Thomas et al.

10. Johnson PM, Barnes RMR, Hart CA, Francis WJA. De­terminants of immunological responsiveness in recurrent spontaneous abortion. Transplantation 1984;38:280.

11. Beer AE, Quebbeman JF, Semprini AE, Smouse PE, Haines RF. Recurrent abortion: analysis of the roles of parental sharing of histocompatibility antigens and ma­ternal immunological responses to paternal antigens. In: Isojima S, Billington WD, eds. Reproduction and Im­munology 1983. Amsterdam: Elsevier, 1983:185-95.

12. Lauritsen J, Kristensen T, Grunnet N. Depressed mixed lymphocyte culture reactivity in mothers with recurrent spontaneous abortion. AM J 0BSTET GYNECOL 1976; 125:35.

13. Shoenbaum SC, Manson RR, Stubblefield PG, Darney PD,

April 15, 1985 Am J Obstet Gynecol

Ryan KJ. Outcome of the delivery following an induced or spontaneous abortion. AM J OBSTET GvNECOL 1980; 136:19.

14. Funderburk SJ, Guthrie D, Meldrum D. Suboptimal preg­nancy outcome among women with prior abortions and premature births. AM J 0BSTET GYNECOL 1976; 126:55.

15. Clarke C, Hobson D, McKendrick OM, Rogers SC, Shep­pard PM. Spina bifida and anencephaly: miscarriage as a possible cause. Br Med J 1975;4:743.

16. Ayme S, Mercier P, Dallest R, MatteiJ-F. HLA and trisomy 21. Confirmation of a trend of restricted HLA hetero­geneity in parents of Down syndrome children. Am J Hum Genet 1984;36:405.

Clinical amniotic fluid infection and its effect on the neonate

Mitzi G. Ferguson, M.D., Philip G. Rhodes, M.D., John C. Morrison, M.D., and Christina M. Puckett, M.D.

Jackson, Mississippi, and Houston, Texas

This study was undertaken to determine the effects of clinical amniotic fluid infection on the neonate in

terms of bacterial infection, hyaline membrane disease, asphyxia, and mortality. A retrospective chart review was made of 1 07 mothers with clinical amniotic fluid infection and their infants at this institution

over a 3-year period. The next live-born infant with a birth weight within 100 gm and gestational age within

2 weeks was chosen as a control for each study patient. The rate of prematurity in the study group was 71%. When prematurity was controlled for, there was no significant difference in regard to asphyxia,

hyaline membrane disease, bacterial sepsis, and death between the study and control groups. These

findings suggest that the adverse outcome for infants delivered to mothers with clinical amniotic fluid

infection at this institution was related primarily to their prematurity. (AM J OBSTET GYNECOL 1985;151 :1 058-61.)

Key words: Amniotic fluid, bacterial infection, prematurity, neonatal mortality

Chorioamnionitis has been associated with high rates of morbidity and mortality for both the mother and the fetus or neonate.'·' The adverse effects on the fetus and neonate are assumed to be primarily related to an increased risk of infection in these infants. Studies on chorioamnionitis, however, did not previously correct for the increased rate of prematurity which is known to be associated with a higher incidence of infection.5

For this reason, we undertook the present study in or­der to examine the effects of chorioamnionitis on the mortality and morbidity rates of the neonate, with a control for gestational age and birth weight.

From the Division of Newborn Medicine, Department of Pediatrics, and the Division of Maternal-Fetal Medicine, Department of Ob­stetrics and Gynecology, University of Mississippi Medical Center, and the Division of Newborn Medicine, Department of Pediatrics, University of Texas Medical Center.

Received for publication July 23, 1984; revised October 8, 1984; accepted November I, 1984.

Reprint requests: Philip G. Rhodes, M.D., University of Mississippi Medical Center, 2500 North State St., Jackson, MS 39216.

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Patients and methods

This study was a retrospective review of all cases of chorioamnionitis during the period of January 1, 1980, to December 31, 1982, at the University of Mississippi Medical Center. The study group was composed of all cases of mothers with chorioamnionitis and their in­fants. The criteria for diagnosis of chorioamnionitis in the mother was any one or any combination of the following: (1) fever prior to delivery (> 100.4° F or 38° C) without other sites of infection, (2) uterine tenderness, and/or (3) peripheral blood leukocyto­sis (>20,000/mm'). Since placental histologic findings were not available in all cases, the term chorioamnionitis

will not be used. Instead, the clinical maternal features described above will be referred to as clinical amniotic fluid infection.

