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Morphological studies of Dalkon Shield tails removed from patients
MORPHOLOGICAL
Howard
STUDIES OF DALKON SHIELD TAILS REMOVED FROM PATIENTS
J. Tatum, M.D., Ph.D., Frederick H. Schmidt, and David M. Phillips, Ph.D.
The Population Council, The Rockefeller New York, New York 10021
M.A.
University
Abstract Examination of the tails of Dalkon Shields removed from patients showed that approximately 34% of the tails had breaks or holes in the nylon sheath immediately below the double knot at the base of the Shield. The location of these holes is such that most of them would have been within the endometrial cavity. For control purposes, unused sterile Shields were removed from their pouches, and the tails were inspected for breaks in the sheath. Breaks were found in approximately 9% of these. Most of the holes were in the same location as those seen in tails removed from patients. The internal contents of the short terminal segments of Dalkon tails located beyond the double knot, from Shields removed from patients, were studied. Thirty-five (35) segments were evaluated by phase contrast microscopy and 10 were studied subsequently by transmission electron microscopy. Bacteria were found within the interfilamental spaces inside the sheath of 8 of the 10 tails. These observations suggest that bacteria which have ascended through the tail from the vagina could exit through these breaks in the sheath or from the terminal end of the tail directly into the endometrial cavity. The potential clinical implications of the data presented in this paper must be taken into consideration in the management of the non-pregnant asymptomatic wearer of a Dalkon Shield.
Detailed summaries of these investigations were sent to the U.S. Food and Drug Administration on January 25, 1975, and on February 27, 1975. These data were also presented in part to the National Medical Committee of Planned Parenthood-World Population on January 29, 1975 (New York). Accepted
APRIL
for
1975
publication
February
VOL. 11 NO. 4
6,
1975
465
CONTRACEPTION
Introduction The complex multifilament tail of the Dalkon Shield intrauterine device has been shown by Tatum et al.(l)to function -in vivo as a wick, thus allowing bacteriafrom the vagina to enter the interfibrillar spaces within the nylon sheath of the tail and ascend through the interspaces at least as far as the double knot at the base of the Shield. It was postulated that bacteria from these interfibrillar spaces could gain access to the endometrial cavity by one of three mechanisms. (A) In case of pregnancy with the Shield in situ, gradual enlargement of the uterus often is accompanied be retraction of the tail upward until at 10 or 12 weeks of pregnancy the tail disappears from the vagina and cervix and gradually enters the endometrial cavity. Bacteria which were within the nylon sheath and protected from the bactericidal endocervical environment could then exit from the open end of the tail and enter the extraovular space within the uterus. (B) A break in the nylon sheath near the base of the Shield within the endometrial cavity could allow the escape of bacteria which had ascended from the vagina through the interfibrillar spaces within the sheath. (C) BaCteria from the vagina could ascend through the entire length of the tail and exit from the open end beyond the double knot at the base of the Shield into the endometrial cavity. The purpose of this paper is to present additional new data which support both of the theories described in (B) and (C) above. Materials and Methods Breaks in the Nylon Sheath Distal to Double Knot The tails of 662 Dalkon Shields which had been removed electively from patients were examined under a dissecting microscope for breaks in the nylon sheath. Since we were concerned only with breaks which had been located within the endometrial cavity, we recorded only those breaks which were located 3 mm or less below the double knot which is located at the base of the Shield. The Shields which were examined had been in patients from 2 months to 4 years. A schematic diagram illustrating the location of the breaks in the sheath is shown in Figure 1A. The tails of 239 new Dalkon Shields were examined in a similar manner.
