Spaying - immediately at 6 months or wait until first season?

[diplodocus]

We have a 4 month old rescue bitch who we will be getting spayed. However, I've heard conflicting opinions as to whether it's best to get this done as soon as she's 6 months, or wait until her first season. Our vet has no opinion on this, and the rescue said it was up to us. I'd prefer not to wait (particularly as we live next door to an entire male so although he can't get in things might get a bit lively!) but if there's good reason to wait we're happy to do this. Anyone with thoughts?

I'd get her spayed before her first season.

Reasons;

• Seasons are messy (not the most important reason, but still...)
• A season can lead to a phantom pregnancy which will stress the dog (and you) and will make it harder to plan in a spay date
• I'm sure I read somewhere that each season a bitch has makes her that little bit more likely to get pyometra or certain cancers (mammary cancer seems to be the one that comes up most often)

This is only from a few cursory searches when my friend was deciding when to spay her bitch. My pup's a male, so I'm avoiding the season issue, but that doesn't mean I won't have a bitch in future.

There are some pros and cons to either way:

Spay before season - you don't have to get through the season, no chance of accidental pregnancy, no chance of false pregnancy, best protection against mammary cancer later in life, organs and blood supply are less developed so surgery is simpler, bitch will weigh less which may give a cost saving.
Cons - increased risk of developing sphincter mechanism urinary incontinence in later life, particularly if vulva is underdeveloped at time of spay. This risk is reduced if the bitch has one season first. Some breeds more affected by this (giant breeds and springers) It's normally easily controlled with medication.

Spaying at any age removes the risk of a pyometra as the womb is removed as part of the surgery in the traditional open method. In a laporascopic spay only the ovaries are removed and the womb is left but pyometra only happens after a specific hormonal cycle post season so if you remove the ovarian stimulation you remove the risk. You could still potentially get a uterine tumour if only the ovaries are removed but not common.

I'm a vet and our preference is for pre-season unless in a breed at risk of SMI in which case we let them have one season first. If a bitch has had a season they need to be spayed in the anoestrus period about 3 months after the season finishes.

Thanks so much for this - will certainly now go for pre-season. She's a medium-sized mutt of indeterminant ancestry so not at particular risk of SMI.
Thanks again.

I am going to disagree with Bakingtins on one point that spaying before the first season increases the risk of urinary incontience. The Beauvais review of all the literature on this topic in JSAP in 2012 found no correlation between age of spaying and incidence of urinary incontinence. The review concluded that spaying at any age increases the risk of urinary incontinence, but that as it is easily controlled with medication in the vast majority of cases the risks far outweighed the benefits of spaying. The review concluded that there was no benefit to waiting till after the first season.