AMERICAN JOURNAL OF PERINATOLOGY/VOLUME 8, NUMBER 1
January 1991
ROLE OF AMNIOTIC FLUID CYTOGENETIC ANALYSIS IN THE EVALUATION OF RECENT FETAL DEATH Kim Brady, M.D., Patrick Duff, M.D., Frederick E. Harlass, M.D., and Steven Reid, B.S.
Chromosome abnormalities may be present in approximately 10% of cases of fetal death. Because of cell maceration and autolysis, the likelihood of successful karyotype analysis of fetal tissue varies inversely with the time between fetal death and delivery. In an attempt to reduce the influence of these postmortem changes, we obtained amniotic fluid cells for cytogenetic studies from 12 fetuses as soon as possible after the diagnosis of fetal death was confirmed. We also obtained fetal tissue for cell culture in ten of the cases immediately following evacuation of the uterus. Cell culture was successful in 11 of 12 amniotic fluid specimens and in only one often fetal tissue specimens (p < 0.001). Since the results of cytogenetic studies are of such importance in counseling patients regarding recurrence risk for fetal death, we recommend that amniotic fluid cells be obtained for karyotype analysis at the time of diagnosis of fetal death rather than awaiting delivery of a potentially macerated and autolyzed fetus.
Identification of the cause of fetal death is possible in approximately 50% of cases when appropriate studies are performed, including fetal karyotyping.' >2 However, because of the inevitable delay between actual fetal death and delivery, tissue maceration and autolysis often occur, thus interfering with successful culture and cytogenetic analysis of fetal tissue. In an attempt to circumvent this problem of tissue maceration, we obtained amniotic fluid samples from 11 patients who had experienced a recent fetal death. The principal purpose of this report is to describe the results of amniotic fluid cell cultures in these individuals. A second objective is to compare the results of amniotic fluid cell cultures to cultures of fetal tissue obtained after delivery. MATERIALS AND METHODS
We documented fetal death with a dynamic imaging scanner (General Electric RT 3000). In 10 of 11 patients, we obtained informed written consent in
accordance with guidelines established by the Institutional Review Board. Amniocentesis was then performed under continuous ultrasound guidance. We used a 20 gauge needle to aspirate 10 to 20 ml of amniotic fluid.3 Amniotic fluid was clear in the three patients in whom the interval from last documented viability to diagnosis was less than 8 days. In the remaining eight patients, the amniotic fluid was discolored. In no instance was there evidence of gross blood or meconium. In the one patient who had a twin gestation, we obtained amniotic fluid from both sacs. One patient who initially refused amniocentesis subsequently consented to aspiration of amniotic fluid through an intrauterine pressure catheter following amniotomy. We were able to obtain an adequate sample of amniotic fluid by this method. Eight patients underwent oxytocin induction of labor and had spontaneous vaginal deliveries. Two underwent dilation and evacuation of the uterus. One required hysterotomy because of hemorrhage from placenta previa. We obtained informed written consent for autopsy from all patients. In addition, in 10 of the 12
Division of Maternal-Fetal Medicine, Madigan Army Medical Center, Tacoma, Washington, and the Cytogenetics Laboratory, Nichols Institute, San Juan Capistrano, California The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the United States Department of the Army or the Department of Defense. Reprint requests: Dr. Brady, Department of Obstetrics and Gynecology, Madigan Army Medical Center, Tacoma, WA 98431-5418 68
Copyright © 1991 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
Downloaded by: Universite Laval. Copyrighted material.
ABSTRACT
AMNIOTIC FLUID ANALYSIS IN EVALUATING FETAL DEATH/Brady, Duff, Harlass, Reid
Table 1.
