Genetic study of hydatidiform mole
Volume 164 Number 5, Part 1
8. 9. 10.
II. 12.
13.
14.
Y chromosome-specific probes. Hum Genet 1989;81 :25963. Bagshawe KD, Dent J, Webb j. Hydatidiform mole in England and Wales 1973-83. Lancet 1986;2:673-7. Sheppard DM, Fisher RA, Lawler SD, Povey S. Tetraploid conceptus with three paternal contributions. Hum Genet 1982;62:371-4. Bagshawe KD, DentJ, Newlands ES, Begent RH./, Rustin GJS. The role of low-dose methotrexate and folinic acid in gestational trophoblastic tumours (GTT). Br J Obstet Gynaecol 1989;96:795-802. Royle NJ, Clarkson RE, Wong Z, Jeffreys Aj. Clustering of hypervariable minisatellites in the proterminal regions of human autosomes. Genomics 1988;3:352-60. Jacobs PA, Szulman AE, Funkhouser J, MatsuuraJS, Wilson Cc. Human triploidy: relationship between parental origin of the additional haploid complement and development of partial hydatidiform mole. Ann Hum Genet 1982;46:223-31. Vejerslev LO, Fisher RA, Surti U, Wake N. Hydatidiform mole: cytogenetically unusual cases and their implications for the present classification. A~ J OBSTET GV]'o;ECOL 1987; 157: 180-4. Wake N, Fujino T, Hoshi S, et al. The propensity to malignancy of dispermic heterozygous moles. Placenta 1987; 8:319-26.
15. Bagshawe KD, Lawler SD, Paradinas FJ, Dent J, Brown P, Boxer G. Gestational tumours following an initial diagnosis of partial hydatidiform mole. Lancet 1990; I: 1074-6. 16. Fisher RA, Lawler SD, Povey S, Bagshawe KD. Genetically homozygous choriocarcinoma following pregnancy with hydatidiform mole. Br J Cancer 1988;58:788-92. 17. Surani MAH, Barton SC, Norris ML. Development of reconstituted mouse eggs suggests imprinting of the genome during gametogenesis. Nature 1984;308:548-50. 18. Barton SC, Surani MAH, Norris ML. Role of paternal and maternal genomes in mouse development. Nature 1984;311 :374-6. 19. Spence JE, Perciaccante RG, Greig GM, et al. Uniparental disomy as a mechanism for human genetic disease. Am J Hum Genet 1988;42:217-25. 20. Lawler SD, Fisher RA, The contribution of the paternal genome; hydatidiform mole and choriocarinoma. In: Redman CWG, Sargent IL, Starkey PM, eds. The human placenta: a guide for clinicians and scientists. Oxford: Blackwell Scientific Publications, 1991. Additional references are available from the authors on request.
The effect of sterile water blocks on low back labor pain Birgitta Trolle, MD, Margrethe Maller, MD, Hanne Kronborg, and Seren Thomsen, MD Aalborg, Denmark To evaluate the analgesic effect of intradermal sterile water blocks, 272 women in labor complaining of severe low back pain were randomly assigned to treatment with either sterile water or saline solution blocks. Pain intensity was assessed on a visual analog scale, before the blocks were given and again 1 and 2 hours later. The groups were equal with regard to age, parity, fetal size, progression of labor, and initial pain scoring. Pain scoring 1 and 2 hours after the blocks were given showed a significantly higher degree of analgesia in the sterile water group. No adverse effects were noted, and patient acceptability was high. (AM J OSSTET GVNECOL 1991;164:1277-81.)
Key words: Obstetric analgesia, low back labor pain, sterile water blocks About one third of women in labor have severe, continuous, low back pain, and an additional number feel the pain of contractions primarily in the back.' To reduce this pain, a number of analgesic methods have been tried with varying success, i.e., transcutaneous nerve stimulation," 3 epicutaneous application of a local anesthetic agent,': 5 and intracutaneous or subcutaneous From the Department ofObstetrics and Gynecology, Aalborg Hospital. Received for publication April 24, 1990; revised October 24, 1990; accepted November 28, 1990. Reprint requests: Birgitta Trolle, MD, Hamar Sjukehus, N-2300 Hamar, Nonoa». 6/1 127055 .
infiltration of the skin with procame hydrochloride (Novocain).6.7 Intradermal injection of small amounts of sterile water, called sterile water blocks, was reportedly effective against ureteral colic," and in this article we present the result of a double-blind, randomized trial comparing the analgesic effects of intradermal sterile water blocks with those of isotonic saline solution blocks on low back labor pain. Material and methods
Women in active labor complaining of severe low back pain were asked to participate and given detailed 1277
1278 Trolle et al.
May 1991
Am
Table I. Maternal characteristics for sterile water and groups Sterile water ( n = 141)
Primiparous women( %) Gestational length (wk) Maternal age (yr) Cervical dilatation (em) Ruptured membranes (%)
Saline solution (n = 131)
70.2 75.6 39 .9 :!: 1.6
39.7
26 .2 ± 5. 1 4.73 ± 1.91
25 .9 :!: 3.9 4.68 ± 1.91
59.6
52.7
2.1
:!:
Numbers are mean ± SD or percent. There are no significant differences.
