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    Pregnancy Due Dates Calculator

    Calculates pregnancy dates, forward from last period or backward from due date.
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    INSTRUCTIONS

    Enter last menstrual period (LMP), current gestational age (GA), OR expected due date to determine the other two, plus estimated date of conception.

    When to Use

    Patients who are pregnant or may be pregnant.

    Result:

    Please fill out required fields.

    Next Steps
    Evidence
    Creator Insights

    Critical Actions

    Use to track and estimate pregnancy.

    Formula

    To calculate pregnancy due date from LMP:

    • Determine last date of LMP
    • Add 40 weeks to the date
    • Add another 7 days to the date 40 weeks from the LMP
    Dr. Frank A. Chervenak

    About the Creator

    Leading expert on the Pregnancy Due Dates calculator:

    Frank A. Chervenak, MD, is a professor, chief OB-GYN and chairman of the Department of Obstetrics and Gynecology at the New York Presbyterian Hospital. He is the author of “How Accurate Is Fetal Biometry in the Assessment of Fetal Age”, a comparative study of the gestational age prediction equation for singletons, twins and triplets with other pregnancy prediction formulas. Dr. Chervenak has published 250+ papers and co-authored/edited textbooks on topics including ultrasound and ethics in obstetrics and gynecology and physician leadership.

    To view Dr. Frank A. Chervenak's publications, visit PubMed