Gestational age is one of the most important pieces of information to learn about your pregnancy.

Whether you are considering abortion, adoption, or parenting, you need to know your pregnancy’s gestational age before making your decision. It may affect your options, as well as your health needs.

If you are experiencing an unexpected pregnancy, here’s what you need to know about gestational age.

What is gestational age? 

Gestational age refers to the number of weeks and days that have passed since your pregnancy began. 

When measuring your pregnancy’s age, we consider conception (when the fertilized egg implanted into the wall of your uterus) the moment your pregnancy began. It’s impossible to know the exact date of a natural conception, so we calculate gestational age using the first day of your last menstrual period.


You can only get your period when you aren’t pregnant. Most women get pregnant during their fertile window, which usually occurs about two weeks after your period starts.

What is Gestational Age

Basing your gestational age on the date of your last cycle offers a rough estimate of your pregnancy’s actual age. That said, there are several factors that can affect this calculation, including:

  • An irregular menstrual cycle – If you don’t have a typical 28-day cycle (and most women don’t), you may have become pregnant sooner or later than two weeks after your last period.
  • Pregnancy bleeding – Some women have implantation bleeding at the time of conception. You may also have bleeding during the early weeks of your pregnancy. Sometimes, women mistake this bleeding for their last period. When this happens, your pregnancy may be days or weeks farther along than you think.
  • Remembering the wrong date – It’s easy to forget the exact first day of your last period, especially if it was several months ago. If you use the wrong date for your calculations, your gestational age will be wrong as well.

Thankfully, we can accurately determine your gestational age by measuring your pregnancy with ultrasound technology. During an ultrasound, the sonographer will use the size of the embryo to determine your actual gestational age.

Doctors rely on this method because it is much more accurate and reliable than using your last menstrual period. 

If you haven’t yet, schedule an appointment to get a pregnancy ultrasound to learn how far along you are.

Why does gestational age matter?

1. It affects your pregnancy options

It Affects Your Pregnancy Options

Your pregnancy options, particularly abortion, change depending on your gestational age.

For example, the FDA only allows women to take the abortion pill if they are less than 11 weeks along. If you are farther along, you have a higher risk of serious complications such as hemorrhage, incomplete abortion, and infection.

Your health needs change as your pregnancy progresses. It’s important to get proper care for your health and pregnancy, especially the farther along you are.

2. It can help identify a miscarriage

During your ultrasound, the sonographer will measure the embryo to determine your pregnancy’s gestational age. She will measure the embryo from the top of its head to the bottom of its buttocks. This is known as the crown-rump length (CRL).

At the early stages of pregnancy, genetics do not yet play a part and nearly all embryos are the same size at each week of gestation. This allows the sonographer to use the CRL to determine how far along you are.

These measurements will also show if your pregnancy is progressing as expected. If the embryo or yolk sac is measuring too small, for instance, you may be having a miscarriage. Abnormal measurements may also indicate a health issue with the embryo.

It’s important to see a doctor for further testing, care, and answers after your free ultrasound.

3. It can help you plan for your future

Before you can make a decision about your pregnancy, you need information. Your gestational age clarifies your options and offers a timeline for your decisions.

You may be tempted to make a quick choice, but a rushed decision is one you may regret.

Instead, start with an appointment at Thrive Orlando. You can confirm your pregnancy, learn how far along you are, and get information about all your options.

Armed with this knowledge, you can then figure out the best choice for your pregnancy. You can feel empowered and confident in the decision you make.

It Can Help You Plan for Your Future

Learn your gestational age today

Your appointment at our women’s healthcare clinic will only take about an hour. You’ll receive a confirmation pregnancy test, ultrasound, and possibly STD testing and treatment. During your appointment, you can also talk to a patient advocate and registered nurse about any questions you have about your options and pregnancy.

Best of all, our pregnancy services are completely free!

Come see us for your unplanned pregnancy care today!

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