From The Collaborative International Dictionary of English v.0.48 :
Birthing \Birth"ing\, n.
1. (Naut.) Anything added to raise the sides of a ship.
--Bailey.
[1913 Webster]
2. the act or process of giving birth.
[PJC]
From WordNet (r) 3.0 (2006) :
birthing
n 1: the process of giving birth [syn: parturition, birth,
giving birth, birthing]