Lanugo
Pronunciation: lah-NEW-go
Fine, downy hair covering the fetus and newborn, typically shed before or shortly after birth.
Full Definition
Lanugo is the soft, fine hair that covers much of the fetus during development, usually appearing around 20 weeks of gestation. This hair normally begins to shed around 33-36 weeks of pregnancy, though premature infants may be born with significant lanugo coverage. The presence or absence of lanugo can help estimate gestational age and is a normal finding documented in newborn assessments. Editorial teams should distinguish this from other fetal developmental markers when reviewing perinatal medical records.
Usage
Usage note: Always lowercase unless beginning a sentence. Distinguish from vernix caseosa, which is a waxy coating rather than hair.
In Context
- "The premature infant presented with extensive lanugo coverage, consistent with the estimated gestational age of 34 weeks." — Neonatal assessment report
- "Physical examination revealed minimal residual lanugo on the shoulders and back." — Pediatric chart note