Why I’m Not Sharing My Due Date (And What That Has to Do With Induction)
People keep asking when I’m due.
I usually say, “July or August.”
It sounds vague, and that’s not an accident—it’s intentional. But the follow-up is always the same: “Yeah, but what day?”
I get it. Most people are used to hearing a specific due date—a concrete day circled on the calendar when the baby is “supposed” to arrive. But here’s the thing: I don’t want to tell them a day. I don’t even want to know the exact day myself.
Most providers—and most pregnant people—calculate due dates using something called Naegele’s Rule. It assumes a 28-day menstrual cycle and that ovulation happened right on Day 14. From there, they count 280 days (or 40 weeks) from the first day of your last menstrual period (LMP) to estimate your due date.
The problem?
Most people don’t have perfect 28-day cycles. Ovulation doesn’t always happen on Day 14. Maybe your cycle is irregular. Maybe you weren’t actively trying to conceive and didn’t track your last period. Or maybe—like me—you conceived after a miscarriage, without a period in between.
Unless you were closely tracking ovulation, it’s easy for that “due date” to be off. By a few days. Or even more.
You might be thinking, “Okay, Kels, but does being a few days off really matter?”
It can.
Because your due date isn’t just a nice bit of trivia—it can shape your entire birth experience. Depending on your age, medical history, and how far past that estimated date you go, your provider might start bringing up induction.
And if your due date is off—based on shaky info from the start—you could find yourself facing an induction just because a calendar says your pregnancy has gone “too long.” Even if you and your baby are perfectly healthy.
This matters. Once you’re labeled as “post-term” (typically after 41 weeks), standard protocols often recommend intervention. That might mean more monitoring, more pressure to induce, and fewer options for how and where you give birth. All based on a date that might not be accurate to begin with.
So what about early ultrasounds?
It’s true that ultrasounds done in the first trimester—usually between 8 and 13 weeks—tend to be more accurate than LMP alone. That’s because around that time, embryos grow at a fairly predictable rate. Measuring something like crown-rump length gives a consistent estimate of gestational age, even if you’re not sure when you ovulated.
In fact, a 2015 Cochrane review found that pregnant people who had an early ultrasound were less likely to be induced for post-term pregnancy.
And that’s no small thing. Induction rates are high. So high, in fact, that we no longer have a clear sense of how many people would go into labor spontaneously—before, on, or after their estimated due date—without medical intervention. The data is blurry. And it's been shaped by decades of evolving practices and protocols.
But there is some solid research we can lean on.
A 2001 study published in Obstetrics & Gynecology looked at over 1,400 healthy, low-risk, first-time pregnancies. They found that only 50% of people had given birth by 40 weeks and 5 days. And only 72% had given birth by 41 weeks and 2 days.
In other words?
Most first-time parents are still pregnant after their 40-week “due date.”
So what’s the takeaway?
The idea that pregnancy has a firm expiration date just isn’t backed by the best evidence. We’ve treated 40 weeks like a finish line, but in reality, birth timing follows a bell curve. Most babies arrive somewhere between 37 and 42 weeks—and many come well after that 40-week mark with zero issues.
That’s why I prefer to think of a due date as a range, not a deadline.
So when people ask, I say “July or August.”
Not to be mysterious. Not to be difficult. But because I don’t want a countdown clock ticking in my head. I don’t want to spend the last weeks of pregnancy wondering why my baby hasn’t arrived “on time.” And I definitely don’t want to feel pressured into an induction based on a flawed estimate.
Instead, I’m trusting the evidence.
I’m giving my baby the time they need.
And I’m reminding myself—every day—that birth doesn’t run on a clock.
TL;DR: Due Dates Aren’t Deadlines
Most due dates are based on Naegele’s Rule, which assumes a textbook-perfect 28-day cycle—not reality for most people.
Unless you tracked ovulation or had a first-trimester ultrasound, your due date might be off by days (or more).
That matters, because medical decisions—like when to induce—can hinge on that estimate.
Research shows that most first-time pregnancies go past 40 weeks, and only about half give birth by 40 weeks and 5 days.
Looking for more information and research on due dates? I just covered this topic with my friend Ashley Cooley on the Bringing Up Baby Podcast. You can find the episode here:
Sources:
Jukic, A. M. Z., Baird, D. D., Weinberg, C. R., McConnaughey, D. R., & Wilcox, A. J. (2013). Length of human pregnancy and contributors to its natural variation. Human Reproduction, 28(10), 2848–2855.
Salomon, L. J., Alfirevic, Z., Bilardo, C. M., Chalouhi, G. E., Ghi, T., Kagan, K. O., ... & Tabor, A. (2019). ISUOG Practice Guidelines: performance of first-trimester fetal ultrasound scan. Ultrasound in Obstetrics & Gynecology, 53(5), 715–723.
Savitz, D. A., Terry, J. W., Dole, N., Thorp, J. M., Siega-Riz, A. M., & Herring, A. H. (2002). Comparison of pregnancy dating by last menstrual period, ultrasound scanning, and their combination. American Journal of Obstetrics and Gynecology, 187(6), 1660–1666.
Smith, G. C. S. (2001). Use of time to event analysis to estimate the normal duration of human pregnancy. BMJ, 323(7307), 1323–1324.
Taipale, P., and Hiilesmaa, V. (2001). Predicting delivery date by ultrasound and last menstrual period in early gestation. Obstretrics & Gynecology, 97(2), 189-194.
Whitworth, M., Bricker, L., and Mullan, C. (2025). Ultrasound for fetal assessment in early pregnancy. Cochrane Database of Systematic Reviews https://doi.org/10.1002/14651858.CD007058.pub3