• Skip to content
  • Skip to secondary menu
  • Skip to primary sidebar
  • Skip to footer
  • Home
  • Shop ModernMom
  • Become An Insider

ModernMom

The premiere destination for moms

  • Parenting
    • Pregnancy
    • Baby
    • Kids
    • Tweens and Teens
    • ModernMom Monday Videos
  • Cooking
  • Living Healthy
    • Breast Cancer
    • Health & Fitness
    • Body after Baby
    • Beauty
    • Relationships
    • Love
  • Lifestyle
    • Crafts
    • At Home
    • Education
    • Travel
    • Pets
    • Decorate
    • Money
    • Brooke Burke
  • Celebrate
    • Holidays
      • Easter
      • Valentine’s Day
      • New Year’s
      • Christmas
      • Hanukah
      • Halloween
      • Thanksgiving
    • Birthdays
    • Parties
  • Must Have
  • Contests
  • Entertainment

How to Calculate a Pregnancy Due Date

January 25, 2011 by ds_58890 Leave a Comment

The gestation of a human baby is considered to be 40 weeks. However, the average pregnancy lasts anywhere from 37 to 42 weeks. Yes, a normal pregnancy can last longer than nine months. This is often the first of many pregnancy surprises for first-time moms. Since only 5 percent of babies are born on their due date, according to the American Congress of Obstetricians and Gynecologists (ACOG), use this date as a general time line and not as something set in stone.

Step 1

Determine the first day of your last menstrual period. This would be the first day that you had red blood, not brown spotting.

Step 2

Count 40 weeks, or 280 days, on a calendar from the first day of your last menstrual period. Technically, you were not pregnant the first two or three weeks, but it is part of the calculation. Consider it a bonus that you have already finished the first month of pregnancy before you even knew you were pregnant.

Step 3

Use your estimated conception date to determine your due date if your cycle averages 30 days or longer. Add 266 days, or 38 weeks, to this conception date to estimate your due date. Conception would have occurred about 10 to 14 days before your expected next period. You may have felt some unusual cramping or had spotting at this time.

Comments

comments

Filed Under: Parenting

About ds_58890

Lynn Anders has more than 15 years of professional experience working with animals as a zookeeper and wildlife educator, and in pet rescue. Freelance writing since 2007, her work has appeared on websites such as Modern Mom and Trails, and includes pet-related topics, environmental issues and parenting matters. She has a Bachelor of Arts in environmental studies from Cal State University-Sacramento, and minored in biology.

Reader Interactions

Primary Sidebar

Tell a friend

  • Facebook
  • Instagram
  • Pinterest
  • Twitter
  • YouTube

Search

ModernMom Boutique

ModernMom TV

Featured

Third Child

I Want a Third Child, Except, I Really Don’t

Something strange has been happening to me lately:  I keep … [Read More...] about I Want a Third Child, Except, I Really Don’t

Must Have

ToniBox

Meet Toniebox – A Loveable Storytime Friend For Your Kids

If you are looking for something to occupy your children … [Read More...] about Meet Toniebox – A Loveable Storytime Friend For Your Kids

Did you know?

Baby Brain Development in the Womb

Refrigerate Fresh Lemon Juice

How Long Can You Refrigerate Fresh Lemon Juice?

Child Too Big for a Toddler Bed

When Is a Child Too Big for a Toddler Bed?

How to Help Young Kids Lose Weight

Signs of PMS or Pregnancy

abdominal discomfort during first trimester of pregnancy

Abdominal Discomfort During First Trimester of Pregnancy

How Soon After a C-Section Can I Get Pregnant Again?

Footer

  • About Us
  • Contact ModernMom
  • Advertise With Us
  • Press
  • Privacy Policy
  • Terms of Use
  • Contributors

Copyright © 2021 Modern Mom. All Rights Reserved.

Reproduction of any portion of this website only at the express permission of Mom, Inc.

The information provided on ModernMom is for educational use only. It should not be used as a substitute for professional medical advice, diagnosis or treatment.