What Is Vernix Caseosa? And Why Is It Important for Your Newborn?

When your baby is born, you may notice a white substance covering their skin. This is the vernix caseosa, a coating that develops to protect your child while they are in the womb. But the role of the vernix caseosa goes beyond protection in utero, with benefits for your child’s health in their early days outside the womb. While giving a baby their first bath can remove this coating, there may be reason to delay removal of this beneficial substance.

What Is Vernix Caseosa?

During the third trimester of pregnancy, a greasy, cheese-like covering — the vernix caseosa — begins to cover your baby. This substance helps protect the baby’s delicate skin while they are in the womb. Without it, exposure to abrasions, chapping, and hardening because of the amniotic fluid may occur. That’s why the development of the vernix caseosa is such a significant step.

Vernix caseosa is a complex, proteolipid. In utero, it is made in part by the baby’s sebaceous glands. It is composed of 80% water, 10% protein, and 10% lipids including barrier lipids. 

The term vernix caseosa first appeared in 1846 in the Dunglison dictionary of Medical Sciences. It literally translates to “varnish with a cheesy nature.”

Vernix Caseosa Functions

The vernix caseosa is responsible for protecting the baby’s skin in the womb, but it also has several functions at birth.

For Thermal Regulation

Vernix caseosa helps newborns handle temperature regulation. This is very important because once a baby is born, they face an abrupt drop in surrounding temperature. Keeping the vernix caseosa on your baby’s skin can help them stabilize their body temperature and slowly adjust to the temperature of their new environment. 

To Prevent Water Loss

Newborn babies have an immature epidermal barrier. That epidermal barrier does not have a stratum corneum (the outermost layer of the epidermis) that is strong enough. And as a result, they may suffer from excessive water loss through the skin. The vernix caseosa can help to prevent this.

Antimicrobial Benefits and More

Newborns deal with high oxidative stress, exposure to outside toxins, and the rapid onset of potentially harmful microbes. Vernix has many benefits that can protect your baby with regard to adjusting to several factors in their new environment. It is:

• a cleanser
• a moisturizer
• an anti-infective
• an antioxidant

Vernix caseosa also facilitates acid mantle formation and contributes to good bacterial colonization of newborn skin after birth.

A 2005 study states that the vernix may actually be left in place at birth. It should be viewed as a naturally occurring cream that may facilitate a baby’s adaptation to a dry environment.

Even though many hospitals may offer to give a baby their first bath soon after birth, parents may choose to delay this bath to keep the vernix in place. Nurses may remove blood and amniotic fluid with a soft cloth. And there is usually no need to give a newborn a bath so soon after delivery.

24 to 48 hours should be enough for your newborn to benefit from the vernix, but some parents choose to delay the child’s first bath for longer. Over these days, you may gently massage the vernix caseosa into your baby’s skin.

Key Takeaways

The vernix caseosa performs several important functions aside from protecting a fetus in the womb. The white, creamy, naturally occurring biofilm covers the skin of the fetus during the final trimester and also prepares the fetus for life outside the uterus. It provides a barrier that prevents water loss, regulates temperature, and provides protection against harmful microbes.

Due to these many benefits, parents may choose to delay giving their child a bath for a couple of days or even more.

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