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 28th, 2020.
| 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 | ||
| Tuesday December 24th, 2019 | 35W, 0D | 0.01% | 0.02% | -% | -% | -% | 0.1% | 0.1% | 0.2% |
| Wednesday December 25th, 2019 | 35W, 1D | 0.01% | 0.03% | -% | -% | -% | 0.1% | 0.2% | 0.3% |
| Thursday December 26th, 2019 | 35W, 2D | 0.02% | 0.05% | -% | -% | -% | 0.1% | 0.2% | 0.4% |
| Friday December 27th, 2019 | 35W, 3D | 0.02% | 0.07% | -% | -% | -% | 0.1% | 0.3% | 0.6% |
| Saturday December 28th, 2019 | 35W, 4D | 0.03% | 0.1% | -% | -% | -% | 0.2% | 0.4% | 0.7% |
| Sunday December 29th, 2019 | 35W, 5D | 0.04% | 0.13% | -% | -% | -% | 0.2% | 0.5% | 0.9% |
| Monday December 30th, 2019 | 35W, 6D | 0.06% | 0.19% | -% | -% | 0.1% | 0.3% | 0.6% | 1.2% |
| Tuesday December 31st, 2019 | 36W, 0D | 0.08% | 0.26% | -% | -% | 0.1% | 0.4% | 0.8% | 1.5% |
| Wednesday January 1st, 2020 | 36W, 1D | 0.1% | 0.35% | -% | -% | 0.1% | 0.5% | 1% | 1.9% |
| Thursday January 2nd, 2020 | 36W, 2D | 0.14% | 0.47% | -% | -% | 0.1% | 0.6% | 1.3% | 2.4% |
| Friday January 3rd, 2020 | 36W, 3D | 0.18% | 0.62% | -% | -% | 0.2% | 0.8% | 1.7% | 3% |
| Saturday January 4th, 2020 | 36W, 4D | 0.22% | 0.82% | -% | -% | 0.2% | 1% | 2.1% | 3.7% |
| Sunday January 5th, 2020 | 36W, 5D | 0.28% | 1.07% | -% | -% | 0.3% | 1.2% | 2.5% | 4.5% |
| Monday January 6th, 2020 | 36W, 6D | 0.35% | 1.39% | -% | -% | 0.4% | 1.5% | 3.1% | 5.4% |
| Tuesday January 7th, 2020 | 37W, 0D | 0.44% | 1.79% | -% | -% | 0.4% | 1.8% | 3.8% | 6.4% |
| Wednesday January 8th, 2020 | 37W, 1D | 0.54% | 2.28% | -% | -% | 0.6% | 2.2% | 4.5% | 7.6% |
| Thursday January 9th, 2020 | 37W, 2D | 0.66% | 2.87% | -% | -% | 0.7% | 2.7% | 5.4% | 8.9% |
| Friday January 10th, 2020 | 37W, 3D | 0.79% | 3.59% | -% | -% | 0.8% | 3.2% | 6.3% | 10.4% |
| Saturday January 11th, 2020 | 37W, 4D | 0.94% | 4.46% | -% | -% | 1% | 3.8% | 7.4% | 11.9% |
| Sunday January 12th, 2020 | 37W, 5D | 1.11% | 5.48% | -% | -% | 1.2% | 4.4% | 8.6% | 13.7% |
| Monday January 13th, 2020 | 37W, 6D | 1.3% | 6.68% | -% | -% | 1.4% | 5.2% | 9.8% | 15.5% |
| Tuesday January 14th, 2020 | 38W, 0D | 1.5% | 8.08% | -% | -% | 1.6% | 6% | 11.2% | 17.5% |
| Wednesday January 15th, 2020 | 38W, 1D | 1.71% | 9.68% | -% | -% | 1.9% | 6.9% | 12.7% | 19.7% |
| Thursday January 16th, 2020 | 38W, 2D | 1.94% | 11.51% | -% | -% | 2.2% | 7.8% | 14.3% | 21.9% |
| Friday January 17th, 2020 | 38W, 3D | 2.18% | 13.57% | -% | -% | 2.5% | 8.8% | 16% | 24.2% |
| Saturday January 18th, 2020 | 38W, 4D | 2.42% | 15.87% | -% | -% | 2.9% | 9.9% | 17.8% | 26.6% |
| Sunday January 19th, 2020 | 38W, 5D | 2.66% | 18.41% | -% | -% | 3.3% | 11.1% | 19.7% | 29% |
| Monday January 20th, 2020 | 38W, 6D | 2.9% | 21.19% | -% | -% | 3.7% | 12.3% | 21.6% | 31.5% |
| Tuesday January 21st, 2020 | 39W, 0D | 3.12% | 24.2% | -% | -% | 4.1% | 13.5% | 23.6% | 34% |
| Wednesday January 22nd, 2020 | 39W, 1D | 3.33% | 27.43% | -% | -% | 4.6% | 14.9% | 25.6% | 36.6% |
| Thursday January 23rd, 2020 | 39W, 2D | 3.52% | 30.85% | -% | -% | 5.1% | 16.2% | 27.7% | 39.2% |
| Friday January 24th, 2020 | 39W, 3D | 3.68% | 34.46% | -% | -% | 5.6% | 17.6% | 29.8% | 41.7% |
| Saturday January 25th, 2020 | 39W, 4D | 3.81% | 38.21% | -% | -% | 6.2% | 19.1% | 31.9% | 44.2% |
