Subverted: Alice's pregnancy takes the usual 9 months in the series
Double Subverted: 9 months of "storyline time" that is. The episodes were filmed according to filming time, or made use of a flash forward.
Parodied: Alice is visibly and heavily pregnant as soon as she's done having sex with Bob, and gives birth the morning after.
Zig Zagged: Some pregnancies go fast, others slow, and others at a realistic speed.
Alice's pregnancy lasts for a normal amount of time.
Alice does not become pregnant in-series.
"We need to portray a pregnancy without taking forever to film it."
"The actress that plays Alice is pregnant, and we can't hide it at this point; let's make it part of the storyline."
Lampshaded: "Didn't you just take a pregnancy test yesterday?"
Invoked: Alice, frustrated with the uncomfortable aspects of pregnancy, seeks the help of a witch, who gives her a potion that will speed up her pregnancy.
Defied: Alice has second thoughts about taking the potion, fearing that it could hurt the baby (or her), and decides to just suck it up and deal with her discomfort.
Discussed: "It seems like just yesterday, Alice was just starting to show."
Conversed: "That was just yesterday!"
Deconstructed: It destroys the audience's Willing Suspension of Disbelief; most people know that a pregnancy does not normally go that quickly. (If it does, chances are it's because of a miscarriage or abortion.)
Reconstructed: The timeline makes it clear that it's a realistic amount of time.