A control infant was chosen for each study infant and was the next live-born baby with a birth weight within 100 gm and gestational age within 2 weeks. Anal­ysis of data was performed by X2 and the Student t test. The values were adjusted for multiple comparisons by

Volume 151 Number 8

Table I. Maternal features

Maternal features

Age (yr, mean) 22.8 Duration of ruptured 46.4

membranes (hr, mean)

Maximum temperature 100.2° F during labor (mean)

Heart rate (mean) 99 Previous abortion (%) 30 Fetal tachycardia (%) 39 Purulent or malodo- 45

rous amniotic fluid (%)

Fever, ~100.4° F (%) 48 Uterine tenderness (%) 52 Peripheral blood leu- 17

kocytosis (20,000/ mm3,%)

p Value

22.0 NS 11.7 <0.001

98.4° F <0.05

91 <0.001 19 NS 11 <0.001 5

0.9 3.5 4.5

Bonferroni's method. A 95% confidence interval was calculated for hyaline membrane disease, asphyxia, sepsis, and death.

Results

During the 36-month period, there were 12,585 de­liveries at this institution. A total of 107 mothers met the above-mentioned criteria for clinical amniotic fluid infection. This was 0.9% of the total births during that period.

Maternal features that were reviewed in the study and control groups are summarized in Table I. The 107 study mothers were delivered of 116 infants, in­cluding nine sets of twins. The control infant was paired with each study infant in regard to birth weight. Sev­enty-one percent of the infants in the study weighed <2500 gm, as compared with an 18% low-birth weight rate at this institution. The neonatal mortality and mor­bidity rates in regard to asphyxia, hyaline membrane disease, bacterial sepsis, and death in each group are summarized in Table II.

Those infants who had !-minute Apgar scores of "'5 and 5-minute Apgar scores of "'6 were given a diag­nosis of asphyxia neonatorum. The incidence of as­phyxia in the study group was 81 of 116 or 27%. The

incidence of asphyxia in the control group was 18 of 116 or 16%. The difference in the incidence between the control group and the study group was 11% (NS) with a confidence interval of 0% to 22%.

The diagnosis of hyaline membrane disease in a pre­term infant required the following: grunting respira­tions, retractions, tachypnea, and an oxygen need of more than 50% to maintain the Paa2 >60 mm Hg. Ra­diologic findings of a reticulogranular appearance and air bronchograms were required. Hyaline membrane

Amniotic fluid infection 1 059

Table II. Neonatal outcome

Study Control p group group Value

Birth weight (gm, 1878 1873 NS mean)

Male/female 69/47 50/66 <0.01 Hyaline membrane 33/116 311116 NS

disease Asphyxia 31/116 18/116 NS Sepsis 71116 2/116 NS Death 23/116 13/116 NS

Table III. Organisms causing early onset sepsis

Study group

Enterococcus Group B Streptococcus Pneumococcus Group D Streptococcus Bacteroides Escherichia coli Haemophilus infiuenzae

Control group

Group B Streptococcus Escherichia coli

disease occurred in 28% of the study group and in 27% of the control group, with a difference between the two groups of 1% (NS) and a confidence interval of 0% to 13%.

Blood cultures were obtained on all infants admitted to the newborn intensive care unit and on any other baby who had clinical signs of sepsis (respiratory dis­tress, tachycardia, lethargy, or poor feeding). There were seven cases in the study group (6%) and two cases in the control group (2%) of bacteriologically proved sepsis within the first 3 days of life. The difference in the incidence between the control group and the study group was 4% (NS) with a confidence interval of 0% to 9%. All nine infants with bacteriologically proved sepsis weighed <2100 gm. Seven of the nine infants weighed <1500 gm. The organisms that were identified in early onset sepsis are listed in Table III.

A total of 36 deaths occurred during the neonatal period in the two groups. The incidence of death in the study group was 20%, and that in the control group was 11%. The difference in the incidence between the

two groups was 9% with a confidence interval of 0% to 18%. Of the 36 neonates who died, four died of sepsis within 48 hours of life. All weighed < 1400 gm, and three of the four were in the study group.

Comment

In the past, infants born to mothers with chorioam­nionitis were thought to be at an increased risk for sepsis, respiratory distress syndrome, asphyxia, and death. However, more recent studies have suggested

1 060 Ferguson et al.

that the adverse outcome for these neonates is closely related to their prematurity and the complications of prematurity. 6 Gibbs et a!. 17 reported that the outcome for infants delivered within 12 hours of the onset of clinical amniotic fluid infection was not influenced by the maternal infection. Those authors found no in­crease in the rate of infection in these infants. The outcome was again primarily related to their prema­turity. The present study attempted to control for pre­maturity and compare neonatal outcome in the group with clinical amniotic fluid infection with that in the control group (no clinical amniotic fluid infection).

