Vernix caseosa function

Babies are often born covered in a creamy-looking substance called vernix caseosa, a protective film that benefits sensitive newborn skin. Read on to learn more about what vernix is, what its function is, why some babies are born with the coating still on, and when you should first bathe your baby if your little one was born with lots of vernix still on.

What Is Vernix Caseosa?

Vernix caseosa, or vernix for short, is a white, cheesy-looking substance that coats the skin of your baby while in the uterus. Some babies are born with some of this protective coating still on the skin. The meaning of the name vernix caseosa is “varnish of a cheesy nature.” During your pregnancy, vernix plays an essential role, acting as a waterproof barrier to protect your baby’s skin against the amniotic fluid that surrounds her until she is born. A naturally occurring biofilm, vernix begins to cover your baby’s skin during the second trimester. The sebaceous glands — which are responsible for producing oil in the skin —begin to produce the vernix coating at around 17 weeks of pregnancy.

Vernix caseosa is simply a creamy, greasy substance mostly composed of water, lipids, and proteins. It contains enzymes and other innate immune proteins that have antibacterial properties.

What Are the Benefits of Vernix Caseosa?

You can think of vernix caseosa as a protective layer for your baby’s skin. It helps shield his delicate skin from abrasions, chapping, and hardening that could be caused by prolonged exposure to amniotic fluid, and it also has some benefits for your baby after birth.

The Benefits of Vernix Caseosa in the Womb

Before your baby is born, vernix caseosa’s function in utero is to:

  • Protect the fetus from damaging substances, like urea and electrolytes, in the amniotic fluid.

  • Help with thermoregulation.

During a vaginal delivery, vernix acts as a lubricant and a protective biofilm, and also acts as an antimicrobial cover against any bacteria in the genital tract.

The Benefits of Vernix Caseosa After Birth

Vernix also has a few benefits for your baby after she is born:

  • It acts as a natural moisturizer. Vernix could help prevent your newborn’s skin from becoming dry. Its high water content helps lock moisture into the skin and reduces moisture loss.

  • It may have antibacterial properties. Vernix could protect your newborn baby from getting a skin infection shortly after birth.

  • It has antioxidant properties. Vernix contains antioxidants like vitamin E and melanin, which help slow down cell damage due to free radicals.

When to Wash the Vernix Off

In the past, most hospitals and birthing centers would bathe babies within an hour or two of birth. Now, however, this practice is changing, as more is known about the benefits of vernix and the benefits of postponing the first bath. When your baby is born, he’ll be covered in amniotic fluid, perhaps some blood, and potentially some vernix. It’s natural to want to bathe your baby, but you may also be wondering whether there are benefits in leaving the vernix on for longer, especially given all its benefits. The World Health Organization (WHO) recommends waiting at least 6 hours before bathing the newborn baby and ideally waiting about 24 hours. The WHO also recommends not wiping off the vernix at birth.

The main reasons to wait with your baby’s first bath include:

  • Keeping your little one warm and stabilizing blood sugar levels. Babies who are bathed too soon after birth are more likely to become cold and could develop hypothermia. The stress of having a bath right after birth could also cause a drop in blood sugar levels.

  • Allowing time for breastfeeding and bonding. The “golden hour” period right after you give birth is great for skin-to-skin contact and parent-child bonding. This shared time can also help with early breastfeeding. In fact, one study found a 166 percent increase in hospital breastfeeding success when infants were bathed 12 hours or more after birth compared to those babies who were bathed within hours of birth.

  • Helping prevent dry skin. Leaving vernix on the skin for a few hours can help keep newborn skin supple and hydrated.

How Long Can You Leave Vernix Caseosa on Your Baby?

The WHO recommends leaving vernix on your baby’s skin for at least 6 hours but preferably 24 hours.

If you’re considering leaving it on for longer, ask your baby’s healthcare provider how long it remains beneficial to leave the vernix coating on your baby’s skin and how long to wait with your little one’s first bath.

What Is Lanugo?

Other than vernix, you might also notice a layer of downy hair on your baby’s skin at birth — this is called lanugo.

Lanugo covered your baby’s skin during the latter part of your pregnancy and is usually shed before birth. The presence of lanugo while your baby was in the womb helped the vernix stick to the skin. Lanugo is actually the first type of hair your baby has! About 30 percent of babies are born with some lanugo still present. It's more likely to be present if your little one is born prematurely. If your baby was born with some lanugo still on, it usually sheds within a week or two.

The Bottom Line

Vernix caseosa has lots of benefits for your baby both when he is still in the womb and in the hours after birth. If you can, wait six hours or more before bathing your little one. This won’t just have benefits for your baby’s skin, but it also gives you more time to focus on bonding, skin-to-skin contact, and even on breastfeeding if this is something you would like to try. Although you might think it’s a little icky and sticky to leave the vernix on, its beneficial properties are important for your baby, and it won’t be long before you’ll have your freshly washed baby skin to kiss and cuddle. In the meantime, wrap your baby in a soft blanket and enjoy these unforgettable first few hours with your baby, safe in the knowledge that the coating of vernix is also working to protect your baby’s delicate skin. For more information on baby skin care, read up on caring for delicate newborn skin.