Pregnancy Development Stages

Pregnancy is divided into three distinct stages: the first trimester, second trimester, and third trimester. Vital fetal growth and development happens in each of them, and your body also changes along the way. Check out our guide on pregnancy stages to learn about ultrasounds, important prenatal tests, fetal development, health concerns, about more.
Illustration of a baby's heartbeat
When Can You Hear a Baby's Heartbeat?
mom holding pregnant belly
Your First Trimester of Pregnancy, Week-by-Week
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Your Second Trimester, Week-by-Week
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Your Third Trimester of Pregnancy, Week-by-Week
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How Big Is Your Baby in Third Trimester?
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When does a fetus start to move?
Mom on kitchen floor
Enjoy Those First Kicks
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At what rate is it normal for babies to grow during pregnancy?
How Big Is Your Baby Measuring Pregnant Belly
How Big Is Your Baby in Second Trimester?
Week 22
What Is a 3D Ultrasound?
Close up of indian man feeling pregnant woman stomach. Smiling mid adult couple expecting child while father touching baby bump. Close up hands of happy expectant mixed race couple feeling baby movement.
Normal Fetal Movement During Pregnancy
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Why isn't my baby kicking?
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Is it normal not to find my baby's heart rate at 8 weeks of pregnancy?
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Can my baby taste before she's born?
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Why do I keep crying during pregnancy?
morning sickness
Handling a Tough First Trimester of Pregnancy
pregnant woman typing on computer
9 Strange Pregnancy Symptoms
pregnant woman in bed
Understanding HCG Levels in Pregnancy
Colorful fruits and vegetables
What to Eat in the First Trimester of Pregnancy
mom and dad first trimester
What to Expect in the First Trimester
pregnant mom holding baby sneakers
7 Reasons Pregnancy is Good for You
pregnant woman getting vaccine in doctors office
What Happens When You Get a RhoGAM Shot
Zika virus testing
Why Doctors Test for Rh Factor During Pregnancy
pregnant woman at prenatal visit
What Is NIPT, or Noninvasive Prenatal Testing?
blood samples ready for testing in a lab
What is Rhesus Disease and How Does it Affect Pregnancy?
Heartburn During Pregnancy
How to Relieve Heartburn During Pregnancy
miscarriage sign
Can You Have a Miscarriage at 16 Weeks Pregnant?
Pregnant Woman in Pink Top Looking at Stomach
What to Expect in the Second Trimester
healthy eating
Glucose Tests During Pregnancy: What to Expect
Couple's Hands Making Heart Shape on Pregnant Belly
What to Expect in Your Third Trimester
5 Foods That Cause Heartburn During Pregnancy_still
5 Foods That Cause Heartburn During Pregnancy—And 5 That Don't
third trimester tests
Third Trimester Tests
Pregnant Woman with Doctor Listening to Belly
Should You Get Amniocentesis?
Sperm Meets Egg: Weeks 1 to 3 of Pregnancy
A Special Look at First Trimester Ultrasound Pictures
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Your Baby's Alertness in the Womb
Second Trimester Begins: Weeks 13 to 17 of Pregnancy
Second Trimester Ultrasound Pictures
Sleep Cycles: Weeks 26 to 30 of Pregnancy
Third Trimester Ultrasound Pictures
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Twins: A Closer Look at Your Developing Babies
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Fetal Development Weeks 9 Through 13
Week 35
Week 35 Ultrasound: What It Would Look Like
Week 37
Week 37 Ultrasound: What It Would Look Like
Week 9
9 Week Ultrasound: What It Would Look Like
Week 18
Week 18 Ultrasound: What It Would Look Like
Week 20
Week 20 Ultrasound: What It Would Look Like
Week 14
Week 14 Ultrasound: What It Would Look Like
Week 39
Week 39 Ultrasound: What It Would Look Like
Feeling Baby Move: Weeks 18 to 21 of Pregnancy
What Do Baby Kicks Feel Like (And Answers to Other Common Questions)
Week 21
Week 21 Ultrasound: What It Would Look Like
Week 7
Week 7 Ultrasound: What It Would Look Like
A pregnant couple feeling fetal kicks
Quickening in Pregnancy: Feeling the First Fetal Kicks
Week 12
Week 12 Ultrasound: What It Would Look Like
Week 26
Week 26 Ultrasound: What It Would Look Like
Week 10
Week 10 Ultrasound: What It Would Look Like
Week 11
Week 11 Ultrasound: What It Would Look Like
Sperm swimming to egg
The Inside Story: Your Baby in Weeks 1 Through 4
Week 32
Week 32 Ultrasound: What It Would Look Like
Week 5
Week 5 Ultrasound: What It Would Look Like
Week 23
Week 23 Ultrasound: What It Would Look Like
Week 36
Week 36 Ultrasound: What It Would Look Like
Week 15
Week 15 Ultrasound: What It Would Look Like
Week 16
Week 16 Ultrasound: What It Would Look Like
Week 28
Week 28 Ultrasound: What It Would Look Like
Week 8
Week 8 Ultrasound: What It Would Look Like