The phrase "morning after" interested me while reading this page:

Example 1.8 RU-486 is claimed to be an effective “morning after” contraceptive pill, but is it really effective?

I got to know that the "morning after" pill is the contraceptive pill to prevent unwanted pregnancy after having sex, but I don't know how it relates to morning. Is "morning after" grammatical? It seems like an odd combination of two random words. I read some articles on the history of the morning after pill, but learned nothing about its etymology or probable morphology.

I searched Google for the definition of "morning after", and only found these:

  • a hangover.
  • an unpleasant aftermath of imprudent behavior.
  • the morning after an evening of drinking, when one has a hangover.

Could someone please let me know why it is also called the morning after pill, and the story behind the euphemism?

  • 6
    @mdewey Its efficacy decreases with time. It's best to take it as soon as possible. Commented Mar 10, 2022 at 7:32
  • 8
    An unwanted pregnancy fits the definition "an unpleasant aftermath of imprudent behavior." Commented Mar 10, 2022 at 17:18
  • 5
    @mdewey Well, no, not really.
    – Thierry
    Commented Mar 10, 2022 at 19:04
  • 1
    Side-note: The quote you give is very strange. RU-486 is an abortifacient (causes an active pregnancy to end). It's not a morning-after pill (prevents a pregnancy from occurring at the last minute). They complement each other (if the latter fails or it's too late to take it, the former is an option), but they're not at all the same thing. Commented Mar 11, 2022 at 17:47
  • 1
    @AlabamaScholiast: Neat. News to me. And I guess in the context of a discussion of evaluating a clinical trial it makes sense to use it. It's just very fraught territory there to mix the two; the anti-contraception crowd doesn't need more ammunition in their fight to conflate morning-after contraception (broadly popular) with abortion (more controversial). Commented Mar 11, 2022 at 18:43

4 Answers 4


The assumption is that sex is more prevalent in the evening, especially when engaged in after a date with a casual partner. The "morning after" then refers to the morning after sex.

The phrase "morning-after pill" also includes the additional idea that the woman may wake up the morning after sex and feel dissatisfied then with whatever contraceptive methods the couple may have used the evening before and yet may still have effective contraceptive options "[that] morning after (sex)."

The phrase "morning-after" pill is fully grammatical and is best punctuated with hyphen as in this example.

  • 3
    Your second paragraph is a bit off the mark. A woman would take this pill if she feels she might have gotten pregnant.
    – Lambie
    Commented Mar 10, 2022 at 16:54
  • Comments are not for extended discussion; this conversation has been moved to chat.
    – gotube
    Commented Mar 12, 2022 at 7:52

The “morning after” is an English idiom that refers to the sense of remorse you feel the next morning from a previous night of bad decision-making.

In the context of the pill, it implies a regrettable sexual encounter (perhaps waking up next to a person you had a one-night stand with?), but as you discovered, the expression isn’t limited to sexual situations.

The name basically means you can undo the mistake you made with that guy last night.

  • 2
    And probably also that most the places one might obtain the pill from are closed until the next morning
    – Caius Jard
    Commented Mar 11, 2022 at 22:28

"After" is a preposition, but it can be used without an object. "Morning after" can be understood to be elliptical for "the morning after sex". The phrase "morning after" can be used with the understanding that the audience will infer from context what the morning is after. For instance, a "morning-after hangover" is a hangover the morning after a night of drinking.

The phrase then is used as a noun adjunct to modify "pill". When an entire phrase is used as modifier, it should be grouped together. This can be done by using hyphens or quote marks. So your example "RU-486 is claimed to be an effective 'morning after' contraceptive pill, but is it really effective?" acceptable, as the quote marks set the phrase apart, but if you don't have it in quote marks, it should be "morning-after pill".

The particular term was presumably chosen to evoke a particular time frame: a day or so afterwards, but not too many days. It also evokes the idea that perhaps the reason other contraceptive wasn't used was alcohol, and the pill is used the next morning after sobering up. Also, it may be difficult to find a pharmacy open late at night, and one may need to wait until the next morning. There is also the use case of nonconsensual sex, in which case it might not be immediately possible to use it.

  • 3
    I agree that it's clearest if it's delimited with quotes or a hyphen as you show. But it seems to be a trend in English that hypens and similar punctuation are disappearing (often resulting in compound words, but sometimes, like this, as separate words), so learners will unfortunately need to cope with their absence. Commented Mar 10, 2022 at 8:30

The second Google definition OP found fits - "an unpleasant aftermath of imprudent behavior." In this case, the imprudent behavior was having sex (maybe without protection or with insufficient protection). The unpleasant aftermath is the potential for an unwanted pregnancy.

This is perhaps slightly clearer in Collins Dictionary in the second noun definition

a moment or period of realization in which the consequences of an earlier ill-advised action are recognized or brought home to one

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .