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First Trimester
First trimester will last about 12 weeks -
Week 3
- The baby-in-the-making is a ball of cells called a blastocyst.
- The blastocyst already contains a full set of DNA.
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Week 4
The ball of cells has officially become an embryo and is about the size of a poppy seed. Over the next six weeks, all of the baby's organs will begin to develop, and some will start to function. -
Week 5
The baby's tiny heart begins to beat – at twice the rate of the average human being. Its entire body is only about the size of a sesame seed. -
Week 6
- Facial features, like eyes and nostrils,begin to form.
- Little buds appear where arms and legs will develop.
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Week 8
- Arms and legs are growing, and the baby now has little fingers, as well as a nose and upper lip.
- The baby will start moving but the mother will not be able to feel it.
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Week 9
Eyes have developed, though the baby's eyelids but are fused shut for now. The baby is starting to look more human. -
Week 10
The embryo has become a fetus.
-The baby's vital organs – such as kidneys, intestines, brain, and liver – are starting to function. Tiny fingernails and toenails are forming. -
Week 11
- The baby is almost fully formed.
- The baby's bones are beginning to harden, and its genitalia are developing externally.
- The baby can also hiccup, however it's too soon for the mother to feel it.
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Week 12
- The baby's heartbeat can be heard through an ultrasound.
- The baby will be about just over 2 inches long and will weigh about half an ounce.
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Week 14
The baby's kidneys are producing urine, and it releases it into the amniotic fluid. It can make facial expressions and may have discovered thumb-sucking. -
Second Trimester
Second Trimester lasts 13 weeks. -
Week 15
The baby can see the light that filters in from outside the mother's womb. However, the baby's eyelids at this point are still shut. -
Week 16
-The baby's baby's sex may be detectable.
- Gender is typically detectable between weeks 16 and 20. -
Week 18
-Around this time the mother can start to feel the baby moving inside her.
-It'll take a couple of weeks longer for other people to feel the baby's movements from the outside. -
Week 19
- The baby can hear the mother's heartbeat and sounds that come from outside her body, such as her partner's voice.
- The baby might even be startled by a loud noise.
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Week 23
- The baby's sense of movement has developed, so it can feel the motion of the mother moving or dancing.
- The baby's sense of hearing continues to improve.
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Week 24
The baby's taste buds are developing. The baby's brain is growing very quickly, and its hair may be growing. It is almost a foot long and weighs just over a pound. -
Week 27
The baby's been doing "practice breathing" by inhaling and exhaling amniotic fluid, and if it was born now its lungs could function. The baby can also open and close its eyes. -
Third Trimester
Third Trimester will last 12 weeks. -
Week 28
The baby may be dreaming. It has eyelashes and its eyesight is improving. The baby now weighs about 2 1/4 pounds and is about 15 inches long, head to heel. -
Week 32
The baby's grown little fingernails and toenails. Its almost 17 inches long, head to heel, and weighs about 3 3/4 pounds. -
Week 37
The baby is now considered full-term. Its lungs should work fine if it were to be born now, but ideally the baby should stay in the womb a bit longer. -
Week 40
The baby is due and fully ready for life outside the womb. The average weight of a newborn is about 7 1/2 pounds, and the average length is about 20 inches.