In this study, amniotic fluid infection was associated with a 71% rate of prematurity, which is higher than that previously reported.'-1 This is four times higher than the overall rate of prematurity at this institution. Chorioamnionitis is a factor known to predispose to preterm labor8 that leads to a high rate of prematu­rity.'-'· 7 The exact mechanism by which chorioamnio­nitis triggers preterm labor is unknown. The suggestion has been made that infected fetal membranes may be more prone to rupture than are normal noninfected membranes, thereby leading to premature labor. 9 With premature rupture of the membranes, spontaneous la­bor begins within 72 hours of rupture in 70% of the preterm pregnancies. It is thought that the labor is triggered by the release of phospholipase A2 from fetal membranes, which begins a sequence of events that results in the synthesis of prostaglandins by placental membranes.'" Most bacteria which cause perinatal in­fections have an active phospholipase A2 system, as shown by Bejar et a!. 11 This has also been suggested as a mechanism for the onset of premature labor. The bacteria's phospholipases may initiate premature labor by increasing the production of prostaglandin from the membranes.

Neonatal sepsis, asphyxia, hyaline membrane dis­ease, and death are serious complications of prema­turity. In this study, with gestational age being con­trolled, there was no significant difference in the incidences of sepsis, hyaline membrane disease, as­phyxia, or death in the two groups. There was an in­creased, although not statistically significant, incidence of asphyxia in the study group. Several other studies have observed an increased incidence of asphyxia with prolonged rupture of the membranes. 8•

12•

13 The expla­nation for the asphyxia is unknown, but Bada et a!.'' postulated that fetal breathing movements were absent or restricted with loss of amniotic fluid in premature rupture of the membranes, which resulted in delay of normal respirations at birth. In this study, the group with chorioamnionitis did have a significantly longer time interval for ruptured membranes than that of the control groups. These data suggest that the change in the physical environment related to loss of amniotic

Ap:il 15, 1985 Am J Obstet Gynecol

fluid may be a very important factor in the neonatal complications.

We recognize that this investigation is retrospective and relies on the diagnosis of amniotic fluid infection by various people. However, consistency was generally maintained by protocol and the same maternal-fetal division director. Amniotic fluid infection is a subjective clinical diagnosis and has many variable signs and symptoms. Very few diagnostic techniques are available for a consistent determination of amniotic fluid infec­tion. Although not routinely done at this institution, analysis of amniotic fluid seems to be of value in di­agnosing chorioamnionitis.<· '4

-16 Microbiologic analysis

of amniotic fluid by Gram stain and culture seems to be a reliable predictor of occult chorioamnionitis, but we recognize that this may not be practical in all preg­nancies.

In summary, infants born to mothers with clinical amniotic fluid infection are at an increased risk of being born prematurely. Preterm infants have higher inci­dences of sepsis, hyaline membrane disease, asphyxia, and death. In this study, with gestational age being controlled, there was no statistical significant difference in the incidence of hyaline membrane disease, sepsis, asphyxia, or death between the group with clinical am­niotic fluid infection and the control group (no clinical amniotic fluid infection), thus suggesting that prema­turity and its complications may be the greatest risk to these infants.

REFERENCES

I. Clark DM, Anderson GV. Perinatal mortality and am­nionitis in a general hospital population. Obstet Gynecol 1968;31:714.

2. Lanier LR, Scarbrough RW, Fillingim DW, eta!. Incidence of maternal and fetal complications associated with rup­ture of the membranes before onset oflabor. AM J OBSTET GYNECOL 1965;93:398.

3. Pryles CV, Steg NL, Nair S, et a!. A controlled study of the influence on the newborn of prolonged premature rupture of the amniotic membranes and/or infection in the mother. Pediatrics 1963;31 :608.

4. Garite TJ, Freeman RK. Chorioamnionitis in the preterm gestation. Obstet Gynecol 1982;59:539.

5. Beutow K, Klein S, Lane R. Septicemia in premature in­fants. Am J Dis Child 1965; 110:29.

6. Daikoku NH, Kaltreider DF, Johnson TRB, et a!. Pre­mature rupture of membranes and preterm labor: neo­natal infection and perinatal mortality risks. Obstet Gy­necol 1981 ;58:417.

7. Wilson GM, Armstrong DH, Nelson RC, eta!. Prolonged rupture of fetal membranes. Am J Dis Child 1964; 107:138.

8. Daikoku NH, Kaltreider DF, Khouzami VA, et a!. Pre­mature rupture of membranes and spontaneous preterm labor: maternal endometritis risks. Obstet Gynecol1982; 59:13.

9. Knox IC, Hoerner JK. The role of infection in premature rupture of the membranes. AM j 0BSTET GYNECOL 1950;59: 190.

10. Huddleston JF. Preterm labor. Clin Obstet Gynecol 1982;25: 123.

ll. Bejar R, Curbelo V, Davis C, et a!. Premature labor. II.

