Non-surgical feline contraceptives?

Question
I have 2 11-month old female cats, sisters, who have been through one heat.  They are full-time indoor cats and I plan to keep them that way.  I'm an English teacher and live in a small town in southern Mexico and have heard many horror stories about the local vets so am very reluctant to take my cats in to be spayed. Also one of the cats is quite small (about 5 lbs at 11 months) and I'm concerned about her ability to survive anesthesia.

Can you recommend anything to prevent or minimize their coming into heat other than spaying?

Also are there any long-term problems associated with not spaying female cats who are not bred?

Thanks for your help.

Answer
I can understand your concerns. There is no way to minimize coming into heat. Drugs are being tested, and even used to prevent dogs and cats from coming into heat, but I would not suggest using them yet.

When I had only my conventional training I would have said there was an increased risk of mammary tumors in cats who had not been spayed before their first heat.

With my holistic training, I can say that there is much less chance if you do not vaccinate, feed fresh food (not "cat" food), track the early warning signs of illness (see my web site's articles or prior posts here (I do not have internet access now with my computer) and avoid drug treatment of any illnesses.

There are homeopathic veterinarians who can consult with you by phone or email to help keep your cats so healthy they will not likely get tumors and may even decrease the frequency of being in heat. www.theAVH.org.