Birth Terminology Explained: Lanugo

There is a lot of terminology thrown around when you enter the world of pregnancy, birth, postpartum, breastfeeding, and early parenthood. In our "Terminology Explained" series, we help you break it down, bit by jargony bit. 

The word for today is lanugo.

What is Lanugo? 

Official definition: Lanugo comes from the Latin word lana, meaning wool. Lanugo is the downy (soft, fine) hair that grows on your baby while still in utero, beginning around 5 months' gestation.  (Sources: MedicineNet, Medical News Today) Often, the hair sheds prior to birth. Sometimes, the hair will still be present at birth and shed in the days or weeks after. The presence of lanugo on fetuses and newborns is normally occurring. While not all babies are born with lanugo, all babies have lanugo while still in the womb.

When you will hear/see the term used? Lanugo is a term that may be used to describe the appearance of baby at birth by nurses, doctors, midwives, and childbirth educators. Parents, friends, and family will likely use terms like hairy or fuzzy if there is a noticeable amount of lanugo at/around the time of birth. While it may be surprising or even concerning to see a newborn covered in a significant amount of fine hair, as some babies are, it is completely normal. 

Why is it important/beneficial? Some babies have very little or no lanugo at birth, while others have a lot. Both are normal. Premature babies often have more lanugo at birth. Scientists do not fully understand the role that lanugo plays for developing babies in utero, but believe that its presence, along with vernix, may be related to hormone production and plays an important role in healthy development. It is also believed that lanugo and vernix help protect skin in utero and may help regulate temperature. Researchers continue to study the role of lanugo. 

Published: April 05, 2021

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