Volume 187, Number 1 Letters 259Am J Obstet Gynecol

twins with growth retardation. They describe the resultsof 11 patients undergoing therapy and compare those re-sults with the results of 17 patients treated expectantly. Al-though survival rates were no different between groups,they report “of live-born babies, neurologic handicap waspresent in 3 of 22 babies (13.67%) versus 0 of 12” in the 2groups, “P < .0001,” which they characterize as resultingin “decreased neonatal morbidity.”

Examination of the statistics section in the article de-tails that χ2 Fisher exact tests were used. But on page 692the statistic mentioned to compare the neurologic out-come of 3 of 22 versus 0 of 12 is the χ2 test.

Because the sampling distribution of the χ2 test willconform to the theoretic distribution of χ2 only if the ex-pected number of each cell is >5, the binomial probabil-ity with a Fisher exact test should be used.2 Thatcalculation was [22!12!31!3!/19!12!0!3!34!] = 0.26,demonstrating a 0.26 likelihood the observed differencecould have occurred by chance.

Whatever place the modality described by Quintero etal may achieve and whatever conclusion the authors mayderive from their experience, the conclusion regarding areduction in neonatal morbidity, as it pertains to neuro-logic handicap, should be modified.

Stephen A. Myers, DO, and Timothy L. Bennett, MDDivision of Fetal-Maternal Medicine, Department of Obstetrics and Gy-necology, University of Kansas Medical Center, 3901 Rainbow Dr,Kansas City, KS 66160-7316

REFERENCES

1. Quintero RA, Bornick PW, Morales WJ, Allen MH. Selective pho-tocoagulation of communicating vessels in the treatment ofmonochorionic twins with selective growth retardation. Am JObstet Gynecol 2001;185:689-96.

2. Bahn AK. Basic medical statistics. New York: Grune & Stratton;1972.

6/8/124943doi:10.1067/mob.2002.124943

ReplyTo the Editors: We would like to thank Drs Myers and Ben-net for their interest in our paper and for their observa-tions. Indeed, they are correct. Review of the statisticalanalysis conducted for this manuscript showed that aFisher exact test was performed to compare the inci-dence of neurologic morbidity between the two groupsand that the P value was .26. We regret this error.

Optimal management of the patient with selective in-trauterine growth retardation (SIUGR) in a monochori-onic twin pregnancy remains an important clinicalchallenge. Spontaneous death of the SIUGR twin may re-sult in concomitant death of the appropriately grown(AGA) twin in up to 40% of cases or in neurologic dam-age of the AGA twin in up to 30% of cases.1-3 Because theadverse effects resulting from the spontaneous death ofthe SIUGR twin are thought to be mediated by post-mortem fetofetal hemorrhage through placental vascularanastomoses, we proposed that laser ablation of suchanastomoses would protect the unaffected twin. The ex-

perience reported in our paper indicates that (1) the vas-cular anastomoses can be identified through operative fe-toscopy, (2) it is feasible to ablate such anastomoses, thustransforming the pregnancy into a “functionally dichori-onic” twin gestation, and (3) these anastomoses may playa role in the disease, as shown by dramatic improvementin the Doppler indices in some SIUGR fetuses. Collec-tively, these observations have contributed to further theunderstanding of the disease process and have generateda new alternative for patient management.

Although termination of pregnancy or umbilical cordocclusion remain as valid options for these patients, ei-ther one of these procedures deny the affected twin achance to survive. Moreover, these procedures requirethat parents make a decision to terminate the life of oneor both twins. Our approach, selective laser photocoagu-lation of the communicating vessels,4 creates a differenttherapeutic option for the affected twin, the unaffectedtwin, parents, and physicians. The place of this novel sur-gical approach in clinical management will need to be es-tablished in future studies, as originally proposed in ourpaper.

Rubén A. Quintero, MDSt Joseph’s Women’s Hospital, Florida Institute for Fetal Diagnosis andTherapy, 13601 Bruce B. Downs Blvd, Tampa, FL 33613

REFERENCES

1. Dudley D, D’Alton M. Single fetal death in twin gestation. SeminPerinatol 1986;10:65-72.

2. Fusi L, Gordon H. Twin pregnancy complicated by single in-trauterine death: problems and outcome with conservative man-agement. Br J Obstet Gynaecol 1990;97:511-6.

3. Lin Ii, Chen CH, Wang TM, Fu LS, Chi CS. Infants of twin preg-nancies with one twin demise in the uterus: a retrospective study.Taiwan Erh Ko I Heueh Hui Tsa Chih 1999;40:92-6.

4. Quintero R, Morales W, Mendoza G, Allen M, Kalter C, Gian-nina G, et al. Selective photocoagulation of placental vessels intwin-twin transfusion syndrome: evolution of a surgical tech-nique. Obstet Gynecol Surv 1998;53:s97-103.

6/8/124944doi:10.1067/mob.2002.124943

Patients with severe eclampsia benefit from long-term epidural analgesiaTo the Editors: I read with interest the article by Lucas et al1in the October 2001 issue of the Journal. It was a nicelyplanned and well-conducted study with very good numbers,but I could not agree with the authors’ conclusion that theepidural analgesia offers no additional therapeutic benefitin patients with pregnancy-induced hypertension.

I would like to bring to the notice of the authors thatthere have been many recent publications regarding thevascular reactivity of patients with preeclampsia2 and thestate of sympathetic overactivity in them.3 In the back-ground of uncertain etiology and ongoing research tofind a causative factor for preeclampsia, Kanayama et al4in Japan have successfully treated, with long-termepidural analgesia, a group of patients with severe pre-eclampsia. They showed a better outcome compared withconventional management of these patients.4 I believe