Week 1
Your baby is the size of a Poppy seed
Baby Size
Poppy seed
Length
—
Weight
—
Trimester
First Trimester
Your Baby at Week 1
Week 1 of pregnancy is counted from the first day of your last menstrual period. You're not technically pregnant yet, but your body is preparing for the incredible journey ahead.
Key milestone: Your body begins preparing for ovulation. The uterine lining thickens.
Your Symptoms
Menstrual period. Cramping, bloating, fatigue.
Tip for This Week
Start taking prenatal vitamins with folic acid if you haven't already.
Your Body at Week 1
During the first trimester, your body is working overtime to build the placenta and support rapid embryonic development. Hormones like hCG, estrogen, and progesterone surge, causing many of the symptoms you're experiencing. Your blood volume is already increasing, and your uterus is beginning to expand — even if you can't see it yet.
Your baby at week 1 is the size of a Poppy seed, measuring about — and weighing roughly —. The focus is on forming all major organ systems that will sustain your baby through the rest of pregnancy and beyond.
Your Baby's Development This Week
Week 1 of pregnancy is counted from the first day of your last menstrual period. You're not technically pregnant yet, but your body is preparing for the incredible journey ahead. The key milestone this week is that your body begins preparing for ovulation. the uterine lining thickens.
The first trimester is a period of incredible transformation. From a single cell to a fully formed fetus in just 12 weeks — your baby's development is happening at an astonishing pace. Each week brings new organs, new abilities, and new reasons to marvel at the process.
This week's voice theme
“A whisper of anticipation — the journey is just beginning.”
Imagine hearing this every morning — a voice note from your baby that evolves week by week.
Hear your baby's voice →Frequently Asked Questions
Am I actually pregnant in week 1?
Technically no — week 1 is counted from the first day of your last period. Conception hasn't happened yet, but your body is preparing for ovulation.
What should I do during week 1 of pregnancy?
Start taking prenatal vitamins with folic acid, track your cycle, and begin preparing your body for pregnancy.
Can I take a pregnancy test at week 1?
No — it's too early. Pregnancy tests detect hCG, which isn't produced until after implantation (around week 4).