menarche

^[1]^[2]

Introduction

Onset of menstruation, average age is 12.3 years^[1].

↑ ^1.0 ^1.1 Andersone SE & Must A Intepreting the continued decline in the average age at menarche: Results form two nationally representive surveys of US girls studied 10 years apart. J Pediatri 2005; 147:753 PMID: https://www.ncbi.nlm.nih.gov/pubmed/16356426
Biro FM Secular trends in menarche. J Pediatr 2005; 147:725 PMID: https://www.ncbi.nlm.nih.gov/pubmed/16356410
↑ ^2.0 ^2.1 Medical Knowledge Self Assessment Program (MKSAP) 16, American College of Physicians, Philadelphia 2012