Medical Disclaimer

Please read this disclaimer carefully before using any tool on My Baby Math.

Important Notice

The tools and information on this website are for informational purposes only and do not constitute medical advice, diagnosis, or treatment. The results provided by our calculators are statistical estimates and may not reflect your individual clinical situation.

Always consult a qualified healthcare provider — such as an OB-GYN, certified nurse-midwife, or family physician — before making any decisions about your pregnancy or health.

1. Estimates Only

Our pregnancy calculators produce statistical estimates based on standardized clinical formulas applied to population-level data. This means:

  • Population averages, not individual predictions: The formulas used in our calculators were developed from large population studies. They represent averages and statistical norms, not predictions for any individual pregnancy.
  • Individual variation is significant: Every pregnancy is different. Cycle length, ovulation timing, embryo development rates, and many other biological factors vary from person to person. Our calculators cannot account for your individual biology.
  • Input accuracy matters: Our calculators rely on the accuracy of the dates and information you provide. If you are uncertain about the date of your last menstrual period or have irregular cycles, results will be less precise.
  • Estimates are not guarantees: A calculated due date is an estimate, not a commitment. A calculated implantation window is a statistical range, not a certainty.

2. Not a Substitute for Professional Medical Care

Our calculators are not a substitute for prenatal care, clinical evaluation, or the professional judgment of a licensed healthcare provider. This is not a formality — it is a meaningful distinction that can affect your health outcomes.

  • Always establish care with a provider: If you believe you may be pregnant, establishing care with an OB-GYN, certified nurse-midwife, or other qualified provider is the most important step you can take. No calculator replaces that relationship.
  • Ultrasound dating is more accurate: Clinical dating of a pregnancy via ultrasound — particularly a first-trimester ultrasound performed by a qualified sonographer — is significantly more accurate than any calculator. Your provider's clinical assessment always takes precedence over our estimates.
  • We do not know your full history: Your healthcare provider has access to your complete medical history, can perform physical examinations, order and interpret laboratory tests, and consider factors our calculators cannot assess. We have none of that information.
  • Do not delay care based on calculator results: If you have concerns about your pregnancy, do not wait for a calculator to confirm or allay them. Contact your healthcare provider.

3. IVF-Specific Notice

For patients who have undergone in vitro fertilization (IVF), assisted reproductive technology (ART), frozen embryo transfer (FET), or other fertility treatments, additional guidance applies:

  • Follow your RE's guidance: Your reproductive endocrinologist (RE) and their clinical team have detailed information about your embryo quality, transfer conditions, and clinical history that no calculator can replicate. They are the authoritative source for your due date, pregnancy milestones, and clinical management.
  • IVF dating is more precise — and more complex: Because the date of egg retrieval, fertilization, and transfer are known precisely in IVF cycles, dating can in principle be more accurate. However, the interaction of embryo developmental stage (Day 3 vs. Day 5 transfer), freeze-thaw cycles, and individual endometrial response introduces complexities that require clinical oversight.
  • Our IVF calculator is a general reference: Our IVF due date calculator uses standard assumptions. Your clinic may use slightly different conventions or may have specific clinical information that affects your individual dating. Always confirm with your clinic.
  • Monitor beta hCG with your provider: Beta hCG (human chorionic gonadotropin) monitoring in early IVF pregnancies must be interpreted by your clinical team. Do not use our calculators to interpret hCG trends.

4. When to Seek Immediate Medical Help

Call 911 or go to your nearest emergency room immediately if you experience any of the following:

  • Heavy vaginal bleeding — soaking more than one pad per hour, or any bleeding with clots or tissue
  • Severe abdominal or pelvic pain — particularly if sharp, one-sided, or accompanied by shoulder pain
  • Signs of ectopic pregnancy — sharp pain on one side of the abdomen, vaginal bleeding, dizziness, or fainting, particularly in early pregnancy
  • Signs of miscarriage — cramping with bleeding, passage of tissue
  • Reduced or absent fetal movement — after 28 weeks of pregnancy, if you notice a significant decrease in your baby's movements
  • Signs of preeclampsia — sudden severe headache, vision changes, swelling of face or hands, upper abdominal pain, or sudden weight gain
  • Signs of preterm labor — regular contractions before 37 weeks, pressure in the pelvis, low back pain, or fluid leaking from the vagina before 37 weeks
  • High fever — any fever above 100.4°F (38°C) during pregnancy

This list is not exhaustive. If you are ever uncertain about a symptom during pregnancy, contact your healthcare provider or seek emergency care. It is always better to be evaluated and reassured than to wait.

5. Accuracy Limitations of Due Date Estimates

It is important to understand the inherent limitations of any due date estimate, including those produced by our calculators:

  • Only about 5% of babies are born on their estimated due date (EDD). The EDD is a statistical midpoint, not a precise prediction. Healthy, full-term deliveries occur throughout the window from 37 to 42 weeks of gestation.
  • Naegele's Rule, the standard 280-day calculation, assumes a 28-day cycle with ovulation on Day 14. In reality, cycle length and ovulation timing vary considerably. Women with longer or shorter cycles, or irregular ovulation, will have less accurate results from standard LMP-based calculators.
  • First trimester ultrasound dating is considered the clinical gold standard for gestational age assessment, more accurate than LMP-based calculation alone. After 20 weeks, ultrasound dating becomes less precise.
  • Embryonic development timing varies. Standard developmental milestones (heartbeat detection, organ formation timing) represent averages with meaningful variation between individual pregnancies.

6. Contact Your Healthcare Provider If...

Beyond emergencies requiring immediate care, contact your OB-GYN, midwife, or healthcare provider promptly if you experience any of the following:

  • Any vaginal bleeding or spotting at any point in pregnancy
  • Persistent nausea and vomiting preventing you from keeping fluids down
  • Burning or pain with urination (may indicate a urinary tract infection, which requires treatment in pregnancy)
  • A fever of 100.4°F (38°C) or higher
  • Signs of a vaginal infection or unusual discharge
  • Persistent headaches that do not resolve with rest or acetaminophen
  • Swelling in your hands, face, or feet — particularly if sudden or severe
  • Any symptom that worries you, even if it does not appear on this list — trust your instincts

This is not a complete list. During pregnancy, you have a healthcare provider for a reason — do not hesitate to use that relationship.

7. Emergency Resources

  • Emergency services: Call 911 (United States) for any life-threatening emergency.
  • Your OB-GYN or midwife: Most obstetric practices have an on-call provider available after hours for urgent questions. Keep their after-hours number saved in your phone.
  • Hospital labor and delivery triage: Your delivery hospital's labor and delivery unit can often advise you on whether to come in for evaluation. This is an appropriate first call for non-emergency concerns that arise outside of office hours.
  • Nurse advice lines: Many health insurance plans offer 24-hour nurse hotlines. Check your insurance card or member portal for the number. A registered nurse can help you assess whether a symptom requires immediate attention.
  • Poison Control: 1-800-222-1222 (United States) — for concerns about medication exposures or accidental ingestion during pregnancy.

Our Pregnancy Calculators

With these limitations in mind, our calculators are still useful as general reference tools to help you prepare for conversations with your healthcare provider. Use them as a starting point, not a final answer.