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The Effectiveness of the Cervical Cap as a Contraceptive Method
THE EFFECTIVENESS OF THE CERVICAL CAP AS A CONTRACEPTIVE METHOD CHRISTOPHER TIETZE, AND
H.
M.D.,
FALLS CHURCH, VA., HANS LEHFELDT,
GEoRGE LIEBMANN,
M.D.,
widely used in Europe,l-5 the A LTHOUGH by the medical profession of this country.s-u
M.D.,
NEw YoRK, N.Y.
cervical cap has found only linlited acceptance Reasons for this reluctance on the part of American physicians are mainly confusion of the cervical cap with harmful intracervical or intrauterine devices and lack of a statistical evaluation of its effectiveness. To provide the information hitherto lacking, we have compiled a series of cases from our private practice (H. L. and H. G. L.) in New York City. We are grateful to the late Dr. R. L. Dick"nson who encouraged us to write this paper and contributed the illustrations. In most instances, we consider the cervical cap preferable to the vaginal diaphragm for psychological reasons, since it can be left in situ for a number of days up to the full length of the intermenstruum. It is a great comfort for many women to feel fully protected at all hours throughout each cycle, without the neetl for technical preparations at each occasion of intercourse. We have had a surprisingly large number of patients who opposed the diaphragm because the idea of having to insert it prior to intercourse takes away the spontaneity of the act and destroys its romantic mood. Many of these patients :find it equally obnoxious to prepare themselves every evening for possible cohabitation by routine insertion of the diaphragm. 'V"e, therefore, tend to prescribe the cervical cap for all patients in need of protection against pregnancy unless (a) the patient on her own initiative requests a diaphragm, or (b) contraindications to the use of the cap are found on examination. The cap is contraindicated in the presence of deep cervical lacerations extending to the vaginal vault, cervical erosions or Nabothian cysts, extreme shortness or extreme elongail
Volume 66 Numher 4
CERVICAL CAP AS
CONTRACEP'riVI~
METHOD
905
the diameter or length of the cervix makes it ascend. The rim of the cap adheres snugly to the vaginal fornices, but its dome should not be in contact with the external os. The cap attaches itself firmly to the mucous membrane; any attempt to dislodge it increases the partial vacuum between the cap's dome and the cervix. If menstruation sets in unexpectedly while the cap is in place the flow escapes easily. The rim of the cap facilitates self-insertion and removal. ·while some discoloration of the plastic material may occur after prolonged use the same cap c.an be used for several years. 'With the exception of a few extreme cases we have found three sizes satisfactory: "large" ( 36 mm. diameter), "medium" ( 30 mm.), "small" ( 24 mm.), Instruments for measuring the cervical circumference or special fitting caps are superfluous. The size of the cap ean easily be determined by rough estimation. Suffieient space should be allowed between cervical os and cap. Too tight a fit is not desirable. Before insertion, the cap is cleansed with water and soap, but never boiled. It is then half filled with spermicidal jelly or cream. The patient is placed in the lithotomy position, two fingers of one hand separate the labia. The cervical cap is held between index and middle fin~{ers of the other hand and inserted into the vagina, following the posterior wall to the posterior fornix. Here the cap is released and will slip almost automatically over the eervix.
Self - msertion of cervical cap Fig. 1.
For self-insertion the patient is first taught to feel her own cervix. 'l'hen she herself is to follow the same technique as described above. Self-insertion in standing posture is facilitated if the patient will put one foot on a chair while the knee of the other leg is slightly bent. ~'or removal of the eap, index and middle fingers are inserted into the vagina, reaching high up in the fornix. As the rim of the cap is reached it is tilted away :from the eervix. The cap is grasped between the two fingers and removed. The tilting movement is important; this maneuver, by permitting the entry of air into the cap, relieves the suction and thereby allows easy removal of the cap. Even after having been in place for three weeks it is usually found still half-filled with the jelly or cream.
!!Of)
\111.
L
Ob~t. & Gyncl'.
October, 19.1_\
A total of l-t:l eaRe hi:;tories are availablt• for :.;tatisti<·al analysis 11 ·. '1'.1. '!'hi, represents all histories in the files except n·•·ord:.; of patient:; \\'Ill) wore in: to follow up all patiPnb, hut thp <·ondit.ions of privatp prartice mnu<' it impossible to achieve perfeetion in this r<'spP<'l.
Lack of complete follow-up has introd1J<•pd a l.Jias into our data hut the bias increases, rather than reduces the apparent pregnancy rate an
visit~>d
th<' •lodor regularly ev<•ry month for removal and/or
Group B, Patients who remained under his care for reasons other than their ne<:'d for protection against prl'gnancy, Group C, Patients who had ceased to attend the office lmt were located and interviewed, and Group D, Those who retmned from time to time for checkup of the cap or because they had become pregnant while using it.