Age Gestational
Fetal Weight (gm)
Case
(yr)
Age (wk)
1 2 3* 4
24 19 33 23 18 19
30 14
1320
37 39 14
2650 3630
29 20 21 21 28
22
5 6 7 8 9a (twin) 9b (twin)
10 11
17
30 35 16 16 17 36
Interval from Last Documented Viability to Diagnosis* (days)
165 170 158
3345
14
102 680 410
2200
RESULTS
Table 1 summarizes our results. All 12 maternal skin specimens yielded cell growth, thus verifying our methodology in the sampling and processing of the fetal fascia lata specimens. Several of our findings merit additional discussion. First, the frequency of successful amniotic fluid cultures was greater than that of fetal tissue cultures (p < 0.001). Second, the interval from last documentation of fetal viability to diagnosis of fetal death was greater than or equal to 14 days in seven cases. All but one of the cases still had successful amniotic fluid cell growth. Six of these patients also had fetal fascia lata submitted for cell culture, but none of the specimens yielded sufficient growth for karyotype analysis. Fascia lata tissue was successfully cultured in only one patient, in whom the interval from diagnosis of death to delivery was 1 day. In this case, the karyotype result was identical to that obtained from amniotic fluid. However, the amniotic fluid cells were much easier to grow, and the results of the amniotic fluid cell culture were available 3 weeks earlier. Third, in case 4, the amniotic fluid karyotype was 46,XX/47,XX, + 3 in one of the three flasks harvested. The other two cultured flasks grew 20 and 30 cells, and all cells consisted of a normal 46,XX cell line. This suggests that the 46,XX/47,XX,+3 karyotype represented pseudomosaicism.5 Gross examina-
Results of Cytogenetic Analysis in Study Patients
2 28 1 7 21 31 14 14 12 12 20
110
control tissue specimens in order to validate our tissue-sampling technique, culture media, transport method, and genetic laboratory procedures. Tissue samples from maternal skin and fascia lata biopsies were cultured in the same medium as utilized for the amniotic fluid specimens. G-banding was performed on these specimens as already described. We used Fisher's exact test to compare the difference in successful karyotype analysis in amniotic fluid cells versus fetal tissue culture. We considered a probability value
January 1991
ROLE OF AMNIOTIC FLUID CYTOGENETIC ANALYSIS IN THE EVALUATION OF RECENT FETAL DEATH Kim Brady, M.D., Patrick Duff, M.D., Frederick E. Harlass, M.D., and Steven Reid, B.S.
Chromosome abnormalities may be present in approximately 10% of cases of fetal death. Because of cell maceration and autolysis, the likelihood of successful karyotype analysis of fetal tissue varies inversely with the time between fetal death and delivery. In an attempt to reduce the influence of these postmortem changes, we obtained amniotic fluid cells for cytogenetic studies from 12 fetuses as soon as possible after the diagnosis of fetal death was confirmed. We also obtained fetal tissue for cell culture in ten of the cases immediately following evacuation of the uterus. Cell culture was successful in 11 of 12 amniotic fluid specimens and in only one often fetal tissue specimens (p < 0.001). Since the results of cytogenetic studies are of such importance in counseling patients regarding recurrence risk for fetal death, we recommend that amniotic fluid cells be obtained for karyotype analysis at the time of diagnosis of fetal death rather than awaiting delivery of a potentially macerated and autolyzed fetus.
