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Magnesium sulfate and uterine inversion
CORRESPONDENCE
Magnesium
sulfate
and uterine
inversion
7‘0 tll P Editor:
Drs. Platt and Druzin’ ascertained that nine of’ 28 \vomen with inversion of’ the uterus during the third stage of labor had also received magnesium suff’ate fx~renteralfy. This observation fed them to fx-esume that the administration of’ magnesium sulfate and, in turn, relaxation of’ the mymetrium were factors in the inversion. Interestingly. nine of’28 tvomen whose uteri Tvere inverted had I-ecei\ed osytocin. Hoxvever, no attemf~t ~vas made h\ them to implicate osytocin in the fxittiogenrsis of the inversions. f’latt and Dru/in cite as evidence that magnesium sulfate does eftecti\ ely impair mvometriaf contractions a textbook fxtblishetf some years ago’ and the report b! Steer and f’etritil which served to suggest that magnesium sultlte had a tocolvtic efftct when given to women \vho lvere thought to be in early premature labor. Since then, Stall\vorth, Yeh. and Petrie’ have reported that they fount1 only a transient decrease in ti-equency and no decrease in intensit) of’ uterine contractions in \\.omw in active labor \vhen magnesium sulfate was actministered parrnterafly. ,411 identical conclusion had been reached and. in turn, reported many years befijre.” hforeover. blood loss associated \\,ith vaginal deliver! has hcen comf>ared in Ivomen ~.ho did and did not recei\r magnesium sulfate during labor.” No significant ditfcrence ~vas t;~und. It is well established that the major mechanisms fol- effecting hemostasis at the site of placental imf)lantation immediatel! after deli\,VI-~ 01 the f)lacclita we c-ontraction and retraction ot’thc nl\onietl-iuln. Thewfi)re. if myometrial function was af)f~reciabl\- impairctl b\ magnesium sult’;ite. blood loss sho~~f~f ha\ c ken greater in \vomen xv110 recei\ ed the C~qx~“llcL
ft ~multl wem more likely that. rather than magnesium sulfate, the important tactor in the pathogenesis of the uterine inversions observed by Platt and Druzin M.~S that tfclivery ill all of their 2X cases was by either medical students or house officers in their first year of training.
REFERENCES
1. Platt, L. D., and Druzin, M. L.: AM. J. OBSTET. GYNECOL. 141:187, 1981. 2. Donald, I.: Practical Obstetrical Problems. ed. 4. Philadelphia. 1969, J. B. Lippincott Co., p. 609. 3. Steer, C. M.. and Petrie. R. H.: AM. J. OBSTET. GYNECOL. 129:l. 1977. 4. Stallworth, J. C., Yeh, S.-Y., and Petrie, R. H.: AM. J. OBSTET. GYNECOL. 140:702, 1981. 5. Pritchard, J. A.: Surg. Gynecol. Obstet. 100:131. 19%. 6. Rowland, R. C.. and Pritchard. J. .4.: AM. J. ORSTET. G~NECOI.. 89:261. 1964. Reply to Dr. Pritchard To fhp Editon:
We wish to thank Dr. Pritchard for his interest in our article. His contribution to our understanding of the mechanism of action of’ magnesium sulfate and its use in obstetric patients is well known. We agree bvith Dr. Pritchard that the level of training of the responsible physician was likely the most important factor in the cause of the inversion. We do believe, however. that magnesium sultate can be implicated as a possible contributing factor. As shown in Dr. Pritchard’s letter, Dr. Petrie and others did show that magnesium suftate does cause a decrease in frequency of uterine contractions even if not in intensity. This fact may still account f’or our conclusions about the possible association between uterine inversion and magnesium s&ate administration. While it is known that estimating blood loss is difficult, it is interesting to point out that there was no dit‘terence in blood loss betlveen the groups receiving magnesium sulfate and those who did not. This fact confirms Dr. Pritchard’s previous observation. Furthermore, in cases of’ uterine inversion. irrespective of tnagnesium sulfate administration, it appears that most blood loss occurs at the time of and during the inversion. We are not aware of any reports of severe uterine atony occurring at‘ter the uterus has been repositioned. This would seem to contradict what Dr. Pritchard suggests about blood loss. uterine contractions, and uterine inversion. Finally, we would agree wit11 Dr. Pritchard that the fact that osytocin and magnesium sultate \vere administered in equal numbers of‘ patients may also be implicatetf. This was mentioned f,ut we chose not to elaborate on it. 725
