。
She is pregnant.
Literal
She [topic-は] pregnancy-middle is.
妊娠中 uses the suffix ~中 (read ちゅう), attached to a noun to mean 'in the middle of, during.' Other examples: 工事中 ('under construction'), 営業中 ('open for business'), 通話中 ('on a call'). Read じゅう (not ちゅう) for 'throughout': 一日中 ('all day'), 世界中 ('all over the world').