- Email: [email protected]
The Effect of Intranasal Administration of Oxytocin on the Let-Down of Milk in Lactating Women
THE EFFECT OF INTRANASAL ADMINISTRATION OF OXYTOCIN ON THE LET-DOWN OF MILK IN LACTATING WOMEN
JACKSON,
Mrss.
(From the Department of Obstetrics and Gynecology, University of Mississippi School of Medicine)
T
HE smooth course of breast feeding is related to adequate function of the let-down reflex. Stimulation of the nipple in the lactating woman results in the release of an oxytocic factor into the blood stream through the mediation of the central nervous system and the posterior lobe of the pituitary glanast pump could remove it. Most of it could be rt>moved, however, by setting off the let-down reflex artificially with injections of oxytoc•.in. In a study of 103 nursing mothers it was found that mothers whose babies did not need supplemental bottles had significantly more symptoms and signs of let-down than mothers whose babies required supplemental feedings. The reflex appeared to work less prratically in thP successful mothPrs. In these there was significantly less variation in thr amount of milk the baby obtained from one feeding to the next. Failure of the let-down reflex may also predispose to the development of nipple lesions, mastitis, and breast ahscess.5'
G
In relaxed, confident women with babies who suck eagerly the let-down reflt•x usually functions welL A high proportion of new mothers in our culture are tense at the start of breast f<:'eding, however. Furthermore, their babies arP often taught to suck thP bottle in the nursery and are brought to the mother on a rigid schedule when they are not necessarily hungry_ TT111let' these cin·umstances the vigorous sucking that sets off the let-down reflex may be absent. *Work done under a Research Fellowship,
Fnited States Public Health Service :Medical Student Part-tirr.•'
103
104
NEWTON AND EGLJ.
Am . .T.
()b::;L & <3Yne~.
July, 1958
It is often impossible to change hospital routines and the psychological factors responsible for the failure of the let-down refh·x. Artificial production of the reflex may therefore be of value. Subcutaneous, intramuscular, and intravenous injections of Pitoein are f'ffeetive 7 • "· 9 but repeated injections are disagreeable for the mother and require the presence of medical personneL Since oxytocin has been used intranasally for the induction of labor, 10 it was suggested by Quinlan 11 that the intranasal route might he preferable in the management of lactation. The purpose of this study was to test the practicability and effectiveness of intranasal oxytocin in setting off the letdown reflex.
Methods Nineteen women from the postpartum floor of the University of Mississippi Hospital were used as subjects. Their average age was 22.7 years with a range from 15 to 35 years. Seven were primiparas and twelve multiparas. Eight of the multiparas had breast fed the last child for 2 months or more (up to 12 months) while 4 had not done so, or had made abortive attempts at breast feeding. All the women expressed a desire to breast feed their babies at least for a while after they left the hospitaL At the time of the study the breast feeding routine was such that the women were first given their babies to nurse at varying times up to 24 hours after delivery. Babies were then brought to their mothers every 4 hours anJ left with them for from 30 to 45 minutes. No restrictions were placed on the amount of suckling given during this time. All the mothers used in the study had had milk in their breasts for at least 6 hours and the majority for over 12 hours. Experiments were performed at a mean of 79 hours after delivery with a range of from 34 to 167 hours. A total of twenty studies was performed, one subject being used twice. Each study consisted of three experiments, performed 2 hours after each of three successive nursing periods. In 15 instances the three experiments were performed at 7 :00 A.M., 11 :00 A.M., and 3 :00 P.M., and in 5 they were performed at 11 :00 A.M., 3 :00 P.M., and 7 :00 P.M. The subjects were told that a test was being made of their milk. Cooperation and rapport were good at all times. Each experiment was conducted in the same manner. 'l'he subject lay on her back or side in a comfortable position. One breast was pumped with an electric breast pump for 5 minutes. Intermittent suction was applied at a rate of 25 to 30 times a minute by finger control in such a way that the suction pressure rose to 5 to 6 inches of mercury and was then released. There was then a 5 minute delay period, after which the same breast was pumped again in a similar manner for another 5 minutes. The same breast was used in all three experiments on the same woman. The only difference was in the procedure used during the delay period. In one experiment nothing was done (experiment A). In the second, a cotton applicator soaked in 0.5 c. c. saline was inserted into one nostril: at the end of the 5 minute delay period this was removed and a similarly soaked applicator inserted into the same nostril for the duration of the second period of pumping (experiment B). In the third experiment, 0.5 c.c. oxytocin* was used instead of saline and in the same manner (experiment C). The order of the experiments was varied so that in 7 women experiment A was performed first, in 7 experiment B, and in 6 experiment C. •Pitocin, Parke, Davis & Company.
