The following is an excerpt from:
L. Ari Juckowitz, VMD. Reproductive Emergencies; Veterinary Clinics Small Animals. Volume 35

g 397-420.
Box 2. Criteria for the suspicion of dystocia
1. A definite cause is visible (ie, fetus lodged in birth canal,
pelvic fractures).
2. Gestation is prolonged (>70 days) with no evidence of labor.
3. Temperature has dropped to lower than 100F and returned
to normal with no evidence of labor.
4.
Green vaginal discharge (indicates placental separation) or
fetal fluids are seen, and 2 hours have elapsed without
expulsion of fetuses.
5. Strong and persistent contractions fail to result in the
delivery of a puppy within 30 minutes.
6. Weak and infrequent contractions fail to produce a fetus
within 4 hours.
7. More than 4 hours have elapsed since the birth of a puppy,
with no evidence of ongoing labor.
8. Signs of systemic illness or severe pain are presen