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An investigation into the incidence of abortion in baltimore
AN INVE~TXJATION
INTO THZ INCIDENCE IN BALTINIORE
CITRISTOPHICR (From
thr
Ihqnrtment
TIETZE,
of Obstetrics,
M.D., dohns
OF ABORTION
BALTIMORE, Hopkins
Eniversity
MD. and
Hospital)
T
0 DETERMINE the incidence of abortion in the general population a number of studies have been made in the Iinited States, mainly in large cities. A variety of methods have been used, and great caution must be exercised in interpreting the data. One method employed by several investigators is to determint: the number of abortions among the previous pregnancies of a series of obstet,ric patients, seen at the office or dispensary or admitted to a hospital. This method has t.he great advantage that questions’ as to the number and outcome of previous pregnancies are generally accepted as a routine part of the examination, and that there is usually good rapport between the patient and the physician in whom she has a high degree of confidence. To duplicate these conditions is often difficult in other types of studies. The outstanding deficiency of all obstetric series is that no pregnancy will be included unless it is followed by another which brings the case into the investigation. If abortions tend to occur more frequently among last pregnancies they will be underrepresented in the material. In addition, an obstetric series based upon the records of a single physician or a single hospital may be biased by the special professional inl-crests of the doctor or the admission policies of the hospital. The present. paper is based on the case histories of all patients admitted to the Department of Obstetrics of the Johns Hopkins Hospital in Baltimore from 1!!37 to 1946 who had been pregnant at least once before. The number of plurigravidas during the ten-year period was 10,397, and the aggregate number of their previous pregnancies 30,133 or 2.9 per patient.. Of t,hese 30.133 previous pregnancies 25,009, or 83.0 per cent, had produced a viable birth and 5,124, or 17.0 per cent, had ended in abortion. Unfortunately, it is not possible to say on the basis of the available data how many of these abortions were unintent’ional and how many were induced. Of the 10,397 plurigravidas admitted to the service, 9,130, or 87.8 per cent, terminated their current pregnancy with a. viable birth and 1,267, or 12.2 per cent? with an abortion. The greater part of these current abortions were probably unintentional, but an unknown nupber had been illegally initiated prior to admission, and a few were therapeutic, The 9,130 parturient women reported 25,558 previous pregnancies with 4,102, or 16.0 per cent, ending in abortion. On the other hand, the 1,267 aborting women had had 4,575 previous pregnancies, and 1,022, or 22.3 per cent, of these had ended in abortion. The abortion ratio is markedly higher among the previous pregnancies of aborting women than among the previous pregnancies of those who produced a viable birth. This relat,ionship has also been observed by ot.hers. Abortions are underrepresented l1N.l
Volume Number
56 6
INCIDENCE
OF
ABORTION
IN
BALTIMORE
1161
This makes the among the current pregnancies terminated in the hospital. abortion ratio appear a little lower among the previous pregnancies of these patients than it actually is in the population from which they are drawn. Statistical methods have been devised to correct this bias. With the present material, however, the effect of the correction is so slight that it does not seem worth while to introduce it. The total group of 10,397 patients can be broken down by color and pay status into three distinct components: 1,985 private patients, all of whom were white; 4,041 white ward patients ; and 4,371 Negro ward patients. The aggregate numbers of previous pregnancies and the numbers and percentages of abortions in the three groups are presented in Table I, showing separately the findings for parturient and aborting women. TABLE
I.
NUMBER OF WOMEN, OF PREVIOUS PREGNANCIES, AND OP PREGNANCIES ENDING IN ABORTION, BY COLOR AND OUTCOME OF CURRENT PREQNANCY
OF ABORTIONS PAY STATUS
AiXD AND
PER
CENT
COLOR AND PAY STATUS
Private White1
White
ward
viable birth abortion
Negro ward
viable birth abortion
1,985
3,159
793
35.1
3,518 523
9,816 2.036
1,395 432
14.2 21.2
4,041
11,852
1,527
15.4
3,833 538
13,008 2,114
2,060 444
15.8 21.0
4,371
15,122
2,504
16.6
The findings of the present study are in investigations.l? 3 In view of the difference in parable they are with Anna Rochester’s figures based upon a citywide sample of births in 1915, ous pregnancies ending in abortion was 7.5 per for Negro women. TABLE
II.
PER CENT STATUS
PREVIOUSPREGNANCIES One Two Three Four Five Six Seven or more
OF PREVIOUS AND NUMBER 1
PRIVATE
line with the results of earlier method it is doubtful how comfor Baltimore.2 Her data were and the reported ratio of previcent for white and 11.3 per cent
PREGNANCIES OF PREVIOUS
ERODING IN ABORTION BY COLOR PREGNANCIES PER WOMAN
(WHITE) 17.1 26.9 30.9 34.6 36.8 41.7 41.5
(
WHITEWARD 13.0 15.1 15.3 16.0 15.7 15.7 16.2
1
AND
PAY
NEGROWARD 22.7 19.2 20.3 2.1.1 16.2 13.8 13.5
Table II presents abortion ratios for the three color and pay status groups by the number of previous pregnancies per woman. A very striking pattern emerges. Among the private patients the abortion ratio increases steeply with increasing number of previous pregnancies. In the white ward group no clear trend is apparent. Among the Negroes the abortion ratio is seen to decrease with increasing number of pregnancies.
