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Reliability of patient history in determining the possibility of pregnancy
ORIGINAL CONTRIBUTION pregnancy, determination of
Reliability of Patient History in Determining the Possibility of Pregnancy In an effort to assess the reliability of patient history in excluding pregnancy, we studied the correlation between specific historical factors and the presence of a positive qualitative serum beta-human chorionic gonadotropin assay. Two hundred eight patients were studied, and information was collected prospectively on a variety of historical criteria. Three historical variables were statistically less likely to be associated with pregnancy: last menstrual period that was on time, the patient thinking she was not pregnant, and the patient stating there was no chance she could be pregnant (P < .00i). There was, however, still at least a 10% chance of the patient being pregnant. Combinations of historical criteria were likewise unsuccessful at totally excluding pregnancy. These data support the contention that patient history is an unreliable method of excluding pregnancy in emergency department patients and supports the liberal use of pregnancy tests. [Ramoska EA, Sacchetti AD, Nepp M: Reliability of patient history in determining the possibility of pregnancy. Ann Emerg Med January 1989;18: 48-50.] INTRODUCTION
The diagnosis of pregnancy and its complications is of the utmost importance in the emergency department evaluation of any w o m a n of child-bearing ageP To avoid missing this diagnosis, manyemergency physicians make liberal use of the monoclonal antibody assays for the beta-subunit of human chorionJc gonadotropJn {beta-HCG). These newer pregnancy tests, although accurate and readily available, can be expensive. 2-4 In an effort to determine if the ordering of beta-HCGs could be safely reduced, we conducted a prospective study to document the reliability of patient history in diagnosing or excluding pregnancy in ED patients.
Edward A Ramoska, MD, FACEP*t Alfred D Sacchetti, MD, FACEP.11 Mark Nepp, DO1Camden, New Jersey Philadelphia, Pennsylvania From Emergency Services, Our Lady of Lourdes Medical Center, Camden, New Jersey;* Thomas Jefferson University Emergency Medicine Residency, t and Emergency Services, Methodist Hespital,:~ Philadelphia, Pennsylvania. Received for publication May 3, 1988. Accepted for publication September 8, 1988. Presented at the University Association for Emergency Medicine Annual Meeting in Cincinnati, May 1988. Address for reprints: Edward A Ramoska, MD, Department of Emergency Medicine, Methodist Hospital, 2301 South Broad Street, Philadelphia, Pennsylvania 19148.
METHODS
During a three-month study period, physicians were asked to fill out a questionnaire on all patients for w h o m they ordered a qualitative s e r u m beta-HCG determination. The data collection form is shown (Figure). Statistical significance was determined by X2 (P < .001). RESULTS
Two hundred eight patients met the criteria for inclusion in the study. The average age of the patients was 23 years old (range, 12 to 49 years). In 14 of the patients (6.7%), the physician noted a language problem, although in all cases a complete history was obtained. There were 68 positive pregnancy tests (33%). The main indication for ordering a pregnancy test was abdominal pain (138 patients), either alone or associated with vaginal bleeding or discharge. Other reasons included painless vaginal bleeding, irregular or missed periods, patient concern about possible pregnancy, and syncope or dizziness (Table 1). The vast majority of patients (196) admitted to being sexually active, but only 51 (24.5%) used any form of birth control. The methods of contraception were oral contraceptive pills in 28 patients, tubal ligation in 14, condoms in seven, and the vaginal sponge and an IUD in one each. The patient responses to the specific questions, the number and percentage of patients who were pregnant, and whether the percentages were signifi18:1 January 1989
Annals of Emergency Medicine
48/87
PATIENT HISTORY Ramoska, Sacchetti & Nepp
