亲娘 contrasts with
继母 'stepmother' or
养母 'adoptive mother' to specifically mark a biological mother. It also functions as a rural / colloquial alternative to
妈 or
母亲, and as an exclamation
我的亲娘啊! similar to 'oh my god!' / 'Mama mia!' In some northern dialects (e.g. parts of Shandong) it can refer to a paternal grandmother.
