Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Women's Health

Font Size

Estimating Your Due Date

If you know when your baby was conceived, you may have already estimated your baby's due date. At your first prenatal exam, your health care provider will ask questions to try to predict your due date as precisely as possible.

Knowing your baby's due date will help your provider monitor your baby's growth more accurately. Because certain laboratory tests change throughout your pregnancy, knowing an accurate due date will also allow your provider to better track these tests, and, if it occurs, to manage preterm labor.

Recommended Related to Women

Top Women’s Health Stories of 2008: Readers’ Choice

Are you normal? That’s a question on a lot of women’s minds when it comes to personal health. It was also a good year for beating belly fat and finding ways to fight fatigue. Those topics are among the most viewed women’s health stories on WebMD for 2008. 5 Things You Didn't Know About Your Period How to Handle Embarrassing Problems 5 Home Remedy No-Nos Vaginal Problems That Affect Your Sex Life Banish the Bags Under Your Eyes ...

Read the Top Women’s Health Stories of 2008: Readers’ Choice article > >

How Is My Due Date Determined?

Normally, your due date is 280 days (40 weeks or about 10 months -- also known as 10 lunar months) from the first day of your last period. However, if your periods are not regular or are not 28 days apart, your due date may be different from the "280-day rule." Your health care provider may order an ultrasound to more accurately determine your due date.

If you are certain of your conception date (the date when you got pregnant), please tell your health care provider. This information can be helpful in determining your estimated date of delivery (EDD).

A full-term pregnancy ranges from 37 weeks to 40 weeks and 6 days, so your actual date of delivery can be different from your estimated date of delivery, which is sometimes called estimated date of confinement, or EDC. A very small number of babies are actually born on their due dates. Typically, only 5% percent of women deliver on their due date.

WebMD Medical Reference

Reviewed by Kecia Gaither, MD, MPH on September 20, 2014

Today on WebMD

hands on abdomen
Test your knowledge.
womans hand on abdomen
Are you ready for baby?
birth control pills
Learn about your options.
Is it menopause or something else?
woman in bathtub
bp app on smartwatch and phone
estrogen gene

Send yourself a link to download the app.

Loading ...

Please wait...

This feature is temporarily unavailable. Please try again later.


Now check your email account on your mobile phone to download your new app.

Blood pressure check
hot water bottle on stomach
Attractive young woman standing in front of mirror