First of all, please calm down. Your question sounds as if any interaction with your cats would potentially endanger the life of your unborn child, but that is not the case.
It's not the cat itself that poses a danger during pregnancy, but an infection called "toxoplasmosis" that is caused by "Toxoplasma gondii" parasites. This infection can cause severe developmental damages in the baby's eyes and brain, but only if the mother is infected for the first time in her life during pregnancy.
There are very good blood screenings available that test whether or not the mother was ever infected with toxoplasmosis. If that test is positive, it means that the baby is completely protected by the mother's immune system. Please ask your doctor for such a blood test.
If the test is negative, there is a risk of infecting the unborn child if the mother is infected during the pregnancy. Be aware of the symptoms of toxoplasmosis and call your doctor when you notice them. Acute toxoplasmosis can be treated in the mother and the unborn child, which prevents complications in the child.
Read more on Wikipedia, Mayo Clinic, NHS and CDC.
Avoid infectious material
To infect a human with toxoplasmosis, you need:
- An infected rodent or other small animal
- A cat that eats the infected animal
- The infected cat dropping feces
- A human coming into contact with those feces approximately 1 day after they have been dropped.
A second way of infection is eating undercooked meat or shellfish. In some cases unpasteurized milk from infected animals also contains the parasites, so avoid unpasteurized milk, and soft cheeses that can often be made from raw milk (feta, brie, camembert, etc). She will likely be avoiding these foods anyway, as unpasteurized milk is not recommended for pregnant women due to the risk of listeriosis.
The best way to avoid infection is to avoid cat feces. It's great that you clean out the litter box instead of your wife, but you should also do that at least once every day and always wash your hands afterwards. The Toxoplasma parasites only become infectious 1 - 5 days after leaving the cat's body, so make sure to clean them up before that.
Your wife should also avoid touching feral cats and sand or soil that a feral cat might have used as a toilet (no garden work for her). Make sure all fruits and vegetables that touched the ground are washed and cooked well.
Next, try to avoid an infection in your cats. Cats cannot contract toxoplasmosis out of thin air, they must eat an infected rodent or other small animal. If you keep your cats indoors all the time, the risk for that is extremely low. You should also feed your cats commercial dry or wet food instead of raw meat.
The pregnancy of your wife will bring many changes and new experiences into your life. You will face some difficulties, but there are always professional people around you who can help you. Please don't stress yourself more than necessary by fearing for your child any time one of your cats touches your wife.
Several studies found that cat ownership does not strongly increase the risk of a T. gondii infection in pregnant women.
Even your cat jumping onto the belly of your wife poses no risk at all for the baby. The belly is not a glass ball that might shatter, it is a very efficient safety capsule with integrated shock absorbents for the baby. A direct pounce by an animal up to 40 pounds / 18 kg is still considered safe.
It needs a direct, violent impact to the belly (like in a car accident, a hit by an adult or a direct pounce by an animal over 40 pounds / 18 kg) to damage the baby. This guideline applies to the last third of pregnancy, when the belly is very big and therefore more vulnerable to impacts. In the earlier stages of pregnancy, the risk of injury and miscarriage is even smaller, but there are no objective numbers available.
The real danger here is a sudden impact. If a cat decides to lay on top of the belly, it's ok as long as the mother doesn't feel uncomfortable.