Martha suggests by offering her a drink Aziz is testing to see if she's pregnant. However the negative effects of alcohol on pregnancy were not established until the 70s. In fact well into the 60s some doctors still suggested the alcohol was a good way for a pregnant woman to calm her nerves.
The black Electra Buick they drive away in at the end is very similar to the black Ford Futura used in the 1966 Batman TV series