When do fetuses develop pain receptors

These are the facts:. A human fetus does not have the capacity to experience pain until after viability. Rigorous scientific studies have found that the connections necessary to transmit signals from peripheral sensory nerves to the brain, as well as the brain structures necessary to process those signals, do not develop until at least 24 weeks of gestation.

In fact, the perception of pain requires more than just the mechanical transmission and reception of signals. The evidence shows that the neural circuitry necessary to distinguish touch from painful touch does not, in fact, develop until late in the third trimester. The occurrence of intrauterine fetal movement is not an indication that a fetus can feel pain. A heel prick from a needle used for amniocentesis , for example, can result in the fetus recoiling, much as an adult would to a painful pinprick.

In fact, the same response can be seen in anencephalic infants , who are born missing large parts of the brain. Put another way, the experience of pain is different from what is known as nociception. It follows that while pain requires some level of consciousness, nociception does not. Proponents of week abortion bans often also cite Kanwaljeet Anand , a professor of pediatrics, anesthesiology and neurobiology at the University of Tennessee Health Science Center. He has stated that pain may indeed occur in a fetus, through other neurobiological mechanisms than in an adult, as early as 20 weeks post-fertilization or even before.

Kristi Noem, a Republican from South Dakota:. Noem, May This is the stage where we know the baby can feel pain, and could be viable outside the womb with proper care. In testimony before Congress in , however, Anand was specifically asked about this idea.

There is — that is not my opinion. Anand also told the New York Times in that he has turned down many requests to testify in court cases regarding fetal pain, objecting to the politicization of his research.

Virginia Foxx, a Republican from North Carolina, also mentioned this and cited a recent study on extremely preterm infants:. Foxx, May The New York Times reporting just last week on a study that the New England Journal of Medicine published that found that 25 percent of children born prematurely at the stage of pregnancy covered by this legislation survive. The study in question analyzed the outcomes regarding 4, babies born before 27 weeks gestational age.

It is important to note that gestational age and post-fertilization age are different. Post-fertilization age is the time since conception. Wade, the U. Supreme Court gave states the right to legislate abortion restrictions during a woman's second trimester. Many states enacted laws that make it more difficult to terminate a pregnancy.

Among them, Arkansas, Minnesota, and Georgia require physicians to tell women that week-old fetuses can feel pain during the procedure unless they are anesthetized. A newly released review of the scientific evidence, however, suggests the premise of those laws is wrong. Fetuses cannot feel pain until at least the 28th week of gestation because they haven't formed the necessary nerve pathways, says Mark Rosen, an obstetrical anesthesiologist at the University of California at San Francisco.

He and his colleagues determined that until the third trimester, "the wiring at the point where you feel pain, such as the skin, doesn't reach the emotional part where you feel pain, in the brain. Without the thalamus, Rosen says, no information can reach the cortex for processing.