Baby skin: development of your baby’s skin, hair and nails

Your baby’s soft, smooth skin is his body’s largest organ. During pregnancy, your baby’s skin grows into the amniotic fluid inside your uterus. It is a warm and comfortable home for them.

After birth, your baby’s skin goes through subtle changes that help it adapt to the new world around it. A baby develops skin in the womb very early on, and her hair and nails are not far behind.

Read on to learn more about babies’ skin, hair and nails – and the best ways to encourage their healthy development during pregnancy.

Development of baby skin in the womb

just 5 weeks pregnant, your little embryo is made up of three layers. The top layer, called the ectoderm, will grow into the outermost layer of the baby’s skin (the epidermis), its central and peripheral nervous system, eyes and inner ears.

At first, your baby’s skin is so thin and translucent that you can see the blood vessels underneath. During week 13, baby’s skin is still thin, but by week 16 it becomes thicker. When you are 18 weeks pregnant, the layers of skin have finished forming. As your baby approaches birth, the skin becomes thicker and more opaque, but it remains delicate and very soft.

At around 19 weeks pregnant, your baby has developed vernix, a greasy, cheese-like coating that coats her skin. It protects baby’s delicate skin from constant exposure to amniotic fluid. Without the vernix, your baby would be exposed to waste and other irritants that could cause abrasions, cracking and hardening of the skin.

Many babies are born with patches of vernix stuck to their skin. Rather than washing it off immediately, most experts now recommend waiting 24 hours after birth to bathe a baby, which gives the vernix time to absorb into the skin and provides extra protection against germs, water loss and temperature changes. If it is not possible to wait 24 hours, experts suggest waiting at least six hours.

Ridges form in the palms of the baby’s hands and on the soles of the feet during week 23. These ridges will later develop into unique baby fingerprints and footprints. (Even identical twins or multiples that share the same DNA do not have perfectly identical fingerprints, as factors beyond genetics come into play in fingerprint formation.)

During week 24, baby’s skin is wrinkled. It is also translucent and pink or red due to visible blood vessels. After the second trimester ends at 27 weeks, babies continue to gain more fat, which helps their skin look smoother.

At 35 weeks, baby’s skin becomes smooth as at birth. They’re also getting chubpier now, which makes them even cuter, just in time to meet you.

When do babies acquire their skin color?

From 6 to 8 weeks pregnant, the cells that will later produce melanin – the substance that explains skin color – first appear in your baby’s skin. The more melanin that is produced (a process regulated by genes), the darker your baby’s skin, eyes and hair will generally be.

When a baby is born, its skin is dark red to purple in color. When they breathe air, the color changes to red, which usually fades on the first day. A newborn’s hands and feet may initially appear blue as their circulatory system adjusts to the outside world. Newborns can also have milia – tiny white bumps on the nose, cheeks, chin and forehead – as well as vernix, lanugo, baby acne and various birthmarks.

Babies of dark-skinned parents may appear noticeably lighter than their parents at birth, then darken over time. Melanin production increases, darkening your baby’s skin and providing a degree of protection from the sun’s ultraviolet rays – protection your baby didn’t need in the womb. Your baby’s permanent complexion will probably be fully developed around 6 months.

Development of baby’s nails in the womb

The development of the baby’s nails in the womb begins in the first trimester. Baby nails form at 12 weeks of pregnancy. And then at 17 weeks, baby’s nails start to grow.

During your third trimester, baby’s fingernails and toenails have become much longer. Baby nails reach the tips of their fingers at 34 weeks, and baby nails are right behind, reaching the tips of their toes at 38 weeks. (Prepare those baby nail clippers!)

Development of baby hair in the womb

The formation of hair buds occurs in the eighth week of pregnancy and the hair follicles appear in week 10.

During the second trimester, at 15 weeks pregnant, the hair follicles on your baby’s scalp begin to form the pattern you’ll see on her sweet little head at birth – whether it’s just fluff peach or full hair. Between 16 and 20 weeks of pregnancy, hair follicles have formed in the skin of various parts of your baby’s body, including the eyebrows, back and shoulders. Some of the fine hair that grows here – called lanugo – helps maintain the varnish on the skin and will fall off during the first weeks of life.

And at 21 weeks, baby is completely covered in lanugo. Babies lose lanugo before birth around 33 to 36 weeks, but about a third of babies are born with it. Premature babies are more likely to have lanugo at birth. If your baby was born with it, it should go away on its own over time.

Around 22 weeks, your baby’s hair and eyebrows are visible. Indeed, at 30 weeks of pregnancy, your baby could already have beautiful hair.

How to support the development of your baby’s skin, hair and nails

Eating well during pregnancy and taking Prenatal vitamins help support the growth and development of your baby’s skin. Vitamin D in particular is essential for healthy skin. Pregnant women can drink milk fortified with vitamin D and eat fatty fish like salmon once a week. Obtain safe exposure in the sun is also helpful. Talk to your healthcare provider to make sure you eat a balanced diet and take the recommended amount of vitamins and minerals each day.

The key stages of your baby’s skin

weeks of pregnancy Milestone
5 weeks The skin begins to form.
18 weeks The layers of skin have finished forming.
19 weeks Vernix coats the skin.
21 weeks Lanugo completely covers baby’s body.
23 weeks Fingerprints and footprints begin to form.
24 weeks Baby’s skin is wrinkled, translucent, and pink to red in color.
35 weeks The skin becomes smooth.
after birth Melanin production increases, darkening the skin.

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Patricia J. Callender