Vernix caseosa

What is vernix caseosa?

Vernix caseosa is a waxy substance that coats and protects a baby's developing skin during the third trimester and after delivery. It's made up of water, dead skin cells and fat (sebaceous secretions). The name comes from Latin: Vernix means “varnish,” and caseosa means “cheesy.”

Babies, especially those who arrive before their due dates, are born with some amount of vernix on their skin. This coating may cover the skin, or it may just be found in the creases of the neck and between the fingers and toes.

What does vernix caseosa do?

Babies in the womb have very delicate, immature skin that's prone to dryness and irritation. Vernix acts as a barrier for babies' sensitive skin, locking in natural moisture and protecting against bacteria.

What are the benefits of vernix caseosa?

A barrier protecting baby's skin in utero and immediately after birth, vernix caseosa has several benefits.

Helps organs to form

Vernix cells slough off and mix with the amniotic fluid that baby swallows and practice “breathes” in utero. These cells contain amino acids and other substances that promote the growth of cells in the gastrointestinal tract. The substance also pairs up with surfactants to help the lungs function.

Keeps skin moisturized

Made up mostly of water and fatty substances, vernix coats baby's skin in utero to help keep it moisturized and hydrated as it develops and immediately after birth.

Regulates temperature

Evaporation of water from the skin helps you to cool down (it's why you sweat!). Because vernix helps prevent water loss, it helps keep newborns warmer – especially those born preterm, who tend to lose water through the skin faster.

Eases delivery

During delivery, vernix decreases friction as baby passes through the birth canal.

Defends against harmful microbes

Research suggests that vernix has antibiotic properties that bolster the skin's own microbiome, or community of friendly bacteria and other microorganisms, to help it defend against potentially harmful microbes.

Helps skin to heal

The special composition of vernix helps babies' skin to heal. In fact, researchers are investigating whether it's possible to make a vernix-like cream that could help both babies' and adults' skin heal from burns and injuries.

Should I delay my baby's first bath?

Hospitals used to immediately bathe babies after birth, but these days many practitioners are delaying that first dip. The World Health Organization recommends waiting at least 24 hours after birth, or six hours if a full day isn't possible for cultural reasons, before bathing your newborn.

Delaying baby's first bath supports baby's skin microbiome and protects against infection, according to the Association of Women's Obstetric, Health and Neonatal Nurses. It also helps decrease low blood sugar levels, weight loss and jaundice while keeping a newborn's body temperature stable.

How long should I let vernix stay on my baby?

Vernix caseosa usually absorbs into the skin on its own within 24 to 48 hours after birth, which is one reason the American Academy of Pediatrics recommends waiting a full day before giving your baby a bath.

That said, there's no need to wash off the vernix at any set point, according to the International Childbirth Education Association. Some parents bathe their babies for the first time after returning home from the hospital, whenever they feel ready.

Should I ever be concerned about vernix caseosa?

There's usually no reason to be concerned about vernix caseosa staying on your baby's skin after birth. However, healthcare providers bathe babies immediately after birth if a mother is positive for HIV or hepatitis C, to reduce the risk of viral transmission. A bath might also be recommended to lower the risk of bacterial infection if your baby has chorioamnionitis or meconium staining.