cant are shown (Table 2). The timing of the last menstrual period and the patient's perception about w h e t h e r she t h o u g h t she was pregnant or if there was any chance she could be pregnant were all useful in predicting the outcome of a pregnancy test. The effect of combining historical criteria in an effort to develop a subgroup of patients w h o would not be pregnant is shown (Table 3). None of the subgroups combined produced a subgroup that totally excluded pregnancy. DISCUSSION The accurate diagnosis or exclusion of pregnancy is of paramount concern for emergenzy physicians.t, 5 However, the accuracy of history in proving or, more importantly, in excluding pregnancy has not been demonstrated in ED patients. Our study suggests that even with a normal menstrual history and the use of birth control, history is unreliable in absolutely excluding the diagnosis of pregnancy. Only three historical criteria, a last menstrual period that was on time, the patient thinking she was not pregnant, and the patient stating there was no chance she could be pregnant, were identified as being statistically less likely to be associated with pregnancy (P < .001). Even within these groups, there was still a 10% to 15% chance of the patient being pregnant. The use of birth control and patient denial of sexual activity were not significant to exclude pregnancy. In fact, seven patients were found to be pregnant despite the use of birth control, including one patient who had had a tubal ligation. One additional patient denied being sexually active to multiple interviewers until confronted with a positive pregnancy test. An attempt to combine some of the historical variables to produce a subset of questions that would exclude pregnancy was likewise unsuccessful. The combination of an on-time and normal last menstrual period was significantly associated with not being pregnant; however, there was still a 10% chance df pregnancy. The comb i n a t i o n of last m e n s t r u a l p e r i o d being on time and normal and the patient stating there was no chance she could be pregnant was also significant at excluding pregnancy; again, however, there was still a 7% chance of the patient being pregnant. The comb i n a t i o n of last m e n s t r u a l p e r i o d 88/49
TABLE 1. Presenting complaint Complaint Abdominal pain Vaginal bleeding Abdominal pain plus vaginal bleeding Irregular, unknown, or missed period Patient concern about pregnancy Syncope or dizziness Abdominal pain plus vaginal discharge Alleged rape Total
No, 113 28 21 20 11 10 4 1 208
TABLE 2. Predictive value of s~ngle historical criterion
Historical Variables Last menstrual period On time Not on time Normal Not normal Sexually active Not sexually active Uses birth control No birth control Thinks she may be pregnant Does not think she's pregnant A chance she may be pregnant No chance she could be pregnant *P < .001.
No.
No, Positive HCGs
% Positive
92 116 155 53 196 12 51 157 75 133 121 87
10 58 52 16 67 1 7 61 47 21 58 10
10.9" 50.0* 33.6 34.2 34.2 8.3 13.7 38.9 62.7* 15.8" 47.9* 11.5"
TABLE 3. Predictive value of combined criteria
Combinations of Historical Variables LMP on time and normal LMP on time and normal and patient uses birth control LMP on time and normal and there is no chance patient is pregnant according to patient
N 79
No. Positive HCGs 8
% Positive 10.13"
27
1
3.70
55
4
7.27*
LMP, last menstrual period. *P < .001. Annals of Emergency Medicine
18:1 January 1989
F I G U R E . D a t a collection form. Name:
Age: _ _
Date: _ _
/_ _
/ _ _
Chief complaint: Gravida:
Para F : _
LMP: _ _ / _ _ / _ _ On Time: Y
N
Birth Control: Y
A : _
or approx. _ _
Normal: Y
Sexually Active: Y
P : _
L : _
days/weeks/months ago
N
N
N
Type:
Do you think you may be pregnant? Y
SUMMARY The data from our study suggest t h a t h i s t o r y is an unreliable m e t h o d of e x c l u d i n g p r e g n a n c y in the ED p a t i e n t and that t h e liberal use of p r e g n a n c y tests is w a r r a n t e d w h e n e v e r the diagn o s t i c possibilities i n c l u d e p r e g n a n c y or one of its c o m p l i c a t i o n s .
REFERENCES
N
Is there any chance you may be pregnant? Y Serum HCG: +
t h e ED. T h e liberal use of b e t a - H C G d e t e r m i n a t i o n s w h e n e v e r t h e diagnostic possibilities i n c l u d e p r e g n a n c y or o n e of its c o m p l i c a t i o n s is suggested,
-
1. Dorfman SF, Grimes DA, Cates W, et al: Ectopic pregnancy mortality, United States 1979 1980: Clinical aspects. Obstet Gynecol 1984;64: 386-390. 2. Farrell RG, Stair TO: Diagnostic tests in obstetrics and gynecology, in Farrell RG (ed): Ob/Gyn Emergencies. The First 60 Minutes.
