Management of fetal pain during invasive fetal procedures. A review.

In recent years, fetal stress and analgesia draw more and more attention. Evidence that fetuses show a significant endocrinological and hemodynamical response to invasive stimuli, and that these responses can be blocked by analgesia, suggests that fetuses experience a stress response, even if this does not signify they experience "pain". Moreover, it is becoming increasingly clear that experiences of pain of a fetus will be "remembered" by the developing nervous system, perhaps for the entire life of the individual, which can probably lead to abnormal behavioural patterns or altered nociception. But up to now, the entire mechanism of fetal stress response and the optimal analgesic drug, dose and route of administration is not so clear.