。
She had an easy delivery.
Literal
She [topic-は] easy-delivery was.
安産 ('easy/safe childbirth') is a fixed Sino-Japanese compound — 安 ('peaceful, safe') + 産 ('birth'). It's a culturally loaded word: visiting a 子安神社 ('safe-childbirth shrine') and praying for 安産 is a common expectant-mother ritual in Japan, often involving an 腹帯 ('belly band') blessing during pregnancy. The opposite is 難産 ('difficult delivery'). The bare copula だった simply states the outcome.