Volume !51 Number 8

Amniotic fluid infection

Bacterial sources of phospholipase. Obstet Gynecol 1981; 57:479.

12. Jones MD, Burd LI, Bowes WA, eta!. Failure of association of premature rupture of membranes with respiratory­distress syndrome. N Englj Med 1975;292:1253.

15. Bobitt JR, Ledger WJ. Amniotic fluid analysis: its role in maternal and neonatal infection. Obstet Gynecol 1978; 51:56.

13. Bada HS, Alojipan LC, Andrews BF. Premature rupture of membranes and its effect on the newborn. Pediatr Clin of North Am 1977;24:491.

16. Miller JM, Hill GB, Welt Sl. Bacterial colonization of am­niotic fluid in the presence of ruptured membranes. AM j 0BSTET GYNECOL 1980;137:451.

17. Gibbs RS, Castillo MS, Rodgers PJ. Management of acute chorioamnionitis. AMj 0BSTET GYNECOL 1980;136:709.

14. Gibbs RS. Diagnosis of intra-amniotic infection. Semin Perinatol 1977;1:71.

Laboratory and clinical evaluation of a rapid slide agglutination test for phosphatidylglycerol

Philip R. Halvorsen, M.D., and Thomas L. Gross, M.D.

Cleveland, Ohio

Amniostat-FLM is a recently developed rapid slide agglutination test for amniotic fluid phosphatidylglycerol.

We compared phosphatidylglycerol quantitated by two-dimensional thin-layer chromatography with phosphatidylglycerol determined by Amniostat-FLM in 180 amniotic fluid samples. If any level of

phosphatidylglycerol by thin-layer chromatography, including a trace, was considered positive, then phosphatidylglycerol by thin-layer chromatography and Amniostat-FLM were concordant in 171 of 180

samples (95%). Both were positive in 123 and both negative in 48 samples. The nine amniotic fluid

samples with discrepant results were as follows: Five negative Amniostat-FLM results were associated

with trace phosphatidylglycerol by thin-layer chromatography (1% to 2% of total phospholipids), one negative Amniostat-FLM result was associated with 3% phosphatidylglycerol by thin-layer chromatography,

and three positive Amniostat-FLM results were associated with negative phosphatidylglycerol by

thin-layer chromatography results. There were 14 samples with trace phosphatidylglycerol by thin-layer chromatography; of these, there were nine positive and five negative Amniostat-FLM results. If >2% phosphatidylglycerol by thin-layer chromatography was considered positive, concordance between the two

tests was 93% (167 of 180). From these samples, 119 infants were delivered within 72 hours of amniocentesis. There were 100 positive Amniostat-FLM results and all were associated with the absence of respiratory distress syndrome; of the 19 negative Amniostat-FLM results, five were associated with

infants who developed respiratory distress syndrome. The present study confirms that Amniostat-FLM is a

simple, rapid, and accurate test for determining the presence of phosphatidylglycerol in amniotic fluid. (AM J 0BSTET GYNECOL 1985;151 :1 061-6.)

Key words: Phosphatidylglycerol slide agglutination test, amniotic fluid, thin-layer chromatography

Over the years various methods have been proposed for assessment of fetal lung maturity by analysis of am­niotic fluid. Of these, the lecithin/sphingomyelin (LIS)

ratio is the most widely used test for predicting respi­ratory distress syndrome (RDS). 1 However, false posi-

From the Department of Obstetrics and Gynecology and the Perinatal Clinical Research Center, Cleveland Metropolitan General Hos­pital and Case Western Reserve University.

Supported in part by United States Public Health Service Grant M01-RR00210.

Received for publication May 21, 1984; revised September 20, 1984; accepted November 26, 1984.

Reprint requests: Philip R. Halvorsen, M.D., Department of Obstet­rics and Gynecology, Cleveland Metropolitan General Hospital, 3395 Scranton Road, Cleveland, OH 44109.

tive LIS ratios do occur. Recent StJJdies suggest that phosphatidylglycerol may be more reliable in predict­ing RDS and also other less severe complications of prematurity.2

• 3 Two-dimensional thin-layer chroma­

tography is the most widely used method for measuring phosphatidylglycerol but may take as long as 3 hours to perform. If reliable, a simpler, faster, and less ex­pensive method for measuring phosphatidylglycerol could be more useful clinically. Amniostat-FLM is a recently developed rapid slide agglutination test for determination of the presence of phosphatidylglycerol. In the only laboratory correlation study of which we are aware, Garite et a!.< found a 91% concordance be­tween phosphatidylglycerol performed by Amniostat-

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