Vernix caseosa function

Vernix caseosa, or just vernix for short is a waxy white substance some babies are covered in at birth. This sticky film provides a number of protective benefits for your newborn.

Learn more about what vernix is and what its function is, why some babies are born covered in vernix and when you should first bathe your baby if they were covered in vernix at birth.

What Is Vernix Caseosa?

Vernix caseosa, or vernix for short, is a white, sticky substance that covers your baby’s skin while in the womb. It acts as a natural moisturiser that helps protect your little one against infection in the first few days.

Vernix plays a crucial role throughout pregnancy by acting as a barrier to protect your foetus’s skin against the amniotic fluid that surrounds them. It also allows the foetus to move around inside your uterus without chafing the skin.

Vernix begins to cover your baby’s skin during the second trimester. At around 20 weeks of pregnancy, your baby will be covered from head to toe in a white, greasy layer of vernix. During the rest of your pregnancy, the thickness of the vernix layer will increase to reach its peak at 36-38 weeks. By around 40 weeks it is mainly found in the skin creases. Your baby may come out covered in vernix, or it may already be mostly gone by the time they greet the world.

What Are the Benefits of Vernix Caseosa?

The vernix acts as a protective layer for your foetus’s skin in the womb. It helps shield delicate skin from damage that could be caused by prolonged exposure to amniotic fluid, and it also has some benefits for your baby after birth.

Besides helping your newborn to adapt to the dry environment outside of the womb, vernix also helps with the development of the skin’s protective layer known as the ‘acid mantle’. This gives your baby’s skin extra immunity and protection against germs.

Vernix also has acts as a natural moisturiser after birth, locking moisture into the skin to help keep it supple and hydrated. In addition to this, it may have antibacterial properties. Vernix may also have the power to boost your newborn’s protection against infection in the first few days.

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Is It OK to Wash Vernix Off?

Experts advise leaving the vernix to be absorbed naturally unless it is drying and causing sore areas in cracks or fissures. In fact, it’s OK to wait up to 2 to 3 days before giving your baby their first bath.

When your baby is born, they will come out covered in amniotic fluid, perhaps some of your blood, and potentially some vernix. You may find yourself feeling the urge to wash your baby. But you may be interested to know that leaving the vernix on for longer allows your little one to continue benefitting from it.

There’s no need to worry about the mess – it’s better for your baby to be warm than clean. If it does bother you, your midwife can dry your little one and wrap them up in a blanket so you can really enjoy cuddling your newborn.

If your baby is overdue, you may find that their skin is cracked or dry. This is entirely normal as the vernix has all been absorbed by this point. It’s best to avoid reaching for creams and lotions, especially in the first month, as they could actually make things worse. Within a few days the top layer of your baby’s skin will peel off naturally to reveal soft, brand new skin underneath.

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

  • Keeping your little one warm and stabilising blood sugar levels. Research suggests that delaying a baby’s bath until 24 hours after birth may have a positive effect on temperature regulation and blood sugar levels.

  • Allowing time for breastfeeding and bonding. The ‘golden hour’ right after you give birth is great for skin-to-skin contact and parent-child bonding. This time together isn’t just comforting, it comes with many proven benefits for your baby, including reducing the risk of eczema and certain skin allergies, reducing stress and making it easier to start breastfeeding.

  • Helping prevent dry skin. Leaving vernix on the skin until it’s naturally absorbed can help keep newborn skin supple and hydrated.

How Long Can You Leave Vernix Caseosa on Your Baby?

Experts advise keeping the vernix intact on your baby’s skin for as long as possible. It is harmless to your baby and will naturally disappear over the first few days – there is no need to try and remove it.

Sometimes ‘sticky eyes’ encountered after birth can be caused by vernix irritating the eye. However, this can usually be solved with regular eye care. Let your midwife or doctor know if your little one seems to be experiencing sticky eyes.

What Is Lanugo?

Your baby isn’t just protected by vernix at birth. You may also find your little one is covered in a layer of downy hair when born, otherwise known as lanugo.

Lanugo starts to cover your baby’s skin at around 21 weeks pregnant and usually disappears before birth. The purpose of lanugo is not fully understood, but it is thought to help keep your baby at the right temperature in the uterus.

Although lanugo doesn’t usually last until birth, some babies are born with small patches of it here and there. If your little one greets the world with some lanugo still on, it will usually be shed within a week or two.

FAQS AT A GLANCE

  • No. Experts advise keeping the vernix intact on your baby’s skin for as long as possible. It is good for your baby’s skin and will be absorbed naturally – there is no need to try and remove it.

  • Not all babies are born with vernix, but they do all have it in the uterus. The vernix coating is usually at its thickest around 36 to 38 weeks pregnant. This means that the earlier or later your baby is born, relative to this time, the less vernix your baby is likely to have, if any.

The Bottom Line

Vernix caseosa offers a number of benefits for your baby both in the uterus and after birth, so if possible wait until it’s absorbed naturally into the skin before bathing your little one to ensure they absorb all of the beneficial properties of the vernix. This will also give you more time to bond, enjoy skin-to-skin contact and also start breastfeeding.

It may seem a little messy and odd to leave the vernix on, but it’s best for your baby. In the first few hours, warmth is key. You’ll have a clean, washed baby to kiss and cuddle in no time! Meanwhile, wrap your little one in a soft blanket and enjoy these unforgettable first few hours, safe in the knowledge that the coating of vernix is also working to protect your baby’s delicate skin.

Read more about caring for delicate newborn skin.

How We Wrote This Article
The information in this article is based on the expert advice found in trusted medical and government sources, such as the National Health Service (NHS). You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.