The scientific consensus is that fetuses cannot begin to feel pain until at least the 26th week of gestation (in the third trimester). By this time, 99 percent of all abortions have been performed.
The perception of pain is a complex biological and psychological phenomena. First, the ability to experience sensation, perception, and thought requires a minimum number of neurons in the cerebral cortex, and interconnectivity between these neurons. While these synapses start to form at about the third month, the minimum number do not usually develop until about 31 weeks, and most are not formed until after birth.
Second, pain is a subjective experience that requires a conscious interpretation by the brain – it is a complex interplay between thinking, emotion, and sensation. The degree of discomfort or trauma caused by a pain signal is directly related to the anticipation of pain, its duration, understanding of its cause and consequences, the memory of pain, and its lingering traumatic effects, as well as various personal and cultural factors. It’s therefore highly uncertain that even third-trimester fetuses can feel pain, because fetuses are not conscious – they are kept in a “continuous sleep-like unconsciousness or sedation” (RCOG 2010) – and they exist in a very different environment than born humans. As fetal pain expert Stuart W.G. Derbyshire explains:
“The environment of the womb consists of warmth, buoyancy, and a cushion of fluid to prevent tactile stimulation. In contrast to this buffered environment, the intense tactile stimulation of birth and the subsequent separation of the neonate from the placenta, facilitate the rapid onset of behavioural activity and wakefulness in the newborn infant.”
Derbyshire summarizes the research on fetal pain as follows:
- The neuroanatomical system for pain can be considered complete by 26 weeks’ gestation.
- A developed neuroanatomical system is necessary but not sufficient for pain experience.
- Pain experience requires development of the brain but also requires development of the mind [after birth, through interaction with others] to accommodate the subjectivity of pain.
- The absence of pain in the fetus does not resolve the morality of abortion but does argue against legal and clinical efforts to prevent such pain during an abortion.
British Medical Journal, Can fetuses feel pain? by Stuart WG Derbyshire (2006)
Pro-Choice Action Network, Fetal Pain: A Red Herring in the Abortion Debate, by Joyce Arthur (2004)
Royal College of Obstetricians and Gynecologists (RCOG), Fetal Awareness: Review of Research and Recommendations for Practice (2010)
New York Times – Complex Science at Issue in Politics of Fetal Pain, by Pam Belluck, Sept 16, 2013