Self -removal of cervjcal cap Fig-.
~-
These categories are not sharply separated and a patient may move from one class to another. The histories of the patients of Group A are, hy definition, complete and there is no reason to assume that Groups B and C are anything but representative of the generality of eap users who practice self-inset'tion. Class D could introduce a distortion if those women who returned to the physician were either more or less successful in the use of the cap than women who did not return. The fact that a parallel series of diaphragm-and-jelly users from our practice yielded the comparatively high rate of 13.7 pregnancies per 100 years of exposure (based on 44 accidental conceptions in 320 woman-years) indicates that the bias in our data on the cervical cap likewise operates in the direction of increasing the apparent pregnancy rate.
CERVICAL CAP AS
Volume 66
CONTRACEPTIVr~
METHOD
)J umber+
907
Of the 143 patients known to have used the cap for one month or longer, 101 were still users at the time the records were abstracted. The remaining 42 had given it up for one reason or another (Table I). The three patients who discontinued because of an erosion should not have been fitted with a cap. In one case only, the erosion and adnexal disease had apparently grown worse during 3 months' use of the cap, while in two instances the erosion remained stationary. One of these two concerned a newly wed woman for whom the cap was prescribed as a temporary measure prior to cauterization (1 month). The other patient with a small erosion tolerated the cap for 15 months. In one case the cap apparently produced a discharge which ceased upon removal. Of the two "poor fits," one involved a woman with an infantile uterus and an elongated cervix; in the other case, the cervix was too short. Both patients used the cap for one month only. TABLE I. REASONS FOR DISCONTINUING USE OF CERVICAL CAP Discharge Poor fit Discomfort to wife Discomfort to husband Could not learn self-insertion Feels unsafe Accidental pregnancy Wanted to become pregnant Separation of couple Hysterectomy Menopause Cap broke Not recorded
As shown in the cap ranged in exposure amounted of this total was exposure.
..2" 2
.."5 ()
{)
4,,
1" 1 3
Table II, the duration of exposure to the risk of pregnancy while using individual cases from 1 month to more than 20 years. The aggregate to 4,415 woman-months or 368 woman-years. Not less than 92.4 per cent contributed by the 72 patients observed for more than a full year of
TABLE II. NUMBER OF USERS AND AGGREGATE EXPOSURE BY MONTHS OF 0BSERVA'l'lON MONTHS DE' OBSERVATION 1- 6 7-12 13·24 0~
¥')~
-"iJ-UU
37-60 Over 60 Total
NUMBER OF USERS 50 21 21 "' "'"u 14 21 143
AGGREGATE EXPOSURE (MONTHS) 136 201 389 509 622 2,558 4,415
The number of unplanned pregnancies which occurred during the period of observation was 28 corresponding to a rate of 7.6 pregnancies per 100 years of exposure. This rate is not significantly different from the rates obtained by the most succesRful users of the diaphragmand-jelly12 and of condoms.1a, 14 It should be noted that this rate is based on all pregnancies without exception which occurred prior to a definite abandonment of the method. Since it is impracticable to classify users and exposure months by regularity and perfection of technique, any exclusion of pregnancies on similar grounds would result in misleadingly low rates. Among the 28 unplanned pregnancies there were 6 cases apparently related to the omission of a chemical contraceptive in the cap or otherwise faulty technique and 10 instanceR of admittedly irregular use or temporary interruption. In at least three cases in the IattPr
·\m. J.
908
Oh~t.
& Gynec.
