Topical spot on flea treatment for pregnant cat

The tubes contain 0.75 ml of 6% Selamectin is it safe for a pregnant cat?

Hello!   Selamectin is a prescription drug POM-V and so needs to be prescribed for a particular known patient by the vet, pharmacist or other qualified person.  The guidelines for certain drugs are laid out very carefully in the data-sheet and vets are trained to apply this information to the animal in front of them, when deciding on a drug or a dose.  It is illegal to use veterinary medicines in any other circumstances, especially if the patient may be pregnant.  If a drug has been prescribed and then a patient has become pregnant, always call and inform your vet, in case they wish to make changes.  Best of luck.