Diagnosis:
being on t i m e and n o r m a l and t h e use of birth control approached being significantly associated with the nonp r e g n a n t state; again, however, s o m e p a t i e n t s (3.7%) w e r e f o u n d to be pregnant. We did n o t i n c l u d e t h e p a t i e n t ' s p h y s i c a l e x a m i n a t i o n as a f a c t o r in t h e p r e d i c t i o n of pregnancy. Studies h a v e d o c u m e n t e d t h e i n a c c u r a c y of pelvic e x a m i n a t i o n s in correctly diagnosing a c u t e gynecological pathology. 6 T h e ability to recognize an early pregn a n c y on physical e x a m i n a t i o n in an
18:1 January 1989
u n c o m f o r t a b l e or u n c o o p e r a t i v e pat i e n t can be e x t r e m e l y difficult, even for the best physician. F r o m personal e x p e r i e n c e , t h e r e appears to be w i d e i n t e r p h y s i c i a n v a r i a b i l i t y in t h e perf o r m a n c e of pelvic e x a m i n a t i o n s . Bec a u s e of t h i s factor, w e b e l i e v e t h e lack of i n c l u s i o n of p h y s i c a l finding in this s t u d y does n o t d e t r a c t f r o m its a p p l i c a t i o n to t h e p r a c t i c e of emergency m e d i c i n e . These results support the contention t h a t historical criteria a l o n e are n o t a d e q u a t e to exclude p r e g n a n c y in
Annals of Emergency Medicine
Rockville, Maryland, Aspen Publishers, Inc, 1986, p 301-316. 3. Honigman B: Selected serology: Pregnancy testing, hepatitis A and B, and infectious mononucleosis, in Hamilton GC {ed): Emergency Medicine Clinics of North America. Philadelphia, WB Saunders, 1986, p 300-305. 4. Cartwright PS, Victory DF, Moore RA, et al: Performance of a new enzymeqinked immunoassay urine pregnancy test for the detection of ectopic gestation. Ann Emerg Med 1986; 15:1198-1199. 5. Holman JF, Tyrey EL, Hammond CB, et al: A contemporary approach to suspected ectopic pregnancy with use of quantitative and qualitative assays for the beta-subnnit of human chorionic gonadotropin and sonography. Am J Obstet Gynecol 1984;150:151-155. 6. Cunanan RG, Gourey MG, Lippes J, et al: Laproscopic findings in patients with pelvic pain. Am J Obstet Gynecol 1983;146:589-591.
50/89
Reliability of Patient History in Determining the Possibility of Pregnancy In an effort to assess the reliability of patient history in excluding pregnancy, we studied the correlation between specific historical factors and the presence of a positive qualitative serum beta-human chorionic gonadotropin assay. Two hundred eight patients were studied, and information was collected prospectively on a variety of historical criteria. Three historical variables were statistically less likely to be associated with pregnancy: last menstrual period that was on time, the patient thinking she was not pregnant, and the patient stating there was no chance she could be pregnant (P < .00i). There was, however, still at least a 10% chance of the patient being pregnant. Combinations of historical criteria were likewise unsuccessful at totally excluding pregnancy. These data support the contention that patient history is an unreliable method of excluding pregnancy in emergency department patients and supports the liberal use of pregnancy tests. [Ramoska EA, Sacchetti AD, Nepp M: Reliability of patient history in determining the possibility of pregnancy. Ann Emerg Med January 1989;18: 48-50.] INTRODUCTION
The diagnosis of pregnancy and its complications is of the utmost importance in the emergency department evaluation of any w o m a n of child-bearing ageP To avoid missing this diagnosis, manyemergency physicians make liberal use of the monoclonal antibody assays for the beta-subunit of human chorionJc gonadotropJn {beta-HCG). These newer pregnancy tests, although accurate and readily available, can be expensive. 2-4 In an effort to determine if the ordering of beta-HCGs could be safely reduced, we conducted a prospective study to document the reliability of patient history in diagnosing or excluding pregnancy in ED patients.
Edward A Ramoska, MD, FACEP*t Alfred D Sacchetti, MD, FACEP.11 Mark Nepp, DO1Camden, New Jersey Philadelphia, Pennsylvania From Emergency Services, Our Lady of Lourdes Medical Center, Camden, New Jersey;* Thomas Jefferson University Emergency Medicine Residency, t and Emergency Services, Methodist Hespital,:~ Philadelphia, Pennsylvania. Received for publication May 3, 1988. Accepted for publication September 8, 1988. Presented at the University Association for Emergency Medicine Annual Meeting in Cincinnati, May 1988. Address for reprints: Edward A Ramoska, MD, Department of Emergency Medicine, Methodist Hospital, 2301 South Broad Street, Philadelphia, Pennsylvania 19148.
