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    Know Why Your Doctor May Change Your Due Date During Pregnancy

    Due Date

    Know Why Your Doctor May Change Your Due Date During Pregnancy

    Updated on 7 November 2022

    When your doctor announces the date that your little one would pop out of your tummy, aren't you over the moon? You start imagining all sorts of things and plan accordingly. But what happens when your doctor changes the due date? Changes in the due date is not uncommon and happens due to many reasons. But before that, how is the due date calculated?

    Your due date is calculated from the first day of your last period (or LMP) to the next 40 weeks. Your doctor chalks down a date at the end of the 40 weeks!

    What Changes Your Due date?

    The most common reasons why there could have been a mistake with the calculation of your due date are:

    Irregular periods

    If your periods are irregular, then how can your doctor depend on the first day of your last period? For women with irregular periods, an ultrasound is done to get an exact due date!

    First ultrasound in the second trimester

    If you got your first ultrasound during your second trimester instead of the first one, your due date is deemed to be inaccurate.

    A Doppler date

    Non-ultrasound confirmation of pregnancy is common. Maybe your doctor's timing was inaccurate because of this. (An early ultrasound, usually performed between 6 and 9 weeks, can provide the most precise due date estimation.)

    Your Fundal height is above average

    Each session will include a fundal measurement, which is the distance from the top of your pubic bone to the top of your uterus. Your uterine size may not match the normal growth charts (i.e., you measure big). If the measures are inaccurate by three weeks or more, your due date is often rescheduled.

    You have elevated AFP

    Between weeks 14 and 22, your doctor will likely order a blood test to check for AFP, or Alpha-fetoprotein, a protein ordinarily produced by your baby's liver and yolk sac. (Part of the quad screen.) While high levels of AFP can indicate a genetic defect, the most common cause is a missed due date.

    Twin Pregnancy

    Twin pregnancies can also be a cause of faulty due dates.

    Birth Control Pills

    If you got off the birth control pills right before you conceived, your due date could be incorrect.

    Due dates change, and there is nothing to worry about it. All you have to do is take care of yourself and your baby all the time and be positive!

    You may like: All You Need To Know About Pregnancy Due date Calculator (


    1. [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006. (2008). Pregnancy and birth: When your baby’s due date has passed. NCBI

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    Written by

    Mittali Khurana

    Mittali is a content writer by profession. She is a dynamic writer with 04+ years of experience in content writing for E-commerce, Parenting App & Websites, SEO.

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