A newborn's shoulders and hips are wide, the abdomen protrudes slightly, and the arms and legs are relatively long with respect to the rest of their body.
Head A newborn's head is very large in proportion to the body, and the
cranium is enormous relative to their face. While the adult human skull is about one seventh of the total body length, the newborn's is about . Normal head circumference for a full-term infant is 33–36 cm at birth. At birth, many regions of the newborn's skull have not yet been converted to bone, leaving "soft spots" known as
fontanels. The two largest are the diamond-shaped anterior fontanel, located at the top front portion of the head, and the smaller triangular-shaped posterior fontanel, which lies at the back of the head. Later in the child's life, these bones will fuse together in a natural process. A protein called
noggin is responsible for the delay in an infant's skull fusion. During
labour and birth, the infant's skull changes shape to fit through the
birth canal, sometimes causing the child to be born with a misshapen or elongated head. It will usually return to normal on its own within a few days or weeks. Special exercises sometimes advised by
physicians may assist the process.
Hair Some newborns have a fine, downy body hair called
lanugo. It may be particularly noticeable on the back, shoulders, forehead, ears and face of premature infants. Lanugo disappears within a few weeks. Infants may be born with full heads of hair; others, particularly
Caucasian infants, may have very fine hair or may even be bald. Amongst fair-skinned parents, this fine hair may be blonde, even if the parents are not. An infant's hair color and texture can change: red can give way to blond, curly can go straight, and thick, dark hair could reappear a lot sparser and lighter. The
scalp may also be temporarily
bruised or swollen, especially in hairless newborns, and the area around the eyes may be puffy.
Length In
developed countries, the average total body length of a newborn is , although premature newborns may be much smaller. The way to measure a baby's length is to lay the baby down and stretch a measuring tape from the top of the head to the bottom of the heel.
Weight In developed countries, the average
birth weight of a full-term newborn is approximately , and is typically in the range of . Over the first 5–7 days following birth, the body weight of a term neonate decreases by 3–7%, and is largely a result of the resorption and urination of the fluid that initially fills the lungs, in addition to a delay of often a few days before
breastfeeding becomes effective. After the first week, healthy term neonates should gain 10–20 grams/kg/day.
Skin .
Amniotic fluid glistens on her skin, and the
umbilical cord is still attached.|left Immediately after birth, a newborn's skin is often grayish to dusky blue in color. As soon as the newborn begins to breathe, usually within a minute or two, the skin's color reaches its normal tone. Newborns are wet, covered in streaks of blood, and coated with a white substance known as
vernix caseosa, which is hypothesised to act as an
antibacterial barrier. The newborn may also have
Mongolian spots, various other
birthmarks, or peeling skin, particularly on the wrists, hands, ankles, and feet.
Umbilical cord The
umbilical cord of a newborn is bluish-white in color. After birth, the umbilical cord is normally cut, leaving a 1–2 inch stub. The umbilical stub will dry out, shrivel, darken, and spontaneously fall off within about 3 weeks. This will later become a belly-button after it heals. The umbilical cord contains three vessels: two arteries and one vein. The two arteries carry blood from the baby to the placenta while one vein carries blood back to the baby.
Genitals A newborn's
genitals are enlarged and reddened, with male infants having an unusually large
scrotum. The breasts may also be enlarged, even in male infants. This is caused by naturally occurring maternal hormones and is a temporary condition. Females (and sometimes males) may actually discharge milk from their nipples (sometimes called
witch's milk), or a bloody or milky-like substance from the vagina. In either case, this is considered normal and will disappear with time. ==Care and feeding==