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🌱First Trimester•Weeks 1-13
Week 3 of Pregnancy
Your baby is the size of sesame seed
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Length
0.04 inches
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Weight
Less than 1 gram
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Size Comparison
Sesame seed
👶 Baby Development
- •The blastocyst burrows into your uterine lining during implantation, usually 6-12 days after fertilization
- •The cells divide into two distinct groups: the inner cell mass (which becomes your baby) and the outer layer (which becomes the placenta)
- •The amniotic sac begins forming around the embryo, which will fill with fluid to protect your baby
- •Your body starts producing human chorionic gonadotropin (hCG), the pregnancy hormone that pregnancy tests detect
- •The placenta begins developing to provide oxygen and nutrients to your growing baby
- •Three distinct layers form: ectoderm (nervous system, skin), mesoderm (heart, bones, muscles), and endoderm (digestive system, lungs)
💭 Common Symptoms
- •Possible light spotting or pinkish discharge from implantation bleeding (occurs in about 25% of pregnancies)
- •Mild cramping or twinges in your lower abdomen as the embryo implants
- •Early pregnancy may not be detectable yet on home pregnancy tests
- •Some women report feeling unusually tired or fatigued
- •Breast tenderness may begin as hormones start changing
- •You might experience mood swings due to rapidly increasing hormone levels
🥗 Nutrition Tips
- •Continue prenatal vitamins with 400-800 mcg of folic acid to support neural tube development
- •Eat iron-rich foods like lean red meat, chicken, spinach, and fortified cereals to prevent anemia
- •Include 1000mg of calcium daily from sources like yogurt, cheese, milk, and fortified plant milks
- •Stay hydrated with at least 8-10 glasses of water throughout the day
- •Eat protein-rich foods at every meal to support rapid cell division
- •Include vitamin C-rich foods like oranges, strawberries, and bell peppers to help with iron absorption
- •Avoid raw fish, soft cheeses, deli meats, and other foods that may carry listeria
✅ To-Do This Week
- •Watch for early pregnancy signs like breast tenderness, fatigue, and mild cramping
- •Continue taking prenatal vitamins daily, preferably at the same time each day
- •Completely avoid alcohol, smoking, and recreational drugs
- •Maintain a healthy, balanced diet with plenty of whole foods
- •Avoid cat litter boxes due to toxoplasmosis risk
- •Limit exposure to household chemicals and pesticides
- •Consider taking a home pregnancy test if your period is late
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Did You Know?
Implantation typically occurs 6-12 days after fertilization, which is when pregnancy truly begins. The moment implantation is complete, your body recognizes the pregnancy and starts producing hCG hormones.