A Miscarriage Risk Calculator helps bring clarity by using evidence-based data to predict the likelihood of pregnancy loss based on age, embryo quality, embryo type (fresh/frozen), genetic testing, and clinical history.
In other words, A miscarriage calculator gives you a general, Â population-level estimate of pregnancy loss risk based on a few key details, such as age and how many weeks pregnant someone currently is. It does not diagnose anything, and it cannot tell you what will happen in a specific pregnancy. What it can do is help put a number to a question many people are quietly asking themselves.
Gestational week matters because published research shows that pregnancy loss risk is not constant from one week to the next. Early weeks generally carry a different statistical picture than later weeks, which is part of why this tool asks for your current stage of pregnancy.
Intended parents following a surrogacy journey often find this kind of information useful too. When you’re not the one experiencing the pregnancy directly, statistics can feel abstract until you can connect them to an actual week and an actual update from the gestational carrier’s care team. Enter a few details below to see where general research places that stage of pregnancy.
People search for this kind of tool under a few different names — miscarriage risk calculator, miscarriage probability calculator, pregnancy miscarriage calculator, miscarriage odds calculator. These terms are mostly interchangeable. They all describe a tool meant to translate published research into a general estimate, rather than a diagnostic test.
This particular miscarriage calculator works from three simple inputs:
The age of the pregnant person or gestational carrier
the current pregnancy week, counted from the first day of the last menstrual period, covering 4 to 20 weeks
0 (none), 1, 2, or 3 or more
The tool does not ask about ultrasound findings, fetal heartbeat, hCG levels, IVF status, genetic testing, or symptoms, because those aren’t part of what it calculates. If any of those details are relevant to a specific pregnancy, they belong in a conversation with the treating physician or midwife, not in an online estimate.
For a surrogacy pregnancy, the age, current week, and miscarriage history entered should reflect the gestational carrier, since she is the one carrying the pregnancy. An intended parent’s own age or medical history doesn’t factor into the biological risk of pregnancy loss.
A miscarriage calculator by week works from a simple, well-documented pattern: the chance of pregnancy loss tends to be higher earlier in pregnancy and generally decreases as the weeks go on. Some people search for a miscarriage calculator by day, hoping for even finer detail, but research on miscarriage rates by week is typically reported in broader ranges rather than single-day figures, since day-to-day changes in individual risk aren’t something studies can meaningfully isolate.
It’s worth being direct about something important here: there is no single chance of miscarriage by week that applies to every pregnancy. Miscarriage statistics by week describe averages across large groups of people, not a personal forecast.
The probability of miscarriage week by week, and the likelihood of miscarriage week by week, both depend on a wider set of circumstances — age, health history, and findings specific to that pregnancy. In general, published research points to the highest probability of miscarriage by week occurring earliest in pregnancy, with the pattern trending downward from there, though individual results vary.
| Pregnancy Stage | General Risk Range | What This Stage Involves |
|---|---|---|
| Weeks 4–5 | 20%–25% | The highest point on the curve, largely because many pregnancies at this stage haven’t been confirmed yet, and very early losses often go unnoticed. |
| Week 6 | 9%–13.5% | Risk drops noticeably here. If a heartbeat is visible on ultrasound at this stage, the outlook improves further. |
| Week 7 | 4%–8.7% | Continues trending downward as the pregnancy becomes more established. |
| Weeks 8–10 | 0.5%–1.5% | A sharp decline for pregnancies that are developing normally and have reached this milestone. |
| Weeks 12–13 (end of first trimester) | Below 1%–2% | Crossing into the second trimester marks one of the biggest confidence shifts in the entire pregnancy timeline. |
| Weeks 14–20+ (second trimester) | Generally under 1% | Risk stays low overall, though later losses can still occur due to specific medical complications rather than the general early-pregnancy pattern. |
People searching to calculate chance of miscarriage are often trying to understand why some pregnancies are described as higher or lower risk than others. Several factors are generally recognized as relevant:
It’s important to say plainly: most early miscarriages happen for reasons outside anyone’s control, often related to chromosomal factors in the pregnancy itself. A miscarriage is not something a pregnant person or gestational carrier caused through everyday choices.
For surrogacy pregnancies specifically, medical risk assessment centers on the gestational carrier — her health history, her current pregnancy, and her clinical findings. It has nothing to do with the intended parent’s own age or health profile.
People sometimes search “signs of a miscarriages” when they’re worried about symptoms during early pregnancy. The medically correct term is signs of miscarriage, and understanding them can help reduce uncertainty, even though symptoms alone don’t confirm what’s happening.