METHODS
During a three-month study period, physicians were asked to fill out a questionnaire on all patients for w h o m they ordered a qualitative s e r u m beta-HCG determination. The data collection form is shown (Figure). Statistical significance was determined by X2 (P < .001). RESULTS
Two hundred eight patients met the criteria for inclusion in the study. The average age of the patients was 23 years old (range, 12 to 49 years). In 14 of the patients (6.7%), the physician noted a language problem, although in all cases a complete history was obtained. There were 68 positive pregnancy tests (33%). The main indication for ordering a pregnancy test was abdominal pain (138 patients), either alone or associated with vaginal bleeding or discharge. Other reasons included painless vaginal bleeding, irregular or missed periods, patient concern about possible pregnancy, and syncope or dizziness (Table 1). The vast majority of patients (196) admitted to being sexually active, but only 51 (24.5%) used any form of birth control. The methods of contraception were oral contraceptive pills in 28 patients, tubal ligation in 14, condoms in seven, and the vaginal sponge and an IUD in one each. The patient responses to the specific questions, the number and percentage of patients who were pregnant, and whether the percentages were signifi18:1 January 1989
Annals of Emergency Medicine
48/87
PATIENT HISTORY Ramoska, Sacchetti & Nepp
cant are shown (Table 2). The timing of the last menstrual period and the patient's perception about w h e t h e r she t h o u g h t she was pregnant or if there was any chance she could be pregnant were all useful in predicting the outcome of a pregnancy test. The effect of combining historical criteria in an effort to develop a subgroup of patients w h o would not be pregnant is shown (Table 3). None of the subgroups combined produced a subgroup that totally excluded pregnancy. DISCUSSION The accurate diagnosis or exclusion of pregnancy is of paramount concern for emergenzy physicians.t, 5 However, the accuracy of history in proving or, more importantly, in excluding pregnancy has not been demonstrated in ED patients. Our study suggests that even with a normal menstrual history and the use of birth control, history is unreliable in absolutely excluding the diagnosis of pregnancy. Only three historical criteria, a last menstrual period that was on time, the patient thinking she was not pregnant, and the patient stating there was no chance she could be pregnant, were identified as being statistically less likely to be associated with pregnancy (P < .001). Even within these groups, there was still a 10% to 15% chance of the patient being pregnant. The use of birth control and patient denial of sexual activity were not significant to exclude pregnancy. In fact, seven patients were found to be pregnant despite the use of birth control, including one patient who had had a tubal ligation. One additional patient denied being sexually active to multiple interviewers until confronted with a positive pregnancy test. An attempt to combine some of the historical variables to produce a subset of questions that would exclude pregnancy was likewise unsuccessful. The combination of an on-time and normal last menstrual period was significantly associated with not being pregnant; however, there was still a 10% chance df pregnancy. The comb i n a t i o n of last m e n s t r u a l p e r i o d being on time and normal and the patient stating there was no chance she could be pregnant was also significant at excluding pregnancy; again, however, there was still a 7% chance of the patient being pregnant. The comb i n a t i o n of last m e n s t r u a l p e r i o d 88/49
TABLE 1. Presenting complaint Complaint Abdominal pain Vaginal bleeding Abdominal pain plus vaginal bleeding Irregular, unknown, or missed period Patient concern about pregnancy Syncope or dizziness Abdominal pain plus vaginal discharge Alleged rape Total
No, 113 28 21 20 11 10 4 1 208
TABLE 2. Predictive value of s~ngle historical criterion
Historical Variables Last menstrual period On time Not on time Normal Not normal Sexually active Not sexually active Uses birth control No birth control Thinks she may be pregnant Does not think she's pregnant A chance she may be pregnant No chance she could be pregnant *P < .001.
No.