Volume 76
Number 1
10!J
EFFECT OF INTRANASAL OXYTOCIN ON LET-DOWN OF MILK
The amount of milk obtained in each ;) minute period of pumping was n1easured in cubic centimeters. In addition~ as an indication of the oci•urrence of let-down of milk, the subjects were asked during each period o I' pumping whether they noted pain anywhere, and, if so, where. A response of abdominal pain was taken to indicate uterine contractioll. The prcsrne(~ or absence of milk dripping from the breast opposite to that heing pumpt>t1 wab also rPcordPlL Results 'l'he mean amounts of milk obtained in the two 5 minute periods of pumping are shown in Table L Mean amounts obtained in the first 5 minutes were similar. In the second 5 minute period less milk was obtained than in th!' first period in the control experiments (A and B), whereas considerably nHH'r was obtained in the oxytoein experiments (C). TABI.f;
T.
MILK OBTAINED BEFORE AND AFTER INTRANASAL APPLICATION AND OXYTOCIN NUMBER OF
TYPE OF EXPERIMENT
EXPERIMENTS
MILK (MEAN NO. OF C.C. I BEFORE
"""'A___n_o_a_p_p'li;--c-a-;-;tic-o-n_ _ ___.____2;;-:0;;-------:;-]3".""1-;cO B, intranasal saline C, intranasal oxytocin
20 20
m•
15.25 1:3.25
I
SAI.TNE
MEAN
AFTER
DH'FEREI\CE
7.20
- !'i.!lO
6.1fl 27.S5
- !-l.l 0 +14.60*
~--------~---------------------------------------------
•Highly significant difference
P
= less than .01.
when compared with control an
with
salin€'
groups.
Comparison between groups in the diffrrences in amounts of milk obtained in the first and second periods of pumping showed a highly significant differem~e between experiments C and A and between experiments C and B. The differener bet,veen experiments .A. and B 'vas not significant. These findings are exemplified by the fact that in experiment A thP amount of milk obtained in the second period was less than that obtained in the first period in 18 patients and rnore in onl:y__. 2. In experiment 13 tht amount obtained in the second period was less in 17, the samP in 2, and mm·p in one. In the oxytocin experiments the amount obtained in the second prriod was morf' than that obtained in the first in 17, thr same in 2, and less in only one. The symptoms and signs of let-down are shown in Table II. None oecurTed during th<' first pumping period. During the seeond pumping period thPy were noted nine times in the oxytocin Pxperiments. but only twiN· in eontr·nl experiment B, and not at all in control rxperimPnt A. TABLE
II.
SYMPTOMS AN[) SIGNS OF LET-DOWN AFTER TN"TRANASAL APPLICATIONS OF RALINE AND OXYTOCIN
TYPE OF EXPERIMENT
A, no application B, intranasal saline (\ intranasal Pitocin
NTTMBER OF EXPERIMENTS
l'TERIS~;
CRAMPR
MILK OPPOSITE BREAST
20
0
()
20
2
20
6
----------------------------------
0
TO'l'AL.
