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Susceptibility to late postpartum hemorrhage
Susceptibility to late postpartum hemorrhage RALPHS. PAFFENBARGER, JR., M.D., PH.D. Framingham, Massachusetts
"Happy he who could learn the causes of things and who put beneath his feet all fears." Virgil's tribute to Lucretius, Georgics I, line 490.
The findings presented in this paper stem from contrasting evaluations of the control group and the hemorrhage patient group. Disparities between the groups are expressed as group averages or proportions. Maternal age and parity influenced some comparative frequencies; statistical adjustments (indirect method) were made for these wherever needed. The obstetric records available, however, were sketchy, inadequate for quantifying frequencies, and revealed only relative magnitudes for the disparities noted. Statistical significance was determined by chi-square tests or by division of differences between means by the standard error of difference. Where standard deviations are listed, they follow the ± sign after the mean. A probability level of less than 0.05 \vas considered significant.
L A T E postpartum hemorrhage from the placental site is generally ascribed to reten· tion of secundines or to subinvolution of the uterus. Numerous clinical impressions, some tenuous at best, have been advanced as predisposing causes of these abnormalities. This report concerns certain specific factors, of pregnancy and the parapartum period, associated with the development of late hemorrhage and potentially helpful in identification of puerperas susceptible to it. The attack rate of onset of late postpartum hemorrhage approximates 1 to 5 cases per 1,000 deliveries. Although rarely a cause of death, the condition leads to further hospitalization, family disquiet, and separation of mother and infant. Methods Records from 1952 through 1958 in three Cincinnati hospitals were reviewed to identify women who, on the second or later postpartum day, developed excessive uterine bleeding, diagnosed as retained secundines or as uterine subinvolution. Prenatal and perinatal data were compiled from the obstetric records of these cases, and, for comparison, similar data were gathered on a control group composed of the women of the same race who were delivered in the same obstetric unit immediately before and after those who subsequently hemorrhaged.
Findings
Diagnosis. The study group of 90 late postpartum cases of hemorrhage included 70 white and 20 Negro mothers, 87 experiencing their first such hemorrhage and 3 a recurrence. Of the illnesses, 60 were diagnosed as retained secundines and 30 as uterine subinvolution. Since no race- or diagnosis-specific differences in factors of the parapartum period were observed, all these subjects were combined into a single group for comparison with the control group. This added stability to the small numbers available. Onset. Fig. 1 shows the distribution of the 90 cases of hemorrhage by week of onset
From the National Heart Institute, United States Public Health Service, and the Department of Preventive Medicine, Harvard Medical School.
263
264
September 15, 196:! Am. j . Obst. & (; yn
Poffenbarger
ONSET
OF'
fA,JE POSJPAR.TUM. HEMOAAHAG£
30
zs tO
..b
~ .:;::: 15
~
~
10
'$-.
~ ~
~
5 0 1
:5
...
.5
\Veefv of Onset
6-8
Fig. 1. Histogram of 90 patients with hemorrhage by week of onset after the first puerperal day.
after the first puerperal day. Two patients developed excessive uterine bleeding on the second postpartum day, and 20 (22 per cent) by the end of the first week at risk. Twenty-six ( 29 per cent ) of the patients had onset in the second week, this modal number occurring after individuals had returned home and had increased their activity with new duties. There were fewer instances in the succeeding weeks of the puerperium, with 6 patients reporting onset as late as the seventh or eighth week. Some of the latter may represent instances of menstrual re-establishment misclassified as late hemorrhage. The distribution by onset for patients discharged from the obstetric hospital and re· admitted for hemorrhage was similar whether the postpartum stay was 3 days or longer. All of these cases were similar in those predisposing factors that will be shown to characterize the group in which hemorrhage occurred. No seasonal trends or yearly variations were found in the small series observed.