466
APRIL
1975 VOL. 11 NO. 4
CONTRACEP’I’ION
Internal Contents of Terminal End of Proximal Segment of Tail In order to determine whether or not bacteria from the vagina had ascended within the nylon sheath beyond the single knot (Figure 1D) and had passed through the constrictions produced by the double knot (Figure 1C) at the base of the Dalkon Shield, the terminal ends of the tails from 35 Shields were examined either by phase contrast microscopy or by electron microscopy. The location of the segment studied is indicated in Figure 1B. The Dalkon Shields with the attached tail were placed in a solution of glutaraldehyde immediately after their elective removal from patients. Thirty-five (35) tails which had been in place from 5 months to 4 years were sectioned and studied by phase microscopy. A subsequent detailed study of 10 of these was made by transmission electron microscopy. Only those tails which had no visible breaks in the sheath were embedded in plastic (Epon 812) and processed for ultrastructural evaluation. Three Dalkon Shields which had previously perforated the uterus and entered the peritoneal cavity were removed surgically, placed immediately in sterile culture tubes, and sent to us for bacteriologic study. Samples from these tails and the Shields themselves were cultured aerobically and anaerobically immediately after they arrived at our laboratory. The incubation of the samples was initiated 4 to 7 days following their removal from patients. In addition to the cultures, portions from one tail were sectioned for electron microscopy. Results The results of the Dalkon Shields examined for breaks in the sheath are shown in Tables IA and IB. Figure 2A shows a Dalkon Shield which was electively removed from a patient after 2 years of use. A higher magnification of a portion of this Shield showing a break in the sheath and the exposed fibers may be seen in Figure 2B. Preliminary screening of 35 terminal segments by phase contrast microscopy showed unidentified structures and debris within the interspaces of all tails. Bacteria were found within 8 of the 10 tails studied subsequently by electron microscopy. Figures 3, 4 and 5 are electron micrographs showing
APRIL
-1975
VOL. 11 NO. 4
467
Total:
Black Opaque
Transparent
Sheath
Sheath
Types of Sheath
Total:
Breaks
of Unused
239
109
130
Number of Sheaths Examined
in the Sheaths
Table
IB Shield
Tails
13 4 9
4 21
% of Sheaths with Breaks 17
Number of Sheaths with Breaks
Dalkon
225
662
34
14 19 6
13 11 2
94 59 35
Black opaque Sheath Standard Shield Small Shield
37 37 37
Transparent Sheath Standard Shield Small Shield
212 110 102
from Patients
568 295 273
Tails Removed % of Sheaths with Breaks
Shield
IA
Number of Sheaths with Breaks
of Dalkon
Number of Sheaths Examined
in the Sheaths
Type of Sheath and Model of Shield
Breaks
Table
CONTRACEPTION
Figure 1. Standard Dalkon Shield (A) Area of breaks in sheath (B) Terminal end of tail (C) Double knot in tail (D) Single knot in tail
Figure 2. (A) Standard Dalkon Shield removed from patient. Box indicates location of break in sheath. (B) Break in sheath showing exposed internal fibers (x25).
