Short answer
No, it is not safe. Beer contains both alcohol and hops, which are toxic to dogs and pose an even greater risk to a pregnant dog and her developing puppies. There is no safe amount. Ingestion can lead to alcohol poisoning and, from hops, a dangerous rise in body temperature. This is an emergency; contact your vet immediately or call the ASPCA Animal Poison Control Center at 888-426-4435 for guidance.
Beer — Food safety facts
Do not feed · Dogs · full breakdown on the linked food page
Alcohol plus hops, both toxic. Hops ingestion also causes dangerous overheating in dogs.
The full verdict, portion guidance and serving notes are collected on the Beer food facts page.