| Research Article |
Open Access |
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| Fetal Lung Maturity Testing and Neonatal Respiratory Complications in
Women with Type 1 Diabetes mellitus Electively Delivered before 39
Weeks Gestation |
| Gary Ventolini1*, Britta Buchenroth2, Kelly McCluskey1, Marc R. Belcastro3, Daniel L. Hood4 and Ran Neiger1 |
| 1Departments of Obstetrics and Gynecology, Wright State University, Boonshoft School of Medicine, Miami Valley Hospital; Dayton, Ohio, USA |
| 2Medical School, Wright State University Boonshoft School of Medicine, Miami Valley Hospital; Dayton, Ohio |
| 3Neonatal Intensive Care Unit, Miami Valley Hospital; Dayton, Ohio |
| 4Department of Pathology, Miami Valley Hospital; Dayton, Ohio |
| *Corresponding author: |
Gary Ventolini
Departments of Obstetrics and Gynecology
Wright State University, Boonshoft School of Medicine
Miami Valley
Hospital; Dayton, Ohio, USA
E-mail: Gary.ventolini@wright.edu |
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| Received May 09, 2012; Accepted June 18, 2012; Published June 24, 2012 |
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| Citation: Ventolini G, Buchenroth B, McCluskey K, Belcastro MR, Hood DL, et
al. (2012) Fetal Lung Maturity Testing and Neonatal Respiratory Complications
in Women with Type 1 Diabetes mellitus Electively Delivered before 39 Weeks
Gestation. J Women’s Health Care 1:111. doi:10.4172/2167-0420.1000111 |
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| Copyright: © 2012 Ventolini G, et al. This is an open-access article distributed
under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the
original author and source are credited. |
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| Abstract |
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| Objective: To compare the rate of neonatal respiratory complications among newborns of women with type 1
Diabetes mellitus (DM) delivered before 39 weeks gestation following documentation of Fetal Lung Maturity (FLM) to
the neonatal outcome of similar women delivered after 39 weeks. |
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| Material and Methods: We retrospectively studied the neonatal outcome of women with type 1 DM delivered
electively by cesarean section before 39 weeks gestation after documentation of fetal lung maturity. We compared the
outcome of these neonates to neonates born to women with type 1 DM delivered by elective cesarean section after 39
weeks gestation without fetal lung maturity analysis. |
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| Results: Between January 1, 2004 and December 31, 2008, 95 women with type 1 DM underwent fetal lung maturity
testing before 39 weeks gestation. Seventy-eight (82.1%) tests suggested lung maturity and the women were delivered
at 37±1 weeks. Five neonates (5.3%) required respiratory assistance and seven others (7.4%) required admission to
the neonatal intensive care unit due to respiratory related symptoms. The overall respiratory complication rate was
12.6%. Six neonates experienced delay in discharge from the hospital. There were four newborns with respiratory
complications (4.3%) in the control group of 94 similar women delivered after 39 weeks gestation (P=0.0001). |
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| Conclusion: Even when fetal lung maturity had been documented, neonates of women with type 1 DM electively
delivered before 39 weeks gestation are at an increased risk of respiratory complications compared with neonates of
similar women delivered after 39 weeks. |
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| Introduction |
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| The American College of Obstetricians and Gynecologists
(ACOG) recommends documentation of fetal lung maturity when a
delivery is performed before 39 weeks gestation [1]. Despite adherence
to the ACOG guidelines preventable morbidity continues to occur
in women delivered before 39 weeks gestation. Although the false
positive rate of fetal lung maturity tests is very low, it may account
for some of the cases where despite tests that had suggested mature
lungs neonates develop respiratory complications after delivery. The
risk for such complications is higher in newborns delivered by cesarean
section [2] and in those delivered to mothers with diabetes [3]. It is
therefore important to evaluate the occurrence of neonatal respiratory
complications among babies born before 39 weeks after fetal lung
maturity had been documented, especially among women with type 1
DM. |
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| The purpose of this study was to evaluate the rate of neonatal
respiratory complications among neonates delivered to women with
type 1 DM who underwent elective cesarean deliveries before 39 weeks
gestation after documentation of fetal lung maturity, compared to
neonates born to similar women after 39 weeks. We elected to study
only neonates delivered by cesarean sections because these newborns
were at a higher risk of developing respiratory complications than
newborns delivered vaginally [2]. In addition, we wanted to minimize
the possibility that variables associated with vaginal delivery (e.g. length
and mode of induction, risk of chorioamnionitis, instrumental delivery
etc.) may contribute to the respiratory complications we studied. |
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| Materials and Methods |
