During pregnancy, your baby grows and develops at a remarkable pace. It’s important to know what’s happening week by week, so you can take care of yourself and your growing baby. Here’s a guide to your baby’s development during pregnancy, week by week.
Table of Contents
Week 1-2: Conception and Implantation
During the first two weeks of pregnancy, your baby is just a tiny ball of cells. The egg is fertilized by sperm, and the resulting zygote travels down the fallopian tube to the uterus. Once there, it implants into the uterine wall.
Week 3-4: Embryo Development
During weeks three and four, your baby is still only a few cells, but it’s growing rapidly. The cells divide and differentiate into different types of cells, forming the embryo. The placenta also starts to form, which will provide nourishment to the growing embryo.
Week 5-6: Heartbeat Begins
By week five, your baby is about the size of a grain of rice. The heart starts to beat, and blood begins to circulate. The brain, spinal cord, and other organs also start to form. By the end of week six, your baby is about the size of a lentil.
Week 7-8: Limbs Form
During weeks seven and eight, your baby’s limbs start to form. Fingers and toes begin to separate, and the face starts to take shape. The eyes move from the sides of the head to the front, and the ears start to form.
Week 9-10: Teeth and Bones Develop
By week nine, your baby is about an inch long. Teeth and bones start to develop, and the fingers and toes are fully formed. The digestive system also starts to work. By the end of week ten, your baby is about the size of a strawberry.
Week 11-12: Movement Begins
During weeks eleven and twelve, your baby’s movements become more coordinated. The face looks more human-like, and the ears are fully formed. The kidneys start to work, and the baby starts to produce urine. By the end of week twelve, your baby is about the size of a plum.
Week 13-14: Gender Revealed
By week thirteen, your baby is about three inches long. The gender can be determined by ultrasound. The baby’s skin is transparent, and the veins are visible. The bones start to harden, and the baby can make facial expressions. By the end of week fourteen, your baby is about the size of a lemon.
Week 15-16: Senses Develop
During weeks fifteen and sixteen, your baby’s senses start to develop. The eyes can detect light, and the ears can hear sounds. The baby’s hair and nails start to grow. The baby also starts to move more, and you may be able to feel the movements. By the end of week sixteen, your baby is about the size of an avocado.
Week 17-18: Baby’s Skin Thickens
By week seventeen, your baby is about five inches long. The baby’s skin starts to thicken, and fat starts to accumulate. The baby can hiccup, and you may be able to feel it. By the end of week eighteen, your baby is about the size of a bell pepper.
Week 19-20: Baby’s Movements Increase
During weeks nineteen and twenty, your baby’s movements become more frequent and stronger. The baby’s skin is covered in a waxy substance called vernix, which helps protect it. The baby’s eyebrows and eyelashes start to grow. By the end of week twenty, your baby is about the size of a banana.
Week 21-22: Baby’s Organs Mature
By week twenty-one, your baby is about ten inches long. The baby’s organs are maturing, and the lungs start to produce surfactant, which helps them inflate. The baby’s taste buds start to develop. By the end of week twenty-two, your baby is about the size of a papaya.
Week 23-24: Baby’s Brain Develops
During weeks twenty-three and twenty-four, your baby’s brain continues to develop. The baby’s skin is less transparent, and the lungs are almost fully mature. The baby’s movements are more coordinated, and the baby can hear sounds more clearly. By the end of week twenty-four, your baby is about the size of an ear of corn.
Week 25-26: Baby’s Eyes Open
By week twenty-five, your baby is about a foot long. The baby’s eyes open, and the baby can blink. The baby’s lungs continue to mature. By the end of week twenty-six, your baby is about the size of a head of lettuce.
Week 27-28: Baby’s Sleep-Wake Cycle
During weeks twenty-seven and twenty-eight, your baby’s sleep-wake cycle starts to develop. The baby’s brain is developing rapidly. The baby’s eyelashes are fully formed, and the hair on the head is getting thicker. By the end of week twenty-eight, your baby is about the size of an eggplant.
Week 29-30: Baby’s Immune System Develops
By week twenty-nine, your baby is about fifteen inches long. The baby’s immune system is developing, and the baby is producing antibodies. The baby’s skin becomes smoother, and the eyes can focus more. By the end of week thirty, your baby is about the size of a large cabbage.
Week 31-32: Baby’s Bones Harden
During weeks thirty-one and thirty-two, your baby’s bones start to harden. The baby’s brain is developing rapidly, and the baby can control body temperature. The baby also starts to practice breathing. By the end of week thirty-two, your baby is about the size of a jicama.
Week 33-34: Baby’s Nervous System Develops
By week thirty-three,