Table II. Analgesic effects of sterile water and saline solution intradermal blocks on low back pain
I
Sterile water
Immediately before 83 (29-100) blocks (n = 141) After blocks 29 .5 (0- I 00) I hr (n = 132) 53 .5 (0-100) 2 hr (n = 100)
I
Saline solution
p Valu e
81 (3 1- 100)
0.23
(n = 131)
76 (0-100) 1 x 10- 7 (n = 121) 82 (1-100) 4.5 x 10- 6 (n = 99)
Pain scoring (mean and range) and result of significance test before blocks and I and 2 hours later. As some women were delivered, groups diminished.
verbal and written infor mation about the study. Those who accepted were asked to assess pain severity on a visual analog scale, a horizontal line IDem long without any markings, except the number 0 and the words no pain at the left end and the number 10 and unbearable pain at the right. This has proved to be a reliable method of measuring pain intensity." The midwife in charge performed a vaginal examination, noting cervical dilatation. Sterile water and isotonic saline solution were provided in identical I ml ampules that had been randomly mixed and numbered. The midwife used the ampule next in number, giving the blocks by injecting about 0.1 ml intradermally at four different spots in the low back area, approximately corresponding to the borders of the sacrum. The participants were asked whether they noted any analgesic effect from the blocks and, if so, the length of time before the effect began. Pain scoring and vaginal examination were repeated I and 2 hours after the injections if the woman had not yet been delivered. Apart from the blocks, the women were treated ac-
J Obstet Gynecol
Table III. Number of instrument-assisted deliveries specified in cesarean sections and vacuum extractions in sterile water and saline solution groups Saline solution (n = 13l)
Cesarean section Vacuum extraction Total No . of instrument-assisted deliveries
6 22 28
15 13 28
p Value < 0.05
NS NS
cording to the usual principles of the department; they were offered nitrous oxide or pethidine if pa in was severe. Any use of analgesics during the 3-hour period before block placement and the two subsequent hours was registered. Paracervical block and epidural anesthesia were not available. The water blocks could be given onl y once to each patient and onl y to those patients participating in the study. After delivery the patients were asked if the y would request the same type of analgesia at subsequent delivery. Clinical data of patients and infants and all complications during labor and delivery were registered, and a X2 test was used for comparison of frequencies. The scores on the visual analog scales were recorded as the distance in millimeters from point 0, and for each of the hourly intervals the groups were compared by a Mann-Whitney test. A p value of 0.05 was chosen as a significant level. The study was approved by the local ethical com mittee. Results
Two hundred seventy-two women received the blocks and completed the answer forms . Sterile water blocks were given to 141 women and saline solution was given to 131 women. The groups were equal with regard to number of primiparous women, maternal age , and length of gestation and also with regard to mean cervical dilatation and number of patients who had ruptured membranes when the blocks were given (Table I). Before they entered the study, 9.9 % of the women in the sterile water group had already received pethidine in a standard dose of 75 mg intramuscularly, and 3.5 % had received nitrous oxide. Corresponding figures for the saline solution group were 6.9 % and 3.1%, respectively. In the sterile water group 126 (89.4 %) of the women noted an analgesic effect of the blocks, com pared with 59 (45%) in the saline solution group (p < 0.0005). The med ian number of minutes before the effect was apparent was 2 (range, 1 to 30) for both
Sterile water blocks for labor pain 1279
Volume 164 Number 5, Part 1
o
at-rved any anaJgulc effect of the bloc'"
~ Obeerved no anaJge.1c effect or the bloc'" ~:.:.:.: Doe. not know I no . .wer
N umber
0
pa tint e
r-
-
20
10
"'" F o
-100
•
STERilE WATER BlO CKS
r;::
~
f'-"
~
r-e-
r-
~~ - 80
-60
-40
-20
o
n~ 20
40
60
80
100
6, mm
20
SALINE BLOCKS
30 Number or patient.
Fig. 1. Change in pain scoring after sterile water or saline solution blocks for low back labor pain, in relation to patients' answers to questions of any observed analgesia. Change in millimeters (~ mm) is calculated as I-hour scoring on the visual analog scale minus scoring before treatment.
