“She’s expecting.” This is what I call a hidden idiom. The full phrase is so common that it has been shortened into an idiom. The full phrase is “She’s expecting a baby.” In other words, she’s pregnant. In fact, the title of a very famous book about pregnancy is, “What to Expect When You Are Expecting”.

This idiom is especially confusing to ESL students because it appears ungrammatical! In normal usage, the verb expect must be followed by an object.

She is expecting a phone call.

He was expecting his friend to meet him.

The dog expects you to throw the ball.

The only time expect(ing) is used without an object is when it is used as an idiom. Additionally, this idiom is often used when talking about a woman’s weight.

Sarah looks like she’s gained some weight. Is she expecting? (Is she pregnant?)

Also, when talking about pregnancy, “child” is often used instead of “baby”.

The happy couple was expecting their first child. (not baby)

They’re expecting a child in June.

Finally, a common euphemism for a miscarriage is “lost the baby” (“child” is not used).

She was expecting, but she lost the baby. (not child)

After she lost the baby, she became very depressed.