Sleep, twilight: A term applied to the combination of analgesia (pain relief) and amnesia (loss of memory) produced by a mixture of morphine and scopolamine ("scope") given by a hypodermic injection (an injection under the skin). The mixture of the two drugs created a state in which the woman, while responding somewhat to pain, did not remember it after delivering her baby. Twilight sleep was once in vogue in obstetrics.

Morphine and scopolamine are both venerable drugs that are naturally occurring members of a large chemical class of compounds called alkaloids:

• Morphine: The name "morphine" was coined in 1805 by a German pharmacist Adolf Serturner to designate the main alkaloid in opium. Opium, of course, comes from the poppy plant. Morphine is a powerful narcotic agent with strong analgesic action and other significant effects on the central nervous system. It is dangerously addicting. The name "morphine" refers to Morpheus, the mythologic god of dreams.
• Scopolamine: Scopolamine was introduced in 1902. The name comes from the 18th-century Italian naturalist Giovanni Scopoli. Scopolamine is, together with atropine, a component of belladonna which comes from a plant called "deadly nightshade," once used as a means of poisoning. When scopolamine is given in lower (non-poisonous) doses, it causes drowsiness and amnesia.

Scopolamine + morphine provided childbirth without pain (or without the memory of pain), once a much sought-after objective. However, there were serious problems with twilight sleep. It completely removed the mother from the birth experience and it gravely depressed the baby's central nervous system. This sometimes made for a drowsy depressed baby with poor breathing capacity. Twilight sleep therefore has fallen entirely out of favor and is now a chapter in the history of obstetrics.