Berean Standard Bible (BSB)
He went there to register with Mary, who was pledged to him in marriage and was expecting a child.
World English Bible (WEB)
to enroll himself with Mary, who was pledged to be married to him as wife, being pregnant.
Strong's King James
To be taxed{G583}{(G5670)} with{G4862} Mary{G3137} his{G846} espoused{G3423}{(G5772)} wife{G1135}, being{G5607}{(G5752)} great with child{G1471}.
The F.O.G *
(5) to enrol along with Miryam (bitter) betrothed to him being pregnant.
The F.O.G Message *
Young's Literal Translation
to enrol himself with Mary his betrothed wife, being with child.