The neural tube starts forming

Your baby is rapidly developing

Right now, your baby is a tiny disc of cells called an embryo, but they're building the blueprint for every organ they'll ever have. The neural tube, which becomes the brain and spinal cord, starts forming now. By week's end, their heart will begin dividing into chambers.

Your body is working hard too. HCG hormone levels spike this week, which is what makes pregnancy tests turn positive. Progesterone rises to keep the uterine lining thick and cozy, and your blood volume starts its slow increase to eventually support the placenta.

What's happening inside

• Three distinct layers form this week: the ectoderm (brain, skin, nails), mesoderm (heart, bones, muscles), and endoderm (lungs, digestive system).
• Primitive placenta begins. Tiny finger-like projections called chorionic villi form, which will eventually connect to your blood supply.
• Yolk sac does the work. Before the placenta takes over around week 10, this sack provides nutrients and makes blood cells for your baby.

It's incredible to think something so small is already so complex. That sesame seed-sized bundle holds the entire genetic code for who they'll become, eye color, height, even personality traits are all written in those rapidly dividing cells.

Early symptoms and things to watch

This week is all about those early whispers of pregnancy, when symptoms might be subtle or surprisingly strong already. Some people feel completely normal, while others notice tender breasts, fatigue, or mild cramping as the embryo implants deeper.

• Implantation cramping. A twinge or dull ache (like period cramps) is common as your uterus stretches. Call your provider if it's severe one-sided pain or comes with heavy bleeding.
• Spotting vs. bleeding. Light pink or brown spotting can be normal, but bright red blood filling a pad isn't. Always check in about bleeding.
• Aversion city. Suddenly repulsed by coffee or your favorite food? Your sense of smell is on high alert thanks to rising hormones.

Pregnancy tests are most reliable after your missed period. Early tests can give false negatives if hCG levels aren't high enough yet to detect. The 'two week wait' feels endless, but waiting until at least day 12–14 past ovulation cuts confusion.

Appointments and planning ahead

While it's still early for most appointments, this week is prime time to call and schedule prenatal care if you haven't yet. Many providers aim to see you between weeks 8–10 for that first official ultrasound.

• Prenatal vitamins. If you're not already taking one with at least 400 mcg folic acid, start today. It's crucial for preventing neural tube defects as your baby's spine forms this week.
• Your first ultrasound isn't likely yet (most happen around 8 weeks), but some providers offer early scans if you have a history of pregnancy complications.
• Dating confusion? Early ultrasounds are the most accurate for estimating your due date. Last menstrual period dating can be off by days or weeks if your cycle isn't textbook.