-
Week 5
Deep in your uterus your embryo is growing at a furious pace. At this point, he's about the size of a sesame seed, and he looks more like a tiny tadpole than a human. He's now made up of three layers — the ectoderm, the mesoderm, and the endoderm — which will later form all of his organs and tissues -
week 8
Webbed fingers and toes are poking out from your baby's hands and feet, his eyelids practically cover his eyes, breathing tubes extend from his throat to the branches of his developing lungs, and his "tail" is just about gone. In his brain, nerve cells are branching out to connect with one another, forming primitive neural pathways -
week 11
Your baby, just over 1 1/2 inches long and about the size of a fig, is now almost fully formed. Her hands will soon open and close into fists, tiny tooth buds are beginning to appear under her gums, and some of her bones are beginning to harden. -
week 16
In the next few weeks, your baby will double his weight and add inches to his length. Right now, he's about the size of an avocado: 4 1/2 inches long (head to rump) and 3 1/2 ounces. His legs are much more developed, his head is more erect than it has been, and his eyes have moved closer to the front of his head. His ears are close to their final position, too. The patterning of his scalp has begun, though his locks aren't recognizable yet. He's even started growing toenaiIs -
week 20
Your baby weighs about 10 1/2 ounces now. He's also around 6 1/2 inches long from head to bottom and about 10 inches from head to heel — the length of a banana. (For the first 20 weeks, when a baby's legs are curled up against his torso and hard to measure, measurements are taken from the top of his head to his bottom — the "crown to rump" measurement. -
week 23
With her sense of movement well developed by now, your baby can feel you dance. And now that she's more than 11 inches long and weighs just over a pound (about as much as a large mango), you may be able to see her squirm underneath your clothes. Blood vessels in her lungs are developing to prepare for breathing, and the sounds that your baby's increasingly keen ears pick up are preparing her for entry into the outside world. Loud noises that become familiar now. -
week 28
By this week, your baby weighs two and a quarter pounds (like a Chinese cabbage) and measures 14.8 inches from the top of her head to her heels. She can blink her eyes, which now sport lashes. With her eyesight developing, she may be able to see the light that filters in through your womb. She's also developing billions of neurons in her brain and adding more body fat in preparation for life in the outside world. -
week 32
By now, your baby weighs 3.75 pounds and is about 16.7 inches long, taking up a lot of space in your uterus. You're gaining about a pound a week and roughly half of that goes right to your baby. In fact, she'll gain a third to half of her birth weight during the next 7 weeks as she fattens up for survival outside the womb. She now has toenails, fingernails, and real hair (or at least respectable peach fuzz). Her skin is becoming soft and smooth as she plumps up in preparation for birth. -
Week 35
Your baby doesn't have much room to maneuver now that he's over 18 inches long and tips the scales at 5 1/4 pounds because it's so snug in your womb, he isn't likely to be doing somersaults anymore, but the number of times he kicks should remain about the same. His kidneys are fully developed now, and his liver can process some waste products. Most of his basic physical development is now complete — he'll spend the next few weeks putting on weight. -
week 40
It's hard to say for sure how big your baby will be, but the average newborn weighs about 7 1/2 pounds and is about 20 inches long. His skull bones are not yet fused, which allows them to overlap a bit if it's a snug fit through the birth canal during labor. This so-called "molding" is the reason your baby's noggin may look a little conehead-ish after birth.