I
--
SYMPTOMS ANll SIGNR
0
:l
Undesirable side effects of oxytocin were minimal. .Mild disappron1l nf the intranasal applicator was noted on oecasion. Watering of the eyes occm-red commonly with the application of oxytocin but stopped within 2 min-utes. In no case was it necessary to <1iscontinne the <'XJWrime>nt lwramw of unfa \'
106
NEWTON AND EGLI
Am ..T. Ob::L & Grne(. July. \4;S
Comment The demonstration of increases in milk 1low after the application of oxytocin indicates that this substance is absorbed from the nasal mucosa. Presumably it entel's the blood stream and th(•n acts on the myoepithelial dements surrounding the alveoli of the breast in th(' same manner as when it is aLlministered parenterally. It was considered possible that the breast pump itself might stimulate the re1lex and confuse the findings. However, women who are not accustomed to using a breast pump usually take some time to learn to let down their milk to it, and, indeed, they may never respond as fully as to the baby. 'rhe increased flow of milk found in the oxytocin experiments cannot be accounted for by natural let-down stimulated by the breast pump since the breast pump did not have this effect in control c·xperiments A and B. The 5 minute period allowed for absorption was chosen empirically and the intranasal source of oxytocin was maintained by continuing the application during the second period of pumping. It is possible that oxytocin may be absorbed more quickly than this and that less time is needed for such absorption. Certainly no longer time is neeessary. The intranasal dose of oxytocin given was 0.5 c.c. (5 units) in each of the two applications. Again, this was an empirieal choice. One dose of 0.5 c.c. might have been sufficient and, indeed, even less may be necessal'y. Cotton applicators soaked in oxytodn solution were used as the method of administration because of the desirability of maintaining the oxytocin in contact with the nasal mucosa. An altPrnative method might be the insertion of drops of oxytocin solution into the nose by means of a droppe1·. Preliminary studies had suggested that drops might be more uncomfortable and that the solution ran down into tho pharynx rather than remaining in the nose. Quinlan, 11 however, reports sucN•ss with the use of oxytocin nose drops in the clinical management of patients. Our results suggest that the inttanasal application of 0.5 to 1.0 e.c. of oxytocin, given about 5 minutes be'fore the baby starts to nurse, may help the mother overcome inhibition of the let-down re1lex. Thus she may be helped to breast feed successfully. The use of intranasal oxytocin is, howev(·r, essentially symptomatic treatment. Attention to the causes of inhibition and failure of the let-down reflex will reduce the neNl for medication. Particularly important are sucking stimulation ancl emotional factors. Since vig·orous sucking is the primary stimulus which sets off the let-down reflex, the strength of the baby's sucking is a matter of concern. When rooming-in of mother and baby is not possible, it is of advantage to bring the baby in to the mother whenever he is hungry, thus allowing him to nurse when his sucking is likt>ly to be most vigorous. Sucking a bottle rapidly interf'pt·es with the strength of the sucking reflex. 12 Thus, when supplementation is necessary, it can be given after breast feeding and by spoon or cup rather than by bottle. Attention to emotional :factors starts in the antepartal period. Unfamiliar surroundings may inhibit the let-down reflex. New mothers may be prepared for the initiation of breast feeding by allowing them to tour the hospital during pregnancy and giving them a chance to meet the nursing personnel. Specific instruction in the physiology of breast feeding and practice in holding a dummy baby in relaxed breast :feeding positions 13 should be a basic par-t of antepartal education.
Volume 76 Number 1
EFl'ECT OF INTRANASAL OXYTOCTN ON LET-DOWN Ol' ll.llLK
!Oi'
Postpartal emotional support is essential. Sympathetic help from trw nursing staff is of first importance. Discomfort from sore nipples, aftPrpains. perineal repairs, or breast engOl'gernent shonld lw rrlievefl by suitahlr ana.lgesics givt'n brfore nursing. Since embarrassm0nt may inhibit the lnt-
Summary and Conclusions 1. rl'h<> artificial production of the let-down ( P,kction) refl.px by tht· intra nasal application of oxytoein during early laetation has lw<'n t<•sh•d. 2. Intranasal oxytoein proilucPd a signifieant intl'Past> in the flow of milk. indicating that let-down had occmTed. 3. Thr usc of intranasal oxytocin appear~ to be an rffective and practi<'al method of ov0rcoming inhibition of thP let-down reflex. 4. Other methods of promoting smooth functioning of the let-
References 1. Waller, H.: Clinical Studies in Lactation, Lowlon, .HI3~, William Heil1emann, Ltd. :!. J<~ly, F., ani! Petersen, W. E.: ,T. Dairy Ac. 24: 211, Hl41. 3. Newton, M .. and Newton, K. R.: J. Pediat. 33: 698, Hl4,'l. 4. Newton, N. R., and Newton, M.: Pediatrics 5: 72fi, .1H51l. 5. Newton, N. R.: .T. Pediat. 41: 411, 1952. f). Newton, M., and Newton, N. R.: flurg., Gynec. & Ob~t. 91: fi51, 1!150. 7. Haege, K., and Jacobsohn, D.: Acta physiol. scandinav. 30 (supp. III): 1152, l!l/50. 8. Elert, R.: Geburtsh. u. Frauenh. 14: 147, 1054. H. Dougla~, R. G., Kramer, E. E., and Bonsnes, R. W.: AM .•J. 0BST. & GYNE<'. 73: 120fi, 19157. 10. Hofbauer, .J., and Hoerner, ,J. K.: AM. ,J. OBST. & IhNEn. 14: 137, 1927. 11. Quinlan, .T • •f.: Personal communication. 12. Davi~. H. V., Sears, R. H., :Miller, H. C., ami Bro<1heek, A. J.: Pediatrics 2: !i4!l, l!l4S. 13. Newton, K. R.: The Family Book of Child Care, Xew York, Hi5i, Harper & Brothers.