groups. Initial pain scoring did not show any significant difference between the groups, but 1 and 2 hours after the blocks were given, there were highly significant differences (Table II). During the 2-hour observation interval after the blocks were given, 6.4% of the patients in the sterile water group needed pethidine, and 12.8% received nitrous oxide, compared with 8.4% and 16%, respectively, in the saline solution group. These frequencies do not differ significantly. Fig. 1 is a graphic illustration of the results. It shows the difference in analgesic effect between the groups but also demonstrates that even if no analgesia was noted, low back pain was at least constant and not increasing in spite of progressing labor. Except for the initial burning sensation, lasting for about 30 seconds, no local side effects were noted. Progression of labor, expressed as time from application of the blocks until full cervical dilatation, was
equal in the two groups (median, 2 hours; range, 0 to 11 hours). The second stage of labor had a median duration of 0.5 hours (range 0 to 2.25 hours) in both groups. The rate of dystocia necessitating oxytocin stimulation was 39.7% in the saline solution group and 32.6% in the sterile water group. Although the rate of instrument-assisted delivery was similar in the two groups, the rate of cesarean section was significantly higher in the saline solution group (Table Ill). This was caused predominantly by a higher incidence of cephalopelvic disproportion and malposition of the occiput (Table IV). At vaginal delivery the rate of malposition of the occiput was 9.5% in the saline solution group and 5.2% in the sterile water group. The difference is not significant. There was no difference in average blood loss. Infant birth weight and Apgar scores also were equal. A significantly greater proportion of the women in
1280 Trolla at al. Am
Table IV. Indication for operative delivery in sterile water and saline solution groups - -S-te-n-·l-e - ,------ - - Saline solution water
-----------I
II (0)
Threat of asphyxia Cephalopelvic disproportion Lack of progression Malposition of the occiput Exhausted mother Other
5 (1) 12 (10)
5 (5) 4 (I) 1 (I) 11 (I) 1 (I)
o
10 (9) 8 (0) 1 (1)
Numbers in parentheses indicate cesarean section. Some operations were performed for more than one indication. The total number of operative deliveries was 28 in each group.
Table V. Answer to question, "Will you request the same kind of analgesia if you are going to deliver again?" in sterile water and saline solution groups
Yes No Undecided-no answer
Sterile water (n = 141)
Saline solution (n = 131)
96
66
18
27
35 30
p < 0.005, X2 test.
the sterile water group than in the saline solution group would request the same type of analgesia if they again had to undergo delivery(p < 0.005) (Table V).
Comment Danish women do not expect childbirth to be painless. Epidural analgesia is available as a fulltime service in only a few centers. The use of paracervical block was largely abandoned after reports of fetal bradycardia, and pethidine is used mostly for women complaining of severe pain in early labor. Nitrous oxide is the most widely used analgesic, and pudendal block is offered to all women. Psychoprophylaxis is regarded as important, and most primigravid women attend free antenatal classes. Many primigravid, and most multigravid, women are delivered without any request for analgesia, and we find it reasonable to assume that the women who chose to participate in this study felt severe low back labor pain. Pain impulses from the posterior part of the cervix and uterus are transmitted to the spinal cord segments TII-LI, and cutaneous branches from these segments supply the skin over the low back area." This is probably the anatomic background of how pain originating in the cervix can be localized to the back. Low back pain occurs often in labor, especially in connection with an occipitoposterior presentation, where stretching of the posterior part of the lower uterine segment and
J
Mav 1991
Obstet Gvnecol
cervix may be predominant. The hypotonic sterile water injected intradermally causes local irritation and thereby a strong sensory stimulation of the surrounding skin area for about 30 seconds. The analgesia induced by this stimulation may originate in midbrain centers, II. 12 or be caused by "gate control" at the spinal level. I". 14 Hyperstimulation of a skin area can affect perception of visceral pain, and it appears that the mechanism of referred pain can be reversed to produce referred analgesia. Intradermal injection of isotonic saline solution is less painful than sterile water but not painless, and saline solution blocks could theoretically induce some degree of analgesia. To make the study double-blind some kind of injection in the low back area had to be used in the treatment of the control group. Comparing the blocks with any of the established methods of analgesia was abandoned for the same reason. These circumstances make it impossible to state the number of patients having only a placebo effect of the blocks. A great number of women joined the project. A study of this size has a power of almost 90% in detecting a difference in proportions between the two groups of at least 15%. The highly significant difference in pain intensity between the groups after the blocks were given is not reflected in the use of pethidine, which was similar in the two groups. The number of women receiving pethidine is small-smaller than the total number of women who did not have any analgesic effect of the blocks. It is not possible to make any conclusions. We found it important to certify that the analgesic effect