20-week old fetus. Nerve connections in the brain are not sufficiently formed to allow pain perception until after 24-weeks
Fetuses aged 24 weeks or less do not have the brain connections to feel pain, according to a working party report published this week by the UK Royal College of Obstetricians and Gynaecologists (RCOG).
Its conclusion is the latest to challenge the rationale for a law introduced in the US state of Nebraska in April. This law, which bans almost all abortions beyond 20 weeks of pregnancy, was introduced primarily on the grounds that the fetus feels pain.
The report, which reviews recent scientific literature on the subject, also concludes that the fetus is sedated throughout pregnancy by chemicals such as adenosine contained in the amniotic fluid that surrounds it.
Because the fetus is unable to feel pain before 24 weeks, no pain relief is needed for medical procedures up to that time, including abortion, the report concludes. This reverses the position the RCOG took in its previous report on fetal pain in 1997, which supported the use of analgesia.
“We have now advised that analgesia is not indicated up to 24 weeks,” says Allan Templeton, chairman of the working group that produced the report. He adds that administering painkillers carries risks of harming the fetus.
The report concludes that fetuses under 24 weeks must be pain-free, because at that age the wiring doesn’t exist to send pain signals from nerves around the body to the cortex, the area of the brain where pain is experienced. At which later point such connections form is unknown, so analgesia should still be considered after 24 weeks, the RCOG says.
When Nebraska legislators debated the state’s new abortion law, it was claimed that fetuses must feel pain because they have the same reflex reactions to pain as children and adults. Templeton dismisses this reasoning. “There are indeed reflex responses, but in our view, because the nerves are not wired up to the cortex, they are reflex actions without experience of pain,” he says.
The report notes that the same reflexes are seen in seriously malformed fetuses that have no brain at all, and therefore can’t possibly experience pain.
Templeton says the working party rejected the claims of Kanwaljeet Anand of Le Bonheur Children’s Medical Center in Memphis, Tennessee, who contends that young fetuses can feel pain in a more primitive part of the brain called the subcortex, which receives pain signals before the cortex has been wired up.
“Our scientists say there’s no evidence that the subcortex can provide for the pain experience,” Templeton told New Scientist. Anand’s evidence is widely cited by anti-abortion groups.
Templeton says that Anand’s evidence comes mainly from observations of responses in babies born prematurely, and that it cannot be assumed that these are expressions of pain, rather than painless reflex responses.
“Anand’s conclusions apply only to neonates,” Templeton says. “He has written opinions about how that might apply also to fetuses, but it’s not evidence, it’s opinion.”
The report argues that pain responses may begin to develop only after a baby is born, and no longer sedated in the womb, and that this may explain why neonates experience pain differently to fetuses. “It is only after birth, with the separation of the baby from the uterus and the umbilical cord, that wakefulness truly begins,” it concludes.
Via New Scientist