Pregnancy Week 4: Symptoms, Baby Size & What to Expect

Your Baby at Week 4

Your baby measures roughly the size of a poppy seed and weighs about <1g. The major developments this week: Neural tube forming, heart begins to beat around day 22.

Your baby's heart starts beating just 22 days after conception — before most women even know they're pregnant.

Symptoms at Week 4

Common symptoms during week 4 of pregnancy include: Missed period, light spotting (implantation bleeding in ~25% of pregnancies), fatigue, breast tenderness, frequent urination, mild cramping.

Remember that every pregnancy is unique — you may experience all, some, or none of these symptoms. If anything feels unusual or concerning, don't hesitate to contact your healthcare provider.

📖 Also read: Pregnancy Sleep Problems Solutions | Best App Pregnancy Tracker

What to Do This Week

Start prenatal vitamins with at least 400mcg folic acid. Schedule your first prenatal appointment for around week 8. Avoid alcohol, raw fish, and limit caffeine to 200mg/day.

Nutrition & Wellness

Staying well-nourished is crucial at every stage of pregnancy. Focus on folate-rich foods (leafy greens, lentils, fortified cereals), iron (lean meats, beans, spinach), calcium (dairy, fortified plant milks), and omega-3 fatty acids (salmon, walnuts, flaxseed). Stay hydrated with at least 8-10 glasses of water daily.

Frequently Asked Questions

Is it normal to feel [symptom] at week 4?

Yes, most symptoms at week 4 are completely normal. Common experiences include Missed period and light spotting (implantation bleeding in ~25% of pregnancies). However, contact your doctor if you experience severe pain, heavy bleeding, or persistent vomiting that prevents you from keeping fluids down.

How big is my baby at 4 weeks?

At week 4, your baby is approximately the size of a poppy seed, weighing about <1g. Neural tube forming.

What should I avoid at week 4 of pregnancy?

Continue avoiding alcohol, raw/undercooked meats and fish, unpasteurized dairy, high-mercury fish (shark, swordfish, king mackerel), deli meats unless heated until steaming, and limit caffeine to under 200mg per day.