Estimate miscarriage risk (educational tool)
This calculator provides an approximate risk estimate based on common factors. It is not a diagnosis and cannot replace your OB/GYN or midwife.
For educational planning only. If you have pain, bleeding, fever, dizziness, or worsening symptoms, seek urgent medical care.
How this miscarriage calculator works
This miscarriage calculator estimates early pregnancy loss risk using broad population trends. It combines age-related baseline risk with pregnancy timing (gestational week) and common modifiers such as previous miscarriage history, bleeding, smoking, and whether a heartbeat has been seen.
The result is best interpreted as a general probability range, not a prediction of what will happen to you personally. Individual outcomes vary widely, and your clinician can interpret your history, lab tests, and ultrasound findings more accurately.
What factors influence miscarriage risk?
1) Maternal age
Risk rises with age, especially after 35, largely because chromosomal abnormalities become more common. Younger age groups generally have lower baseline risk.
2) Gestational age
Miscarriage risk is usually highest in very early pregnancy and tends to decrease as weeks progress, especially after a viable ultrasound.
3) Prior pregnancy losses
A history of miscarriage can slightly increase future risk, particularly if losses are recurrent. However, many people with prior losses still go on to have healthy pregnancies.
4) Bleeding and ultrasound findings
Light spotting can occur in normal pregnancies, but heavy bleeding is more concerning. A documented fetal heartbeat usually lowers risk estimates.
5) Lifestyle and health factors
Smoking, uncontrolled chronic illness, untreated thyroid problems, and severe infection may increase risk. Prenatal care can help reduce preventable contributors.
How to interpret your result
- Low range: Risk appears below average for this stage and profile.
- Moderate range: Some factors increase risk, but many pregnancies in this group continue normally.
- Elevated range: Closer follow-up is reasonable and may provide clarity.
- High range: Prompt medical evaluation is important, especially with symptoms.
A percentage is not a certainty. Even high estimated risk does not guarantee loss, and low estimated risk does not guarantee no complications.
When to call your doctor or seek urgent care
- Heavy bleeding (soaking pads quickly)
- Severe pelvic or abdominal pain
- Dizziness, fainting, shoulder pain, or weakness
- Fever, chills, or foul vaginal discharge
- Any symptom that is worsening or feels alarming to you
These signs can indicate urgent conditions such as ectopic pregnancy or infection. Do not rely on an online calculator in emergencies.
Important limitations
This tool does not include all medical variables (for example: IVF status, known uterine anomalies, progesterone use, lab hormone trends, clotting disorders, autoimmune disease, or detailed ultrasound data). Because of that, estimates may differ from clinician-assessed risk.
Use this page to guide questions for your prenatal visit, not to self-diagnose. If you are worried, contacting your care team is always the best next step.