APRIL 1975 VOL. 11 NO. 4
469
CONTRACEPTION
Figure 3. Electron micrograph of the terminal Dalkon Shield tail removed from patient after situ. The micrograph shows numerous bacteria monofilaments within the outer sheath (sheath the extreme left). (x 12,000) 470
APRIL
segment of 14 months in between 3 is shown on
1975 VOL. 11 NO. 4
CONTRACEPTION
Figure 4. Electron micrograph of the terminal segment of Dalkon Shield tail removed from patient after 29 months in situ, The micrograph shows bacteria in the space between1 monofilament and the sheath (monofilament located in upper left hand corner; sheath located on bottom). (x 31,000)
Figure 5. Electron micrograph of the terminal segment of Dalkon Shield tail removed from patient after 38 months in situ. The micrograph shows bacteria between 1 monofilament and the sheath (sheath located on bottom). (x 65,000)
APRIL
1975
VOL. 11 NO. 4
471
CONTRACEPTION
bacteria within the interfilamental spaces inside the sheath of 3 terminal segments (Figure 1B) removed from patients. Figure 6 is an electron micrograph showing debris within the interspaces of another terminal segment. No bacteria could be identified in this segment. The results of the aerobic and anaerobic cultures from the intra-abdominal Dalkon Shields are listed in Table II. An electron micrograph showing bacteria within the tail located below the first knot on the tail is shown in Figure 7. Discussion Of the 662 Dalkon Shield tails removed from patients, 225 (34%) had breaks in the nylon sheath. Of the 239 tails of unused Dalkon Shields, 21 (9%) had breaks in their sheaths. The location of these breaks is such that most of them would have been within the endometrial cavity. It is possible that bacteria which have ascended through the tail from the vagina could exit through these breaks in the sheath directly into the endometrial cavity, whether or not the patient was pregnant. From the observations in this study, it is apparent that the incidence of breaks in the sheaths of Dalkon Shield tails removed from patients is approximately 4 times that found in unused Shields. It is possible that some of the holes found in the tails removed from patients were tears resulting from the stress of removal. It is impossible to know how many of the holes which were detected in Shield tails removed from patients were present (a) prior to the insertion of the device, or (b) developed while they were within the endometrial cavity, or (c) were the result of tears incurred during their extraction. It seems probable that each of the three conditions contributed to the end result. Our data suggest that at least 9% of the holes in sheaths removed from patients were present prior to the insertions of the Shields. Two types of nylon sheaths were found. One was transparent while the other was black and opaque. Although the diameter of the black tail is greater and the number of fibers within it is fewer than found for the transparent sheathed tail, there was no consistency in regard to the size of Shield to which they were affixed. This point has considerable practical relevance since the breaks in the sheaths occurred almost three times as frequently in the transparent sheath as in the black sheath. This frequency relationship was essentially the same for devices removed from patients and for unWithin our random sample, these differences used devices. Because of the lack of are statistically significant.
472
APRIL
1975
VOL.
11 NO. 4
CONTRACEPTION
Figure 6. Electron micrograph of the terminal segment of Dalkon Shield tail removed from patient after 5 months in The micrograph shows unidentified debris betweensitu. 4 monofilaments. (x 17,000)
APRIL 1975 VOL. 11 NO. 4
473
Shield Tail attached to Shield Tail above 1st knot Tail below 1st knot
3
N.G.* - No growth
Shield Tail attached to Shield Tail just below Shield
2
Shield
Cultured
Shield Tail just below
Sample
1
Patient Number
II
N.G. N.G. N.G. Lactobacillus
Staphylococcus Staphylococcus Not cultured
Staphylococcus Lactobacillus epidermidis epidermidis
epidermidis
Types of Aerobic Bacteria
N.G. N.G. Peptostreptococcus N.G.
Bacteroides fragilis Not cultured N.G.
Fusobacterium N.G.*
Types of Anaerobic Bacteria
Types of Aerobic and Anaerobic Bacteria from Intra-Abdominal Dalkon Shields Removed from Patients
Table
CONTRACEPTION
l
.
I
b
. ‘.