of the blocks was not connected with an impairment of labor, as this would only postpone pain. No such effect was noted. The incidence of dystocia and oxytocin infusion was high in both groups, but this was to be expected because only women with low back pain entered the study and low back pain commonly occurs with malrotation of the fetus. There was no difference between the groups with regard to the rate of instrument-assisted delivery. However, the rate of cesarean section in the saline solution group was similar to the usual rate of cesarean section in our department (3000 deliveries per year), whereas the rate of cesarean section in the sterile water group was significantly lower (4.2% vs 11.4%). We have no definite explanation for this. The most frequent indications for cesarean section in the saline solution group were malposition of the occiput and cephalopelvic disproportion. In the Danish population the latter condition is usually relative, reflecting a fetal malrotation. It is not possible to determine if there was a primary difference between the study groups regarding fetal position or a higher rate of correction of fetal position in the sterile water group. Generally, the relation be-
Sterile water blocks for labor pain
Volume 164 Number 5, Part 1
tween labor pain and fetal position and the effect of analgesia on pelvic floor tone, cervical tension, contraction pattern, and fetal rotation are interesting and an evident subject for further studies. REFERENCES I. Melzack R, Schaffelberg D. Low-back pain during labor. AMJ OBSTET GYNECOL 1987;156:901-5. 2. Erkkola R, Pikkola P, Kanto J. Transcutaneous nerve stimulation for pain relief during labour: a controlled study. Ann Chir Gynaecol 1980;69:273-7. 3. Miller Jones CMH. Transcutaneous nerve stimulation in labour. Anaesthesia 1980;35:372-5. 4. Permin M, Ipsen L, Hansen MK, et al. Relief from pain localized to the lower back in early labour. Z Geburtshilfe PerinatoI1981;185:3601-3. 5. Ulmsten U, Sandahl B, Lundin C, Andersson KE. Treatment of labour pain with locally applied ketocaine. Acta Obstet Gynecol Scand 1980;59:209-12. 6. Rose D. Local anaesthesia in first and second stage labour. N EnglJ Med 1929;201:117-25.
7. Abrams AA. Obliteration of pain at the site of reference by intradermal infiltration anesthesia in first-stage labor. N Engl J Med 1950;243:636-40. 8. Bengtsson J, Worning AM, Gertz J, et al. Pain due to urolithiasis treated by intracutaneous injection of sterile water. Ugeskr Laeger 1981;143:3463-5. 9. Scott J, Huskisson EC. Graphic representation of pain. Pain 1976;2: 175-84. 10. Bonica JJ. Peripheral mechanisms and pathways of parturition pain. Br J Anaesth 1979;51:35-95. I I. Basbaum AI, Fields HL. Endogenous pain control mechanisms: review and hypothesis. Ann Neurol 1978;4:45161. 12. Sherman JE, Liebeskind JC. An endorphinergic, centrifugal substrate of pain modulation: recent findings, current concepts, and complexities. In: Bonica JJ, ed. Pain. New York: Raven Press, 1980:191-204. 13. Melzack R, Wall PD. Pain mechanism: a new theory. Science 1965;150:971-9. 14. Wall PD. The role of substantia gelatinosa as a gate control. In: Bonica JJ, ed. Pain. New York: Raven Press, 1980:205-31.
Electronic fetal heart monitoring, auscultation, and neonatal outcome Patricia H. Ellison, MD: Mark Foster, MA: Margaret Sheridan-Pereira, MD: and Dermot MacDonald, MDc Denver, Colorado, and Dublin, Ireland In a large randomized, controlled study of fetal heart rate monitoring with either continuous electronic fetal heart monitoring or auscultation at specified intervals, only one pattern of deviation in the fetal heart rate correlated significantly with neonatal neurologic examinations at 0 to 48 hours and 72 hours to 1 week: late decelerations in stage 1 and in stage 2. Other variables from labor and delivery, specifically, duration of labor after hospital admission, failure of labor to progress, number of fetal scalp pH values, and presence of meconium were important predictors of neonatal outcome in the regression analyses. The fetal heart rate deviations did contribute significantly to the percent variance accounted for in the regression analyses with neonatal outcomes of Apgar scores at 1 and 5 minutes and serial neonatal neurologic examinations. (AM J OBSTET GYNECOL 1991;164:1281-9.)
Key words: Continuous electronic fetal heart monitoring, late decelerations, Apgar scores at I and 5 minutes, neonatal neurologic examination Electronic fetal heart monitoring, when introduced in the 1960s and refined in subsequent years, brought hope that there could be a way to detect, in utero, an From the Department of Psychology, University of Denver," and Coombs Hospital' and National Maternity Hospital,' Dublin. Supported in part by the Presbyterian/ St. Luke's Foundation, Denver, Colorado. Received for publication March 6, 1990; revised December 3, 1990; accepted December 21, 1990. Reprint requests: Patricia H. Ellison, MD, Research Professor, Department of Psychology, University of Denver, Denver, CO 80208. 6/1 /27569
already compromised fetus, as well as a fetus in the process of deterioration, particularly during labor and delivery. In certain situations this technology has been fairly reliable, e.g., in the recognition of a dying fetus who previously might have been stillborn. It has been less reliable in the detection of fetuses with hypoxiaischemia of the central nervous system and secondarily decreased regulation of heart rate. In the majority of studies the relation was examined between fetal heart rate and the Apgar score, usually at I and 5 minutes. Very few studies have examined 1281
Volume 164 Number 5, Part 1
8. 9. 10.
