Spaying a Female Dog in Heat: Is It Safe and What to Expect?

Quick answer: Yes, a female dog can be spayed while she's in heat, and it's done safely every day, but the reproductive tissues are more engorged with blood during a season, so the surgery takes more care and time. Because of that, an additional charge (around $150) usually applies, and your vet may suggest waiting a few weeks until the heat has passed unless there's a reason not to.

Plans don't always line up with a dog's cycle. Maybe your dog came into season just before her scheduled spay, or you've only just decided to sterilise and she happens to be on heat now. The good news is that being in heat doesn't rule out surgery, but it does change a few things worth understanding before you go ahead.

Can you spay a dog while she's in heat?

Yes. Spaying during a season (oestrus) is a routine variation of the standard procedure, and vets perform it regularly, for example when there's a risk of unplanned mating, or when delaying isn't practical. The surgery achieves exactly the same outcome. The difference is not whether it can be done, but how the surgery is approached.

Why it carries extra care (and an extra charge)

During a heat, a female's hormones cause the reproductive tract to become more vascular, the blood vessels supplying the ovaries and uterus enlarge and the tissues are more engorged. That has practical consequences in surgery:

• More careful haemostasis. Larger, fuller vessels mean the vet must take extra care to control bleeding.
• A little more time. The procedure is often slower and more meticulous than a routine spay on a dog not in season.
• Closer monitoring. As with any surgery, full anaesthetic monitoring applies, but the increased vascularity makes careful technique especially important.

Because of the added complexity and time, an additional $150 typically applies on top of the standard sterilisation fee. This is the same kind of complication surcharge that applies to other more involved cases. Where bleeding control needs it, vessel-sealing technology such as LigaSure may be used at the vet's discretion or when clinically indicated, at an additional charge, it isn't part of every routine spay.

Why your vet may advise waiting

If there's no urgency, many vets will suggest postponing the spay until the season has fully passed, usually a few weeks to a couple of months after it ends, once the tissues have settled back to their normal, less vascular state. Waiting can mean a more straightforward procedure and avoids the surcharge. Your vet will weigh:

• Risk of unplanned mating: if she can't be reliably kept away from entire males, waiting carries its own risk.
• The reason for spaying: a medical indication may make proceeding the better choice.
• Her overall health and your circumstances.

There's no single right answer; it's a judgement call made with your vet.

What to expect on the day

Whether your dog is in heat or not, the core of the procedure is the same general-anaesthesia surgery. In brief, you can expect:

• Fasting before surgery: no food from midnight and no water from 6am on the morning of surgery (we will confirm the timings when you book).
• A pre-surgical examination and recommended pre-anaesthetic bloodwork to confirm she's fit for anaesthesia.
• General anaesthesia with IV fluids and full anaesthetic monitoring throughout, with ventilator support available if needed.
• The spay itself, with the extra care described above if she's in season.
• Same-day discharge in most cases, with pain relief and aftercare instructions.

For the full walk-through, see our guide on what to expect during the surgery, and plan ahead with our post-op recovery care tips.

How we help at AVH Animal Ark

If your dog is in season and you're not sure whether to proceed or wait, the best move is to talk to a vet who can examine her. At AVH Animal Ark Veterinary Group, our team will assess her stage of heat, your circumstances and any risk of mating, then advise whether to go ahead now or postpone. When you're ready to arrange female dog sterilisation, we'll give you a clear, personalised quote. We're at Springleaf and Tampines, open 7 days a week.

Spaying starts from $440 (under 10kg), $550 (10-20kg) and $660 (over 20kg), inclusive of 9% GST; prices vary by vet, medication and any extras. Spaying a dog on heat adds $150. Basic pre-anaesthetic blood testing is not included in those prices; it is an add-on from $250.

Frequently asked questions

Is it more dangerous to spay a dog in heat?

It's more involved rather than dangerous. The reproductive tissues are more engorged with blood, so the vet takes extra care with bleeding and the surgery may take a little longer. Done properly, it's a safe, routine variation.

How long should I wait after a heat to spay?

Typically a few weeks to a couple of months after the season ends, once the tissues have returned to their normal state. Your vet will confirm the best window for your dog.

Why does it cost more to spay a dog in heat?

The added vascularity makes the procedure more complex and time-consuming, so an additional charge (around $150) usually applies, the same complication surcharge used for other more involved cases.

Can I spay my dog if she's pregnant?

This is a separate situation and a decision to discuss directly with your vet, who will advise based on the stage and your dog's health.

Medically reviewed by Dr Regina Khoo, Veterinarian (University of Glasgow), special interest in internal medicine and surgery. Read Dr Regina's profile

Last reviewed: October 2026. This article is general information and not a substitute for a consultation with your vet.

References / Further reading

• WSAVA (World Small Animal Veterinary Association) - surgical and welfare guidelines
• AAHA (American Animal Hospital Association) - preventive care and surgical guidelines
• AVMA (American Veterinary Medical Association) - spay/neuter owner resources