No, Positive HCGs
% Positive
92 116 155 53 196 12 51 157 75 133 121 87
10 58 52 16 67 1 7 61 47 21 58 10
10.9" 50.0* 33.6 34.2 34.2 8.3 13.7 38.9 62.7* 15.8" 47.9* 11.5"
TABLE 3. Predictive value of combined criteria
Combinations of Historical Variables LMP on time and normal LMP on time and normal and patient uses birth control LMP on time and normal and there is no chance patient is pregnant according to patient
N 79
No. Positive HCGs 8
% Positive 10.13"
27
1
3.70
55
4
7.27*
LMP, last menstrual period. *P < .001. Annals of Emergency Medicine
18:1 January 1989
F I G U R E . D a t a collection form. Name:
Age: _ _
Date: _ _
/_ _
/ _ _
Chief complaint: Gravida:
Para F : _
LMP: _ _ / _ _ / _ _ On Time: Y
N
Birth Control: Y
A : _
or approx. _ _
Normal: Y
Sexually Active: Y
P : _
L : _
days/weeks/months ago
N
N
N
Type:
Do you think you may be pregnant? Y
SUMMARY The data from our study suggest t h a t h i s t o r y is an unreliable m e t h o d of e x c l u d i n g p r e g n a n c y in the ED p a t i e n t and that t h e liberal use of p r e g n a n c y tests is w a r r a n t e d w h e n e v e r the diagn o s t i c possibilities i n c l u d e p r e g n a n c y or one of its c o m p l i c a t i o n s .
REFERENCES
N
Is there any chance you may be pregnant? Y Serum HCG: +
t h e ED. T h e liberal use of b e t a - H C G d e t e r m i n a t i o n s w h e n e v e r t h e diagnostic possibilities i n c l u d e p r e g n a n c y or o n e of its c o m p l i c a t i o n s is suggested,
-
1. Dorfman SF, Grimes DA, Cates W, et al: Ectopic pregnancy mortality, United States 1979 1980: Clinical aspects. Obstet Gynecol 1984;64: 386-390. 2. Farrell RG, Stair TO: Diagnostic tests in obstetrics and gynecology, in Farrell RG (ed): Ob/Gyn Emergencies. The First 60 Minutes.
Diagnosis:
being on t i m e and n o r m a l and t h e use of birth control approached being significantly associated with the nonp r e g n a n t state; again, however, s o m e p a t i e n t s (3.7%) w e r e f o u n d to be pregnant. We did n o t i n c l u d e t h e p a t i e n t ' s p h y s i c a l e x a m i n a t i o n as a f a c t o r in t h e p r e d i c t i o n of pregnancy. Studies h a v e d o c u m e n t e d t h e i n a c c u r a c y of pelvic e x a m i n a t i o n s in correctly diagnosing a c u t e gynecological pathology. 6 T h e ability to recognize an early pregn a n c y on physical e x a m i n a t i o n in an
18:1 January 1989
u n c o m f o r t a b l e or u n c o o p e r a t i v e pat i e n t can be e x t r e m e l y difficult, even for the best physician. F r o m personal e x p e r i e n c e , t h e r e appears to be w i d e i n t e r p h y s i c i a n v a r i a b i l i t y in t h e perf o r m a n c e of pelvic e x a m i n a t i o n s . Bec a u s e of t h i s factor, w e b e l i e v e t h e lack of i n c l u s i o n of p h y s i c a l finding in this s t u d y does n o t d e t r a c t f r o m its a p p l i c a t i o n to t h e p r a c t i c e of emergency m e d i c i n e . These results support the contention t h a t historical criteria a l o n e are n o t a d e q u a t e to exclude p r e g n a n c y in
Annals of Emergency Medicine
Rockville, Maryland, Aspen Publishers, Inc, 1986, p 301-316. 3. Honigman B: Selected serology: Pregnancy testing, hepatitis A and B, and infectious mononucleosis, in Hamilton GC {ed): Emergency Medicine Clinics of North America. Philadelphia, WB Saunders, 1986, p 300-305. 4. Cartwright PS, Victory DF, Moore RA, et al: Performance of a new enzymeqinked immunoassay urine pregnancy test for the detection of ectopic gestation. Ann Emerg Med 1986; 15:1198-1199. 5. Holman JF, Tyrey EL, Hammond CB, et al: A contemporary approach to suspected ectopic pregnancy with use of quantitative and qualitative assays for the beta-subnnit of human chorionic gonadotropin and sonography. Am J Obstet Gynecol 1984;150:151-155. 6. Cunanan RG, Gourey MG, Lippes J, et al: Laproscopic findings in patients with pelvic pain. Am J Obstet Gynecol 1983;146:589-591.
50/89