Essential Pregnancy Terms Guide

Understanding key pregnancy terminology from preterm to post-term delivery. Learn when your baby is considered ready for birth and what each term means.

October 3, 2025
15 min read
Pregnancy Education

Why Understanding Pregnancy Terms Matters

As you progress through your pregnancy journey, you'll encounter various medical terms that describe different stages and timing of delivery. Understanding these terms helps you:

  • Better communicate with your healthcare provider
  • Understand your baby's development and readiness for birth
  • Know what to expect at different stages of pregnancy
  • Make informed decisions about your pregnancy care

Understanding Gestational Age

Before diving into specific terms, it's important to understand how pregnancy is measured.Gestational age is calculated from the first day of your last menstrual period (LMP), not from conception. A full-term pregnancy is considered 40 weeks of gestational age.

Key Point

Gestational age = Current date - First day of last menstrual period (LMP)

Essential Pregnancy Terms

Preterm (Premature)

Born before 37 weeks

Preterm birth occurs when a baby is born before completing 37 weeks of pregnancy. Preterm babies may need special medical care as their organs may not be fully developed.

Subcategories:

  • Extremely preterm: Less than 28 weeks
  • Very preterm: 28-32 weeks
  • Moderate to late preterm: 32-37 weeks

What This Means:

  • • May require NICU care
  • • Higher risk of complications
  • • Lungs may not be fully mature
  • • Special monitoring needed
  • • Often excellent long-term outcomes with care

Early Term

37 weeks 0 days - 38 weeks 6 days

Babies born during this period are considered "term" but on the earlier side. While generally healthy, they may have slightly higher risks compared to full-term babies.

Many healthcare providers now prefer to wait until at least 39 weeks for elective deliveries (like scheduled C-sections) unless there's a medical reason for earlier delivery.

What This Means:

  • • Generally healthy babies
  • • Slightly higher risk of breathing issues
  • • May have feeding challenges initially
  • • Usually no special care needed
  • • Close monitoring in first days

Full Term

39 weeks 0 days - 40 weeks 6 days

This is considered the optimal time for birth. Babies born during this period have the lowest risk of complications and the best outcomes. Their organs, especially the lungs and brain, are fully mature.

The traditional "due date" of 40 weeks falls within this range. Most spontaneous labors occur during this period.

What This Means:

  • • Optimal timing for birth
  • • Fully developed organs
  • • Lowest risk of complications
  • • Best feeding outcomes
  • • Excellent long-term development

Late Term

41 weeks 0 days - 41 weeks 6 days

Babies born during this period are still considered healthy, though they're past the traditional 40-week due date. Many healthcare providers begin increased monitoring during this time.

About 5-10% of pregnancies naturally extend into this period. While generally safe, some providers may discuss induction options.

What This Means:

  • • Still considered normal timing
  • • Increased monitoring recommended
  • • May discuss induction options
  • • Generally excellent outcomes
  • • Baby may be larger

Post-Term (Overdue)

42 weeks or more

Post-term pregnancies occur in about 3-5% of pregnancies. While many babies are born healthy, there are increased risks that require careful monitoring and often medical intervention.

Most healthcare providers will recommend induction by 42 weeks to reduce risks to both mother and baby.

What This Means:

  • • Requires close medical monitoring
  • • May need induction of labor
  • • Increased risk of complications
  • • Baby may be larger (macrosomia)
  • • Higher chance of C-section

Understanding Fetal Viability

Fetal viability refers to the ability of a fetus to survive outside the womb with medical support. This is an important concept in pregnancy care.

Key Milestones:

  • 22-24 weeks: Threshold of viability with intensive medical care
  • 28 weeks: Significantly improved survival rates
  • 32 weeks: Excellent survival rates with good outcomes
  • 37+ weeks: Considered term with minimal intervention needed

Important Factors:

  • • Lung development (surfactant production)
  • • Brain development and maturation
  • • Immune system development
  • • Temperature regulation ability
  • • Feeding and digestive capabilities

Pregnancy Timeline Summary

Less than 37 weeks:Preterm (Premature)
37-38 weeks 6 days:Early Term
39-40 weeks 6 days:Full Term (Optimal)
41-41 weeks 6 days:Late Term
42+ weeks:Post-Term (Overdue)

Key Takeaways for Expecting Parents

Remember:

  • Every pregnancy is unique - these are guidelines
  • 39-40 weeks is the optimal time for birth
  • Your healthcare provider will monitor you closely
  • Most babies are born healthy regardless of exact timing

When to Contact Your Provider:

  • Signs of preterm labor before 37 weeks
  • Decreased baby movement at any stage
  • Any concerning symptoms or changes
  • Questions about your pregnancy timeline

Related Articles

Stay Informed Throughout Your Pregnancy

Get weekly pregnancy updates, essential health tips, and important milestone reminders delivered to your inbox. Join thousands of expecting parents on their journey.

No spam, unsubscribe at any time. We respect your privacy.