.F
Figure 7. Electron micrograph of a Da&on Shield tail removed from the abdomen of a patient. The micrograph shows bacteria in the space between 1 monofilament and the sheath (sheath is shown on the extreme left). The bacteria shown here resemble sections of chains of cocci(2). (x36,000) APRIL
1975 VOL. 11 NO. 4
473
CONTRACEPTION
consistency between the type of tail and the model of the Shield (Standard or Small), the higher frequency of breaks in the transparent sheathed tail should not correlate with the gravidity of the patient. Study of the Dalkon Shield's terminal segment by transmission electron microscopy established conclusively that the interfibrillar spaces within the sheaths of 8 of the 10 tails contained numerous viable appearing bacteria as well as considerable unidentified debris. Although no bacteria were identified in the random sections from the remaining two tails, their interspaces contained much debris. The presence of bacteria within the terminal segment of the tail permits the postulation that some bacteria may have passed through the constrictions produced by the double knot at the base of the Shield. It is possible that these bacteria could escape from the open end of the tail into the endometrial cavity. A very preliminary bacteriological study has been made on three Dalkon Shields and their tails which were removed surgically from the peritoneal cavity of three patients. Cultures from two of the Shields and from the tails of each of these three devices were positive for aerobic and/or anaerobic bacteria. No conclusions should be drawn concerning these intra-abdominal Shields because of the preliminary and limited nature of the data, and because of the 4-7 day delay between removal of the devices and their culture. Cultures could not be obtained from the 35 terminal segments (Figure 1B) since they had been immediately placed in fixative for morphologic studies. The potential clinical implications of the data presented in this paper must be taken into consideration in the management of the non-pregnant asymptomatic wearer of a Dalkon Shield. Acknowledgements We wish to express our gratitude to the personnel of each of the many clinics throughout the United States who provided us with Dalkon Shields removed electively from their patients. Without their willing cooperation and participation, this investigation would not have been possible. We would also like to express our thanks to Dr. William M. O'Leary and Mrs. Maija Skangalis for the classification of the microorganisms obtained from cultures of the Dalkon Shield tails.
476
APRIL
1975 VOL. 11 NO. 4
CONTRACEPTION
References 1.
Tatum, H.J., Schmidt, F.H., Phillips, D., McCarty, M. and O'Leary, W.M. The Dalkon Shield Controversy. Structural and Bacteriological Studies of IUD Tails. JAMA 231(7): 711-717, February 17, 1975.
2.
Swanson, J. and McCarty, M. Electron Microscopic Studies on Opaque Colony Variants of Group A Streptococci. J. Bacterial. 100(1):505-511, October 1969.
Address requests for reprints to: Howard J. Tatum, M.D., Ph.D. The Population Council The Rockefeller University York Avenue and 66th Street New York, New York 10021
APRIL 1975
VOL. 11 NO. 4
477
Howard
STUDIES OF DALKON SHIELD TAILS REMOVED FROM PATIENTS
J. Tatum, M.D., Ph.D., Frederick H. Schmidt, and David M. Phillips, Ph.D.
The Population Council, The Rockefeller New York, New York 10021
M.A.
University
Abstract Examination of the tails of Dalkon Shields removed from patients showed that approximately 34% of the tails had breaks or holes in the nylon sheath immediately below the double knot at the base of the Shield. The location of these holes is such that most of them would have been within the endometrial cavity. For control purposes, unused sterile Shields were removed from their pouches, and the tails were inspected for breaks in the sheath. Breaks were found in approximately 9% of these. Most of the holes were in the same location as those seen in tails removed from patients. The internal contents of the short terminal segments of Dalkon tails located beyond the double knot, from Shields removed from patients, were studied. Thirty-five (35) segments were evaluated by phase contrast microscopy and 10 were studied subsequently by transmission electron microscopy. Bacteria were found within the interfilamental spaces inside the sheath of 8 of the 10 tails. These observations suggest that bacteria which have ascended through the tail from the vagina could exit through these breaks in the sheath or from the terminal end of the tail directly into the endometrial cavity. The potential clinical implications of the data presented in this paper must be taken into consideration in the management of the non-pregnant asymptomatic wearer of a Dalkon Shield.