II. 12.
13.
14.
Y chromosome-specific probes. Hum Genet 1989;81 :25963. Bagshawe KD, Dent J, Webb j. Hydatidiform mole in England and Wales 1973-83. Lancet 1986;2:673-7. Sheppard DM, Fisher RA, Lawler SD, Povey S. Tetraploid conceptus with three paternal contributions. Hum Genet 1982;62:371-4. Bagshawe KD, DentJ, Newlands ES, Begent RH./, Rustin GJS. The role of low-dose methotrexate and folinic acid in gestational trophoblastic tumours (GTT). Br J Obstet Gynaecol 1989;96:795-802. Royle NJ, Clarkson RE, Wong Z, Jeffreys Aj. Clustering of hypervariable minisatellites in the proterminal regions of human autosomes. Genomics 1988;3:352-60. Jacobs PA, Szulman AE, Funkhouser J, MatsuuraJS, Wilson Cc. Human triploidy: relationship between parental origin of the additional haploid complement and development of partial hydatidiform mole. Ann Hum Genet 1982;46:223-31. Vejerslev LO, Fisher RA, Surti U, Wake N. Hydatidiform mole: cytogenetically unusual cases and their implications for the present classification. A~ J OBSTET GV]'o;ECOL 1987; 157: 180-4. Wake N, Fujino T, Hoshi S, et al. The propensity to malignancy of dispermic heterozygous moles. Placenta 1987; 8:319-26.
15. Bagshawe KD, Lawler SD, Paradinas FJ, Dent J, Brown P, Boxer G. Gestational tumours following an initial diagnosis of partial hydatidiform mole. Lancet 1990; I: 1074-6. 16. Fisher RA, Lawler SD, Povey S, Bagshawe KD. Genetically homozygous choriocarcinoma following pregnancy with hydatidiform mole. Br J Cancer 1988;58:788-92. 17. Surani MAH, Barton SC, Norris ML. Development of reconstituted mouse eggs suggests imprinting of the genome during gametogenesis. Nature 1984;308:548-50. 18. Barton SC, Surani MAH, Norris ML. Role of paternal and maternal genomes in mouse development. Nature 1984;311 :374-6. 19. Spence JE, Perciaccante RG, Greig GM, et al. Uniparental disomy as a mechanism for human genetic disease. Am J Hum Genet 1988;42:217-25. 20. Lawler SD, Fisher RA, The contribution of the paternal genome; hydatidiform mole and choriocarinoma. In: Redman CWG, Sargent IL, Starkey PM, eds. The human placenta: a guide for clinicians and scientists. Oxford: Blackwell Scientific Publications, 1991. Additional references are available from the authors on request.
The effect of sterile water blocks on low back labor pain Birgitta Trolle, MD, Margrethe Maller, MD, Hanne Kronborg, and Seren Thomsen, MD Aalborg, Denmark To evaluate the analgesic effect of intradermal sterile water blocks, 272 women in labor complaining of severe low back pain were randomly assigned to treatment with either sterile water or saline solution blocks. Pain intensity was assessed on a visual analog scale, before the blocks were given and again 1 and 2 hours later. The groups were equal with regard to age, parity, fetal size, progression of labor, and initial pain scoring. Pain scoring 1 and 2 hours after the blocks were given showed a significantly higher degree of analgesia in the sterile water group. No adverse effects were noted, and patient acceptability was high. (AM J OSSTET GVNECOL 1991;164:1277-81.)
Key words: Obstetric analgesia, low back labor pain, sterile water blocks About one third of women in labor have severe, continuous, low back pain, and an additional number feel the pain of contractions primarily in the back.' To reduce this pain, a number of analgesic methods have been tried with varying success, i.e., transcutaneous nerve stimulation," 3 epicutaneous application of a local anesthetic agent,': 5 and intracutaneous or subcutaneous From the Department ofObstetrics and Gynecology, Aalborg Hospital. Received for publication April 24, 1990; revised October 24, 1990; accepted November 28, 1990. Reprint requests: Birgitta Trolle, MD, Hamar Sjukehus, N-2300 Hamar, Nonoa». 6/1 127055 .
infiltration of the skin with procame hydrochloride (Novocain).6.7 Intradermal injection of small amounts of sterile water, called sterile water blocks, was reportedly effective against ureteral colic," and in this article we present the result of a double-blind, randomized trial comparing the analgesic effects of intradermal sterile water blocks with those of isotonic saline solution blocks on low back labor pain. Material and methods
Women in active labor complaining of severe low back pain were asked to participate and given detailed 1277
1278 Trolle et al.
May 1991
Am
Table I. Maternal characteristics for sterile water and groups Sterile water ( n = 141)
Primiparous women( %) Gestational length (wk) Maternal age (yr) Cervical dilatation (em) Ruptured membranes (%)
Saline solution (n = 131)
70.2 75.6 39 .9 :!: 1.6
39.7
26 .2 ± 5. 1 4.73 ± 1.91
25 .9 :!: 3.9 4.68 ± 1.91
59.6
52.7
2.1
:!:
Numbers are mean ± SD or percent. There are no significant differences.