October, 1915
group the history suggested strongly the presPnee of a more or less uneonseious desire for " baby (or another baby) on the part of the woman-against hPr own and her husband's well~ considered judgment. For 12 pregnaueies no explanation was recorded. Insertion by the physician compriseu a little more than two-fifths of thP aggregat<' ex~ posure with the cervical cap. The prPgnanc.v rate during this time was not signifieantly lower than during exposure with self-insPrtion, suggesting a high degree of success in in structing the patients. It is our impression that the great majorit;r of patients are ewntually able to learn self-insertion of the eervical cap, but lwcause our series dol's not inelude any casPs followed for less than a month it is not possible to computP the exact pPrct•ntage nor tiH• average time required by them for mastering the technique. It has been demonstrat.,dt5 that when couplE's discontinue contraceptive measures in order to have a baby, at least one couple in four an•l pPrhaps as many as three in ten are ablf' to achieve pregnancy within one month after the abandonment of birth control. At that time, the chance of conception is between 0.:25 anleetive process and retains its high reproductive potential rPpres<>nted by a chance of concPption of 0.25 to 0.30 per month. A pregnancy rate of 7.6 per 100 years of exposur<', as computPd for our CPrvieal cap users, corresponds to a rate of about 0.005 per lunar month. Since 0.005 is 2 per cPnt of 0.25 and an even smaller fraction of 0.30, it ean rPadily he >namentarium of the physieian who has to a
References 1. Kafka, K.: Klin.-therap. Wchnschr. 15: 1390, HHlll. :2. Grotjahn, A.: Geburtenriickgang und Gehurtenregelung, Berlin, 1!114, Loui8 ~Iarcn~ Verlag. 3. Lehfeldt, H.: Contraceptive Methods Requiring Medical Assistance, Lecture at Rexttal Reform Congress of World League for Sexual Reform, London, 1929; 'l'he Physical and Psychological Aspects of Contraception, in Sanger, M., and Stone, H. M.: The Practice of ContracPption, Baltimore, 1931, Williams & Wilkins Company, pp. 27, 130, 141-149. 4. FraPnkel, L.: Die Empfiingnisverhuc>tung, Stuttgart, 1932, Ferdinand Enk<' Yerlag. 5. Pust, W.: Discussion of Mechanical Occlusive Methods, in Sanger, M., and Stone, H. M.: The Practice of Contraceptio:1, Baltimore, 1D31, Williams & 'Vilkins Company, pp. 24-26. 6. Stone, H. M.: J. Contraception 2: 102, 1937. 7. Dickinson, R. L.: J. Contraception 2: 105, 1937. 8. Greenhill, J. P.: The 1949 Year Book of Obstetries and Gynecology, Chicago, H!4~1, The Year Book Publishers, Inc., p. 384. 9. Grafenberg, E., and Dickinson, R. L.: Western J. Surg. 52: 335, 1944. 10. Moses, B. I.: Human Fertil. 6: 138, 1944. 11. Lehfeldt, H.: J. Contraception 2: 106, 1937; J. Sex Education 1: 132,1949. 12. Dewees, L., and Beebe, G. W.: J. A.M. A. 110: 1169, 1938. 13. Tietze, C., and Gamble, C. J.: Human Fertil. 9: 97, 1944. 14. Stix, R. K., and Notestein, F.: Controlled Fertility, Baltimore, 1940, Williams & Wilkins Company. 15. Tietze, C., Guttmacher, A. F., and Rubin, S.: Fertil. & Steril. 1: 338, Hl50.
H.
M.D.,
FALLS CHURCH, VA., HANS LEHFELDT,
GEoRGE LIEBMANN,
M.D.,
widely used in Europe,l-5 the A LTHOUGH by the medical profession of this country.s-u
M.D.,
NEw YoRK, N.Y.
cervical cap has found only linlited acceptance Reasons for this reluctance on the part of American physicians are mainly confusion of the cervical cap with harmful intracervical or intrauterine devices and lack of a statistical evaluation of its effectiveness. To provide the information hitherto lacking, we have compiled a series of cases from our private practice (H. L. and H. G. L.) in New York City. We are grateful to the late Dr. R. L. Dick"nson who encouraged us to write this paper and contributed the illustrations. In most instances, we consider the cervical cap preferable to the vaginal diaphragm for psychological reasons, since it can be left in situ for a number of days up to the full length of the intermenstruum. It is a great comfort for many women to feel fully protected at all hours throughout each cycle, without the neetl for technical preparations at each occasion of intercourse. We have had a surprisingly large number of patients who opposed the diaphragm because the idea of having to insert it prior to intercourse takes away the spontaneity of the act and destroys its romantic mood. Many of these patients :find it equally obnoxious to prepare themselves every evening for possible cohabitation by routine insertion of the diaphragm. 'V"e, therefore, tend to prescribe the cervical cap for all patients in need of protection against pregnancy unless (a) the patient on her own initiative requests a diaphragm, or (b) contraindications to the use of the cap are found on examination. The cap is contraindicated in the presence of deep cervical lacerations extending to the vaginal vault, cervical erosions or Nabothian cysts, extreme shortness or extreme elongail
Volume 66 Numher 4
CERVICAL CAP AS
CONTRACEP'riVI~
METHOD
905
the diameter or length of the cervix makes it ascend. The rim of the cap adheres snugly to the vaginal fornices, but its dome should not be in contact with the external os. The cap attaches itself firmly to the mucous membrane; any attempt to dislodge it increases the partial vacuum between the cap's dome and the cervix. If menstruation sets in unexpectedly while the cap is in place the flow escapes easily. The rim of the cap facilitates self-insertion and removal. ·while some discoloration of the plastic material may occur after prolonged use the same cap c.an be used for several years. 'With the exception of a few extreme cases we have found three sizes satisfactory: "large" ( 36 mm. diameter), "medium" ( 30 mm.), "small" ( 24 mm.), Instruments for measuring the cervical circumference or special fitting caps are superfluous. The size of the cap ean easily be determined by rough estimation. Suffieient space should be allowed between cervical os and cap. Too tight a fit is not desirable. Before insertion, the cap is cleansed with water and soap, but never boiled. It is then half filled with spermicidal jelly or cream. The patient is placed in the lithotomy position, two fingers of one hand separate the labia. The cervical cap is held between index and middle fin~{ers of the other hand and inserted into the vagina, following the posterior wall to the posterior fornix. Here the cap is released and will slip almost automatically over the eervix.
