A Pregnancy Trope. The moment a pregnant woman's water breaks, FAZAM! Her vagina is now her baby's personal waterslide, and she's going to give birth right there, right then. Bonus points if 'right there' is somewhere extremely cramped, uncomfortable or inaccessible (say, an elevator) and 'right then' is precisely when it will be least convenient for her or any other bystanders (such as when the aforementioned elevator has stopped working). And don't expect Baby to wait for the situation to improve; as long as there's somebody there who's so much as witnessed a birth before, it's ready to jump into that person's open arms.
Other variants include childbirth in the backseat of a car (taxis are quite popular for this purpose). Inevitably leads to a Screaming Birth, often performed by someone with no medical training whatsoever.
As with many tropes, this one has one foot in Truth in Television — the water breaking is a reliable early indication that labor has started, and active labor can be quite a quick process (although also quite a slow one). However, the 'instant birth' part happens far more frequently on television than it does in real life, and in many real-life labors the amniotic sac remains intact until well into labor or even until birth. Likewise, in most of these fictitious situations, the woman's baby is her first — which, on average, rarely precedes a labor-period of less than twelve hours, which would outlast almost any "crisis." On the other hand, there are documented cases of Real Life second or third babies who begin to deliver so quickly that the mother barely has time to get into a bathtub, let alone a backseat.
Usually combined with Clean Pretty Childbirth. Not to be confused with Express Delivery.
This happens in Chapter 13 of Extended Stay when the Mistress goes into labor at the altar during her and the Warden's wedding. However, this is subverted as she doesn't actually give birth at the altar right away. There's actually enough time for Warden to send Jailbot and NOVA out to find a doctor, for the robots to come back with said doctor, and for Mistress to be moved into another room where she eventually gives birth to brother-sister twins.
Played straight in Gone. Diana gives at the bottom of a certain mineshaft, with hardly any assistance and not a lot of preparation either.
Frasier, particularly Daphne's birth. Needless to say, this was Daphne's first child; and as usual, twelve hours of average labor was condensed down to twelve seconds.
Everybody Loves Raymond, in the back of Robbie's police car. Only it was a false start, and Robbie had started to go through his emergency birth procedures, much to Ray's chagrin.
Star Trek: The Next Generation: In the episode "Disaster" Worf has to deliver Keiko and Miles O'Brien's daughter in these circumstances (with the "no medical training" bonus).
Well, he did take one on a holodeck years ago, per Starfleet regulations—thus his irritation that Keiko's birth isn't going as it's "supposed" to.
In LOST, this happens when Claire gives birth on the island. Unfortunately, the only doctor, Jack, is tending to a dying Boone. Charlie and a non-English speaking Jin have to aid her delivery, on a rock in the jungle.
Made even more odd by the next morning, where Claire is up and walking around with no limp or pain and carrying her newborn. After a birth with no anesthetic, this is a little bit hard to believe. This, paired with Locke's sudden ability to walk after years of paralysis, was an early hint that the island itself has Healing Hands.
Played very straight once again with Claire in sideways (it takes the same amount of time for Claire to give birth that it does for Charlie to get a towel) but it's partially saved because it's not real anyway... sideways is purgatory.
In Psych, Chief Vick's labor takes most of the day, and she is calm and level-headed throughout it. Lassiter, on the other hand...
Roseanne had an episode like this when Jackie had her baby, but semi-averted the Trope. Her water broke at the diner and Roseanne was able to take her home, get her suitcase, and take her to a hospital without being too rushed. While Jackie was nervous through the whole thing, Roseanne was very calm, reminding her the first baby takes several hours. Of course, Roseanne was largely using this to justify her not telling Jackie's fiance she was in labor, since she didn't approve of him, which came back to bite her when Jackie went into early labor (not sudden, but gradual), and she had to scramble to find him.
In the season 1 finale of Glee, the labor only lasts as long as a performance of Bohemian Rhapsody.
Well, it's a pretty long song...
In a season 2 episode of Community, Shirley's water breaks in the Anthropology 101 classroom and she ends up giving birth in front of the chalkboard. Justified in that she's been having contractions all day (although she's either not realized or refused to believe they were contractions) and this is her third child.
