Validity of Lamellar Body Count as a Fetal Lung Maturity Assessment in Twin Pregnancy

ArticleinTwin Research and Human Genetics 15(4):547-9 · August 2012with48 Reads
Impact Factor: 2.30 · DOI: 10.1017/thg.2012.29 · Source: PubMed
Abstract

Fetal lung maturity assessment in twin pregnancy has been discussed, but is still controversial. The purpose of this study is to predict the occurrence of respiratory distress syndrome (RDS) using lamellar body count (LBC) and analyze the validity of LBC for fetal lung maturity assessment in twin pregnancy. Three-hundred two amniotic fluid samples were obtained at cesarean section from 29 to 38 weeks of gestation. Samples were analyzed immediately with no centrifugation and the number of lamellar bodies was counted using a platelet channel on the Sysmex SF-3000. There were 18 neonates (6.0%) suffering from RDS. An LBC cut-off value of 2.95×10⁴/μL resulted in 91.5% sensitivity and 83.3% specificity for predicting RDS. This cut-off value for predicting RDS was the same as that in singleton pregnancy. Moreover, the median LBC value in RDS cases was significantly lower than in non-RDS cases (1.50±1.1×10⁴/μL vs. 10.6±7.5×10⁴/μL; p<.001). This is the first report on the validity of LBC in twin pregnancy and also the largest study on fetal lung maturity assessment in twin pregnancy. An LBC value of >2.95×10⁴/μL means reassuring findings for RDS even in twin pregnancy. We believe the data in this study provide valuable, new information for the management of twin pregnancies.