| Sunday January 26th, 2020 | 39W, 5D | 3.91% | 42.07% | -% | -% | 6.7% | 20.6% | 34% | 46.7% |
| Monday January 27th, 2020 | 39W, 6D | 3.97% | 46.02% | -% | -% | 7.4% | 22.1% | 36.2% | 49.2% |
| Tuesday January 28th, 2020 | 40W, 0D | 3.99% | 50% | -% | -% | 8% | 23.6% | 38.3% | 51.6% |
| Wednesday January 29th, 2020 | 40W, 1D | 3.97% | 53.98% | 7.9% | 8% | 8.6% | 25.1% | 40.4% | 54% |
| Thursday January 30th, 2020 | 40W, 2D | 3.91% | 57.93% | 7.8% | 15.9% | 9.3% | 26.7% | 42.5% | 56.2% |
| Friday January 31st, 2020 | 40W, 3D | 3.81% | 61.79% | 7.6% | 23.6% | 10% | 28.2% | 44.5% | 58.5% |
| Saturday February 1st, 2020 | 40W, 4D | 3.68% | 65.54% | 7.4% | 31.1% | 10.7% | 29.8% | 46.6% | 60.6% |
| Sunday February 2nd, 2020 | 40W, 5D | 3.52% | 69.15% | 7% | 38.3% | 11.4% | 31.3% | 48.6% | 62.7% |
| Monday February 3rd, 2020 | 40W, 6D | 3.33% | 72.57% | 6.7% | 45.1% | 12.1% | 32.9% | 50.5% | 64.7% |
| Tuesday February 4th, 2020 | 41W, 0D | 3.12% | 75.8% | 6.2% | 51.6% | 12.9% | 34.4% | 52.4% | 66.6% |
| Wednesday February 5th, 2020 | 41W, 1D | 2.9% | 78.81% | 5.8% | 57.6% | 13.7% | 36% | 54.3% | 68.5% |
| Thursday February 6th, 2020 | 41W, 2D | 2.66% | 81.59% | 5.3% | 63.2% | 14.4% | 37.5% | 56.1% | 70.2% |
| Friday February 7th, 2020 | 41W, 3D | 2.42% | 84.13% | 4.8% | 68.3% | 15.2% | 39% | 57.9% | 71.9% |
| Saturday February 8th, 2020 | 41W, 4D | 2.18% | 86.43% | 4.4% | 72.9% | 16.1% | 40.5% | 59.6% | 73.5% |
| Sunday February 9th, 2020 | 41W, 5D | 1.94% | 88.49% | 3.9% | 77% | 16.9% | 42% | 61.3% | 75.1% |
| Monday February 10th, 2020 | 41W, 6D | 1.71% | 90.32% | 3.4% | 80.6% | 17.7% | 43.4% | 62.9% | 76.4% |
| Tuesday February 11th, 2020 | 42W, 0D | 1.5% | 91.92% | 3% | 83.8% | 18.6% | 44.8% | 64.5% | 77.8% |
| Wednesday February 12th, 2020 | 42W, 1D | 1.3% | 93.32% | 2.6% | 86.6% | 19.5% | 46.3% | 65.9% | 79.2% |
| Thursday February 13th, 2020 | 42W, 2D | 1.11% | 94.52% | 2.2% | 89% | 20.3% | 47.6% | 67.3% | 80.5% |
| Friday February 14th, 2020 | 42W, 3D | 0.94% | 95.54% | 1.9% | 91.1% | 21.1% | 48.9% | 68.8% | 81.6% |
| Saturday February 15th, 2020 | 42W, 4D | 0.79% | 96.41% | 1.6% | 92.8% | 22% | 50.1% | 70.2% | 82.7% |
| Sunday February 16th, 2020 | 42W, 5D | 0.66% | 97.13% | 1.3% | 94.3% | 23% | 51.6% | 71.4% | 83.6% |
| Monday February 17th, 2020 | 42W, 6D | 0.54% | 97.72% | 1.1% | 95.4% | 23.7% | 53.1% | 72.8% | 84.6% |
| Tuesday February 18th, 2020 | 43W, 0D | 0.44% | 98.21% | 0.9% | 96.4% | 24.6% | 54.2% | 73.7% | 85.5% |
| Wednesday February 19th, 2020 | 43W, 1D | 0.35% | 98.61% | 0.7% | 97.2% | 25.2% | 55.4% | 74.8% | 86.3% |
| Thursday February 20th, 2020 | 43W, 2D | 0.28% | 98.93% | 0.6% | 97.9% | 26.2% | 56.1% | 75.7% | 87.9% |
| Friday February 21st, 2020 | 43W, 3D | 0.22% | 99.18% | 0.4% | 98.4% | 26.8% | 57.3% | 76.8% | -% |
| Saturday February 22nd, 2020 | 43W, 4D | 0.18% | 99.38% | 0.4% | 98.8% | 29% | 58.1% | 79% | -% |
| Sunday February 23rd, 2020 | 43W, 5D | 0.14% | 99.53% | 0.3% | 99.1% | 29.8% | 59.6% | -% | -% |
| Monday February 24th, 2020 | 43W, 6D | 0.1% | 99.65% | 0.2% | 99.3% | 28.6% | 62.9% | -% | -% |
| Tuesday February 25th, 2020 | 44W, 0D | 0.08% | 99.74% | 0.2% | 99.5% | 30.8% | -% | -% | -% |
| Wednesday February 26th, 2020 | 44W, 1D | 0.06% | 99.81% | 0.1% | 99.6% | 31.6% | -% | -% | -% |
| Thursday February 27th, 2020 | 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.