Identification of the cause of fetal death is possible in approximately 50% of cases when appropriate studies are performed, including fetal karyotyping.' >2 However, because of the inevitable delay between actual fetal death and delivery, tissue maceration and autolysis often occur, thus interfering with successful culture and cytogenetic analysis of fetal tissue. In an attempt to circumvent this problem of tissue maceration, we obtained amniotic fluid samples from 11 patients who had experienced a recent fetal death. The principal purpose of this report is to describe the results of amniotic fluid cell cultures in these individuals. A second objective is to compare the results of amniotic fluid cell cultures to cultures of fetal tissue obtained after delivery. MATERIALS AND METHODS
We documented fetal death with a dynamic imaging scanner (General Electric RT 3000). In 10 of 11 patients, we obtained informed written consent in
accordance with guidelines established by the Institutional Review Board. Amniocentesis was then performed under continuous ultrasound guidance. We used a 20 gauge needle to aspirate 10 to 20 ml of amniotic fluid.3 Amniotic fluid was clear in the three patients in whom the interval from last documented viability to diagnosis was less than 8 days. In the remaining eight patients, the amniotic fluid was discolored. In no instance was there evidence of gross blood or meconium. In the one patient who had a twin gestation, we obtained amniotic fluid from both sacs. One patient who initially refused amniocentesis subsequently consented to aspiration of amniotic fluid through an intrauterine pressure catheter following amniotomy. We were able to obtain an adequate sample of amniotic fluid by this method. Eight patients underwent oxytocin induction of labor and had spontaneous vaginal deliveries. Two underwent dilation and evacuation of the uterus. One required hysterotomy because of hemorrhage from placenta previa. We obtained informed written consent for autopsy from all patients. In addition, in 10 of the 12
Division of Maternal-Fetal Medicine, Madigan Army Medical Center, Tacoma, Washington, and the Cytogenetics Laboratory, Nichols Institute, San Juan Capistrano, California The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the United States Department of the Army or the Department of Defense. Reprint requests: Dr. Brady, Department of Obstetrics and Gynecology, Madigan Army Medical Center, Tacoma, WA 98431-5418 68
Copyright © 1991 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
Downloaded by: Universite Laval. Copyrighted material.
ABSTRACT
AMNIOTIC FLUID ANALYSIS IN EVALUATING FETAL DEATH/Brady, Duff, Harlass, Reid
Table 1.
Age Gestational
Fetal Weight (gm)
Case
(yr)
Age (wk)
1 2 3* 4
24 19 33 23 18 19
30 14
1320
37 39 14
2650 3630
29 20 21 21 28
22
5 6 7 8 9a (twin) 9b (twin)
10 11
17
30 35 16 16 17 36
Interval from Last Documented Viability to Diagnosis* (days)
165 170 158
3345
14
102 680 410
2200
RESULTS
Table 1 summarizes our results. All 12 maternal skin specimens yielded cell growth, thus verifying our methodology in the sampling and processing of the fetal fascia lata specimens. Several of our findings merit additional discussion. First, the frequency of successful amniotic fluid cultures was greater than that of fetal tissue cultures (p < 0.001). Second, the interval from last documentation of fetal viability to diagnosis of fetal death was greater than or equal to 14 days in seven cases. All but one of the cases still had successful amniotic fluid cell growth. Six of these patients also had fetal fascia lata submitted for cell culture, but none of the specimens yielded sufficient growth for karyotype analysis. Fascia lata tissue was successfully cultured in only one patient, in whom the interval from diagnosis of death to delivery was 1 day. In this case, the karyotype result was identical to that obtained from amniotic fluid. However, the amniotic fluid cells were much easier to grow, and the results of the amniotic fluid cell culture were available 3 weeks earlier. Third, in case 4, the amniotic fluid karyotype was 46,XX/47,XX, + 3 in one of the three flasks harvested. The other two cultured flasks grew 20 and 30 cells, and all cells consisted of a normal 46,XX cell line. This suggests that the 46,XX/47,XX,+3 karyotype represented pseudomosaicism.5 Gross examina-
Results of Cytogenetic Analysis in Study Patients
2 28 1 7 21 31 14 14 12 12 20
110
control tissue specimens in order to validate our tissue-sampling technique, culture media, transport method, and genetic laboratory procedures. Tissue samples from maternal skin and fascia lata biopsies were cultured in the same medium as utilized for the amniotic fluid specimens. G-banding was performed on these specimens as already described. We used Fisher's exact test to compare the difference in successful karyotype analysis in amniotic fluid cells versus fetal tissue culture. We considered a probability value