Self - msertion of cervical cap Fig. 1.
For self-insertion the patient is first taught to feel her own cervix. 'l'hen she herself is to follow the same technique as described above. Self-insertion in standing posture is facilitated if the patient will put one foot on a chair while the knee of the other leg is slightly bent. ~'or removal of the eap, index and middle fingers are inserted into the vagina, reaching high up in the fornix. As the rim of the cap is reached it is tilted away :from the eervix. The cap is grasped between the two fingers and removed. The tilting movement is important; this maneuver, by permitting the entry of air into the cap, relieves the suction and thereby allows easy removal of the cap. Even after having been in place for three weeks it is usually found still half-filled with the jelly or cream.
!!Of)
\111.
L
Ob~t. & Gyncl'.
October, 19.1_\
A total of l-t:l eaRe hi:;tories are availablt• for :.;tatisti<·al analysis 11 ·. '1'.1. '!'hi, represents all histories in the files except n·•·ord:.; of patient:; \\'Ill) wore in:
Lack of complete follow-up has introd1J<•pd a l.Jias into our data hut the bias increases, rather than reduces the apparent pregnancy rate an
visit~>d
th<' •lodor regularly ev<•ry month for removal and/or
Group B, Patients who remained under his care for reasons other than their ne<:'d for protection against prl'gnancy, Group C, Patients who had ceased to attend the office lmt were located and interviewed, and Group D, Those who retmned from time to time for checkup of the cap or because they had become pregnant while using it.
Self -removal of cervjcal cap Fig-.
~-
These categories are not sharply separated and a patient may move from one class to another. The histories of the patients of Group A are, hy definition, complete and there is no reason to assume that Groups B and C are anything but representative of the generality of eap users who practice self-inset'tion. Class D could introduce a distortion if those women who returned to the physician were either more or less successful in the use of the cap than women who did not return. The fact that a parallel series of diaphragm-and-jelly users from our practice yielded the comparatively high rate of 13.7 pregnancies per 100 years of exposure (based on 44 accidental conceptions in 320 woman-years) indicates that the bias in our data on the cervical cap likewise operates in the direction of increasing the apparent pregnancy rate.
CERVICAL CAP AS
Volume 66
CONTRACEPTIVr~
METHOD
)J umber+
907
Of the 143 patients known to have used the cap for one month or longer, 101 were still users at the time the records were abstracted. The remaining 42 had given it up for one reason or another (Table I). The three patients who discontinued because of an erosion should not have been fitted with a cap. In one case only, the erosion and adnexal disease had apparently grown worse during 3 months' use of the cap, while in two instances the erosion remained stationary. One of these two concerned a newly wed woman for whom the cap was prescribed as a temporary measure prior to cauterization (1 month). The other patient with a small erosion tolerated the cap for 15 months. In one case the cap apparently produced a discharge which ceased upon removal. Of the two "poor fits," one involved a woman with an infantile uterus and an elongated cervix; in the other case, the cervix was too short. Both patients used the cap for one month only. TABLE I. REASONS FOR DISCONTINUING USE OF CERVICAL CAP Discharge Poor fit Discomfort to wife Discomfort to husband Could not learn self-insertion Feels unsafe Accidental pregnancy Wanted to become pregnant Separation of couple Hysterectomy Menopause Cap broke Not recorded
As shown in the cap ranged in exposure amounted of this total was exposure.
