primigravida
A woman or female animal who is pregnant for the first time, or who has been pregnant once.
[...] [Friedrich] Schatz advises all pregnant women, especially primigravidæ, to consult a physician during the last portion of their pregnancy, and ascertain from him the position of the child, and the necessity, if present, of altering it before labor sets in.
Where it comes from
From Latin prīmus (“first”) (modelled after primipara) + Medieval Latin gravida (“pregnant woman”), feminine singular of Latin gravidus (“pregnant, gravid”), from gravō (“to burden, weigh down; to make pregnant”) + -idus (adjective-forming suffix meaning “tending to”).
Adapted from the Wiktionary entry primigravida (CC BY-SA 4.0).