JACKSON,
Mrss.
(From the Department of Obstetrics and Gynecology, University of Mississippi School of Medicine)
T
HE smooth course of breast feeding is related to adequate function of the let-down reflex. Stimulation of the nipple in the lactating woman results in the release of an oxytocic factor into the blood stream through the mediation of the central nervous system and the posterior lobe of the pituitary glan
G
In relaxed, confident women with babies who suck eagerly the let-down reflt•x usually functions welL A high proportion of new mothers in our culture are tense at the start of breast f<:'eding, however. Furthermore, their babies arP often taught to suck thP bottle in the nursery and are brought to the mother on a rigid schedule when they are not necessarily hungry_ TT111let' these cin·umstances the vigorous sucking that sets off the let-down reflex may be absent. *Work done under a Research Fellowship,
Fnited States Public Health Service :Medical Student Part-tirr.•'
103
104
NEWTON AND EGLJ.
Am . .T.
()b::;L & <3Yne~.
July, 1958
It is often impossible to change hospital routines and the psychological factors responsible for the failure of the let-down refh·x. Artificial production of the reflex may therefore be of value. Subcutaneous, intramuscular, and intravenous injections of Pitoein are f'ffeetive 7 • "· 9 but repeated injections are disagreeable for the mother and require the presence of medical personneL Since oxytocin has been used intranasally for the induction of labor, 10 it was suggested by Quinlan 11 that the intranasal route might he preferable in the management of lactation. The purpose of this study was to test the practicability and effectiveness of intranasal oxytocin in setting off the letdown reflex.
Methods Nineteen women from the postpartum floor of the University of Mississippi Hospital were used as subjects. Their average age was 22.7 years with a range from 15 to 35 years. Seven were primiparas and twelve multiparas. Eight of the multiparas had breast fed the last child for 2 months or more (up to 12 months) while 4 had not done so, or had made abortive attempts at breast feeding. All the women expressed a desire to breast feed their babies at least for a while after they left the hospitaL At the time of the study the breast feeding routine was such that the women were first given their babies to nurse at varying times up to 24 hours after delivery. Babies were then brought to their mothers every 4 hours anJ left with them for from 30 to 45 minutes. No restrictions were placed on the amount of suckling given during this time. All the mothers used in the study had had milk in their breasts for at least 6 hours and the majority for over 12 hours. Experiments were performed at a mean of 79 hours after delivery with a range of from 34 to 167 hours. A total of twenty studies was performed, one subject being used twice. Each study consisted of three experiments, performed 2 hours after each of three successive nursing periods. In 15 instances the three experiments were performed at 7 :00 A.M., 11 :00 A.M., and 3 :00 P.M., and in 5 they were performed at 11 :00 A.M., 3 :00 P.M., and 7 :00 P.M. The subjects were told that a test was being made of their milk. Cooperation and rapport were good at all times. Each experiment was conducted in the same manner. 'l'he subject lay on her back or side in a comfortable position. One breast was pumped with an electric breast pump for 5 minutes. Intermittent suction was applied at a rate of 25 to 30 times a minute by finger control in such a way that the suction pressure rose to 5 to 6 inches of mercury and was then released. There was then a 5 minute delay period, after which the same breast was pumped again in a similar manner for another 5 minutes. The same breast was used in all three experiments on the same woman. The only difference was in the procedure used during the delay period. In one experiment nothing was done (experiment A). In the second, a cotton applicator soaked in 0.5 c. c. saline was inserted into one nostril: at the end of the 5 minute delay period this was removed and a similarly soaked applicator inserted into the same nostril for the duration of the second period of pumping (experiment B). In the third experiment, 0.5 c.c. oxytocin* was used instead of saline and in the same manner (experiment C). The order of the experiments was varied so that in 7 women experiment A was performed first, in 7 experiment B, and in 6 experiment C. •Pitocin, Parke, Davis & Company.