..2" 2
.."5 ()
{)
4,,
1" 1 3
Table II, the duration of exposure to the risk of pregnancy while using individual cases from 1 month to more than 20 years. The aggregate to 4,415 woman-months or 368 woman-years. Not less than 92.4 per cent contributed by the 72 patients observed for more than a full year of
TABLE II. NUMBER OF USERS AND AGGREGATE EXPOSURE BY MONTHS OF 0BSERVA'l'lON MONTHS DE' OBSERVATION 1- 6 7-12 13·24 0~
¥')~
-"iJ-UU
37-60 Over 60 Total
NUMBER OF USERS 50 21 21 "' "'"u 14 21 143
AGGREGATE EXPOSURE (MONTHS) 136 201 389 509 622 2,558 4,415
The number of unplanned pregnancies which occurred during the period of observation was 28 corresponding to a rate of 7.6 pregnancies per 100 years of exposure. This rate is not significantly different from the rates obtained by the most succesRful users of the diaphragmand-jelly12 and of condoms.1a, 14 It should be noted that this rate is based on all pregnancies without exception which occurred prior to a definite abandonment of the method. Since it is impracticable to classify users and exposure months by regularity and perfection of technique, any exclusion of pregnancies on similar grounds would result in misleadingly low rates. Among the 28 unplanned pregnancies there were 6 cases apparently related to the omission of a chemical contraceptive in the cap or otherwise faulty technique and 10 instanceR of admittedly irregular use or temporary interruption. In at least three cases in the IattPr
·\m. J.
908
Oh~t.
& Gynec.
October, 1915
group the history suggested strongly the presPnee of a more or less uneonseious desire for " baby (or another baby) on the part of the woman-against hPr own and her husband's well~ considered judgment. For 12 pregnaueies no explanation was recorded. Insertion by the physician compriseu a little more than two-fifths of thP aggregat<' ex~ posure with the cervical cap. The prPgnanc.v rate during this time was not signifieantly lower than during exposure with self-insPrtion, suggesting a high degree of success in in structing the patients. It is our impression that the great majorit;r of patients are ewntually able to learn self-insertion of the eervical cap, but lwcause our series dol's not inelude any casPs followed for less than a month it is not possible to computP the exact pPrct•ntage nor tiH• average time required by them for mastering the technique. It has been demonstrat.,dt5 that when couplE's discontinue contraceptive measures in order to have a baby, at least one couple in four an•l pPrhaps as many as three in ten are ablf' to achieve pregnancy within one month after the abandonment of birth control. At that time, the chance of conception is between 0.:25 anleetive process and retains its high reproductive potential rPpres<>nted by a chance of concPption of 0.25 to 0.30 per month. A pregnancy rate of 7.6 per 100 years of exposur<', as computPd for our CPrvieal cap users, corresponds to a rate of about 0.005 per lunar month. Since 0.005 is 2 per cPnt of 0.25 and an even smaller fraction of 0.30, it ean rPadily he >
References 1. Kafka, K.: Klin.-therap. Wchnschr. 15: 1390, HHlll. :2. Grotjahn, A.: Geburtenriickgang und Gehurtenregelung, Berlin, 1!114, Loui8 ~Iarcn~ Verlag. 3. Lehfeldt, H.: Contraceptive Methods Requiring Medical Assistance, Lecture at Rexttal Reform Congress of World League for Sexual Reform, London, 1929; 'l'he Physical and Psychological Aspects of Contraception, in Sanger, M., and Stone, H. M.: The Practice of ContracPption, Baltimore, 1931, Williams & Wilkins Company, pp. 27, 130, 141-149. 4. FraPnkel, L.: Die Empfiingnisverhuc>tung, Stuttgart, 1932, Ferdinand Enk<' Yerlag. 5. Pust, W.: Discussion of Mechanical Occlusive Methods, in Sanger, M., and Stone, H. M.: The Practice of Contraceptio:1, Baltimore, 1D31, Williams & 'Vilkins Company, pp. 24-26. 6. Stone, H. M.: J. Contraception 2: 102, 1937. 7. Dickinson, R. L.: J. Contraception 2: 105, 1937. 8. Greenhill, J. P.: The 1949 Year Book of Obstetries and Gynecology, Chicago, H!4~1, The Year Book Publishers, Inc., p. 384. 9. Grafenberg, E., and Dickinson, R. L.: Western J. Surg. 52: 335, 1944. 10. Moses, B. I.: Human Fertil. 6: 138, 1944. 11. Lehfeldt, H.: J. Contraception 2: 106, 1937; J. Sex Education 1: 132,1949. 12. Dewees, L., and Beebe, G. W.: J. A.M. A. 110: 1169, 1938. 13. Tietze, C., and Gamble, C. J.: Human Fertil. 9: 97, 1944. 14. Stix, R. K., and Notestein, F.: Controlled Fertility, Baltimore, 1940, Williams & Wilkins Company. 15. Tietze, C., Guttmacher, A. F., and Rubin, S.: Fertil. & Steril. 1: 338, Hl50.