From when does a human fetus feel pain?

One of the most frequent and controversial questions that have been generated in the area of ​​sexual health and reproductive health, along with the discussions on the legislation and management of abortion, is the following: Does a human fetus feel pain? In part these discussions have followed the idea that early central nervous system development is a sufficient condition for the experience of pain.

Considering that there is no consensus on the approach to this issue, in this article we present some of the research and theories that have been carried out to discuss the issue.

• Related article: "The 3 phases of intrauterine or prenatal development: from the zygote to the fetus"

Can a human fetus feel pain?

In 2006 Stuart Derbyshire, a member of the psychology department at the National University of Singapore and an expert in cognitive science, he discusses this issue taking a United States government policy as its axis. The latter determined that it was the obligation of the doctor advise women who intend to abort

about the existence of some indications that abortion may cause pain to the fetus.

Based on this, the doctor also had the obligation to offer the woman the option of reducing said pain by applying drugs before aborting. The consequence of not warning about all of the above could cost doctors thousands of dollars.

On the other side of the world, in England, at the beginning of the last decade a series of images were offered that sought to argue for the idea that the fetus has a series of cognitive and emotional. Said images finally impacted on British policies on pre-abortion pharmacological interventions to ease the pain of the fetus.

Stuart Derbyshire discusses the available evidence on all of the above, looking at the neurobiological development of the fetal period together with the experiential dimension of pain.

• You may be interested in: "Nociceptors (pain receptors): definition and types"

When does fetal development begin?

Fetal development is that which occurs after the 12th week. In other words, the embryo that has evolved after the first 3 months of gestation is considered a “fetus”.

Over the course of the next 5 to 6 months until delivery occurs, the fetus is expected to develop cells, organs, tissues and even systems that will be a necessary condition to ensure its birth. Having said this, we will define what pain is from a psychological perspective, as well as those elements that are considered necessary to be able to experience it.

What is the pain?

The International Association for the Study of Pain (IASP) says that pain is an unpleasant sensation and emotional experience associated with potential or actual tissue damage, or, it is an experience described in terms of said damage.

From this we can say that pain is a conscious experience, and not just a response to noxious stimuli (Derbyshire, 2006). With which it is also a subjective experience that can be qualitatively modified from one person to another. In addition, for an organism to experience pain, it needs a series of physiologically mature structures. A complex network of cortical regions has to be activated; which can occur even in the absence of actual noxious stimulation.

In the event that harmful stimulation occurs, the latter is an external event that generates electrical activity between the brain and the nerves in the skin, which ultimately generates an experience painful. That is, for an organism to feel pain, there must first be the possibility of the nervous system being activated.

Likewise, for the experience of pain to occur, other cognitive processes related to the state of consciousness and memory must be developed, which allow in turn signify and discriminate an event as "painful" (an issue in which the way in which we learn to name said event through the the rest).

In other words, although pain is an individual experience (of physiological processes and cognitive processes with which we generate a mental representation of pain), it can also be seen as an experience that is experienced in interaction with others.

Pain experience and fetal development

Approximately, it is in the 7th week of gestation when the nerve terminals begin to develop, as well as some parts of the spinal cord (which is a fundamental connector of the brain and which will give rise to the thalamus, an important organ for sensory experiences).

This lays the foundation for creating a hypothalamic structure that is a necessary condition for the experience of pain. But the latter does not mean that hypothalamic activity is consolidated: the density of neuronal cells lining the brain is in the process of consolidation. Before this consolidation ends, the neuronal cells are not capable of processing harmful information. from the periphery.

In other words, the nervous system is not fully developed and mature, with which, we can hardly sustain or conclude that the experience of pain occurs during development fetal.

The first evidence of sufficient hypothalamic activity begins to appear between the 12th and 16th week of gestation.. It is then that the neural connections within the cerebral cortex begin to mature. Afferent fibers develop from 23 to 25 weeks. However, there is not enough functional neuronal activity to speak of an experience of pain in the fetus, because the spinothalamic fibers have not connected in the cortical plate cerebral.

The 26th week and other fundamental stages

The thalamic projections on the plate of the cerebral cortex are the minimum anatomical condition necessary to experience pain, and are completed by the 23rd week of gestation. At the same time, the peripheral nerve terminals that will generate reflexes in the cerebral cortex develop.

For this reason, several investigations have suggested that the minimum gestational week to suspect the pain experience in the fetus is number 26 (around 7 months of gestation), which is when the activity electrical is similar to that presented by children and adults when they respond to harmful situationsOr, when they explain an experience as painful.

On the other hand, the secretion of different hormones is also needed; process that begins to be observable in fetuses from the first 18 weeks of gestation.

The problem, Derbyshire (2006) tells us, is that what happens inside the placenta is significantly different from what happens outside the placenta, both in neurochemical terms and in the way of responding to noxious stimuli, and therefore on sensitive experiences.

In this same sense, the most classic studies on pain experiences have consisted of relating the electrical activity of the brain with the experience of pain that is verbally reported by the same person.

Because this cannot be done with a fetus, scientific investigations have focused on to theorize about the possibility that there is an experience of pain by analyzing the embryonic development of the nervous system. From there they suggest that the experience of pain exists because it is similar to what a child or an adult already verbalizes.

In other words, investigations have had to resort to the interpretation of secondary evidence, and for the same reason reason they have only been able to speak of indications, not of conclusive results about the experience of pain in the development fetal.

In summary

To feel pain not only we need the ability to discriminate between different sensory stimuli. Nor is it about reacting to potentially harmful stimuli (a quality known as “nociception”). The experience of pain also implies responding consciously, that is, we also need the ability to discriminate between different experiences; issue that is generated by interactions with our caregivers after birth, among other processes such as the development of the mind.

Therefore, we need a mature nervous system that allows us to process and represent said stimulus as harmful and later as painful.

There are numerous Important neurobiological processes that begin at week 7, week 18, and week 26 of gestation. These same ones have been considered by many as the stages where a human fetus could feel pain. What Derbyshire (2006) quickly warns us about is that the subjective experience that accompanies pain cannot be deduced directly from anatomical development, since these developments are not the ones that give rise to the conscious contents proper to the pain.

Bibliographic references:

• Derbyshire, S. (2006). Can fetuses feel pain? BMJ, 332: 909-912.