Magnesium
sulfate
and uterine
inversion
7‘0 tll P Editor:
Drs. Platt and Druzin’ ascertained that nine of’ 28 \vomen with inversion of’ the uterus during the third stage of labor had also received magnesium suff’ate fx~renteralfy. This observation fed them to fx-esume that the administration of’ magnesium sulfate and, in turn, relaxation of’ the mymetrium were factors in the inversion. Interestingly. nine of’28 tvomen whose uteri Tvere inverted had I-ecei\ed osytocin. Hoxvever, no attemf~t ~vas made h\ them to implicate osytocin in the fxittiogenrsis of the inversions. f’latt and Dru/in cite as evidence that magnesium sulfate does eftecti\ ely impair mvometriaf contractions a textbook fxtblishetf some years ago’ and the report b! Steer and f’etritil which served to suggest that magnesium sultlte had a tocolvtic efftct when given to women \vho lvere thought to be in early premature labor. Since then, Stall\vorth, Yeh. and Petrie’ have reported that they fount1 only a transient decrease in ti-equency and no decrease in intensit) of’ uterine contractions in \\.omw in active labor \vhen magnesium sulfate was actministered parrnterafly. ,411 identical conclusion had been reached and. in turn, reported many years befijre.” hforeover. blood loss associated \\,ith vaginal deliver! has hcen comf>ared in Ivomen ~.ho did and did not recei\r magnesium sulfate during labor.” No significant ditfcrence ~vas t;~und. It is well established that the major mechanisms fol- effecting hemostasis at the site of placental imf)lantation immediatel! after deli\,VI-~ 01 the f)lacclita we c-ontraction and retraction ot’thc nl\onietl-iuln. Thewfi)re. if myometrial function was af)f~reciabl\- impairctl b\ magnesium sult’;ite. blood loss sho~~f~f ha\ c ken greater in \vomen xv110 recei\ ed the C~qx~“llcL
ft ~multl wem more likely that. rather than magnesium sulfate, the important tactor in the pathogenesis of the uterine inversions observed by Platt and Druzin M.~S that tfclivery ill all of their 2X cases was by either medical students or house officers in their first year of training.
REFERENCES
1. Platt, L. D., and Druzin, M. L.: AM. J. OBSTET. GYNECOL. 141:187, 1981. 2. Donald, I.: Practical Obstetrical Problems. ed. 4. Philadelphia. 1969, J. B. Lippincott Co., p. 609. 3. Steer, C. M.. and Petrie. R. H.: AM. J. OBSTET. GYNECOL. 129:l. 1977. 4. Stallworth, J. C., Yeh, S.-Y., and Petrie, R. H.: AM. J. OBSTET. GYNECOL. 140:702, 1981. 5. Pritchard, J. A.: Surg. Gynecol. Obstet. 100:131. 19%. 6. Rowland, R. C.. and Pritchard. J. .4.: AM. J. ORSTET. G~NECOI.. 89:261. 1964. Reply to Dr. Pritchard To fhp Editon:
We wish to thank Dr. Pritchard for his interest in our article. His contribution to our understanding of the mechanism of action of’ magnesium sulfate and its use in obstetric patients is well known. We agree bvith Dr. Pritchard that the level of training of the responsible physician was likely the most important factor in the cause of the inversion. We do believe, however. that magnesium sultate can be implicated as a possible contributing factor. As shown in Dr. Pritchard’s letter, Dr. Petrie and others did show that magnesium suftate does cause a decrease in frequency of uterine contractions even if not in intensity. This fact may still account f’or our conclusions about the possible association between uterine inversion and magnesium s&ate administration. While it is known that estimating blood loss is difficult, it is interesting to point out that there was no dit‘terence in blood loss betlveen the groups receiving magnesium sulfate and those who did not. This fact confirms Dr. Pritchard’s previous observation. Furthermore, in cases of’ uterine inversion. irrespective of tnagnesium sulfate administration, it appears that most blood loss occurs at the time of and during the inversion. We are not aware of any reports of severe uterine atony occurring at‘ter the uterus has been repositioned. This would seem to contradict what Dr. Pritchard suggests about blood loss. uterine contractions, and uterine inversion. Finally, we would agree wit11 Dr. Pritchard that the fact that osytocin and magnesium sultate \vere administered in equal numbers of‘ patients may also be implicatetf. This was mentioned f,ut we chose not to elaborate on it. 725