This happened in the Australian soap, Home and Away, in early 2011. Nicole was on the beach with Angelo at the time, and there was no way to get her to the car or for an ambulance to reach them. So she gave birth on the sand, within minutes of her water breaking.
Played straight in The Suite Life of Zack and Cody's Christmas episode, which is a shout out to the birth of Jesus Christ on Christmas day (complete w/ no room for the couple).
Averted in Xena: Warrior Princess. A minor character going through her first pregnancy meets Xena and Gabrielle in the middle of the day. She mentions that her contractions had already started (and thus, her water had broken). The baby is delivered just after nightfall.
Averted in Friends with every on screen labour. Both Phoebe's and Rachel's waters break suddenly, but both have ample time to get to the hospital and have normal labours (very lengthy in Rachel's case). Phoebe is in labour long enough for Joey to be diagnosed with kidney stones, Monica getting set up, Chandler freaking out, an Operation Jealousy, the triplets parents to arrive and Rachel asking if Phoebe can keep a baby. Rachel's labour lasts 24 hours and a double-length episode.
While Carol is giving birth the gang also have time to fall into various mishaps and problems.
Invoked (?) in Leverage, where Sophie is pretending to be pregnant, needs to get away from questioning police officers, and so waits until their backs are turned and pours water on the ground. Then starts acting her heart out until the paramedics whisk her away.
In the Halloween episode of Desperate Housewives, Danielle's water breaks at a party and she gives birth within the space of just a few minutes. Because Bree is attempting to cover up the pregnancy, she has to claim to everyone that it was just a popped water balloon, then go back to get Adam (who is a trained gynecologist and figured it out) to help deliver the baby when Orson is too drunk to do it.
Averted in Malcolm in the Middle where when Lois's water's break she still has time to try to get her husband, who took the boys out for the day, back home to take her to the hospital. Unfortunately, he ends up in hospital from driving into a streetlight, so Lois spends the rest of the episodic having a lengthy childbirth without him.
Stargate Atlantis: Rodney lampshades this when Teyla gives birth on a Hive ship with no one else around ("No one has babies this quickly!") which Teyla handwaves by saying her water broke a long time before that.
General Hospital. Carly feels the first twinge of labor pains (there's not even a mention of her water breaking) and immediately declares that there's no time to get to the hospital and that her dinner companion has to deliver the baby right then and there. Even for a second child, that's ridiculously fast. Though this was a dream sequence. . .
Amen. When Thelma goes into labor at a telethon (again with no mention of her water breaking), she declares that there's no time to get to the hospital. Yet there's enough time for an EMS crew to get to there and tend to her. Again, given that this is her first child, the rapidity of this is unlikely.
Lampshaded on Seed with the birth of Rose's baby. Her water broke while she was in a hardware store and she is brought to a hospital. She then gives birth 45 minutes later and it was apparently quite easy and rather painless. When the mothers of Harry's other children find out about this, they are livid. Their births were long and painful. Anastasia's mother spent 56 hours in labor.
Ars Magica takes this to wizard-did-it extremes with a spell that instantly teleports the baby out of the womb. Justified in that the game is set in medieval Europe, where childbirth was a dangerous process for both the mother and child. One feels compelled to note that the rules allow an entrepreneurial mage to imbue the spell into a top hat...
Avatar The Last Airbender in the serpent's pass episode. Parts of the trope are averted - Katara is an experienced midwife and takes charge.
Ice Age: Dawn of the Dinosaurs Ellie gives birth in the middle of a raptor fight, and only Diego, who knows nothing about delivering a baby, is present! Ellie screams and winces, and Peaches comes out already happy and sleepy, in one of the most exaggerated Hollywood births ever.
Legendary Russian ballet dancer Rudolf Nureyev was born on a train traveling through Siberia. He was his mother's fourth child, and it was in 1938. Such births tend to be faster than first-timers, and hospitals were few and far-between at that time and place; likewise, a doctor was more likely to be on such a train than most other civilians (except for Dr. Zhivago, who missed his). In comparison, a normal passenger-jet today can circle almost half the globe, in the time than it takes for the average first-time childbirth.