Miscarriage Risk Calculator (2026)
If you're here, you're probably feeling some mix of hope and worry - that's completely normal in early pregnancy. This tool won't tell you what will happen in your specific pregnancy; no calculator can. What it can do is show you the general, published statistics on how risk changes by gestational week, age, and history, so the number in your head is based on real data instead of worst-case scrolling. Please read it alongside, not instead of, guidance from your own healthcare provider.
This tool gives a general, population-based estimate only - it cannot know anything specific about your pregnancy, and it is not a diagnosis, prediction, or medical opinion. It cannot replace an ultrasound, bloodwork, or your own doctor or midwife's assessment. If you're experiencing heavy bleeding, severe pain, fever, or you're simply worried, please contact your healthcare provider directly rather than relying on any calculator - including this one.
| Factor | Value |
|---|
What Actually Affects Miscarriage Risk
Miscarriage risk isn't one fixed number - it moves with three main factors that research has studied closely: how far along the pregnancy is, the birthing parent's age, and pregnancy loss history. Understanding how these interact gives a far more accurate (and often more reassuring) picture than a single statistic pulled from a worried late-night search.
- Risk is highest in the earliest weeks and drops substantially as pregnancy progresses
- A confirmed fetal heartbeat (typically 6-8 weeks) is linked to a meaningful risk reduction
- Reaching the end of the first trimester (~12-13 weeks) is linked to a further, larger drop in risk
- Most miscarriages are caused by random chromosomal issues in the embryo, not anything the pregnant person did
- One previous loss barely changes future risk; it's recurrent (2+) losses where risk rises more meaningfully
- This calculator gives a general estimate only - it is not a personal diagnosis or prediction
Risk by Maternal Age
| Age Range | General Miscarriage Risk* |
|---|---|
| Under 35 | ~10-15% |
| 35-39 | ~20-25% |
| 40-44 | ~35-40% |
| 45 and older | ~50% or higher |
*Figures represent overall risk for a clinically recognized pregnancy from a positive test, before accounting for gestational week already reached. They are population averages, not a prediction for any individual.
The rise in risk with age is primarily linked to age-related changes in egg quality, which increases the likelihood of chromosomal differences that are the most common cause of early miscarriage - it is not a reflection of anything a person did or didn't do.
Risk by Gestational Week
| Gestational Week | Relative Risk Remaining** |
|---|---|
| 4-5 weeks (just confirmed) | Highest point - full baseline risk |
| 6-7 weeks | ~70% of baseline |
| 8-9 weeks (after heartbeat confirmed) | ~50% of baseline |
| 10-11 weeks | ~30% of baseline |
| 12-13 weeks (end of 1st trimester) | ~10% of baseline |
| 14-19 weeks | ~3% of baseline |
| 20+ weeks | ~1% of baseline (loss after this point is termed differently) |
**"Relative risk remaining" reflects how much of the original age-based risk is estimated to still apply at each stage, based on commonly cited progressive decline patterns in early pregnancy research - not an exact clinical figure for any individual pregnancy.
This is the single most reassuring part of the data for most people: every week that passes with a healthy, ongoing pregnancy meaningfully lowers the risk going forward, and it drops especially sharply right after a heartbeat is confirmed.
Risk After a Previous Loss
| Prior Consecutive Losses | General Future Risk |
|---|---|
| 0 (no previous losses) | Baseline (age-based figure above) |
| 1 previous loss | ~20% - only modestly above baseline for most ages |
| 2 previous losses | ~28% |
| 3 or more previous losses | ~33-42% (often termed "recurrent pregnancy loss") |
One miscarriage is common - it happens in a large share of all pregnancies, and the vast majority of people who experience one go on to carry a future pregnancy successfully. It's specifically after two or more consecutive losses that doctors typically recommend further evaluation to look for an underlying, often treatable, cause.
How This Calculator Combines Factors
This calculator starts with a baseline risk figure based on your age (or your prior-loss history figure, if higher), then applies the gestational-week decline factor for how far along your pregnancy already is. The result is framed as your estimated risk from this point forward - not the risk you faced back at the very start - which is a more useful and more accurate way to think about it than a single flat percentage.
Worked Examples
Age 29, 5 weeks pregnant, no previous losses. Baseline risk (under 35): ~12%. At 5 weeks, that's the full baseline: ~12% estimated risk from this point.
Same person, now at 9 weeks with a confirmed heartbeat. Baseline ~12% × ~50% remaining = ~6% estimated risk from this point - already roughly half of where she started.
Baseline for age 37 (~22%) vs. one-prior-loss figure (~20%) - the calculator uses the higher, more age-specific number here (~22%). At 13 weeks: ~22% × ~10% remaining = ~2% estimated risk from this point.