None of these automatically mean a miscarriage is occurring. Spotting and mild cramping are common in ongoing, healthy pregnancies too. A miscarriage calculator cannot diagnose miscarriage, confirm it, or rule it out — only clinical evaluation, such as an ultrasound or blood test, can do that.
Some symptoms call for prompt medical attention, and a few warrant emergency care: heavy bleeding, severe abdominal or pelvic pain, pain concentrated on one side, fainting, severe dizziness, or shoulder pain. If any of these occur, contacting a healthcare provider or seeking emergency evaluation is the right next step, not waiting to see how symptoms develop.
The chance of miscarriage by week changes as pregnancy progresses. Early weeks usually carry a higher risk, but the risk of miscarriage by week gradually decreases as the pregnancy reaches important developmental milestones.
| Term | Meaning | Used by |
|---|---|---|
| Surrogate | Woman who carries a pregnancy for intended parents | Everyone |
| Gestational surrogate / gestational carrier | Surrogate carrying an embryo from someone else’s egg; no genetic link | Clinics, lawyers, contracts |
| Traditional surrogate | Surrogate whose own egg is used; genetic mother | Older usage; rare today |
| Surrogate mother | Older general term; imprecise for gestational arrangements | Media, general public |
| Intended parent(s) | The person or couple who will raise the child | Contracts, agencies |
The probability of miscarriage by week depends on several factors, including maternal age, genetic health of the embryo, and overall pregnancy conditions. While the risk cannot be predicted with complete certainty, tracking pregnancy milestones and receiving regular medical care can help support a healthy pregnancy journey.
Miscarriage and stillbirth both describe pregnancy loss, but they are not the same thing, and understanding the difference between stillborn and miscarriage matters for anyone trying to make sense of these terms.
Stillbirth and stillborn refer to the same event — a pregnancy loss occurring later than the miscarriage stage — described from slightly different angles (the event versus the outcome).
The exact still birth meaning, in terms of gestational age cutoffs, isn’t universal. Different countries and healthcare systems use different thresholds for where miscarriage ends and stillbirth begins, so it’s more accurate to think of these as related but distinct categories rather than one fixed global rule.
Understanding what causes stillbirth requires some caution, because in a meaningful number of cases, a specific cause is never identified. Where a cause or contributing factor can be found, it may include:
Placental complications
Certain infections during pregnancy
Fetal or genetic conditions
Complications involving the umbilical cord
Maternal health conditions
Other pregnancy complications
A miscarriage calculator, including this one, does not predict stillbirth. It’s built around general miscarriage-risk research at earlier gestational stages, not later-pregnancy outcomes.
After you use the calculator, you’ll see a general estimate. Here’s how to think about it. A probability is not the same as a certainty — it describes a pattern seen across many pregnancies with similar characteristics, not a guaranteed outcome for any one pregnancy.
A lower estimated risk doesn’t guarantee a pregnancy will continue without complications. A higher estimated risk doesn’t mean a loss will happen. Statistics describe groups of people, and no online tool can perfectly predict what will happen in an individual case. Clinical findings — bloodwork, ultrasounds, a physical exam — carry information that a calculator simply doesn’t have access to.
For intended parents following a gestational carrier’s pregnancy, this kind of estimate can help make sense of where a pregnancy stands statistically at a given week. When something in the result raises a question, that’s a good prompt to bring to the carrier’s healthcare team, who can interpret it alongside her actual clinical picture.
It reflects general, published research averages, not a personalized medical assessment. Accuracy depends on how closely a given pregnancy matches the population the underlying research describes, which is why results should be treated as a starting point for understanding, not a firm prediction.
Yes. Gestational week is one of the main factors this type of tool uses, since research consistently shows that risk generally shifts as pregnancy progresses. That said, week alone doesn’t capture everything relevant to an individual pregnancy.
Not necessarily. Published research on pregnancy loss is generally organized by week rather than by single day, so day-level precision isn’t something the underlying data actually supports in most cases.
The highest risk of miscarriage is during the first trimester, especially around weeks 5 to 6 of pregnancy. As the embryo continues to develop and important milestones, like detecting a heartbeat, are reached, the chance of miscarriage generally becomes lower.
In general, yes — this is one of the more consistent findings in pregnancy-loss research. It doesn’t mean risk disappears entirely at any point, but the average pattern trends downward with advancing gestational age.