Table II. Analgesic effects of sterile water and saline solution intradermal blocks on low back pain
I
Sterile water
Immediately before 83 (29-100) blocks (n = 141) After blocks 29 .5 (0- I 00) I hr (n = 132) 53 .5 (0-100) 2 hr (n = 100)
I
Saline solution
p Valu e
81 (3 1- 100)
0.23
(n = 131)
76 (0-100) 1 x 10- 7 (n = 121) 82 (1-100) 4.5 x 10- 6 (n = 99)
Pain scoring (mean and range) and result of significance test before blocks and I and 2 hours later. As some women were delivered, groups diminished.
verbal and written infor mation about the study. Those who accepted were asked to assess pain severity on a visual analog scale, a horizontal line IDem long without any markings, except the number 0 and the words no pain at the left end and the number 10 and unbearable pain at the right. This has proved to be a reliable method of measuring pain intensity." The midwife in charge performed a vaginal examination, noting cervical dilatation. Sterile water and isotonic saline solution were provided in identical I ml ampules that had been randomly mixed and numbered. The midwife used the ampule next in number, giving the blocks by injecting about 0.1 ml intradermally at four different spots in the low back area, approximately corresponding to the borders of the sacrum. The participants were asked whether they noted any analgesic effect from the blocks and, if so, the length of time before the effect began. Pain scoring and vaginal examination were repeated I and 2 hours after the injections if the woman had not yet been delivered. Apart from the blocks, the women were treated ac-
J Obstet Gynecol
Table III. Number of instrument-assisted deliveries specified in cesarean sections and vacuum extractions in sterile water and saline solution groups Saline solution (n = 13l)
Cesarean section Vacuum extraction Total No . of instrument-assisted deliveries
6 22 28
15 13 28
p Value < 0.05
NS NS
cording to the usual principles of the department; they were offered nitrous oxide or pethidine if pa in was severe. Any use of analgesics during the 3-hour period before block placement and the two subsequent hours was registered. Paracervical block and epidural anesthesia were not available. The water blocks could be given onl y once to each patient and onl y to those patients participating in the study. After delivery the patients were asked if the y would request the same type of analgesia at subsequent delivery. Clinical data of patients and infants and all complications during labor and delivery were registered, and a X2 test was used for comparison of frequencies. The scores on the visual analog scales were recorded as the distance in millimeters from point 0, and for each of the hourly intervals the groups were compared by a Mann-Whitney test. A p value of 0.05 was chosen as a significant level. The study was approved by the local ethical com mittee. Results
Two hundred seventy-two women received the blocks and completed the answer forms . Sterile water blocks were given to 141 women and saline solution was given to 131 women. The groups were equal with regard to number of primiparous women, maternal age , and length of gestation and also with regard to mean cervical dilatation and number of patients who had ruptured membranes when the blocks were given (Table I). Before they entered the study, 9.9 % of the women in the sterile water group had already received pethidine in a standard dose of 75 mg intramuscularly, and 3.5 % had received nitrous oxide. Corresponding figures for the saline solution group were 6.9 % and 3.1%, respectively. In the sterile water group 126 (89.4 %) of the women noted an analgesic effect of the blocks, com pared with 59 (45%) in the saline solution group (p < 0.0005). The med ian number of minutes before the effect was apparent was 2 (range, 1 to 30) for both
Sterile water blocks for labor pain 1279
Volume 164 Number 5, Part 1
o
at-rved any anaJgulc effect of the bloc'"
~ Obeerved no anaJge.1c effect or the bloc'" ~:.:.:.: Doe. not know I no . .wer
N umber
0
pa tint e
r-
-
20
10
"'" F o
-100
•
STERilE WATER BlO CKS
r;::
~
f'-"
~
r-e-
r-
~~ - 80
-60
-40
-20
o
n~ 20
40
60
80
100
6, mm
20
SALINE BLOCKS
30 Number or patient.
Fig. 1. Change in pain scoring after sterile water or saline solution blocks for low back labor pain, in relation to patients' answers to questions of any observed analgesia. Change in millimeters (~ mm) is calculated as I-hour scoring on the visual analog scale minus scoring before treatment.
