metzhuia.

Headword: 
metzhuia.
Principal English Translation: 

to menstruate (see Molina)

Orthographic Variants: 
metzuia
Alonso de Molina: 

metzuia. nino. (pret. oninometzui.) tener la muger su costumbre.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 55v. col. 2. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in English: 

The word for month is at the root.