As of 2010, the U.S. Supreme Court has never addressed the issue of fetal pain. Only one U.S. Court of Appeals has mentioned "fetal pain" (without addressing it) in Keith v. Daley, 764 F.2d 1265 (7th Cir. 1985).
Dr. Kanwaljeet Anand, a highly trained specialist in development of unborn children, has said that research has shown that babies feel pain before birth as early as 20 weeks into the pregnancy.  In a report describing the capacity of the fetus to feel pain, requested by the U.S. Department of Justice, he stated:
|“||It is my opinion that the human fetus possesses the ability to experience pain from 20 weeks of gestation, if not earlier, and the pain perceived by a fetus is possibly more intense than that perceived by term newborns or older children.||”|
|“||...specialized nerve endings involved in pain transmission are seen as early as seven weeks and are found throughout all organs by 20 weeks gestation… The mid brain, brain stem and cortex are all present in the fetus by 20 weeks gestation. This means that all the elements for the perception of pain are present by 20 weeks gestation.||”|
Dr. Grissom later added:
|“||It is the general practice in the field of fetal surgery to treat the mother for pain as if we are treating the fetus. All the components are there for feeling pain, and we can quantify the physiological responses associated with pain at 20 weeks, such as the production of hormones .... And shouldn’t the burden of proof be on those arguing there is no fetal pain at this point rather than on those arguing there is?||”|
An early study that has been cited by nearly 1000 scholarly articles confirms the existence of fetal pain during abortion as follows:
|“||Various putative neurotransmitters called the tachykinins (substance P, neurokinin A, neuromedin K, and so forth) have been identified in the central nervous system, but only substance P has been investigated thoroughly and shown to have a role in the transmission and control of pain impulses. Neural elements containing substance P and its receptors appear … at 12 to 16 weeks of gestation. A high density of substance P fibers and cells have been observed in multiple areas of the fetal brain stem associated with pathways for pain perception and control and visceral reactions to pain.||”|
U.S. Law & Fetal Pain
The legal strategy to limit abortions by prohibiting fetal pain after 20 weeks has had no effect on the overall increasing rate of abortion. "The Guttmacher Institute says only a small number — 1.5 percent — of abortions occur in the second half of pregnancy."
Congress first sought to pass laws to protect against fetal pain during the George W. Bush Administration, but nothing became law at the national level. Instead, and more recently, these states have enacted bans: Alabama, Arizona, Georgia, Idaho, Indiana, Kansas, Louisiana, Nebraska, and Oklahoma.
Specifically, Nebraska's Pain Capable Unborn Child Protection Act became law April 13, 2010. It bans all abortions past 20 weeks based on studies that babies assuredly feel pain at that point, corroborated by emerging protocols requiring surgeons who operate on late-term preborn babies provide them pain relief. 
- Life News
- Fetal Pain Report
- Anand, K.J.S. & Hickey, P.R. (1987). Pain and its effects in the human neonate and fetus. New England Journal of Medicine, 317(21), 1321-1329 (internal citations omitted).
- Legislative History of Pain Capable Unborn Child Protection Act