This stage of labor is very long, lasting 6 - 12 hours and culminates with full dilation of the cervix in preparation to expel a puppy. (marvistavet.com)
Some women with premature labor and early dilation of the cervix are put on bed rest until the pregnancy progresses. (americanpregnancy.org)
Preterm labor occurs when contractions or dilation of the cervix begin before the 38th week of pregnancy. (pregnancy-info.net)