Miscarriage Risk Calculator: Understanding Your Odds

Navigating the early weeks of pregnancy can bring a mix of joy and anxiety. If you’re looking for information about the likelihood of miscarriage, you are not alone. Our tool is here to offer a clear, data-driven perspective on the statistical risk, helping you understand the numbers behind this journey.

Miscarriage Risk Calculator

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How to Use This Calculator

This tool provides a personalized estimate in two simple steps:

  1. Enter Your Age: Input your current age in years.
  2. Select Your Week: Choose your current week of pregnancy from the dropdown menu. This is the number of weeks since the first day of your last menstrual period.
  3. See Your Estimate: Click the “Understand My Chances >” button to see the statistical estimate based on your inputs.
A screenshot of the Miscarriage Risk Calculator with example age and week selected.

The Science Behind Miscarriage Risk

It’s important to know that miscarriage is not anyone’s fault. It is most often a result of chromosomal abnormalities in the embryo that make a healthy pregnancy impossible. The statistical risk is influenced primarily by two well-documented factors, which our calculator uses to generate its estimate.

1. Maternal Age (The Primary Factor): The single most significant factor influencing miscarriage risk is the age of the mother. This is because the risk of chromosomal issues in an egg increases with age. Our calculator uses a baseline risk model established by large-scale studies.¹

2. Gestational Week (The Reassuring Timeline): The risk of miscarriage decreases significantly as a pregnancy progresses. The highest risk is very early on, often before a pregnancy is even confirmed. After a fetal heartbeat is detected (usually around 6-7 weeks), the chances of the pregnancy continuing increase dramatically each week.

Our calculator combines these two factors to provide a snapshot of the statistical risk at a specific point in time. It shows how the baseline risk associated with age is significantly reduced by each successful week of pregnancy.

A line chart showing risk decreasing over time for different age groups.

¹The data model is based on findings from a landmark study on fetal loss: Nybo Andersen, A. M., Wohlfahrt, J., Christens, P., Olsen, J., & Melbye, M. (2000). Maternal age and fetal loss: a population-based register-linkage study. BMJ, 320(7251), 1708–1712.

Frequently Asked Questions

Is this calculator a diagnosis?
Absolutely not. This is a statistical tool for educational purposes only. It cannot and should not replace a conversation with your doctor or healthcare provider. Every pregnancy is unique, and this tool does not account for individual health history or conditions.

What about other risk factors like BMI or smoking?
While factors like a very high or low BMI, smoking, and certain medical conditions can influence risk, maternal age and gestational week are the most dominant predictors in broad statistical models. This calculator focuses on these two primary data points to provide a clear, understandable estimate. For a complete picture of your personal risk profile, please consult a healthcare professional.

I’m experiencing spotting. What should I do?
While some light spotting can be normal in early pregnancy (such as during implantation), it can also be a sign of a potential issue. You should contact your doctor or midwife immediately if you experience any bleeding, cramping, or have concerns about your symptoms.

The result is causing me anxiety. Where can I find support?
It is completely normal to feel anxious. Remember that statistics are not your personal story. If you are struggling, please reach out. You can talk to your healthcare provider, a therapist, or connect with support communities like the March of Dimes or other local and online pregnancy loss support groups. You are not alone.

What is the difference between a miscarriage and a stillbirth?
Medically, a pregnancy loss that occurs before the 20th week of gestation is defined as a miscarriage. A loss that occurs at 20 weeks or later is defined as a stillbirth.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a healthcare provider for any health concerns or before making any decisions related to your health or pregnancy.

Research Studies We Used

  1. Tong S, Kaur A, Walker SP, et al. Miscarriage Risk for Asymptomatic Women After a Normal First-Trimester Prenatal Visit. Obstet Gynecol. 2008;111(3):710-714. DOI | PubMed
  2. Wang JX, Davies MJ, Norman RJ. Obesity Increases the Risk of Spontaneous Abortion during Infertility Treatment. Obesity Res. 2002;10(6):551-554. DOI | PubMed
  3. Maconochie N, Doyle P, Prior S, Simmons R. Risk Factors for First-Trimester Miscarriage — UK Population-Based Case–Control Study. BJOG. 2007;114:170-186. DOI | PubMed
  4. Avalos LA, Galindo C, Li DK. A Systematic Review to Calculate Background Miscarriage Rates Using Life-Table Analysis. Birth Defects Res A. 2012;94(6):417-423. DOI | PubMed
  5. Mukherjee S, Velez-Edwards DR, Baird DD, et al. Risk of Miscarriage Among Black and White Women in a US Cohort. Am J Epidemiol. 2013;177(11):1271-1278. DOI | PubMed
  6. Nybo Andersen AM, Wohlfahrt J, Christens P, et al. Maternal Age and Fetal Loss: Population-Based Register Linkage Study. BMJ. 2000;320:1708-1712. DOI | PubMed