Am. J. Obrt. R Gynec. December, 1948
TIETZE
1162
The high abortion ratio observed among the private patients and the pattern t a population which controls its by pregnancy order seen in this group su reproduotion mainly by contraceptive methods, but without achieving complete success. In such a group many women will resort to induced abortion if a conception has occurred in exeess of the number planned or at a time when it was not wanted. Those, on the other hand, who have had one or more unintentional abortions continue their efforts to have the number of babies they originally intended. Both mechanisms tend to produce a high abortion ratio which increases with the number of previous pregnancies. The pattern among the Negroes, which is just the opposite from that seen in the private group, is an artefact resulting from the admission policies of the hospital. During the years covered by the present study, the number of hospital beds on the Negro ward has never been sufficient to accommodate all patients seeking admission and preference has been given-among others-to two categories : To those who had produced no previous viable birth and to those who had had very many. The effect of this policy has been to increase the abortion ratio among the secundigravidas and to reduce it among the multigravidas of the hospital material on which the study is based.
Summary 1. Report is made on 30,133 previous pregnancies of 10,397 patients on an obstetric service. 2. Of these pregnancies 5,124, or 17.0 per cent, ended in abortion. 3. The abortion ratio was higher among the previous pregnancies of aborting than of parturient women. 4. The abortion ratio was 25.1 per cent for private patients (white), 15.4 per cent for white ward patients, and 16.6 per cent for Negro patients. 5. With increasing number of previous pregnancies the abortion ratio increased for private patients, decreased for Negro patients, with no clear trend for white ward patients. Mr.
I want to thank L. Omar Huesman
Dr. Nicholson J. Eastman for his for his aid in tabulating the data.
permission
t,o URC t,heae
records,
and
References 1. National
Committee on Maternal Health: The Abortion Problem, Baltimore, 1944, Chapters I and II deal with the frequency of abortion. 2. United States: Childrens Bureau. Infant Mortality. (Bureau Publication No. IlQ), Washington, 1923. Data from which computation was made are included in Appendix Tables 69, 70, and 187. 3. Wiehl, D. G.: A summary of data on reported incidence of ahortion. Milbank Memorial Fund Quarterly 16(l): 80-88, 1938. 815
NORTH
WOLFE
STREET
INTO THZ INCIDENCE IN BALTINIORE
CITRISTOPHICR (From
thr
Ihqnrtment
TIETZE,
of Obstetrics,
M.D., dohns
OF ABORTION
BALTIMORE, Hopkins
Eniversity
MD. and
Hospital)
T
0 DETERMINE the incidence of abortion in the general population a number of studies have been made in the Iinited States, mainly in large cities. A variety of methods have been used, and great caution must be exercised in interpreting the data. One method employed by several investigators is to determint: the number of abortions among the previous pregnancies of a series of obstet,ric patients, seen at the office or dispensary or admitted to a hospital. This method has t.he great advantage that questions’ as to the number and outcome of previous pregnancies are generally accepted as a routine part of the examination, and that there is usually good rapport between the patient and the physician in whom she has a high degree of confidence. To duplicate these conditions is often difficult in other types of studies. The outstanding deficiency of all obstetric series is that no pregnancy will be included unless it is followed by another which brings the case into the investigation. If abortions tend to occur more frequently among last pregnancies they will be underrepresented in the material. In addition, an obstetric series based upon the records of a single physician or a single hospital may be biased by the special professional inl-crests of the doctor or the admission policies of the hospital. The present. paper is based on the case histories of all patients admitted to the Department of Obstetrics of the Johns Hopkins Hospital in Baltimore from 1!!37 to 1946 who had been pregnant at least once before. The number of plurigravidas during the ten-year period was 10,397, and the aggregate number of their previous pregnancies 30,133 or 2.9 per patient.. Of t,hese 30.133 previous pregnancies 25,009, or 83.0 per cent, had produced a viable birth and 5,124, or 17.0 per cent, had ended in abortion. Unfortunately, it is not possible to say on the basis of the available data how many of these abortions were unintent’ional and how many were induced. Of the 10,397 plurigravidas admitted to the service, 9,130, or 87.8 per cent, terminated their current pregnancy with a. viable birth and 1,267, or 12.2 per cent? with an abortion. The greater part of these current abortions were probably unintentional, but an unknown nupber had been illegally initiated prior to admission, and a few were therapeutic, The 9,130 parturient women reported 25,558 previous pregnancies with 4,102, or 16.0 per cent, ending in abortion. On the other hand, the 1,267 aborting women had had 4,575 previous pregnancies, and 1,022, or 22.3 per cent, of these had ended in abortion. The abortion ratio is markedly higher among the previous pregnancies of aborting women than among the previous pregnancies of those who produced a viable birth. This relat,ionship has also been observed by ot.hers. Abortions are underrepresented l1N.l
Volume Number
56 6
INCIDENCE
OF
ABORTION
IN
BALTIMORE
1161
This makes the among the current pregnancies terminated in the hospital. abortion ratio appear a little lower among the previous pregnancies of these patients than it actually is in the population from which they are drawn. Statistical methods have been devised to correct this bias. With the present material, however, the effect of the correction is so slight that it does not seem worth while to introduce it. The total group of 10,397 patients can be broken down by color and pay status into three distinct components: 1,985 private patients, all of whom were white; 4,041 white ward patients ; and 4,371 Negro ward patients. The aggregate numbers of previous pregnancies and the numbers and percentages of abortions in the three groups are presented in Table I, showing separately the findings for parturient and aborting women. TABLE
I.
