | 1.71% | 9.68% | -% | -% | 1.9% | 6.9% | 12.7% | 19.7% |
| Monday January 11th, 2021 | 38W, 2D | 1.94% | 11.51% | -% | -% | 2.2% | 7.8% | 14.3% | 21.9% |
| Tuesday January 12th, 2021 | 38W, 3D | 2.18% | 13.57% | -% | -% | 2.5% | 8.8% | 16% | 24.2% |
| Wednesday January 13th, 2021 | 38W, 4D | 2.42% | 15.87% | -% | -% | 2.9% | 9.9% | 17.8% | 26.6% |
| Thursday January 14th, 2021 | 38W, 5D | 2.66% | 18.41% | -% | -% | 3.3% | 11.1% | 19.7% | 29% |
| Friday January 15th, 2021 | 38W, 6D | 2.9% | 21.19% | -% | -% | 3.7% | 12.3% | 21.6% | 31.5% |
| Saturday January 16th, 2021 | 39W, 0D | 3.12% | 24.2% | -% | -% | 4.1% | 13.5% | 23.6% | 34% |
| Sunday January 17th, 2021 | 39W, 1D | 3.33% | 27.43% | -% | -% | 4.6% | 14.9% | 25.6% | 36.6% |
| Monday January 18th, 2021 | 39W, 2D | 3.52% | 30.85% | -% | -% | 5.1% | 16.2% | 27.7% | 39.2% |
| Tuesday January 19th, 2021 | 39W, 3D | 3.68% | 34.46% | -% | -% | 5.6% | 17.6% | 29.8% | 41.7% |
| Wednesday January 20th, 2021 | 39W, 4D | 3.81% | 38.21% | -% | -% | 6.2% | 19.1% | 31.9% | 44.2% |
| Thursday January 21st, 2021 | 39W, 5D | 3.91% | 42.07% | -% | -% | 6.7% | 20.6% | 34% | 46.7% |
| Friday January 22nd, 2021 | 39W, 6D | 3.97% | 46.02% | -% | -% | 7.4% | 22.1% | 36.2% | 49.2% |
| Saturday January 23rd, 2021 | 40W, 0D | 3.99% | 50% | 8% | 0% | 8% | 23.6% | 38.3% | 51.6% |
| Sunday January 24th, 2021 | 40W, 1D | 3.97% | 53.98% | 7.9% | 8% | 8.6% | 25.1% | 40.4% | 54% |
| Monday January 25th, 2021 | 40W, 2D | 3.91% | 57.93% | 7.8% | 15.9% | 9.3% | 26.7% | 42.5% | 56.2% |
| Tuesday January 26th, 2021 | 40W, 3D | 3.81% | 61.79% | 7.6% | 23.6% | 10% | 28.2% | 44.5% | 58.5% |
| Wednesday January 27th, 2021 | 40W, 4D | 3.68% | 65.54% | 7.4% | 31.1% | 10.7% | 29.8% | 46.6% | 60.6% |
| Thursday January 28th, 2021 | 40W, 5D | 3.52% | 69.15% | 7% | 38.3% | 11.4% | 31.3% | 48.6% | 62.7% |
| Friday January 29th, 2021 | 40W, 6D | 3.33% | 72.57% | 6.7% | 45.1% | 12.1% | 32.9% | 50.5% | 64.7% |
| Saturday January 30th, 2021 | 41W, 0D | 3.12% | 75.8% | 6.2% | 51.6% | 12.9% | 34.4% | 52.4% | 66.6% |
| Sunday January 31st, 2021 | 41W, 1D | 2.9% | 78.81% | 5.8% | 57.6% | 13.7% | 36% | 54.3% | 68.5% |
| Monday February 1st, 2021 | 41W, 2D | 2.66% | 81.59% | 5.3% | 63.2% | 14.4% | 37.5% | 56.1% | 70.2% |
| Tuesday February 2nd, 2021 | 41W, 3D | 2.42% | 84.13% | 4.8% | 68.3% | 15.2% | 39% | 57.9% | 71.9% |
| Wednesday February 3rd, 2021 | 41W, 4D | 2.18% | 86.43% | 4.4% | 72.9% | 16.1% | 40.5% | 59.6% | 73.5% |
| Thursday February 4th, 2021 | 41W, 5D | 1.94% | 88.49% | 3.9% | 77% | 16.9% | 42% | 61.3% | 75.1% |
| Friday February 5th, 2021 | 41W, 6D | 1.71% | 90.32% | 3.4% | 80.6% | 17.7% | 43.4% | 62.9% | 76.4% |
| Saturday February 6th, 2021 | 42W, 0D | 1.5% | 91.92% | 3% | 83.8% | 18.6% | 44.8% | 64.5% | 77.8% |
| Sunday February 7th, 2021 | 42W, 1D | 1.3% | 93.32% | 2.6% | 86.6% | 19.5% | 46.3% | 65.9% | 79.2% |
| Monday February 8th, 2021 | 42W, 2D | 1.11% | 94.52% | 2.2% | 89% | 20.3% | 47.6% | 67.3% | 80.5% |
| Tuesday February 9th, 2021 | 42W, 3D | 0.94% | 95.54% | 1.9% | 91.1% | 21.1% | 48.9% | 68.8% | 81.6% |
| Wednesday February 10th, 2021 | 42W, 4D | 0.79% | 96.41% | 1.6% | 92.8% | 22% | 50.1% | 70.2% | 82.7% |
| Thursday February 11th, 2021 | 42W, 5D | 0.66% | 97.13% | 1.3% | 94.3% | 23% | 51.6% | 71.4% | 83.6% |
| Friday February 12th, 2021 | 42W, 6D | 0.54% | 97.72% | 1.1% | 95.4% | 23.7% | 53.1% | 72.8% | 84.6% |
| Saturday February 13th, 2021 | 43W, 0D | 0.44% | 98.21% | 0.9% | 96.4% | 24.6% | 54.2% | 73.7% | 85.5% |
| Sunday February 14th, 2021 | 43W, 1D | 0.35% | 98.61% | 0.7% | 97.2% | 25.2% | 55.4% | 74.8% | 86.3% |
| Monday February 15th, 2021 | 43W, 2D | 0.28% | 98.93% | 0.6% | 97.9% | 26.2% | 56.1% | 75.7% | 87.9% |
| Tuesday February 16th, 2021 | 43W, 3D | 0.22% | 99.18% | 0.4% | 98.4% | 26.8% | 57.3% | 76.8% | -% |
| Wednesday February 17th, 2021 | 43W, 4D | 0.18% | 99.38% | 0.4% | 98.8% | 29% | 58.1% | 79% | -% |
| Thursday February 18th, 2021 | 43W, 5D | 0.14% | 99.53% | 0.3% | 99.1% | 29.8% | 59.6% | -% | -% |
| Friday February 19th, 2021 | 43W, 6D | 0.1% | 99.65% | 0.2% | 99.3% | 28.6% | 62.9% | -% | -% |
| Saturday February 20th, 2021 | 44W, 0D | 0.08% | 99.74% | 0.2% | 99.5% | 30.8% | -% | -% | -% |
| Sunday February 21st, 2021 | 44W, 1D | 0.06% | 99.81% | 0.1% | 99.6% | 31.6% | -% | -% | -% |
| Monday February 22nd, 2021 | 44W, 2D | 0.04% | 99.87% | 0.1% | 99.7% | 30.8% | -% | -% | -% |
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.