Incidence. In two hospitals, records were believed to be complete for the active years of study, 1957 and 1958. Here a total of 42 cases of late hemorrhage were recognized following 17,168 live births, an attack rate of 2.4 per 1,000. Rates were similar by race and by husband's occupation, a crude measure of economic status. Age and parity. Patients with hemorrhage averaged 27. 1 ± 6.7 years of age, similar to the control group average of 26.1 ± 6.1. The groups were comparable also in age at each parity. The mean parity for subjects with hemorrhage was 2.8 ± 1.8 pregnancies reaching 20 or more weeks' gestation, compared to 3.0 ± 1.8 for control subjects. Primiparas comprised 26 and 22 per cent of the respective groups. Past pregnancies. For multigravidous women the frequencies of prior spontaneous abortions were reviewed (Table I ) . A total of 25 (37 per cent) of 67 hemorrhage patients had an abortion of an earlier pregnancy, a significantly higher proportion than represented by the 28 (20 per cent)
Volume 87 Number 2
265
Late postpartum hemorrhage
fant may increase the risk of early hemorrhage post partum, infant size would seem to have little influence on the risk of late hemorrhage. No differences were found in the amounts or scheduling of prenatal obstetric care afforded patients and controls during the recent pregnancy. Uterine hemorrhage. The only significant difference in frequency of an abnormality is shown in Table III. More subjects with hemorrhage had sustained uterine bleeding in the second or third trimester of pregnancy than had the control subjects. Seventeen per cent of the patients reported bleeding in either the second or third trimester, as opposed to 4 per cent of the controls. Although a significant difference, this is insufficient alone to distinguish the cases of hemorrhage. V/hen a prior history of abortion is taken into account, however, the data become more impressive; 46 per cent of patients reported either a prior abortion or bleeding in the second or third trimester of the present pregnancy, as compared with 19 per cent of controls. It is of further interest that near equal proportions of patients and controls reported bleeding in the first trimester (Table III) when threatened abortion wouid have produced this symptom. One might presume that bleeding in the second half of pregnancy signified placenta
of the 141 control subjects. In like manner, the proportion of the patients' prior pregnancies ending in abortion ( 15 per cent) exceeded the figure for the controls ( 10 per cent). The records of habitual abortion and fetal deaths were similar in the two groups. The intervals between prior pregnancies among hemorrhage and control subjects were similar. The prior histories of chronic diseases and obstetric abnormalities (other than frequencies of abortion) revealed no differences between patients and controls. Gestation. Table II shows that significantly shorter gestational periods (39.0 ± 2.7 weeks) were noted for hemorrhage patients than for control subjects ( 39.7 ± 1. 7 weeks) in the recent pregnancy. The direction of this disparity held for each standard age and parity class, but within these subgroups the numbers are small and the differences not statistically significant. Presumably as a result of shorter gestational intervals, the birth weight of liveborn infants of hemorrhage patients averaged 130 grams less than that of infants of control subjects. This difference is not statistically significant, but its direction persisted in each age and parity class. The birth weights of prior infants of the same study groups were essentially equal. Although overdistention of the uterus from bearing a large in-
Table I. Prior history of spontaneous abortion Category
No. of women with prior pregnancies
Patients with hemorrhage Control subjects
Women with abortions No.
I
%*
Abortions
No. of prior pregnancies
No.
I
25
37
195
29
15
141
28
20
404
39
10
*P < 0.01. tP = 0.05.
Table II. Length of gestation Category Patients with hemorrhage Control subjects
%t
67
Gestation (weeks)
No. of women
Range
Mean*
S.D.
89 172
31 to 43 33 to 44
39.0 39.7
2.7
*Observed difference between means == 2.1 times its standard error.
1.7
266
September 1.1. 1963 Am. J. Obst. & GyJl("C.
Poffenbarger
Table III. Uterine bleeding during pregnancy Control subjects (1 80)
Patients with hemorrhage (90)
-------------,----~--~~---------------~------------
Trimester First Second Third Second or third* *P
<
I
%
No.
7 6
12
7
10
8 7 11
2 5
I 3
15
17
7
4
No.
%
0.001.
