Share:
Glossary Health & Fitness

Gestational age

Gestational age is how far along a pregnancy is, counted in weeks and days from the first day of the last menstrual period.

Last reviewed:

AdSense Placeholder
Slot: header_reference_page

In more detail

A full-term pregnancy is 40 weeks (280 days), and conception happens roughly 14 days after the last period, so 38 weeks pregnant means 36 weeks since conception. The trimesters begin at 0, 14 and 28 weeks. See How Pregnancy Due Dates Are Calculated.

Try these tools

Pregnancy Calculator

Calculate your due date, current gestational age, and trimester milestones from your last menstrual period.

Due Date Calculator

Calculate your estimated due date from your last period, conception date, IVF transfer date, or an ultrasound scan.

Pregnancy Weight Gain Calculator

Calculate your recommended total pregnancy weight gain range and weekly gain rate based on your pre-pregnancy BMI, using IOM guidelines.

See also

  • Glossary Ovulation
    Ovulation is the release of an egg from an ovary, which happens about 14 days before the next period.
  • Guide How Pregnancy Due Dates Are Calculated
    The 280-day rule from the last period, conception, IVF and ultrasound dating, ovulation and fertile days.
Back to Glossary
AdSense Placeholder
Slot: footer_leaderboard