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| The study population included a cohort of neonates delivered by
elective cesarean section to women with type 1 DM before 39 weeks gestation after documentation of fetal lung maturity by amniotic fluid
analysis. All deliveries took place at Miami Valley Hospital in Dayton,
Ohio between January 1, 2004 and December 31, 2008. Indications for
fetal lung maturity testing included: scheduled repeat cesarean section
due to previous classical uterine incision or history of uterine incision
extension, suspected fetal macrosomia (defined as equal or above
4,500g), or inadequate glycemic control (fasting blood sugar values ≥ 95
mg/dl or blood sugar values that were repeatedly ≥ 140 mg/dl or ≥ 120
mg/dl one or two hours after meals, respectively) with suspected fetal
macrosomia and polyhydramnios. The algorithm used to assess fetal
lung maturity is described in Figure 1 [4]. The cutoffs used to define
lung maturity were not altered for maternal diabetes (lamellar body
count cutoff of 50,000; for Fetal Lung Maturity test (FLM III): 55, and
Lecithin/Sphingomyelin ratio: 2.0) [5,6]. Neonatal outcome parameters
included Apgar scores at 5 minutes, umbilical cord blood gases, birth
weight, need for respiratory assistance at birth, admission to the
Neonatal Intensive Care Unit (NICU) due to respiratory complications
(e.g. episodes of apnea, requirement of oxygen, ventilation or CPAP), and delay in hospital discharge due to Respiratory Related Symptoms
(RRS) defined as hospital stay longer than 96 hours after the c-section. |
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Figure 1: Lamellar body count algorithm. |
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| The control group consisted of neonates delivered by elective
caesarean section at the same hospital during the same period after
39 weeks gestation without fetal lung maturity studies to women
with type 1 DM. The women were similar by age, race, gravidity and
parity, duration of maternal diabetes, and insulin requirement. Similar
neonatal outcome parameters were assessed in the control group. |
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| Statistical analysis was performed using Graphpad Software
(Graphpad Software, Inc., San Diego, California); we used two tailed
t-tests for continuous data and/or chi-square analysis for proportions.
A p value of less than 0.05 was considered significant. The study was
approved by the Institutional Review Board. |
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| Results |
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| The study population included 95 women with type 1 DM who
underwent amniocentesis for fetal lung maturity studies at 37±1 weeks
gestation. Seventy eight lung maturity tests (82.1%) suggested maturity
and these women underwent elective cesareans. Seventeen tests (17.9%)
suggested immaturity; these women were retested one week later, at an
average gestational age of 38±2 weeks; all tests suggested maturity and
the women were delivered. |
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| All deliveries were by cesarean sections. The indications for surgery
were: 45 repeat cesarean sections (47.4%), 12 breech presentations
(12.6%), 12 women had poor glycemic control (12.6%), 10 with
estimated fetal weight over 4,500 g (10.5%), seven had 4th degree
perineal tear during previous delivery (7.4%), seven were done at
patients request (7.4%) and two had low cervical leiomyomas (2.1%).
The indications for cesarean delivery in the control group were
comparable to the study group. |
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| Seven of the 78 neonates (9%) whose lung maturity studies were
mature at the time of the first amniocentesis required admission to the
Neonatal Intensive Care Unit (NICU) due to respiratory complications. Five additional neonates from this group (6.4%) required respiratory
assistance at birth. The overall neonatal respiratory complication rate
in the group of women delivered after the first amniocentesis was
15.4%, and the rate for the entire study group of 95 women was 12.6%.
The hospital discharge of six of the study group’s neonates was delayed
due to RRS. The number of respiratory complications in the control
group was four of 94 (4.3%) (P=0.0001) (Table 1). |
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Table 1: Neonatal Complications. |
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| Discussion |
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| In 1996 ACOG’s published the recommendation to confirm fetal
maturity before elective delivery prior to 39 weeks gestation [1]. The
validity of this recommendation was demonstrated in recent studies.
Stutchfield et al. [7] reported in 2005 that delaying cesarean deliveries
until 39 weeks gestation reduced the rate of admissions to neonatal
special care units due to respiratory distress [7]. However, even when
the ACOG’s recommendation is followed and fetal lung maturity is
documented prior to delivery, a small number of newborns delivered
by elective deliveries before 39 weeks gestation develop respiratory
complications. The risk of such complications is increased among
babies delivered early by planned cesarean section since cesarean
delivery is associated with an increased risk of neonatal respiratory
complications compared with vaginal delivery. Recently Kamath et al.