previa or abruptio placentae, both of which have been proposed as causes of late hemorrhage. In· the small series studied, however, similar proportions of hemorrhage patients and control subjects were reported with placenta previa (patients 2 per cent, controls 1 per cent) and abruptio placentae (patients 4 per cent, controls 2 per cent). Differences between subjects with hemorrhage and control subjects '\vere not significant for such abnormalities as preeclampsia, malpresentation, cephalopelvic disproportion, or uterine dysfunction. Labor. Muscle fatigue and atony of the myometrium are recognized to follow a labor that is either long and difficult or short and stormy. The resulting maternal exhaustion has been suggested as causative of uterine hemorrhage, both early and late. That this mechanism did not play an important role in the series reported here is indicated by a study of labor. Hemorrhage subjects and control subjects did not differ significantly in duration of labor, mean figures being 8.3 ± 6.4 and 7.9 ± 6.0 hours, respectively. Other obstetric conditions. No differences were found in types or frequencies of: (a) infectious disease, (b) maternal weight gain, (c) position of infant, (d) anesthesia, (e) operative procedure, or (f) drug administration between hemorrhage and control groups. Nor did outcome of pregnancy, perinatal mortality, sex of offspring, or frequency of congenital defect recognized at hospital discharge, differ in the two groups. Hospital stay. Eighty-five of the patients who had hemorrhage were discharged from the obstetric hospital before being readmitted with late hemorrhage. Their average ob-
stetric hospitalization was 5.0 ± 2.1 days as compared with 4.9 ± 2.0 days for control subjects. Although perhaps an inept measure of early ambulation, which has been proposed as a cause of late hemorrhage, the near equal durations of confinement suggest likeness of both groups in type and quality of postpartum care. Anemia. It has been suggested that anemia predisposes to postpartum bleeding. That this does not hold for late hemorrhage is suggested from the hemoglobin levels recorded upon admission for delivery and on the third postpartum day. Ante partum, the average level for patients was 11.3 ± 1.6 Grn. and for controls 11.3 ± 1.4 Gm. Post partum, corresponding figures were 12.1 ± 1.8 and 12.0 ± 1. 7 Gm. Breast-feeding. It is well known that suckling exerts a beneficial influence on uterine involution, and that repeated stimulation of the nipples produces reflex uterine contraction. Therefore, it is logical to assume that the nursing mother is at lesser risk of late hemorrhage than the nonnursing mother. This proposal was tested as shown in Table IV. Only 6 ( 10 per cent) of the 58 patients with hemorrhage for whom data were available were nursing their infants at the time of discharge from the obstetric hospital.
Table IV. Breast-feeding of infants born to study subjects Category Patients with hemorrhage Control subjects *P
<
0.05.
No. of
I, infants
I Breast-feeding , No.
I %*
58
6
10
107
36
34
Volume 87 Number 2
This contrasted with 36 (34 per cent) of the 107 control subjects. Although information on the duration of breast-feeding is not available, it is likely that a larger proportion of women nursing at the time of hospital discharge will continue the practice through the puerperium than of those not nursing at discharge. Comment
Some popular clinical impressions as to predisposing causes of postpartum uterine hemorrhage could not be explored. These included polyhydramnios, deep inhalation anesthesia, and mismanagement of the third stage of labor. Other impressions that were considered, such as the influence of racial and sociocultural variables, may have been obscured by the method of choosing controls. Nevertheless, uterine bleeding in the second or third trimester, failure to breast-feed the infant, and a history of prior abortion distinguished those with hemorrhage from the control subjects. These distinguishing features would seem to increase the risk of late hemorrhage and may help to identify puerperas susceptible to this condition. Summary
Ninety cases of late postpartum hemorrhage of the placental site were identified from records of three Cincinnati hospitals from 1952 through 1958. Pertinent information on each patient was compiled from hospital obstetric data recorded before hemorrhage occurred. To establish control subjects, similar data were obtained for the immediately preceding and following puerperas of the same race who were delivered in the same obstetric unit. The onsets of excessive hemorrhage in the 90 cases were scattered over 8 weeks
Late postpartum hemorrhage
267
post partum, half occurring within the first two weeks. In two hospitals where records were presumed complete, the attack rate of onset was 2.4 cases per 1,000 live births in 1957 and 1958. In mean age and parity the subjects with hemorrhage and control subjects were similar. Likewise they were similar in duration of labor and obstetric hospitalization; frequencies of placenta previa and abruptio placentae; and in their types, frequencies, and amounts of operative obstetrics and drug usage. In contrast those with hemorrhage experienced shorter gestational periods and were delivered of lighter infants than were the controls. Patients were more apt to sustain uterine bleeding during the second and third trimesters of pregnancy. They were also less apt to breast-feed their infants before (and presumably after) discharge from the obstetric unit. Spontaneous abortion of prior pregnancies in multigravidous women had occurred among more hemorrhage patients than among control subjects. Uterine bleeding during the second or third trimester, absence of breast-feeding, and a prior history of abortion were indicted as increasing the risk of late hemorrhage from the placental site. Attention to these factors may offer a rational basis to identify the puerperas susceptible to late postpartum hemorrhage. Appreciation is extended to Barbara G. Pooler, Robert T. Hyde, Charles H. Steinmetz, M.D., Ph.D., Dale D. Feist, Georgiana Pearson, Melvyn C. Thorm~. M.D., and Daniel P. Asnes, for assistance in the conduct of the study reported here. 25 Evergreen St. Framingham, Massachusetts
"Happy he who could learn the causes of things and who put beneath his feet all fears." Virgil's tribute to Lucretius, Georgics I, line 490.
