Lanugo - Definition & Explanation for Mothers

Table of Contents

Definition

Lanugo is a term in motherhood that refers to the fine, soft hair that covers a baby’s body while it’s in the womb. It is usually shed and replaced by regular hair just before or shortly after birth. It serves to protect and insulate the baby during gestation.

Key Takeaways

Lanugo is a very fine, soft, and usually unpigmented hair that covers the body of fetuses and newborns. It is one of the common characteristics seen during the early stages of a baby’s development inside the womb.
Even though lanugo primarily appears on preemies, it might also make an appearance on full-term newborns, especially on their shoulders, backs, ears, and faces. However, it eventually falls out within a few weeks after birth, replaced by the thicker, coarser hair we associate with babies.
While Lanugo generally falls off by the time the baby is born, its persistence can sometimes indicate certain medical conditions such as eating disorders like anorexia nervosa or genetic disorders. Thus, though it’s typically normal and healthy, it can sometimes be a marker for health concerns.

Importance

The term Lanugo is significant in motherhood as it pertains to the development of the fetus.

Lanugo is the first hair that a baby’s body produces and it often covers the fetus’s entire body.

This fine, soft hair is usually unpigmented and its primary purpose is to provide an anchor for the vernix caseosa — the protective substance coating a baby’s skin.

Lanugo typically forms around the fifth month of pregnancy and usually sheds before birth, although some newborns may still have remnants of it.

Its presence can also be an indicator of newborn health, while in adults, it could potentially signify certain health issues.

Explanation

Lanugo plays a crucial role in the development of a fetus while in the womb, particularly in regards to temperature regulation. It aids in holding body heat, offsetting the lack of body fat present in early fetal development stages.

This thin, soft growth of hair covers practically the entire surface area of the fetus, including areas not normally considered hairy. It starts making an appearance around the fifth month of gestation, serving as an insulator to keep the unborn baby warm in the intrauterine environment.

Additionally, in a remarkably intricate biological function, Lanugo helps with the collection of the vernix caseosa—a greasy white substance composed of sebum and shed skin cells. This substance adheres to the Lanugo, further contributing to the fetus’s skin protection inside the womb.

It shields the skin from the long-term exposure to the amniotic fluid, which could otherwise lead to the skin getting chapped or wrinkled prior to birth. Hence, Lanugo performs a dual role of temperature regulation and skin protection, which are integral to a fetus’s development.

Examples of Lanugo

Pregnancy: During pregnancy, some women may notice the growth of Lanugo, which is a soft and fine hair, all over their body. This is a natural body response to hormonal changes and usually shed off after the baby’s birth.

Newborn Babies: Newborn babies are often covered in Lanugo. This is especially common in babies born prematurely. This type of hair helps to keep them warm and regulate their body temperature in the womb, and they usually shed it within a few weeks after birth.

Eating Disorders: In severe cases of eating disorders like anorexia nervosa and bulimia, adults can develop Lanugo as their body’s way to insulate itself due to extreme weight loss. The malnutrition causes a drop in body temperature and, to compensate, the body grows a layer of Lanugo.

Frequently Asked Questions about Lanugo

What is Lanugo?

Lanugo is a thin, soft hair that covers the body of a fetus and newborn baby. It is one of the first types of hair that an embryo develops and is usually replaced by coarser hair as the baby grows.

Why do babies have Lanugo?

Lanugo helps to keep the baby’s skin protected from surrounding amniotic fluid in the womb. It also aids in holding the vernix caseosa (a waxy coating that protects the baby’s skin) in place.

Does Lanugo indicate preterm birth?

Not necessarily. While it’s true that preterm babies might still have more lanugo on their skin at birth, full-term babies can also be born with some lanugo, notably on the shoulders and back.

How long does Lanugo stay on a newborn?

Most lanugo is shed before birth, typically around 32 to 36 weeks gestation. If a baby is born with lanugo, it usually falls off naturally within a few weeks after birth.

Is it harmful if a baby consumes Lanugo while in the womb?

No, it is not harmful. Lanugo that is shed and swallowed by the fetus becomes part of the baby’s first bowel movement, known as meconium.

Related Motherhood Terms

Neonate: This term refers to a newborn child, usually within the first 28 days of birth. During this period, the baby may still have some traces of lanugo.
Vernix Caseosa: It is a greasy deposit covering the skin of a baby at birth. It usually mixes with lanugo on the skin of the fetus.
Third Trimester: This term relates to the final phase of pregnancy where lanugo starts shedding off, although some babies are born with it.
Fetus: This is an unborn offspring, from the 8th week after conception to birth, which develops lanugo around the 22nd to 24th week of gestation.
Amniotic Fluid: The fluid surrounding and protecting the fetus in the womb. Lanugo can often be found floating in the amniotic fluid after being shed towards the end of pregnancy.

Sources for More Information

Mayo Clinic: A nonprofit academic medical center based in Rochester, Minnesota, focused on integrated clinical practice, education, and research.
NHS (National Health Service): The NHS is the UK’s state healthcare system providing a wide range of health care services including appointments, prescriptions, treatments, and more.
WebMD: An American corporation known for providing comprehensive medical information to doctors and patients.
Healthline: A provider of health information and guidance, whose mission is to make the people of the world healthier through the power of information.