Somewhere deep inside your pelvis, a microscopic miracle has just occurred: a tiny, primitive tube has begun to rhythmically contract. Your baby's heart is beating for the very first time. At roughly 80 to 100 beats per minute, it is actively pumping early blood cells through an intricate new circulatory system.
🍼 What's Happening With Your Baby
Now the size of a sesame seed, your baby is growing at a furious pace. The embryo has morphed from a flat disc into a distinct C-shape, resembling a tiny tadpole with a distinct head and tail.
The neural tube (the precursor to the brain and spinal cord) officially closes this week. If the tube fails to close completely, it results in neural tube defects like spina bifida — which is why folic acid is so critical right now.
Tiny buds are beginning to emerge on the sides of the embryo. Over the next few weeks, these tiny nubs will stretch out and articulate to become your baby's arms and legs.
🤰 What You're Feeling This Week
Welcome to the beginning of morning sickness. For many women, week 5 is when the nausea hits — and despite the name, it can strike at any hour of the day or night. This is caused by surging levels of hCG and estrogen.
You might suddenly find yourself making frantic dashes to the bathroom. This frequent urination isn't just from the uterus pressing on your bladder; your kidneys are actually expanding and working overtime to process the increased blood volume in your body.
Your sense of smell may become terrifyingly acute. An evolutionary mechanism believed to protect pregnant women from ingesting spoiled food, this 'super-smeller' ability often turns your favorite foods into instant nausea triggers.
The First Heartbeats
The cardiovascular system is the very first organ system to achieve functional state. Though it's just two primitive tubes fusing together, it is already pushing blood to sustain rapid cellular growth.
✅ What To Do This Week
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Switch to small, frequent meals — an empty stomach exacerbates nausea because stomach acids have nothing to digest. Keep plain crackers on your nightstand and eat a few before even getting out of bed.
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Check your cat litter protocol — if you have a cat, hand litter box duties over to your partner. Cat feces can carry Toxoplasmosis, a parasitic infection that is highly dangerous to a developing embryo.
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Avoid unpasteurized foods — steer clear of raw milk, soft unpasteurized cheeses, and raw sushi. Your immune system is naturally suppressed right now so it doesn't attack the embryo, making you highly susceptible to foodborne illnesses like Listeria.
"The nausea is brutal, but it's a profound biological signal. The hormones making you feel so sick are the exact same hormones securing the pregnancy and building the placenta. Your discomfort is literally building a life."
— A Note From Your Body, Week 5