Treatment methods for urethritis in pregnant dogs:

1. Anti-inflammatory. To treat urethritis in dogs and reduce inflammation, you can consider injecting the dog with long-acting anti-inflammatory injections or feeding them anti-inflammatory drugs.

2. Catheterization. If your dog has difficulty urinating and cannot urinate, you will need to insert a urinary catheter and perform a B-ultrasound examination on your dog to check whether there are stones or blood clots in the dog's urethra.

3. Antibiotic treatment. Conduct urine culture and drug sensitivity tests on sick dogs to select the most appropriate antibiotics. For example, common treatment drugs include amoxicillin and clavulanate potassium or quinolone ofloxacin.

4. Replenish water. Find ways to increase your dog's urine output, help it dilute its urine, and reduce urine irritation to its urethral mucosa.

5. Prevent infection. During treatment, be sure to wear an Elizabethan collar on the dog to prevent the dog from licking its own genitals due to discomfort and causing repeated infections.