Detailed summaries of these investigations were sent to the U.S. Food and Drug Administration on January 25, 1975, and on February 27, 1975. These data were also presented in part to the National Medical Committee of Planned Parenthood-World Population on January 29, 1975 (New York). Accepted
APRIL
for
1975
publication
February
VOL. 11 NO. 4
6,
1975
465
CONTRACEPTION
Introduction The complex multifilament tail of the Dalkon Shield intrauterine device has been shown by Tatum et al.(l)to function -in vivo as a wick, thus allowing bacteriafrom the vagina to enter the interfibrillar spaces within the nylon sheath of the tail and ascend through the interspaces at least as far as the double knot at the base of the Shield. It was postulated that bacteria from these interfibrillar spaces could gain access to the endometrial cavity by one of three mechanisms. (A) In case of pregnancy with the Shield in situ, gradual enlargement of the uterus often is accompanied be retraction of the tail upward until at 10 or 12 weeks of pregnancy the tail disappears from the vagina and cervix and gradually enters the endometrial cavity. Bacteria which were within the nylon sheath and protected from the bactericidal endocervical environment could then exit from the open end of the tail and enter the extraovular space within the uterus. (B) A break in the nylon sheath near the base of the Shield within the endometrial cavity could allow the escape of bacteria which had ascended from the vagina through the interfibrillar spaces within the sheath. (C) BaCteria from the vagina could ascend through the entire length of the tail and exit from the open end beyond the double knot at the base of the Shield into the endometrial cavity. The purpose of this paper is to present additional new data which support both of the theories described in (B) and (C) above. Materials and Methods Breaks in the Nylon Sheath Distal to Double Knot The tails of 662 Dalkon Shields which had been removed electively from patients were examined under a dissecting microscope for breaks in the nylon sheath. Since we were concerned only with breaks which had been located within the endometrial cavity, we recorded only those breaks which were located 3 mm or less below the double knot which is located at the base of the Shield. The Shields which were examined had been in patients from 2 months to 4 years. A schematic diagram illustrating the location of the breaks in the sheath is shown in Figure 1A. The tails of 239 new Dalkon Shields were examined in a similar manner.
466
APRIL
1975 VOL. 11 NO. 4
CONTRACEP’I’ION
Internal Contents of Terminal End of Proximal Segment of Tail In order to determine whether or not bacteria from the vagina had ascended within the nylon sheath beyond the single knot (Figure 1D) and had passed through the constrictions produced by the double knot (Figure 1C) at the base of the Dalkon Shield, the terminal ends of the tails from 35 Shields were examined either by phase contrast microscopy or by electron microscopy. The location of the segment studied is indicated in Figure 1B. The Dalkon Shields with the attached tail were placed in a solution of glutaraldehyde immediately after their elective removal from patients. Thirty-five (35) tails which had been in place from 5 months to 4 years were sectioned and studied by phase microscopy. A subsequent detailed study of 10 of these was made by transmission electron microscopy. Only those tails which had no visible breaks in the sheath were embedded in plastic (Epon 812) and processed for ultrastructural evaluation. Three Dalkon Shields which had previously perforated the uterus and entered the peritoneal cavity were removed surgically, placed immediately in sterile culture tubes, and sent to us for bacteriologic study. Samples from these tails and the Shields themselves were cultured aerobically and anaerobically immediately after they arrived at our laboratory. The incubation of the samples was initiated 4 to 7 days following their removal from patients. In addition to the cultures, portions from one tail were sectioned for electron microscopy. Results The results of the Dalkon Shields examined for breaks in the sheath are shown in Tables IA and IB. Figure 2A shows a Dalkon Shield which was electively removed from a patient after 2 years of use. A higher magnification of a portion of this Shield showing a break in the sheath and the exposed fibers may be seen in Figure 2B. Preliminary screening of 35 terminal segments by phase contrast microscopy showed unidentified structures and debris within the interspaces of all tails. Bacteria were found within 8 of the 10 tails studied subsequently by electron microscopy. Figures 3, 4 and 5 are electron micrographs showing
APRIL
-1975
VOL. 11 NO. 4
467
Total:
Black Opaque
Transparent
Sheath
Sheath
Types of Sheath
Total:
Breaks
of Unused
239
109
130
Number of Sheaths Examined
in the Sheaths
Table
IB Shield
Tails
13 4 9
4 21
% of Sheaths with Breaks 17
Number of Sheaths with Breaks
Dalkon
225
662
34
14 19 6
13 11 2
94 59 35
Black opaque Sheath Standard Shield Small Shield
37 37 37
Transparent Sheath Standard Shield Small Shield
212 110 102
from Patients
568 295 273
Tails Removed % of Sheaths with Breaks
Shield
IA
Number of Sheaths with Breaks
of Dalkon
Number of Sheaths Examined
in the Sheaths
Type of Sheath and Model of Shield
Breaks
Table
CONTRACEPTION
Figure 1. Standard Dalkon Shield (A) Area of breaks in sheath (B) Terminal end of tail (C) Double knot in tail (D) Single knot in tail
Figure 2. (A) Standard Dalkon Shield removed from patient. Box indicates location of break in sheath. (B) Break in sheath showing exposed internal fibers (x25).
