First Trimester
Weeks 1–12
The first trimester is the most transformative period of pregnancy. In just 12 weeks, your baby grows from a single fertilized cell to a fully formed fetus with a beating heart, recognizable facial features, and all major organs in place. Meanwhile, your body undergoes enormous hormonal changes that may cause symptoms like nausea, fatigue, and breast tenderness.
Week by Week
Week 4
Poppy Seed
Implantation occurs
Week 5
Sesame Seed
Heart begins forming
Week 6
Lentil
Facial features start
Week 7
Blueberry
Brain grows rapidly
Week 8
Raspberry
Baby moves for the first time
Week 9
Cherry
Now officially a fetus!
Week 10
Strawberry
Fingers & toes formed
Week 11
Fig
Baby is acrobatic!
Week 12
Lime
Risk of miscarriage drops significantly
Key Milestones
Implantation & Heart Formation
The embryo implants in the uterine wall and the primitive heart begins to beat by week 5-6, at a rate of 80-160 bpm.
Facial Features & Limb Buds
Tiny dots mark the future eyes and nostrils. Arm and leg buds appear. The brain is growing at an incredible rate of ~100 new cells per minute.
Spontaneous Movement
Your baby begins making spontaneous movements that you can't yet feel. Fingers are starting to separate and eyelids are forming.
Embryo → Fetus
This is the official graduation! All essential organs have begun forming. Your baby is now called a fetus rather than an embryo.
Fully Formed
All vital organs are formed and starting to function. Fingernails and toenails begin growing. Bones start to harden.
Risk Drops Significantly
The risk of miscarriage drops dramatically at 12 weeks. Most parents choose to share their pregnancy news around this time.
Common First Trimester Symptoms
Morning Sickness
Affects ~75% of pregnant women; peaks around week 8-9. Try small, frequent meals and ginger tea.
Extreme Fatigue
Your body is building an entire placenta! Rest when you can and accept that fatigue is normal.
Breast Tenderness
Breasts become sore and swollen due to hormonal changes. A supportive bra helps.
Frequent Urination
hCG hormone increases blood flow to the kidneys. Stay hydrated but reduce fluids before bed.
Food Aversions
Strong smell sensitivity and food aversions are very common. Eat whatever you can tolerate.
Mood Swings
Surging hormones cause emotional ups and downs. This is completely normal and will ease.
Light Spotting
Implantation bleeding (week 4) is normal. Any heavier bleeding warrants a call to your doctor.
Bloating & Cramping
Mild uterine cramping as it expands, plus digestive changes, are common in early pregnancy.