Volume 76
Number 1
10!J
EFFECT OF INTRANASAL OXYTOCIN ON LET-DOWN OF MILK
The amount of milk obtained in each ;) minute period of pumping was n1easured in cubic centimeters. In addition~ as an indication of the oci•urrence of let-down of milk, the subjects were asked during each period o I' pumping whether they noted pain anywhere, and, if so, where. A response of abdominal pain was taken to indicate uterine contractioll. The prcsrne(~ or absence of milk dripping from the breast opposite to that heing pumpt>t1 wab also rPcordPlL Results 'l'he mean amounts of milk obtained in the two 5 minute periods of pumping are shown in Table L Mean amounts obtained in the first 5 minutes were similar. In the second 5 minute period less milk was obtained than in th!' first period in the control experiments (A and B), whereas considerably nHH'r was obtained in the oxytoein experiments (C). TABI.f;
T.
MILK OBTAINED BEFORE AND AFTER INTRANASAL APPLICATION AND OXYTOCIN NUMBER OF
TYPE OF EXPERIMENT
EXPERIMENTS
MILK (MEAN NO. OF C.C. I BEFORE
"""'A___n_o_a_p_p'li;--c-a-;-;tic-o-n_ _ ___.____2;;-:0;;-------:;-]3".""1-;cO B, intranasal saline C, intranasal oxytocin
20 20
m•
15.25 1:3.25
I
SAI.TNE
MEAN
AFTER
DH'FEREI\CE
7.20
- !'i.!lO
6.1fl 27.S5
- !-l.l 0 +14.60*
~--------~---------------------------------------------
•Highly significant difference
P
= less than .01.
when compared with control an
with
salin€'
groups.
Comparison between groups in the diffrrences in amounts of milk obtained in the first and second periods of pumping showed a highly significant differem~e between experiments C and A and between experiments C and B. The differener bet,veen experiments .A. and B 'vas not significant. These findings are exemplified by the fact that in experiment A thP amount of milk obtained in the second period was less than that obtained in the first period in 18 patients and rnore in onl:y__. 2. In experiment 13 tht amount obtained in the second period was less in 17, the samP in 2, and mm·p in one. In the oxytocin experiments the amount obtained in the second prriod was morf' than that obtained in the first in 17, thr same in 2, and less in only one. The symptoms and signs of let-down are shown in Table II. None oecurTed during th<' first pumping period. During the seeond pumping period thPy were noted nine times in the oxytocin Pxperiments. but only twiN· in eontr·nl experiment B, and not at all in control rxperimPnt A. TABLE
II.
SYMPTOMS AN[) SIGNS OF LET-DOWN AFTER TN"TRANASAL APPLICATIONS OF RALINE AND OXYTOCIN
TYPE OF EXPERIMENT
A, no application B, intranasal saline (\ intranasal Pitocin
NTTMBER OF EXPERIMENTS
l'TERIS~;
CRAMPR
MILK OPPOSITE BREAST
20
0
()
20
2
20
6
----------------------------------
0
TO'l'AL.
I
--
SYMPTOMS ANll SIGNR
0
:l
Undesirable side effects of oxytocin were minimal. .Mild disappron1l nf the intranasal applicator was noted on oecasion. Watering of the eyes occm-red commonly with the application of oxytocin but stopped within 2 min-utes. In no case was it necessary to <1iscontinne the <'XJWrime>nt lwramw of unfa \'
106
NEWTON AND EGLI
Am ..T. Ob::L & Grne(. July. \4;S
Comment The demonstration of increases in milk 1low after the application of oxytocin indicates that this substance is absorbed from the nasal mucosa. Presumably it entel's the blood stream and th(•n acts on the myoepithelial dements surrounding the alveoli of the breast in th(' same manner as when it is aLlministered parenterally. It was considered possible that the breast pump itself might stimulate the re1lex and confuse the findings. However, women who are not accustomed to using a breast pump usually take some time to learn to let down their milk to it, and, indeed, they may never respond as fully as to the baby. 