APRIL 1975 VOL. 11 NO. 4
469
CONTRACEPTION
Figure 3. Electron micrograph of the terminal Dalkon Shield tail removed from patient after situ. The micrograph shows numerous bacteria monofilaments within the outer sheath (sheath the extreme left). (x 12,000) 470
APRIL
segment of 14 months in between 3 is shown on
1975 VOL. 11 NO. 4
CONTRACEPTION
Figure 4. Electron micrograph of the terminal segment of Dalkon Shield tail removed from patient after 29 months in situ, The micrograph shows bacteria in the space between1 monofilament and the sheath (monofilament located in upper left hand corner; sheath located on bottom). (x 31,000)
Figure 5. Electron micrograph of the terminal segment of Dalkon Shield tail removed from patient after 38 months in situ. The micrograph shows bacteria between 1 monofilament and the sheath (sheath located on bottom). (x 65,000)
APRIL
1975
VOL. 11 NO. 4
471
CONTRACEPTION
bacteria within the interfilamental spaces inside the sheath of 3 terminal segments (Figure 1B) removed from patients. Figure 6 is an electron micrograph showing debris within the interspaces of another terminal segment. No bacteria could be identified in this segment. The results of the aerobic and anaerobic cultures from the intra-abdominal Dalkon Shields are listed in Table II. An electron micrograph showing bacteria within the tail located below the first knot on the tail is shown in Figure 7. Discussion Of the 662 Dalkon Shield tails removed from patients, 225 (34%) had breaks in the nylon sheath. Of the 239 tails of unused Dalkon Shields, 21 (9%) had breaks in their sheaths. The location of these breaks is such that most of them would have been within the endometrial cavity. It is possible that bacteria which have ascended through the tail from the vagina could exit through these breaks in the sheath directly into the endometrial cavity, whether or not the patient was pregnant. From the observations in this study, it is apparent that the incidence of breaks in the sheaths of Dalkon Shield tails removed from patients is approximately 4 times that found in unused Shields. It is possible that some of the holes found in the tails removed from patients were tears resulting from the stress of removal. It is impossible to know how many of the holes which were detected in Shield tails removed from patients were present (a) prior to the insertion of the device, or (b) developed while they were within the endometrial cavity, or (c) were the result of tears incurred during their extraction. It seems probable that each of the three conditions contributed to the end result. Our data suggest that at least 9% of the holes in sheaths removed from patients were present prior to the insertions of the Shields. Two types of nylon sheaths were found. One was transparent while the other was black and opaque. Although the diameter of the black tail is greater and the number of fibers within it is fewer than found for the transparent sheathed tail, there was no consistency in regard to the size of Shield to which they were affixed. This point has considerable practical relevance since the breaks in the sheaths occurred almost three times as frequently in the transparent sheath as in the black sheath. This frequency relationship was essentially the same for devices removed from patients and for unWithin our random sample, these differences used devices. Because of the lack of are statistically significant.
472
APRIL
1975
VOL.