No. This tool provides a general statistical estimate, not a diagnostic assessment. If you’re experiencing symptoms like bleeding or cramping, that requires evaluation from a healthcare provider, not an online calculator.
A pregnancy that implants outside the uterine cavity, most often in a fallopian tube, where it cannot develop safely. It’s medically distinct from a miscarriage and requires prompt evaluation — a calculator cannot diagnose or rule it out.
A condition where the placenta detaches from the uterine wall before delivery, cutting into the baby’s oxygen and nutrient supply. There’s no fixed survival window — outcome depends on how much separates, gestational age, and how fast care is given. It’s treated as a medical emergency.
The Miscarriage Risk Calculator for Surrogacy gives intended parents a general estimate based on factors such as pregnancy week. It can help them prepare for informed conversations with the gestational carrier’s medical team.
This is called a retained placenta — when part or all of it stays in the uterus after birth instead of delivering naturally. Left untreated, it can lead to heavy bleeding or infection, so it usually needs prompt medical attention.
Maternal age is the strongest predictor because egg quality declines over time. The rate of chromosomal abnormalities increases significantly after age 35. However, embryo genetics, uterine health, androgen levels, and chronic illnesses also contribute. A risk estimator combines all these factors to give a more accurate prediction.
Yes. IVF allows for embryo grading, blastocyst selection, and optional PGT-A testing, which lowers miscarriage risk compared to natural conception, where the genetic status is unknown. However, if IVF uses untested embryos, miscarriage rates may be similar to natural conception for the same age group.
PGT-A can reduce risk by identifying chromosomally normal (euploid) embryos before transfer. For example, a 40-year-old may have a natural miscarriage risk of ~45–50%, but transferring a euploid embryo typically reduces it to 10–15%.
While egg quality plays the dominant role, severe sperm DNA fragmentation or chromosomal issues can contribute to pregnancy loss. In IVF/ICSI cycles, embryologists can reduce—but not eliminate—these risks through selection.
Not necessarily. One miscarriage—especially early—may not indicate a long-term problem. Recurrent pregnancy loss (three or more) suggests the need for further evaluation. The calculator factors in past history to adjust the prediction.
If you’re trying to understand pregnancy-loss statistics at a specific stage, the calculator above provides a quick estimate based on age, and current week. It can help support conversations with a doctor, midwife, or gestational carrier’s care team, including those working with Surrogacy4All.
Remember, the result is informational, not diagnostic, and doesn’t replace prenatal care, medical testing, or professional medical advice.
Talk with our physician-led team about your family, embryos, timeline and budget. We’ll explain your options and next steps with no obligation.
Our job is to listen, to connect the dots between your needs, and to determine how we can best help you have your baby. If you’re asking how much does it cost for a surrogate, we’ll walk you through every step of the process to ensure there are no surprises.
To make an appointment with one of our counselors or physicians, please call (212) 661-7673 or email info@surrogacy4all.com. We look forward to hearing from you.
Since 2006, Surrogacy4All has helped intended parents in the United States and around the world build their families through physician-led gestational surrogacy and egg donation.
Secret Guide to Minimizing Surrogacy Costs
NYS Surrogacy Program License GSP220903 · NYS Tissue Bank License ID 1570 · California Tissue Bank License CTB00082276 · Maryland Tissue Bank License TB3527 · FDA HCT/P Establishment Registration FEI 3021544308 · Health Canada Establishment Registration 000119 Verify: How to check our licenses
THIS WEBSITE DOES NOT PROVIDE MEDICAL ADVICE AND MAY BE OUT OF DATE. The information, including but not limited to text, PDFs, graphics, images, and other material contained on this website, is for general educational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment, and does not create a patient-doctor relationship. Pricing on the website may be out of date, is subject to change without notice, and may be subject to additional terms and conditions. No information on this site is intended to be a financial quote for medical services. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition, lifestyle or dietary changes, treatments, and before undertaking a new healthcare regimen. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
Disclaimer: THIS WEBSITE DOES NOT PROVIDE MEDICAL ADVICE AND MAY BE OUT OF DATE. The information, including but not limited to text, PDFs, graphics, images, and other material contained on this website, is for general educational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment, and does not create a patient-doctor relationship. Pricing on the website may be out of date, is subject to change without notice, and may be subject to additional terms and conditions. No information on this site is intended to be a financial quote for medical services. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition, lifestyle or dietary changes, treatments, and before undertaking a new healthcare regimen. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
All Rights Reserved to Surrogacy4all