'rhe increased flow of milk found in the oxytocin experiments cannot be accounted for by natural let-down stimulated by the breast pump since the breast pump did not have this effect in control c·xperiments A and B. The 5 minute period allowed for absorption was chosen empirically and the intranasal source of oxytocin was maintained by continuing the application during the second period of pumping. It is possible that oxytocin may be absorbed more quickly than this and that less time is needed for such absorption. Certainly no longer time is neeessary. The intranasal dose of oxytocin given was 0.5 c.c. (5 units) in each of the two applications. Again, this was an empirieal choice. One dose of 0.5 c.c. might have been sufficient and, indeed, even less may be necessal'y. Cotton applicators soaked in oxytodn solution were used as the method of administration because of the desirability of maintaining the oxytocin in contact with the nasal mucosa. An altPrnative method might be the insertion of drops of oxytocin solution into the nose by means of a droppe1·. Preliminary studies had suggested that drops might be more uncomfortable and that the solution ran down into tho pharynx rather than remaining in the nose. Quinlan, 11 however, reports sucN•ss with the use of oxytocin nose drops in the clinical management of patients. Our results suggest that the inttanasal application of 0.5 to 1.0 e.c. of oxytocin, given about 5 minutes be'fore the baby starts to nurse, may help the mother overcome inhibition of the let-down re1lex. Thus she may be helped to breast feed successfully. The use of intranasal oxytocin is, howev(·r, essentially symptomatic treatment. Attention to the causes of inhibition and failure of the let-down reflex will reduce the neNl for medication. Particularly important are sucking stimulation ancl emotional factors. Since vig·orous sucking is the primary stimulus which sets off the let-down reflex, the strength of the baby's sucking is a matter of concern. When rooming-in of mother and baby is not possible, it is of advantage to bring the baby in to the mother whenever he is hungry, thus allowing him to nurse when his sucking is likt>ly to be most vigorous. Sucking a bottle rapidly interf'pt·es with the strength of the sucking reflex. 12 Thus, when supplementation is necessary, it can be given after breast feeding and by spoon or cup rather than by bottle. Attention to emotional :factors starts in the antepartal period. Unfamiliar surroundings may inhibit the let-down reflex. New mothers may be prepared for the initiation of breast feeding by allowing them to tour the hospital during pregnancy and giving them a chance to meet the nursing personnel. Specific instruction in the physiology of breast feeding and practice in holding a dummy baby in relaxed breast :feeding positions 13 should be a basic par-t of antepartal education.
Volume 76 Number 1
EFl'ECT OF INTRANASAL OXYTOCTN ON LET-DOWN Ol' ll.llLK
!Oi'
Postpartal emotional support is essential. Sympathetic help from trw nursing staff is of first importance. Discomfort from sore nipples, aftPrpains. perineal repairs, or breast engOl'gernent shonld lw rrlievefl by suitahlr ana.lgesics givt'n brfore nursing. Since embarrassm0nt may inhibit the lnt-
Summary and Conclusions 1. rl'h<> artificial production of the let-down ( P,kction) refl.px by tht· intra nasal application of oxytoein during early laetation has lw<'n t<•sh•d. 2. Intranasal oxytoein proilucPd a signifieant intl'Past> in the flow of milk. indicating that let-down had occmTed. 3. Thr usc of intranasal oxytocin appear~ to be an rffective and practi<'al method of ov0rcoming inhibition of thP let-down reflex. 4. Other methods of promoting smooth functioning of the let-
References 1. Waller, H.: Clinical Studies in Lactation, Lowlon, .HI3~, William Heil1emann, Ltd. :!. J<~ly, F., ani! Petersen, W. E.: ,T. Dairy Ac. 24: 211, Hl41. 3. Newton, M .. and Newton, K. R.: J. Pediat. 33: 698, Hl4,'l. 4. Newton, N. R., and Newton, M.: Pediatrics 5: 72fi, .1H51l. 5. Newton, N. R.: .T. Pediat. 41: 411, 1952. f). Newton, M., and Newton, N. R.: flurg., Gynec. & Ob~t. 91: fi51, 1!150. 7. Haege, K., and Jacobsohn, D.: Acta physiol. scandinav. 30 (supp. III): 1152, l!l/50. 8. Elert, R.: Geburtsh. u. Frauenh. 14: 147, 1054. H. Dougla~, R. G., Kramer, E. E., and Bonsnes, R. W.: AM .•J. 0BST. & GYNE<'. 73: 120fi, 19157. 10. Hofbauer, .J., and Hoerner, ,J. K.: AM. ,J. OBST. & IhNEn. 14: 137, 1927. 11. Quinlan, .T • •f.: Personal communication. 12. Davi~. H. V., Sears, R. H., :Miller, H. C., ami Bro<1heek, A. J.: Pediatrics 2: !i4!l, l!l4S. 13. Newton, K. R.: The Family Book of Child Care, Xew York, Hi5i, Harper & Brothers.