Basic Trope: The harder a couple tries to conceive a child, the less likely they actually will conceive.
Straight: Alice and Bob are trying to have a baby, but they notice that during this time, conception does not happen.
Exaggerated: Alice and Bob schedule the sex for the instant Alice ovulates, and have even tried seeing a fertility specialist and still nothing happens in their favor.
Downplayed: Alice manages to get pregnant, yet it takes a little longer than expected.
Alice and/or Bob may be infertile.
Alice stresses out so much about trying to get pregnant that she makes her menstrual cycle irregular. And Bob feels like he's under so much pressure to get her pregnant every time they have sex that he can't even get it up.
Inverted: Alice and Bob try to conceive, and they do conceive, though maybe not right away.
Subverted: Alice and Bob don't get it on their first try, but they try again next month and it works.
Double Subverted: But Alice has a miscarriage early in the pregnancy, or the egg gets fertilized, but for some reason does not implant in her uterus in the first place.
Deconstructed: Alice and Bob are so lost in each other that they forget all about contraception or aren't using it correctly, resulting in a baby, which, being unwanted and all, will cause some serious issues.
Reconstructed: Alice and Bob deal with Alice's unplanned pregnancy (whether by marrying and raising the child, Alice having an abortion, or putting the child up for adoption), and resolve to be more careful in the future. They learn An Aesop about not thinking that something can't happen to you.
Played For Drama: Alice and Bob have to deal with Alice's unplanned and unwanted pregnancy, and the impact it will have on them both as individuals and as a couple.