When to Contact Your Provider
Heavy bleeding (soaking through a pad in an hour or less), severe or worsening abdominal pain, tissue passing with bleeding, fever, dizziness or fainting, or simply a strong gut feeling that something is wrong. Light spotting is common in early pregnancy and often not a cause for alarm, but any bleeding is worth mentioning to your provider so they can assess it properly rather than guessing from statistics alone.
If You've Experienced a Loss
If this page finds you after a loss rather than before one: it was very likely not something you caused, and it was not something you could have prevented. The overwhelming majority of early miscarriages are due to random chromosomal events in the embryo that have nothing to do with exercise, stress, work, sex, or minor everyday choices. Grief after a loss is real and valid regardless of how early it happened, and support - from your provider, a therapist, or a loss support community - is worth seeking if you want it, not just if you think you "need" it.
Common Misconceptions
- "The risk stays the same the whole first trimester." It doesn't - risk drops substantially week by week, especially after a confirmed heartbeat.
- "One miscarriage means it will likely happen again." Most people who experience one loss go on to have a successful pregnancy; risk only rises more meaningfully after recurrent (2+) losses.
- "Something I did caused it." The vast majority of early losses are due to random chromosomal factors, not lifestyle choices.
- "A calculator can tell me what will happen to my pregnancy." No tool can do that - these are population statistics, not a personal prediction.
- "Spotting always means a miscarriage is happening." Light spotting is common in healthy pregnancies; it's still worth mentioning to a provider, but it isn't automatically a bad sign.
Glossary
- Miscarriage
- The spontaneous loss of a pregnancy before 20 weeks of gestation.
- Gestational week
- How many weeks pregnant someone is, typically counted from the first day of the last menstrual period.
- Chemical pregnancy
- A very early loss occurring around the time of expected menstruation, often before it would be visible on ultrasound.
- Recurrent pregnancy loss (RPL)
- Typically defined as two or more consecutive miscarriages, at which point further medical evaluation is usually recommended.
- Viability / fetal heartbeat
- A key early pregnancy milestone, usually confirmed by ultrasound around 6-8 weeks, associated with meaningfully lower ongoing risk.
Frequently Asked Questions
Q: What is the average miscarriage risk in early pregnancy?
A: For clinically recognized pregnancies overall, commonly cited miscarriage risk is around 10 to 20 percent, with the large majority of losses happening in the first trimester. That risk is not constant, though - it is highest in the earliest weeks right after a positive pregnancy test and drops substantially each week the pregnancy continues, especially once a heartbeat is confirmed on ultrasound.
Q: How does miscarriage risk change week by week?
A: Miscarriage risk drops sharply as a pregnancy progresses through the first trimester. Risk is highest in weeks 4 to 6, decreases meaningfully once a fetal heartbeat is confirmed around weeks 6 to 8, drops further through weeks 9 to 11, and becomes quite low by the end of the first trimester around week 12 to 13. After 20 weeks, pregnancy loss is uncommon and is typically classified differently (as stillbirth) rather than miscarriage.
Q: Does age affect miscarriage risk?
A: Yes, maternal age is one of the most well-documented factors affecting miscarriage risk. Commonly cited research shows risk is roughly 10 to 15 percent for people under 35, rising to around 20 to 25 percent between ages 35 and 39, roughly 35 to 40 percent between 40 and 44, and 50 percent or higher for pregnancies after age 45, largely related to age-related changes in egg quality.
Q: Does having a previous miscarriage mean I'll have another one?
A: No, one previous miscarriage does not mean a future pregnancy is likely to end the same way - most people who experience one loss go on to have a successful pregnancy afterward. Research suggests risk after a single prior miscarriage is only modestly higher than baseline, around 20 percent; it's typically after two or more consecutive losses (recurrent pregnancy loss) that risk rises more meaningfully and further medical evaluation is usually recommended.
Q: Once a heartbeat is confirmed, how much does miscarriage risk drop?
A: Confirming a fetal heartbeat on ultrasound, typically around 6 to 8 weeks, is one of the most reassuring milestones in early pregnancy, since it's associated with a meaningful drop in miscarriage risk compared to before that point - commonly cited figures suggest risk falls to somewhere around 5 to 10 percent after a confirmed heartbeat, and continues dropping further as the pregnancy progresses.
This calculator provides general, population-based estimates for educational purposes only. It is not medical advice, a diagnosis, or a prediction for any individual pregnancy, and it should never replace guidance from a qualified healthcare provider. If you have concerns about bleeding, pain, or any symptoms during pregnancy, please contact your doctor or midwife directly. Sources: commonly cited clinical and epidemiological statistics on miscarriage risk by maternal age, gestational week, and pregnancy loss history, as published across reproductive health and obstetric literature.