A spay can prevent both conception and fake, or 'phantom' pregnancies, in which your pet's body mimics the symptoms of pregnancy. This might cause a hormonal imbalance in your pet, making them feel out of sorts. Worse, it may lead your pet to get mastitis, a condition in which the mammary glands become infected. This, too, has the potential to be fatal.
Any surgery comes with its own set of risks, and the procedure itself is fraught with difficulties. Issues may occur due to various factors, including an unfavorable reaction to the anesthetic or surgical complications during the process. Before beginning, your veterinarian may request a blood test to rule out any anomalies that could compromise the anesthetic's efficiency and safety, as well as a comprehensive physical examination. While this does not guarantee that nothing unexpected will happen to your pet during the procedure, it should protect him from any problems with his kidneys or liver.
Even if the operation goes smoothly, there may be complications during recuperation. Following a general anesthetic, some pets have nausea and vomiting, and because the surgery needs incisions, your bitch may suffer from a bit of pain. If your pet is in discomfort, your veterinarian should provide you with the necessary medications. Don't give your pet human medications because they won't react the same way we would.
Many pet owners see their pet gaining weight after spaying and assume it's just a side effect of the procedure. In reality, after a spay, a pet's Basal Metabolic Rate (the number of calories they need to carry out their basic processes) drops, and they don't need to eat as much. If a pet's portions aren't decreased, she will put on weight. Unfortunately, many owners are unaware of this, and their pets become overweight or obese. This can lead to many other problems, including joint and muscle strain, diabetes, and an increased risk of some malignancies.
The most significant benefit of both spaying and castration is population control. We will need certified dog breeders to keep a supply of both working dogs and pets. However, if we prevented many unwanted pregnancies, there would be better control and quality of dogs on the planet. Plus, if there were fewer unwanted pregnancies, there would be more demand for rescue dogs and fewer strays on the streets. I always find it strange how people are obsessed about getting puppies and certain breeds when you could go into a rescue center and choose to change a dog's life around totally.
Whether you are neutering your puppy or not is your decision unless local and national laws demand it, but your Vet will be able to help you out with that knowledge. As with many things in life, there are pros and cons to the decision, but I think it should be something you should do in most cases.