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When Will My Baby Arrive? The Birth Prediction Tool.

If you’re at risk for preterm birth, it can be stressful not knowing when to expect your likely-to-be-early baby.  Many factors affect when preemies arrive. Knowing the exact birth date for every baby, especially a likely-to-be-early baby, is hardly a perfect science.

But until science catches up, we built the next best thing: a Preterm Birth Prediction Tool. This tool shows you windows of time when your preemie baby’s arrival is least and most likely, based based on your individual risk factors.


birth prediction tool

During week 25, your labor probability is %


(Note: You’re most likely to give birth after your probability hits 80%. CLICK HERE to learn more about how our model works).

How we built this…

Our Preterm Birth Prediction Tool is built on a mathematical model. First, we  considered over 20 different factors and their relation to preterm birth risk. From there, we winnowed our model down to a few factors that statistically shift when labor is most likely.

Keep in mind, this tool does not give a diagnosis and it can’t tell for certain if you will deliver early. It’s not a perfect crystal ball. Every woman and every pregnancy is different, but any mathematical model relies on averages. It won’t tell your story exactly.


A note to low risk mamas:

This calculator is not a due date calculator. Instead it is built around preterm labor risk estimates. This calculator gives you a probability of going into labor at a each specific week of pregnancy… if you end up delivering early. The data we used in our model comes from women with known risk factors who go on to deliver earlier than 37 weeks. So it doesn’t apply as well to women who anticipate a fully cooked baby. Sorry for that!

Instead, check out our Better Due Date Calculator. That might satisfy the itch (just a little) know when your baby is likely to arrive.


The science and the math of preterm birth prediction

Part of our mission at Bloomlife is to improve birth outcomes by better understanding, predicting and detecting preterm labor. Four years ago, as a first step, we set out to design a better way to calculate preterm birth risk.

Our amazing data scientist combed through data captured by The Division of Vital Statistics of the National Center for Health Statistics (NCHS). The dataset includes over 100 potential risk factors  for over 4 million deliveries each year.

Using these data, he modeled how each risk factor influences preterm birth risk. We built this model into our 37 app (no longer available but email me if you’d like to try it!) which allowed users to tune specific parameters to reach a more individualized assessment of risk. Since the data also provided information on when women delivered, we can use it to  predict probability of delivering at a given week. See your results using our Preterm Birth Prediction Tool.

Below is how the model looks behind the scenes when we play with the model for a low risk mom, a high risk mom (hypertension, prior preterm birth), and a twin mom:

preterm birth prediction

The model tells you how likely labor is each week. You are most likely to give birth when your graph levels off (showing an 80% probability of giving birth that week).

For example, consider a mom with hypertension. Women with hypertension have a greater risk for developing preeclampsia, a pregnancy complication associated with high blood pressure which accounts for 15% of all preterm birth in the U.S. Therefore, women with hypertension tend to deliver earlier than 37 weeks.  In our birth prediction tool, a mom in her 20’s with hypertension, but no other risk factors, hits peak likelihood of delivery around 36 weeks when she has a 81% labor probability.


Help us better understand preterm birth

The current rate for preterm birth in the United States is around 10%. Since one of the biggest risk factors for preterm birth is a prior preterm birth, it’s hard to predict the risk of preterm birth for first time moms.

As cool as our Birth Prediction Tool is, other specific aspects of your pregnancy, could better predict when your baby arrives.  At Bloomlife we’re hard at work developing a better way to detect early labor.


Every woman who uses Bloomlife can contribute to our research, helping out high risk pregnancies of the not-so-distant future.

If you are currently experiencing a high risk pregnancy you can also join our feedback team. As part of the feedback team, you’ll get a super discounted rate on Bloomlife ($10/week!).

Fill out the survey below to see if you qualify:



If you’re interested in what we’re up to on the research side of things, please drop us a note. We’re always looking for partners and we love hearing feedback (the good, the bad, and the ugly) from experts like you.

Get in touch!

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Molly Dickens, PhD

About Molly

Molly has her PhD in Physiology and spent over a decade as an academic research scientist slightly obsessed with the colliding worlds of brain science, hormones, stress and the reproductive system. Nowadays she heads up Content and Community at Bloomlife and edits Preg U. Science is still her jam and she can't help but continue to dive into the research world to find interesting bits about pregnancy and parenting.


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