This word is from the Spanish matriz (meaning: ‘womb’ or ‘uterus’).
mababa ang matrís
“womb is low”
= prone to miscarry
= has a difficult time to conceive
Mababa ang matrís ng babae.
The woman has a tendency to miscarry.
Nahihirapan siyang mabuntis kasi mababa ang matrís niya.
She’s having a hard time getting pregnant because her womb is low.
In the Philippines, a Filipina would refer to the lower part of her abdomen as the location of her matrís.