Synopsis of 'Lancet' Article On Fetal Pain

Author: Thomas Jackson

The article on fetal pain entitled, "Fetal plasma cortisol and beta-endorphin response to intrauterine needling" by Xenophon Giannakoulopoulus BSc. et al, out of the Department of Chemical Pathology, Institute of Obstetrics and Gynaecology, Royal Postgraduate Medical School, Queen Charlotte's and Chelsea Hospital, London W6 OXG, UK, appears in volume 344, n. 8915, pp 77-81 of "The Lancet". Correspondence is directed to Professor Nicholas M Fisk, Centre for Fetal Care at the same institution.

In brief, the investigators wished to find out whether the fetus mounts a hormonal response to potentialy painful procedures, such as intrauterine surgery. Previously they had noticed that during the placement of a catheter for a fetal transfusion, the fetus would respond with vigorous body and breathing movements. They noted that such movements were present when the catheter placement required abdominal puncture but not when there was direct cannulation of the umbilical cord (the umbilical cord is without nerves and therefore cannot cause pain). Measuring a stress hormonal response during these procedures would support the hypothesis that the fetus was experiencing pain.

They studied subjects between 20 and 34 weeks gestational age that were undergoing clinically indicated fetal blood sampling. They excluded infants with conditions that they would expect to cause hormonal elevations, such as severe anaemia, bradycardia and hypoxemia. 31 subjects were eventualy found to meet the criteria. About half had umbilical vein sampling (no nerves, no possibility of pain) and half had hepatic vein sampling (required intra-abdominal puncture with the possibility of pain). No difference was found in the plasma levels measured. However, the investigators felt that perhaps the amount of time it took to obtain the samples was insufficient to mount a hormonal response. Therefore, in a second set of 17 subjects that were undergoing transfusions they resampled the blood after the transfusion was completed. This produced a distinct difference between the hormonal levels in the hepatic vein cannulated group and the umbilical vein cannulated group. The group that had undergone hepatic vein cannulation (and therefore had a relatively huge needle stuck in their bellies) had a marked rise in their plasma cortisol and beta-endorphin levels. This response is consistent with an acute stress, such as pain. The umbilical vein group had no elevation in hormones.

The authors concluded that their study provides further evidence that the fetus can experience pain. They noted that the youngest subject that they studied was 23 weeks gestational age and that this subject's response was as vigorous as the older subject's. They suggested that physicians consider modifying their clinical practices accordingly, providing for analgesia when performing fetal procedures. In a final note they added:

"This applies not just to diagnostic and therapeutic procedures on the fetus, but possibly also to termination of pregnancy, especially by surgical techniques involving dismemberment."

Thomas R Jackson, M.D.