A mother can expect her body to prepare for the baby in the first weeks, as the cells of the baby form, according to What To Expect. In weeks four and five, the cells split into the placenta, embryo and a circulatory system.
In week five, a mother's hormones elevate enough to detect pregnancy, according to What To Expect. In weeks six and seven, baby's face and brain are growing, as are the mother's breasts. The baby moves and builds muscle, bones and cartilage during week eight, nine and 10. In weeks 11 through 13, a baby bump appears when baby grows to peach size.
During weeks 14 through 16, baby grows hair, kicks his legs and develops eyesight, says What To Expect. In weeks 17 through 19, baby starts to practice movements required to suckle, while the mother's hormones and backaches increase. In week 19, baby grows outer skin layers, while week 20 reveals gender. In weeks 21 through 24, baby grows rapidly, as do the mother's foot and belly size. The second trimester lasts through week 27, as baby begins breathing and opening eyes, while the mother endures insomnia.
In week 28, baby blinks and dreams, according to What To Expect. Braxton Hicks contractions begin in week 32, while the mother's sight becomes duller in week 34. In week 35, baby's brain becomes heavy, putting pressure on the mother's bladder. In weeks 37 through 40, baby turns, the mother's body produces colostrum and the birth canal begins contracting.