The findings presented in this paper stem from contrasting evaluations of the control group and the hemorrhage patient group. Disparities between the groups are expressed as group averages or proportions. Maternal age and parity influenced some comparative frequencies; statistical adjustments (indirect method) were made for these wherever needed. The obstetric records available, however, were sketchy, inadequate for quantifying frequencies, and revealed only relative magnitudes for the disparities noted. Statistical significance was determined by chi-square tests or by division of differences between means by the standard error of difference. Where standard deviations are listed, they follow the ± sign after the mean. A probability level of less than 0.05 \vas considered significant.
L A T E postpartum hemorrhage from the placental site is generally ascribed to reten· tion of secundines or to subinvolution of the uterus. Numerous clinical impressions, some tenuous at best, have been advanced as predisposing causes of these abnormalities. This report concerns certain specific factors, of pregnancy and the parapartum period, associated with the development of late hemorrhage and potentially helpful in identification of puerperas susceptible to it. The attack rate of onset of late postpartum hemorrhage approximates 1 to 5 cases per 1,000 deliveries. Although rarely a cause of death, the condition leads to further hospitalization, family disquiet, and separation of mother and infant. Methods Records from 1952 through 1958 in three Cincinnati hospitals were reviewed to identify women who, on the second or later postpartum day, developed excessive uterine bleeding, diagnosed as retained secundines or as uterine subinvolution. Prenatal and perinatal data were compiled from the obstetric records of these cases, and, for comparison, similar data were gathered on a control group composed of the women of the same race who were delivered in the same obstetric unit immediately before and after those who subsequently hemorrhaged.
Findings
Diagnosis. The study group of 90 late postpartum cases of hemorrhage included 70 white and 20 Negro mothers, 87 experiencing their first such hemorrhage and 3 a recurrence. Of the illnesses, 60 were diagnosed as retained secundines and 30 as uterine subinvolution. Since no race- or diagnosis-specific differences in factors of the parapartum period were observed, all these subjects were combined into a single group for comparison with the control group. This added stability to the small numbers available. Onset. Fig. 1 shows the distribution of the 90 cases of hemorrhage by week of onset
From the National Heart Institute, United States Public Health Service, and the Department of Preventive Medicine, Harvard Medical School.
263
264
September 15, 196:! Am. j . Obst. & (; yn
Poffenbarger
ONSET
OF'
fA,JE POSJPAR.TUM. HEMOAAHAG£
30
zs tO
..b
~ .:;::: 15
~
~
10
'$-.
~ ~
~
5 0 1
:5
...
.5
\Veefv of Onset
6-8
Fig. 1. Histogram of 90 patients with hemorrhage by week of onset after the first puerperal day.
after the first puerperal day. Two patients developed excessive uterine bleeding on the second postpartum day, and 20 (22 per cent) by the end of the first week at risk. Twenty-six ( 29 per cent ) of the patients had onset in the second week, this modal number occurring after individuals had returned home and had increased their activity with new duties. There were fewer instances in the succeeding weeks of the puerperium, with 6 patients reporting onset as late as the seventh or eighth week. Some of the latter may represent instances of menstrual re-establishment misclassified as late hemorrhage. The distribution by onset for patients discharged from the obstetric hospital and re· admitted for hemorrhage was similar whether the postpartum stay was 3 days or longer. All of these cases were similar in those predisposing factors that will be shown to characterize the group in which hemorrhage occurred. No seasonal trends or yearly variations were found in the small series observed.