Figures

Full-text

Available from: Tomomi Kotani, May 10, 2014
Twin Research and Human Genetics
Volume 15 Number 4 pp. 547–549
C
The Authors 2012 doi:10.1017/thg.2012.29
Validity of Lamellar Body Count as a Fetal Lung
Maturity Assessment in Twin Pregnancy
Hiroyuki Tsuda,
1
Tomomi Kotani,
1
Seiji Sumigama,
1
Ichiro Kawabata,
2
Yuichiro Takahashi,
2
Shigenori Iwagaki,
2
Kaori Kigoshi,
2
and Fumitaka Kikkawa
1
1
Department of Obstetrics and Gynecology, Nagoya University School of Medicine, Nagoya, Japan
2
Department of Fetal and Maternal Medicine, Nagara Medical Center, Gifu City, Japan
Fetal lung maturity assessment in twin pregnancy has been discussed, but is still controversial. The purpose
of this study is to predict the occurrence of respiratory distress syndrome (RDS) using lamellar body count
(LBC) and analyze the validity of LBC for fetal lung maturity assessment in twin pregnancy. Three-hundred
two amniotic fluid samples were obtained at cesarean section from 29 to 38 weeks of gestation. Samples
were analyzed immediately with no centrifugation and the number of lamellar bodies was counted using a
platelet channel on the Sysmex SF-3000. There were 18 neonates (6.0%) suffering from RDS. An LBC cut-off
value of 2.95 × 10
4
/μL resulted in 91.5% sensitivity and 83.3% specificity for predicting RDS. This cut-off
value for predicting RDS was the same as that in singleton pregnancy. Moreover, the median LBC value
in RDS cases was significantly lower than in non-RDS cases (1.50 ± 1.1 × 10
4
/μL vs. 10.6 ± 7.5 × 10
4
/μL;
p
< .001). This is the first report on the validity of LBC in twin pregnancy and also the largest study on fetal
lung maturity assessment in twin pregnancy. An LBC value of >2.95 × 10
4
/μL means reassuring findings
for RDS even in twin pregnancy. We believe the data in this study provide valuable, new information for
the management of twin pregnancies.
Keywords: amniotic fluid, lamellar body, fetal lung maturity, respiratory distress syndrome, twin
pregnancy
Fetal lung maturity assessment in twin pregnancy has been
discussed, but is still controversial. In singleton pregnancy,
several studies have shown the lamellar body count (LBC)
to be an accurate predictor of fetal lung maturity (Karcher
et al., 2005; Piazze et al., 2005; Wijnberger et al., 2001). The
LBC can be performed quickly and cheaply, so it is a more
cost-effective predictor for the occurrence of respiratory
distress syndrome (RDS) than the lecithin/sphingomyelin
(L/S) ratio (Wijnberger et al., 2001). In a recent study, an
LBC on gastric aspirates could also be used alone or in
combination with the stable microbubble test as a predictor
of RDS (Daniel et al., 2010). Nothing has been reported
abouttheLBCvaluesintwinpregnancies.Thus,inthis
study, we performed LBCs in twin pregnancies and analyzed
the validity of LBC for fetal lung maturityassessment in twin
pregnancy.
Materials a nd Methods
Data were collected from April 2006 to March 2010 at Na-
gara Medical Center, Gifu City, Japan. We registered 302
neonates (151 twin pairs) including 81 dichorionic twin
(DCT) pairs and 70 monochorionic twin (MCT) pairs
without any anomalies or complications such as twin–
twin transfusion syndrome. Chorionicity was determined
by early ultrasound findings and placental pathology fol-
lowing delivery. All amniotic fluid samples were obtained
from each sac at cesarean section from 29 to 38 weeks of
gestation with informed consent. Samples were analyzed
immediately after arrival at the laboratory with no centrifu-
gation, according to a standardized methodology for LBC
reported by Neerhof et al. (Neerhof et al., 2001). Amniotic
fluid samples contaminated with blood and meconium were
excluded. The LBC was determined using a platelet channel
on the Sysmex SF-3000 (Sysmex, Kobe, Japan). The diag-
noses of RDS were established by the neonatologist based
RECEIVED 10 November 2010; ACCEPTED 3 November 2011.
ADDRESS FOR CORRESPONDENCE: Hiroyuki Tsuda, Department
of Obstetrics and Gynecology, Nagoya University School of
Medicine,65 Tsurumai-cho, Showa-ku, Nagoya466-8550, Japan.
E-mail: hiro-t@med.nagoya-u.ac.jp
547
Page 1
Hiroyuki Tsuda et al.
FIGURE 1
Correlation between lamellar body count (LBC) and gestational weeks at delivery. Solid horizontal lines in the figure indicate the cut-off
value of LBC for predicting RDS.
on the combination of clinical signs, chest X-ray findings,
and clinical course; the neonatologist was unaware of the
LBC data. The data were collected and entered on a com-
puterized spreadsheet (Excel spreadsheet, Microsoft, Tokyo,
Japan). The data were statistically analyzed with Dr. SPSS
II (SPSS Inc., Tokyo, Japan) using Student’s t-test, Mann–
Whitney U test, and an ROC curve. A p-value of less than
.05 was considered significant.
Results
There were 18 neonates (6.0%) suffering from RDS. The rate
of RDS was not different between DCT and MCT (4.3%
vs. 7.9%; p = .196). Maternal outcomes were as follows:
delivered before 34 weeks of gestation (n = 29, 19.2%);
pregnancy-induced hypertension (n = 27, 17.9%); diabetes
mellitus (n = 4, 2.6%); and preterm rupture of membrane
(n = 12, 7.9%). There were no significant differences be-
tween DCT and MCT. We analyzed the cut-off value of LBC
for predicting RDS using an ROC curve. An LBC cut-off
