One of the sources of the claim:


The fetus can feel pain at 20 weeks. This is probably a conservatively late estimate, but it is scientifically solid. Elements of the pain-conveying system (spino-thalamic system) begin to be assembled at 7 weeks; enough development has occurred by 12-14 weeks that some pain perception is likely, and continues to build through the second trimester. By 20 weeks, the spino- thalamic system is fully established and connected.

The bolded text indicates that the pain may be felt between weeks 12-18.

Are the claims in the bolded statement accurate according to research?

FYI here is a copy of the statement by a neurologist (and one-time expert witness), on which the above claim is based but which is 404 in the above article: Dr. Paul J. Ranalli Statement

Converging scientific evidence suggests that pain perception is present, at the very latest, by 20 weeks gestation.

  • 2
    Props to @DVK for adding a claim.
    – Oddthinking
    Oct 20, 2011 at 14:00
  • 2
    This seems hard to answer "according to research". How? Would anyone do a research on 20 weeks old fetus? Perhaps some answer by analogy would do? Other question seems to suggest a lobster can feel pain. Could perhaps a fetus nervous system be compared to that of a lobster?
    – Suma
    Jan 13, 2012 at 8:46
  • The terrible irony to me is that research on this would most likely be considered unethical :(
    – Benjol
    Jun 26, 2015 at 13:31

1 Answer 1


No, Human fetus cannot feel pain at 20 weeks per three research studies mentioned.

  1. Per conclusions of the 2005 JAMA study

    Evidence Synthesis Pain perception requires conscious recognition or awareness of a noxious stimulus. Neither withdrawal reflexes nor hormonal stress responses to invasive procedures prove the existence of fetal pain, because they can be elicited by nonpainful stimuli and occur without conscious cortical processing. Fetal awareness of noxious stimuli requires functional thalamocortical connections. Thalamocortical fibers begin appearing between 23 to 30 weeks’ gestational age, while electroencephalography suggests the capacity for functional pain perception in preterm neonates probably does not exist before 29 or 30 weeks.

    Conclusions Evidence regarding the capacity for fetal pain is limited but indicates that fetal perception of pain is unlikely before the third trimester. Little or no evidence addresses the effectiveness of direct fetal anesthetic or analgesic techniques. Similarly, limited or no data exist on the safety of such techniques for pregnant women in the context of abortion.


    While the presence of thalamocortical fibers is necessary for pain perception, their mere presence is insufficient—this pathway must also be functional. It has been proposed that transient, functional thalamocortical circuits may form via subplate neurons around midgestation, but no human study has demonstrated this early functionality. Instead, constant SEPs appear at 29 weeks’ PCA, and EEG patterns denoting wakefulness appear around 30 weeks’ PCA. Both of these tests of cortical function suggest that conscious perception of pain does not begin before the third trimester. Cutaneous withdrawal reflexes and hormonal stress responses present earlier in development are not explicit or sufficient evidence of pain perception because they are not specific to noxious stimuli and are not cortically mediated.

  2. Per conclusions of the 2006 study 'Can fetuses feel pain?'

    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 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.

  3. Per conclusions of the 1999 study Fetal pain: implications for research and practice

    The physical system for nociception is present and functional by 26 weeks and it seems likely that the fetus is capable of feeling pain from this stage.

The Royal College of Obstetricians and Gynaecologists' Fetal Awareness -- Review of Research and Recommendation for Practice (March 2010) says,

In reviewing the neuroanatomical and physiological evidence in the fetus, it was apparent that connections from the periphery to the cortex are not intact before 24 weeks of gestation and, as most neuroscientists believe that the cortex is necessary for pain perception, it can be concluded that the fetus cannot experience pain in any sense prior to this gestation.

The American Congress of Obstetricians and Gynecologists issued a statement in 2012:


The American Congress of Obstetricians and Gynecologists (ACOG) opposes HR 3803, the District of Columbia Pain-Capable Unborn Child Protection Act, and other legislative proposals that are not based on sound science or that attempt to prescribe how physicians should care for their patients.

Fetal Pain
The medical profession produced a rigorous scientific review of the available evidence on fetal pain in Journal of the American Medical Association (JAMA) in 20051. The review concluded that fetal perception of pain is unlikely before the third trimester. No new studies since the publication of the JAMA paper have changed this dominant view of the medical profession.

1. Lee SJ, Ralston HJP, Drey EA, Partridge JC, Rosen MA. Fetal pain: A systematic multidisciplinary review of the evidence. JAMA 2005; 294: 947-954.

  • 9
    I'd like to +1 this answer for referencing expert evidence, but I'm wary: because these studies were authored by the same species who until recently taught that babies and animals couldn't feel pain. Reason suggests to me that ability to feel physical pain as we know it must develop (and previously be absent), and that physical "pain" and self-conscious "suffering" aren't the same thing ... yet I'm wary of the authors. :-)
    – ChrisW
    Jun 26, 2015 at 12:08
  • 4
    The quote from the third reference states only that the fetus is likely able to feel pain by 26 weeks; it says nothing about whether or not it can feel pain before that, and (that quote at least) does not support your conclusion that "[h]uman fetus cannot feel pain at 20 weeks." Jun 26, 2015 at 14:00
  • I quoted a couple of extra paragraphs from the JAMA study because that explains their reasoning (i.e. the reasons for their conclusions).
    – ChrisW
    Jun 26, 2015 at 16:31

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