Incidence. In two hospitals, records were believed to be complete for the active years of study, 1957 and 1958. Here a total of 42 cases of late hemorrhage were recognized following 17,168 live births, an attack rate of 2.4 per 1,000. Rates were similar by race and by husband's occupation, a crude measure of economic status. Age and parity. Patients with hemorrhage averaged 27. 1 ± 6.7 years of age, similar to the control group average of 26.1 ± 6.1. The groups were comparable also in age at each parity. The mean parity for subjects with hemorrhage was 2.8 ± 1.8 pregnancies reaching 20 or more weeks' gestation, compared to 3.0 ± 1.8 for control subjects. Primiparas comprised 26 and 22 per cent of the respective groups. Past pregnancies. For multigravidous women the frequencies of prior spontaneous abortions were reviewed (Table I ) . A total of 25 (37 per cent) of 67 hemorrhage patients had an abortion of an earlier pregnancy, a significantly higher proportion than represented by the 28 (20 per cent)
Volume 87 Number 2
265
Late postpartum hemorrhage
fant may increase the risk of early hemorrhage post partum, infant size would seem to have little influence on the risk of late hemorrhage. No differences were found in the amounts or scheduling of prenatal obstetric care afforded patients and controls during the recent pregnancy. Uterine hemorrhage. The only significant difference in frequency of an abnormality is shown in Table III. More subjects with hemorrhage had sustained uterine bleeding in the second or third trimester of pregnancy than had the control subjects. Seventeen per cent of the patients reported bleeding in either the second or third trimester, as opposed to 4 per cent of the controls. Although a significant difference, this is insufficient alone to distinguish the cases of hemorrhage. V/hen a prior history of abortion is taken into account, however, the data become more impressive; 46 per cent of patients reported either a prior abortion or bleeding in the second or third trimester of the present pregnancy, as compared with 19 per cent of controls. It is of further interest that near equal proportions of patients and controls reported bleeding in the first trimester (Table III) when threatened abortion wouid have produced this symptom. One might presume that bleeding in the second half of pregnancy signified placenta
of the 141 control subjects. In like manner, the proportion of the patients' prior pregnancies ending in abortion ( 15 per cent) exceeded the figure for the controls ( 10 per cent). The records of habitual abortion and fetal deaths were similar in the two groups. The intervals between prior pregnancies among hemorrhage and control subjects were similar. The prior histories of chronic diseases and obstetric abnormalities (other than frequencies of abortion) revealed no differences between patients and controls. Gestation. Table II shows that significantly shorter gestational periods (39.0 ± 2.7 weeks) were noted for hemorrhage patients than for control subjects ( 39.7 ± 1. 7 weeks) in the recent pregnancy. The direction of this disparity held for each standard age and parity class, but within these subgroups the numbers are small and the differences not statistically significant. Presumably as a result of shorter gestational intervals, the birth weight of liveborn infants of hemorrhage patients averaged 130 grams less than that of infants of control subjects. This difference is not statistically significant, but its direction persisted in each age and parity class. The birth weights of prior infants of the same study groups were essentially equal. Although overdistention of the uterus from bearing a large in-
Table I. Prior history of spontaneous abortion Category
No. of women with prior pregnancies
Patients with hemorrhage Control subjects
Women with abortions No.
I
%*
Abortions
No. of prior pregnancies
No.
I
25
37
195
29
15
141
28
20
404
39
10
*P < 0.01. tP = 0.05.
Table II. Length of gestation Category Patients with hemorrhage Control subjects
%t
67
Gestation (weeks)
No. of women
Range
Mean*
S.D.
89 172
31 to 43 33 to 44
39.0 39.7
2.7
*Observed difference between means == 2.1 times its standard error.
1.7
266
September 1.1. 1963 Am. J. Obst. & GyJl("C.
Poffenbarger
Table III. Uterine bleeding during pregnancy Control subjects (1 80)
Patients with hemorrhage (90)
-------------,----~--~~---------------~------------
Trimester First Second Third Second or third* *P
<
I
%
No.
7 6
12
7
10
8 7 11
2 5
I 3
15
17
7
4
No.
%
0.001.