11 NO. 4
CONTRACEPTION
Figure 6. Electron micrograph of the terminal segment of Dalkon Shield tail removed from patient after 5 months in The micrograph shows unidentified debris betweensitu. 4 monofilaments. (x 17,000)
APRIL 1975 VOL. 11 NO. 4
473
Shield Tail attached to Shield Tail above 1st knot Tail below 1st knot
3
N.G.* - No growth
Shield Tail attached to Shield Tail just below Shield
2
Shield
Cultured
Shield Tail just below
Sample
1
Patient Number
II
N.G. N.G. N.G. Lactobacillus
Staphylococcus Staphylococcus Not cultured
Staphylococcus Lactobacillus epidermidis epidermidis
epidermidis
Types of Aerobic Bacteria
N.G. N.G. Peptostreptococcus N.G.
Bacteroides fragilis Not cultured N.G.
Fusobacterium N.G.*
Types of Anaerobic Bacteria
Types of Aerobic and Anaerobic Bacteria from Intra-Abdominal Dalkon Shields Removed from Patients
Table
CONTRACEPTION
l
.
I
b
. ‘.
.F
Figure 7. Electron micrograph of a Da&on Shield tail removed from the abdomen of a patient. The micrograph shows bacteria in the space between 1 monofilament and the sheath (sheath is shown on the extreme left). The bacteria shown here resemble sections of chains of cocci(2). (x36,000) APRIL
1975 VOL. 11 NO. 4
473
CONTRACEPTION
consistency between the type of tail and the model of the Shield (Standard or Small), the higher frequency of breaks in the transparent sheathed tail should not correlate with the gravidity of the patient. Study of the Dalkon Shield's terminal segment by transmission electron microscopy established conclusively that the interfibrillar spaces within the sheaths of 8 of the 10 tails contained numerous viable appearing bacteria as well as considerable unidentified debris. Although no bacteria were identified in the random sections from the remaining two tails, their interspaces contained much debris. The presence of bacteria within the terminal segment of the tail permits the postulation that some bacteria may have passed through the constrictions produced by the double knot at the base of the Shield. It is possible that these bacteria could escape from the open end of the tail into the endometrial cavity. A very preliminary bacteriological study has been made on three Dalkon Shields and their tails which were removed surgically from the peritoneal cavity of three patients. Cultures from two of the Shields and from the tails of each of these three devices were positive for aerobic and/or anaerobic bacteria. No conclusions should be drawn concerning these intra-abdominal Shields because of the preliminary and limited nature of the data, and because of the 4-7 day delay between removal of the devices and their culture. Cultures could not be obtained from the 35 terminal segments (Figure 1B) since they had been immediately placed in fixative for morphologic studies. The potential clinical implications of the data presented in this paper must be taken into consideration in the management of the non-pregnant asymptomatic wearer of a Dalkon Shield. Acknowledgements We wish to express our gratitude to the personnel of each of the many clinics throughout the United States who provided us with Dalkon Shields removed electively from their patients. Without their willing cooperation and participation, this investigation would not have been possible. We would also like to express our thanks to Dr. William M. O'Leary and Mrs. Maija Skangalis for the classification of the microorganisms obtained from cultures of the Dalkon Shield tails.
476
APRIL
1975 VOL. 11 NO. 4
CONTRACEPTION
References 1.
Tatum, H.J., Schmidt, F.H., Phillips, D., McCarty, M. and O'Leary, W.M. The Dalkon Shield Controversy. Structural and Bacteriological Studies of IUD Tails. JAMA 231(7): 711-717, February 17, 1975.
2.
Swanson, J. and McCarty, M. Electron Microscopic Studies on Opaque Colony Variants of Group A Streptococci. J. Bacterial. 100(1):505-511, October 1969.
Address requests for reprints to: Howard J. Tatum, M.D., Ph.D. The Population Council The Rockefeller University York Avenue and 66th Street New York, New York 10021
APRIL 1975
VOL. 11 NO. 4
477