No. If you are concerned or there are signs that things aren't going normally or it's a breed that generally needs c-section and is in labor or anything like that, you would call the vet.
If they are having difficulty and need assistance with contractions or getting things back on track then you would need to see the vet for an injection that helps stimulate contractions and if that doesn't help or isn't a good idea because the pups just aren't likely to make it through the canal or there are other indications then a c-section would be necessary. There are more whelping basics and detailed links and danger signs for you in the links.
q3525724.html#a2810229
http://drnelsonsveterinaryblog.com/2009/01/01/canine-labor--when-to-call-the-vet.aspx
If they are having difficulty and need assistance with contractions or getting things back on track then you would need to see the vet for an injection that helps stimulate contractions and if that doesn't help or isn't a good idea because the pups just aren't likely to make it through the canal or there are other indications then a c-section would be necessary. There are more whelping basics and detailed links and danger signs for you in the links.
q3525724.html#a2810229
http://drnelsonsveterinaryblog.com/2009/01/01/canine-labor--when-to-call-the-vet.aspx