groups. Initial pain scoring did not show any significant difference between the groups, but 1 and 2 hours after the blocks were given, there were highly significant differences (Table II). During the 2-hour observation interval after the blocks were given, 6.4% of the patients in the sterile water group needed pethidine, and 12.8% received nitrous oxide, compared with 8.4% and 16%, respectively, in the saline solution group. These frequencies do not differ significantly. Fig. 1 is a graphic illustration of the results. It shows the difference in analgesic effect between the groups but also demonstrates that even if no analgesia was noted, low back pain was at least constant and not increasing in spite of progressing labor. Except for the initial burning sensation, lasting for about 30 seconds, no local side effects were noted. Progression of labor, expressed as time from application of the blocks until full cervical dilatation, was
equal in the two groups (median, 2 hours; range, 0 to 11 hours). The second stage of labor had a median duration of 0.5 hours (range 0 to 2.25 hours) in both groups. The rate of dystocia necessitating oxytocin stimulation was 39.7% in the saline solution group and 32.6% in the sterile water group. Although the rate of instrument-assisted delivery was similar in the two groups, the rate of cesarean section was significantly higher in the saline solution group (Table Ill). This was caused predominantly by a higher incidence of cephalopelvic disproportion and malposition of the occiput (Table IV). At vaginal delivery the rate of malposition of the occiput was 9.5% in the saline solution group and 5.2% in the sterile water group. The difference is not significant. There was no difference in average blood loss. Infant birth weight and Apgar scores also were equal. A significantly greater proportion of the women in
1280 Trolla at al. Am
Table IV. Indication for operative delivery in sterile water and saline solution groups - -S-te-n-·l-e - ,------ - - Saline solution water
-----------I
II (0)
Threat of asphyxia Cephalopelvic disproportion Lack of progression Malposition of the occiput Exhausted mother Other
5 (1) 12 (10)
5 (5) 4 (I) 1 (I) 11 (I) 1 (I)
o
10 (9) 8 (0) 1 (1)
Numbers in parentheses indicate cesarean section. Some operations were performed for more than one indication. The total number of operative deliveries was 28 in each group.
Table V. Answer to question, "Will you request the same kind of analgesia if you are going to deliver again?" in sterile water and saline solution groups
Yes No Undecided-no answer
Sterile water (n = 141)
Saline solution (n = 131)
96
66
18
27
35 30
p < 0.005, X2 test.
the sterile water group than in the saline solution group would request the same type of analgesia if they again had to undergo delivery(p < 0.005) (Table V).
Comment Danish women do not expect childbirth to be painless. Epidural analgesia is available as a fulltime service in only a few centers. The use of paracervical block was largely abandoned after reports of fetal bradycardia, and pethidine is used mostly for women complaining of severe pain in early labor. Nitrous oxide is the most widely used analgesic, and pudendal block is offered to all women. Psychoprophylaxis is regarded as important, and most primigravid women attend free antenatal classes. Many primigravid, and most multigravid, women are delivered without any request for analgesia, and we find it reasonable to assume that the women who chose to participate in this study felt severe low back labor pain. Pain impulses from the posterior part of the cervix and uterus are transmitted to the spinal cord segments TII-LI, and cutaneous branches from these segments supply the skin over the low back area." This is probably the anatomic background of how pain originating in the cervix can be localized to the back. Low back pain occurs often in labor, especially in connection with an occipitoposterior presentation, where stretching of the posterior part of the lower uterine segment and
J
Mav 1991
Obstet Gvnecol
cervix may be predominant. The hypotonic sterile water injected intradermally causes local irritation and thereby a strong sensory stimulation of the surrounding skin area for about 30 seconds. The analgesia induced by this stimulation may originate in midbrain centers, II. 12 or be caused by "gate control" at the spinal level. I". 14 Hyperstimulation of a skin area can affect perception of visceral pain, and it appears that the mechanism of referred pain can be reversed to produce referred analgesia. Intradermal injection of isotonic saline solution is less painful than sterile water but not painless, and saline solution blocks could theoretically induce some degree of analgesia. To make the study double-blind some kind of injection in the low back area had to be used in the treatment of the control group. Comparing the blocks with any of the established methods of analgesia was abandoned for the same reason. These circumstances make it impossible to state the number of patients having only a placebo effect of the blocks. A great number of women joined the project. A study of this size has a power of almost 90% in detecting a difference in proportions between the two groups of at least 15%. The highly significant difference in pain intensity between the groups after the blocks were given is not reflected in the use of pethidine, which was similar in the two groups. The number of women receiving pethidine is small-smaller than the total number of women who did not have any analgesic effect of the blocks. It is not possible to make any conclusions. We found it important to certify that