Timing for elective caesarean
Often you know in advance that your bitch will be having an elective caesarean. This may be due to her breed, her history, health conditions, problems with the size of the puppies compared to the bitches pelvic opening, risk of uterine inertia – there are many reasons.
You want to get the timing right so that the pups are ready to be born – remembering that ovulation and release of eggs and implantation occurs over a number of days so within a litter there may be a lot of variation. If pups are born too early (undercooked), they may not be fully developed. Often you will see red nose and muzzle and red paws. Size of the pups is not a good indicator of readiness as this is variable with genetics and the number of pups in litter.
If pups are delivered late (overcooked) they may be bradycardic and acidotic (slow heart rate and metabolic changes affect breathing and will make pups difficult to resuscitate).
Timing involves many factors:
- Gestation length: know your mating dates.
65 days from L.H surge +/- 1 day
63 days from ovulation
If you test progesterone, then LH surge is after progesterone is over 15 n/mol (5ng). ovulation would be 24-48 hours after this. However, gestation length is affected by number of pups in the litter and by the weight of the mum (and pups).
- Signs from bitch that birth is near:
Nesting, milk may be coming in, spine will appear more prominent, abdomen will be deformed, pups will move caudally, vulva drops down. Your vet may do a vaginal exam to check.
- Progesterone tests:
Although some say progesterone should be less than 6nmol/L before caesarean is done, this is not accurate. There is diurnal variation in progesterone and a morning test can be 50% higher than an afternoon test. The tube blood is collected in can also affect the result and results can differ between laboratories also. Whether or not a bitch has eaten can affect results, so it is really important that serial progesterone testing is done to ensure accurate information is obtained. A serial progesterone test can only be helpful when combined with signs.
- Imaging/X rays
- a) X-rays are useful to see development of pups, but the bones of the skeleton of the pups is not visible until after 42 days of pregnancy. However, if no mating dates are known X-rays help to determine how many days to go but are not as accurate as needed for timing a c-section.
- b) Ultrasounds can be very helpful as your vet can see gastrointestinal development of the puppies in the last 48 hours before birth and can monitor foetal heartrate. Serial ultrasounds may be needed.
Your vet will advise you on the best time, but remember the health of mum is very important and if she has breathing issues or anything that is life-threatening to her, her health must be primary concern for pups to be born healthy and for good survival of all.
If you are having any trouble raising pups it will not just be due to the timing of the c-section, ask your vet or vet nurse for help.