1) Labor 
The contracting of the muscles of the uterus during labour. The uterus contracts in an effort to expel the foetus into and out of the birth canal
[pronounce: con-track-shuns] The uterus starts to push out the baby during labour. 
The regular tightening of the uterine muscles as they work to dilate the cervix in labour and push the baby down the birth canal.
Tightening of the uterus to expel the baby; contractions become stronger and more frequent as labor progresses
The rhythmic tightening and relaxation of the uterine muscles that results in effacement and dilation of the cervix and the delivery of the baby. True labor contractions usually come in a regular pattern, gradually becoming closer together and increasing in intensity. The frequency of contractions is measured from the beginning of one contraction t...