4 Major Reasons Why a Woman’s Pregnancy Due Date Changes

4 Major Reasons Why a Woman’s Pregnancy Due Date Changes

There are a variety of factors that cause shifts in your due date. Read on to find out more.

Pregnancy due date changes are just one of the surprising things pregnancy can bring.

When your doctor gave you a due date, your mom-to-be mind surely started to anticipate the big day. You estimated when to start buying baby clothes, or mentally scheduled renovations to transform your study into a nursery. You may have even considered the perfect start date for your nanny.

But what if your doctor takes it all back and says it’s not your due date after all?

Don’t worry, pregnancy due date changes happen. Here are 4 major reasons why they do, and what these shifts can mean for your pregnancy.

Your pregnancy due date changes because you have irregular periods

Blood Loss During Period

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To estimate your date of delivery, your doctor will ask when your last menstrual period was.

For women with irregular cycles, this can be tricky. An irregular period is when your cycle lasts for more than 28 days.

To calculate your due date, it’s important to remember that the time from ovulation to your next menstruation is about 14 days. So if your cycle is 33 days long, then ovulation most likely happened on day 18.

If, for instance, your last menstrual period (LMP) was October 1, just add 21 days (October 22) and then subtract 14 days to find out your LMP (October 8).

To remove all confusion, some doctors may recommend an ultrasound exam during the first trimester to find out a fetus’ gestational age.

Your pregnancy due date changes because you had a second-trimester ultrasound

4 Major Reasons Why a Woman’s Pregnancy Due Date Changes

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A study by the American Journal of Obstetrics and Gynecology found that ultrasounds are done in the first trimester – or specifically until 13 weeks of pregnancy – are more accurate in predicting your due date.

If your pregnancy is the result of in vitro fertilization or IVF, your doctor will take into account the embryo’s age and the date of transfer to calculate your due date.

Your pregnancy due date changes because of an irregular fundal measurement

During every doctor’s visit, your fundal measurement will be examined. This examination gives a clearer picture of how far along you are, based on the size of your uterus.

When you are carrying a bigger or smaller than average baby, your predicted due date can change. After your fundal measurement, your doctor can adjust your due date accordingly.

Your pregnancy due date changes because of abnormal Alpha-fetoprotein levels

4 Major Reasons Why a Woman’s Pregnancy Due Date Changes

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Your alpha-fetoprotein (AFP) levels, which is a protein produced by your growing baby’s liver and yolk sac, is usually measured between week 14 and week 22. 

If your AFP level is high, it can mean your predicted due date is inaccurate.

In some cases, it means there is a chance your unborn child has a genetic abnormality.

Due date miscalculation can cause anxiety for most parents, but the important thing is to be prepared for the unexpected. This is, after all, a useful skill that parents can start honing even before their baby comes.

It’s true that you can’t plan every little thing about parenting. But you can prepare yourself for whenever your baby is ready to come out into the world!

sources: What to Expect, Healthline, ACOG

READ THIS ALSO: The 4 things you should do when you’re past your due date

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Written by

Bianchi Mendoza

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