NUMBER OF WOMEN, OF PREVIOUS PREGNANCIES, AND OP PREGNANCIES ENDING IN ABORTION, BY COLOR AND OUTCOME OF CURRENT PREQNANCY
OF ABORTIONS PAY STATUS
AiXD AND
PER
CENT
COLOR AND PAY STATUS
Private White1
White
ward
viable birth abortion
Negro ward
viable birth abortion
1,985
3,159
793
35.1
3,518 523
9,816 2.036
1,395 432
14.2 21.2
4,041
11,852
1,527
15.4
3,833 538
13,008 2,114
2,060 444
15.8 21.0
4,371
15,122
2,504
16.6
The findings of the present study are in investigations.l? 3 In view of the difference in parable they are with Anna Rochester’s figures based upon a citywide sample of births in 1915, ous pregnancies ending in abortion was 7.5 per for Negro women. TABLE
II.
PER CENT STATUS
PREVIOUSPREGNANCIES One Two Three Four Five Six Seven or more
OF PREVIOUS AND NUMBER 1
PRIVATE
line with the results of earlier method it is doubtful how comfor Baltimore.2 Her data were and the reported ratio of previcent for white and 11.3 per cent
PREGNANCIES OF PREVIOUS
ERODING IN ABORTION BY COLOR PREGNANCIES PER WOMAN
(WHITE) 17.1 26.9 30.9 34.6 36.8 41.7 41.5
(
WHITEWARD 13.0 15.1 15.3 16.0 15.7 15.7 16.2
1
AND
PAY
NEGROWARD 22.7 19.2 20.3 2.1.1 16.2 13.8 13.5
Table II presents abortion ratios for the three color and pay status groups by the number of previous pregnancies per woman. A very striking pattern emerges. Among the private patients the abortion ratio increases steeply with increasing number of previous pregnancies. In the white ward group no clear trend is apparent. Among the Negroes the abortion ratio is seen to decrease with increasing number of pregnancies.
Am. J. Obrt. R Gynec. December, 1948
TIETZE
1162
The high abortion ratio observed among the private patients and the pattern t a population which controls its by pregnancy order seen in this group su reproduotion mainly by contraceptive methods, but without achieving complete success. In such a group many women will resort to induced abortion if a conception has occurred in exeess of the number planned or at a time when it was not wanted. Those, on the other hand, who have had one or more unintentional abortions continue their efforts to have the number of babies they originally intended. Both mechanisms tend to produce a high abortion ratio which increases with the number of previous pregnancies. The pattern among the Negroes, which is just the opposite from that seen in the private group, is an artefact resulting from the admission policies of the hospital. During the years covered by the present study, the number of hospital beds on the Negro ward has never been sufficient to accommodate all patients seeking admission and preference has been given-among others-to two categories : To those who had produced no previous viable birth and to those who had had very many. The effect of this policy has been to increase the abortion ratio among the secundigravidas and to reduce it among the multigravidas of the hospital material on which the study is based.
Summary 1. Report is made on 30,133 previous pregnancies of 10,397 patients on an obstetric service. 2. Of these pregnancies 5,124, or 17.0 per cent, ended in abortion. 3. The abortion ratio was higher among the previous pregnancies of aborting than of parturient women. 4. The abortion ratio was 25.1 per cent for private patients (white), 15.4 per cent for white ward patients, and 16.6 per cent for Negro patients. 5. With increasing number of previous pregnancies the abortion ratio increased for private patients, decreased for Negro patients, with no clear trend for white ward patients. Mr.
I want to thank L. Omar Huesman
Dr. Nicholson J. Eastman for his for his aid in tabulating the data.
permission
t,o URC t,heae
records,
and
References 1. National
Committee on Maternal Health: The Abortion Problem, Baltimore, 1944, Chapters I and II deal with the frequency of abortion. 2. United States: Childrens Bureau. Infant Mortality. (Bureau Publication No. IlQ), Washington, 1923. Data from which computation was made are included in Appendix Tables 69, 70, and 187. 3. Wiehl, D. G.: A summary of data on reported incidence of ahortion. Milbank Memorial Fund Quarterly 16(l): 80-88, 1938. 815
NORTH
WOLFE
STREET