What Is the Vernix and Why Is It Important?

If you’ve ever seen a just-born baby, you might’ve noticed that his skin is covered in cheesy, white clumps or patches. What is this stuff — and when your little one comes into the world, should you leave it there or clean it off right away?

That strange coating is called the vernix caseosa, and it’s actually good for your baby (and maybe even you, too). Here’s a look at what the vernix does, why it's important and why you might want to leave it on your newborn's skin for a little while longer.

What is the vernix caseosa and what does it do?

The vernix caseosa is a greasy, cheese-like coating that covers babies’ skin during their time in the womb. It’s made up of shed skin cells and sebaceous secretions. That might sound a little yucky, but the vernix actually serves an important function: It protects your sweet pea’s fragile skin from getting pickled by amniotic fluid in utero.  

The vernix typically shows up around week 19 of pregnancy and continues to thicken until week 34. The coating starts to slough off into the amniotic fluid itself a few weeks later, and your baby swallows it. (Isn’t Mother Nature fascinating?) By week 40, the vernix is mostly gone.

Babies born earlier tend to have more vernix than those born later. If your little one arrives a few weeks before his due date, he might still be well coated. If he’s born on time, he might only have a little bit of vernix left in the folds of his skin or under his nails. If he’s born late, he might not have any vernix left at all (and his skin might be wrinkled or peeling as a result, but don’t worry — it’s temporary!).

What are the benefits of the vernix caseosa?

The vernix caseosa helps form a barrier between your baby’s skin and the surrounding amniotic fluid. Its primary role is to protect and hydrate, kind of like a heavy-duty moisturizer. But it’s thought to have other benefits too:

• During pregnancy: The vernix your baby swallows may also help nourish his developing gut bacteria.
• During labor: Vernix’s greasy, oily texture could serve as a natural lubricant to minimize friction as your baby makes his way down the birth canal.
• After delivery: Vernix can continue to protect your baby’s skin by helping it retain moisture and stave off bacterial infections. It might help babies latch on too. The scent of vernix might be involved in triggering neural connections in babies’ brains needed for breastfeeding.
• For moms: Vernix contains compounds thought to promote perineal wound healing, so it may aid in recovery for vaginal births.

Should you delay baby’s first bath at the hospital?

Bathing immediately after birth used to be seen as the best thing for babies. But more and more hospitals are changing that practice. Today it’s becoming increasingly common to delay that first bath. That keeps the vernix on a baby’s skin for a while longer. It also gives more time for skin-to-skin contact in those first few hours after birth.

So should you hold off on the bath? The World Health Organization (WHO) recommends waiting at least six hours — and if you can go a full 24 hours, even better. Whatever you choose, just note it on your birth plan along with any other important decisions so the nurse doesn’t accidentally bathe your baby sooner.

How long should you let the vernix stay on your baby?

WHO recommends leaving the vernix on your baby for at least six hours, and preferably 24. As for an upper limit? There’s no official recommendation.

According to the International Childbirth Education Association, there’s no set time by when you have to bathe your baby. So do what makes you feel comfortable. And if you’re not sure or feel like you need some guidance, ask your baby’s pediatrician.

Are there any risks associated with leaving the vernix on your baby after birth?

There’s usually no downside to leaving the vernix on your baby after he’s born. But there are some exceptions. Babies born with chorioamnionitis or meconium staining need to be bathed right after delivery to reduce the risk of bacterial infection. Babies born to moms who have transmissible viral diseases (like HIV or hepatitis) should also be bathed ASAP.

The vernix caseosa might look a bit off-putting. But it protects your baby while he’s in the womb — and can provide some valuable benefits to both of you during and after delivery. So consider leaving it on your newborn's skin for a little while after birth, if possible. You can always clean him up for a cuter newborn photo session on day two!