[2] conducted a retrospective study on neonatal outcomes after elective
cesarean delivery and reported significantly higher rates of respiratory
morbidity, NICU admissions, and longer hospital stay compared to
vaginal birth after cesareans. |
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| The positive predictive value of fetal lung maturity tests is over
95%, [1] however, some test results can be falsely positive. Women with
diabetes, especially when poorly controlled, may have delayed fetal lung
maturation, an increased risk of false fetal lung maturity test results, or
both [1]. In 2002, Moore postulated that fetal pulmonary maturation,
as evidenced by the onset of posphatidylglycerol production in the
amniotic fluid, is delayed in pregnancy complicated by maternal
diabetes by 1 to 1.5 weeks [3]. The possibility of false positive test results
may be even higher in pregnancies complicated by pre-pregnancy
diabetes. The risk of a false positive test may be minimized by avoiding
fetal lung maturity all together: in a recent study, Kjos et al. [8] studied
the rate of Respiratory Distress Syndrome (RDS) among newborns
of diabetic mothers and concluded that routine FLM testing did not
change the prevalence of RDS when pregnancies were reliably dated,
and suggested that such testing be abandoned. They also reported that
cesarean delivery was associated with an increased rate of RDS [8]. |
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| It is possible that the method we used for assessing fetal lung
maturity in these women was responsible for the relatively high number
of newborns with respiratory complications. The algorithm we used
for testing fetal lung maturity was previously described in an earlier
study [4]. It was based on a consensus protocol published by Neehof
and his associates in 2001 [5]. We previously reported that employing
this algorithm for analyzing amniotic fluid samples resulted in a
significant monetary saving [9]. Recently Janicki et al. [6] questioned
the 50,000 lamellar body count thresholds and demonstrated the need
for hematology analyzer specific thresholds. |
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| This was a retrospective cohort study conducted at a single tertiary
care center; nevertheless, it raises concern regarding elective cesarean
deliveries performed prior to 39 weeks gestation, especially in women
with type 1 DM. Similar findings were recently reported by Kamath et al.
[2] who conducted a retrospective study of neonatal outcomes among
non-diabetic mothers who underwent elective cesarean delivery. They
observed significantly higher rates of respiratory morbidity, NICU
admissions and longer length of hospital stay compared with newborns
delivered vaginally [2]. It should be noted that we did not study other
potential neonatal complications that may also develop in immature
neonates. |
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| Providing appropriate medical care limits physical and emotional
hardship to newborns and their families and contributes to patient’s
satisfaction. The financial savings associated with avoidance of costs
associated with prolonged care and delayed hospital discharge is an
additional benefit. |
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| Conclusion |
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| Preventing adverse neonatal outcomes is one of the higher priorities
of obstetric care. Our findings emphasize the importance minimizing
the number of elective cesarean deliveries prior to 39 weeks gestation,
especially in women with pre-pregnancy diabetes mellitus. |
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| References |
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- ACOG (1996) American College of Obstetrics and Gynecology ACOG. Educational Bulletin.
- Kamath BD, Todd JK, Glazner JE, Lezotte D, Lynch AM (2009) Neonatal outcomes after elective cesarean delivery. Obstet Gynecol 113: 1231-1238.
- Moore TR (2002) A comparison of amniotic fluid fetal pulmonary phospholipids in normal and diabetic pregnancy. Am J Obstet Gynecol 186: 641-650.
- Ventolini G, Neiger R, Hood D, Belcastro C (2005) Update on assessment of fetal lung maturity. J Obstet Gynaecol 25: 535-538.
- Neerhof MG, Dohnal JC, Ashwood ER, Lee IS, Anceschi MM (2001) Lamellar body counts: a consensus on protocol. Obstet Gynecol 97: 318-320.
- Janicki MB, Dries LM, Egan JF, Zelop CM (2009) Determining a cutoff for fetal lung maturity with lamellar body count testing. J Matern Fetal Neonatal Med 22: 419-422.
- Stutchfield P, Rhiannon W, Russell I (2005) On behalf of the Antenatal Steroids for Term Elective Cesarean Section ( ASTECS ) Research Team. BMJ 1-6.
- Kjos SL, Berkowitz KM, Kung B (2002) Prospective delivery of reliably dated term infants of diabetic mothers without determination of fetal lung maturity: comparison to historical control. J Matern Fetal Neonatal Med 12: 433-437.
- Ventolini G, Neiger R, Hood DL, Belcastro MR (2006) Changes in the threshold of fetal lung maturity testing and neonatal outcome of infants delivered electively before 39 weeks gestation: implications and cost-effectiveness. J Perinatol 26: 264-267.
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