value of 2.95 ×10
4
/μL resulted in 91.5% sensitivity, 83.3%
specificity, and area under the ROC curve of 96.1%. In sin-
gleton pregnancy, the same LBC cut-off value of 2.95 ×
10
4
/μL resulted in 94.0% sensitivity, 82.4% specificity, and
area under the ROC curve of 92.7% for predicting RDS,
as we reported previously (n = 365) (Tsuda et al., 2010).
Moreover, the median LBC value in RDS cases was signifi-
cantly lower than in non-RDS cases (1.50 ± 1.1 × 10
4
/μL
vs. 10.6 ± 7.5 × 10
4
/μL; p < .001). The correlation between
the LBC value and gestational weeks at delivery is shown in
Figure 1.
548 AUGUST 2012 TWIN RESEARCH AND HUMAN GENETICS
Page 2
Amniotic Lamellar Body Count in Twin Pregnancy
Discussion
There is currently no consensusregarding whether fetal lung
maturation differs between singleton and twin pregnancies
because some factors such as gender, birth weight, first-
or second-born, and vaginal or cesarean delivery can affect
the incidence rates of RDS (Marttila et al., 2004; McElrath
et al., 2000). Moreover, there is also no consensus regard-
ing whether fetal lung maturity assessment differs between
singleton and twin pregnancies. Leveno et al. reported that
lung maturity, as indicated by a L/S ratio >2, was reached
in twin pregnancies at an average of 32 weeks’ gestation,
compared with 36 weeks’ gestation for singleton pregnan-
cies (Leveno et al., 2000). Further, beyond 31 weeks’ gesta-
tion, twin pregnancies appeared to have a TDx fetal lung
maturity value that was 22 mg/g higher than that in sin-
gleton pregnancies (McElrath et al., 2000). However, the
underlying cut-off values for RDS in twin pregnancy were
not considered in these studies. Our results in this study
can answer this question, and the cut-off value for predict-
ing RDS with LBC was the same for singleton and twin
pregnancies.
Our results showed that the LBC cut-off value for pre-
dicting RDS in twin pregnancy had a high sensitivity rate
(91.5%) and high specificity rate (83.3%) using the ROC
curve.Butweshouldbecarefulfortheinterpretationof
these data because high sensitivity and specificity rates may
in part be due to the fact that the incidence of RDS was
very low. Then, there are some limitations in this study. We
don’t compare the LBC values between the twin pairs and
thegenderinthisstudy.Weneedfurtherstudiesaboutthese
questions.
This is the first report on the validity of LBC in twin
pregnancy and also the largest study on fetal lung maturity
assessment in twin pregnancy. We conclude that we can use
thesamecut-offvalueforpredictingRDSevenintwinpreg-
nancy. Therefore, an LBC value of >2.95 × 10
4
/μL means
reassuring findings for RDS even in twin pregnancy. Our
data in this study may have some limitations, but we believe
this provides valuable, new information for the manage-
ment of twin pregnancies.
Acknowledgment
This study was approved by the Ethical Commit-
tee of Nagoya University Hospital. The authors thank
Mr. John Cole for correcting the English of the
manuscript.
References
Daniel,I.W.,Fiori,H.H.,Piva,J.P.,Munhoz,T.P.,Nectoux,
A. V., & Fiori, R. M. (2010). Lamellar body count and
stable microbubble test on gastric aspirates from preterm
infants for the diagnosis of respiratory distress syndrome.
Neonatology, 98, 150–155.
Karcher, R., Sykes, E., Batton, D., Uddin, Z., Ross, G.,
Hockman, E., & Shade, G. H., Jr. (2005). Gestational
age-specific predicted risk of neonatal respiratory distress
syndrome using lamellar body count and surfactant-to-
albumin ratio in amniotic fluid. American Journal of Ob-
stetrics and Gynecology, 193, 1680–1684.
Leveno, K. J., Quirk, J. G., Whalley, P. J., Herbert, W. N., &
Trubey, R. (1984). Fetal lung maturation in twin gestation.
American Journal of Obstetrics and Gynecology, 148, 405–
411.
Marttila, R., Kaprio, J., & Hallman, M. (2004). Respiratory
distress syndrome in twin infants compared with singletons.
American Journal of Obstetrics and Gynecology, 191, 271–
276.
McElrath, T. F., Norwitz, E. R., Robinson, J. N., Tanasijevic,
M. J., & Lieberman, E. S. (2000). Differences in TDx fetal
lung maturity assay values between twin and singleton ges-
tations. American Journal of Obstetrics and Gynecology, 182,
1110–1112.
Neerhof,M.G.,Dohnal,J.C.,Ashwood,E.R.,Lee,I.S.,&
Anceschi,M.M.(2001).Lamellarbodycounts:Aconsensus
on protocol. Obstetrics and Gynecology, 97, 318–320.
Piazze, J. J., Maranghi, L., Cerekja, A., Meloni, P., Gioia, S., Fu-
mian, L., Cosmi, E. V., & Anceschi, M. M. (2005). Amniotic
fluid lamellar body counts for the determination of fetal
lung maturity: An update. Journal of Perinatal Medicine, 33,
156–160.
Tsuda, H., Takahashi, Y., Iwagaki, S., Kawabata, I., Hayakawa,
H., Kotani, T., Shibata, K., & Kikkawa, F. (2010). Intra-
amniotic infection increases amniotic lamellar body count
before 34 weeks of gestation. The Journal of Maternal–Fetal
& Neonatal Medicine, 23, 1230–1236.
Wijnberger,L.D.E.,Huisjes,A.J.M.,Voorbij,H.A.M.,Franx,
A., Bruinse, H. W., & Mol, B. W. J. (2001). The accuracy
of lamellar body count and lecithin/sphingomyelin ratio in
the prediction of neonatal respiratory distress syndrome: A
meta-analysis. British Journal of Obstetrics and Gynecology,
108, 583–588.
TWIN RESEARCH AND HUMAN GENETICS AUGUST 2012 549
Page 3