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Sign InWeek 3 — The Magic Moment
Overall Pregnancy
Your Baby is About
smaller than a grain of sand
Fertilisation happens this week. One sperm out of hundreds of millions penetrates the egg, and in that instant your baby's complete genetic blueprint is locked in — eye colour, hair colour, blood type, and more. The fertilised egg (now called a zygote) immediately starts dividing as it travels down the fallopian tube toward the uterus. By the end of the week, it's a ball of around 100 cells called a blastocyst.
The zygote divides rapidly — from 1 cell to 2, 4, 8, 16, and so on. The outer cells will become the placenta; the inner cells will become your baby. The blastocyst arrives at the uterus around Day 5–6 after fertilisation and spends a couple of days floating before implanting. A pregnancy test won't show positive yet — hCG isn't high enough.
Out of the 200–300 million sperm that set off, only about 200 make it anywhere near the egg — and just one gets through. That single successful sperm determined half of everything about your baby: their sex, one copy of every gene they'll ever have, and characteristics that may not show up for decades. One in 300 million. Your baby was already a long shot, and they made it.
Keep taking your prenatal vitamins and avoid alcohol entirely from this point — even before a positive test, the earliest stages of development are sensitive to alcohol exposure. If you smoke, now is the time to stop. The support line for quitting smoking during pregnancy is worth a call if you need help.
Zinc supports healthy sperm and early cell division. Good sources include pumpkin seeds, chickpeas, beef, and cashews.
Fertilisation just happened — this is a good moment for partners to cut out alcohol too, in solidarity and because it makes things easier at home.
This content is for informational purposes only and is not medical advice. Always consult your healthcare provider for guidance specific to your situation. Read full disclaimer