previa or abruptio placentae, both of which have been proposed as causes of late hemorrhage. In· the small series studied, however, similar proportions of hemorrhage patients and control subjects were reported with placenta previa (patients 2 per cent, controls 1 per cent) and abruptio placentae (patients 4 per cent, controls 2 per cent). Differences between subjects with hemorrhage and control subjects '\vere not significant for such abnormalities as preeclampsia, malpresentation, cephalopelvic disproportion, or uterine dysfunction. Labor. Muscle fatigue and atony of the myometrium are recognized to follow a labor that is either long and difficult or short and stormy. The resulting maternal exhaustion has been suggested as causative of uterine hemorrhage, both early and late. That this mechanism did not play an important role in the series reported here is indicated by a study of labor. Hemorrhage subjects and control subjects did not differ significantly in duration of labor, mean figures being 8.3 ± 6.4 and 7.9 ± 6.0 hours, respectively. Other obstetric conditions. No differences were found in types or frequencies of: (a) infectious disease, (b) maternal weight gain, (c) position of infant, (d) anesthesia, (e) operative procedure, or (f) drug administration between hemorrhage and control groups. Nor did outcome of pregnancy, perinatal mortality, sex of offspring, or frequency of congenital defect recognized at hospital discharge, differ in the two groups. Hospital stay. Eighty-five of the patients who had hemorrhage were discharged from the obstetric hospital before being readmitted with late hemorrhage. Their average ob-
stetric hospitalization was 5.0 ± 2.1 days as compared with 4.9 ± 2.0 days for control subjects. Although perhaps an inept measure of early ambulation, which has been proposed as a cause of late hemorrhage, the near equal durations of confinement suggest likeness of both groups in type and quality of postpartum care. Anemia. It has been suggested that anemia predisposes to postpartum bleeding. That this does not hold for late hemorrhage is suggested from the hemoglobin levels recorded upon admission for delivery and on the third postpartum day. Ante partum, the average level for patients was 11.3 ± 1.6 Grn. and for controls 11.3 ± 1.4 Gm. Post partum, corresponding figures were 12.1 ± 1.8 and 12.0 ± 1. 7 Gm. Breast-feeding. It is well known that suckling exerts a beneficial influence on uterine involution, and that repeated stimulation of the nipples produces reflex uterine contraction. Therefore, it is logical to assume that the nursing mother is at lesser risk of late hemorrhage than the nonnursing mother. This proposal was tested as shown in Table IV. Only 6 ( 10 per cent) of the 58 patients with hemorrhage for whom data were available were nursing their infants at the time of discharge from the obstetric hospital.
Table IV. Breast-feeding of infants born to study subjects Category Patients with hemorrhage Control subjects *P
<
0.05.
No. of
I, infants
I Breast-feeding , No.
I %*
58
6
10
107
36
34
Volume 87 Number 2
This contrasted with 36 (34 per cent) of the 107 control subjects. Although information on the duration of breast-feeding is not available, it is likely that a larger proportion of women nursing at the time of hospital discharge will continue the practice through the puerperium than of those not nursing at discharge. Comment
Some popular clinical impressions as to predisposing causes of postpartum uterine hemorrhage could not be explored. These included polyhydramnios, deep inhalation anesthesia, and mismanagement of the third stage of labor. Other impressions that were considered, such as the influence of racial and sociocultural variables, may have been obscured by the method of choosing controls. Nevertheless, uterine bleeding in the second or third trimester, failure to breast-feed the infant, and a history of prior abortion distinguished those with hemorrhage from the control subjects. These distinguishing features would seem to increase the risk of late hemorrhage and may help to identify puerperas susceptible to this condition. Summary
Ninety cases of late postpartum hemorrhage of the placental site were identified from records of three Cincinnati hospitals from 1952 through 1958. Pertinent information on each patient was compiled from hospital obstetric data recorded before hemorrhage occurred. To establish control subjects, similar data were obtained for the immediately preceding and following puerperas of the same race who were delivered in the same obstetric unit. The onsets of excessive hemorrhage in the 90 cases were scattered over 8 weeks
Late postpartum hemorrhage
267
post partum, half occurring within the first two weeks. In two hospitals where records were presumed complete, the attack rate of onset was 2.4 cases per 1,000 live births in 1957 and 1958. In mean age and parity the subjects with hemorrhage and control subjects were similar. Likewise they were similar in duration of labor and obstetric hospitalization; frequencies of placenta previa and abruptio placentae; and in their types, frequencies, and amounts of operative obstetrics and drug usage. In contrast those with hemorrhage experienced shorter gestational periods and were delivered of lighter infants than were the controls. Patients were more apt to sustain uterine bleeding during the second and third trimesters of pregnancy. They were also less apt to breast-feed their infants before (and presumably after) discharge from the obstetric unit. Spontaneous abortion of prior pregnancies in multigravidous women had occurred among more hemorrhage patients than among control subjects. Uterine bleeding during the second or third trimester, absence of breast-feeding, and a prior history of abortion were indicted as increasing the risk of late hemorrhage from the placental site. Attention to these factors may offer a rational basis to identify the puerperas susceptible to late postpartum hemorrhage. Appreciation is extended to Barbara G. Pooler, Robert T. Hyde, Charles H. Steinmetz, M.D., Ph.D., Dale D. Feist, Georgiana Pearson, Melvyn C. Thorm~. M.D., and Daniel P. Asnes, for assistance in the conduct of the study reported here. 25 Evergreen St. Framingham, Massachusetts