the analgesic effect of the blocks was not connected with an impairment of labor, as this would only postpone pain. No such effect was noted. The incidence of dystocia and oxytocin infusion was high in both groups, but this was to be expected because only women with low back pain entered the study and low back pain commonly occurs with malrotation of the fetus. There was no difference between the groups with regard to the rate of instrument-assisted delivery. However, the rate of cesarean section in the saline solution group was similar to the usual rate of cesarean section in our department (3000 deliveries per year), whereas the rate of cesarean section in the sterile water group was significantly lower (4.2% vs 11.4%). We have no definite explanation for this. The most frequent indications for cesarean section in the saline solution group were malposition of the occiput and cephalopelvic disproportion. In the Danish population the latter condition is usually relative, reflecting a fetal malrotation. It is not possible to determine if there was a primary difference between the study groups regarding fetal position or a higher rate of correction of fetal position in the sterile water group. Generally, the relation be-
Sterile water blocks for labor pain
Volume 164 Number 5, Part 1
tween labor pain and fetal position and the effect of analgesia on pelvic floor tone, cervical tension, contraction pattern, and fetal rotation are interesting and an evident subject for further studies. REFERENCES I. Melzack R, Schaffelberg D. Low-back pain during labor. AMJ OBSTET GYNECOL 1987;156:901-5. 2. Erkkola R, Pikkola P, Kanto J. Transcutaneous nerve stimulation for pain relief during labour: a controlled study. Ann Chir Gynaecol 1980;69:273-7. 3. Miller Jones CMH. Transcutaneous nerve stimulation in labour. Anaesthesia 1980;35:372-5. 4. Permin M, Ipsen L, Hansen MK, et al. Relief from pain localized to the lower back in early labour. Z Geburtshilfe PerinatoI1981;185:3601-3. 5. Ulmsten U, Sandahl B, Lundin C, Andersson KE. Treatment of labour pain with locally applied ketocaine. Acta Obstet Gynecol Scand 1980;59:209-12. 6. Rose D. Local anaesthesia in first and second stage labour. N EnglJ Med 1929;201:117-25.
7. Abrams AA. Obliteration of pain at the site of reference by intradermal infiltration anesthesia in first-stage labor. N Engl J Med 1950;243:636-40. 8. Bengtsson J, Worning AM, Gertz J, et al. Pain due to urolithiasis treated by intracutaneous injection of sterile water. Ugeskr Laeger 1981;143:3463-5. 9. Scott J, Huskisson EC. Graphic representation of pain. Pain 1976;2: 175-84. 10. Bonica JJ. Peripheral mechanisms and pathways of parturition pain. Br J Anaesth 1979;51:35-95. I I. Basbaum AI, Fields HL. Endogenous pain control mechanisms: review and hypothesis. Ann Neurol 1978;4:45161. 12. Sherman JE, Liebeskind JC. An endorphinergic, centrifugal substrate of pain modulation: recent findings, current concepts, and complexities. In: Bonica JJ, ed. Pain. New York: Raven Press, 1980:191-204. 13. Melzack R, Wall PD. Pain mechanism: a new theory. Science 1965;150:971-9. 14. Wall PD. The role of substantia gelatinosa as a gate control. In: Bonica JJ, ed. Pain. New York: Raven Press, 1980:205-31.
Electronic fetal heart monitoring, auscultation, and neonatal outcome Patricia H. Ellison, MD: Mark Foster, MA: Margaret Sheridan-Pereira, MD: and Dermot MacDonald, MDc Denver, Colorado, and Dublin, Ireland In a large randomized, controlled study of fetal heart rate monitoring with either continuous electronic fetal heart monitoring or auscultation at specified intervals, only one pattern of deviation in the fetal heart rate correlated significantly with neonatal neurologic examinations at 0 to 48 hours and 72 hours to 1 week: late decelerations in stage 1 and in stage 2. Other variables from labor and delivery, specifically, duration of labor after hospital admission, failure of labor to progress, number of fetal scalp pH values, and presence of meconium were important predictors of neonatal outcome in the regression analyses. The fetal heart rate deviations did contribute significantly to the percent variance accounted for in the regression analyses with neonatal outcomes of Apgar scores at 1 and 5 minutes and serial neonatal neurologic examinations. (AM J OBSTET GYNECOL 1991;164:1281-9.)
Key words: Continuous electronic fetal heart monitoring, late decelerations, Apgar scores at I and 5 minutes, neonatal neurologic examination Electronic fetal heart monitoring, when introduced in the 1960s and refined in subsequent years, brought hope that there could be a way to detect, in utero, an From the Department of Psychology, University of Denver," and Coombs Hospital' and National Maternity Hospital,' Dublin. Supported in part by the Presbyterian/ St. Luke's Foundation, Denver, Colorado. Received for publication March 6, 1990; revised December 3, 1990; accepted December 21, 1990. Reprint requests: Patricia H. Ellison, MD, Research Professor, Department of Psychology, University of Denver, Denver, CO 80208. 6/1 /27569
already compromised fetus, as well as a fetus in the process of deterioration, particularly during labor and delivery. In certain situations this technology has been fairly reliable, e.g., in the recognition of a dying fetus who previously might have been stillborn. It has been less reliable in the detection of fetuses with hypoxiaischemia of the central nervous system and secondarily decreased regulation of heart rate. In the majority of studies the relation was examined between fetal heart rate and the Apgar score, usually at I and 5 minutes. Very few studies have examined 1281
