Download Management in pregnancy after 41 weeks of gestation

Archives of Perinatal Medicine 19(2), 101-106, 2013
ORIGINAL PAPER
Management in pregnancy after 41 weeks of gestation
AGATA SZPERA-GOŹDZIEWICZ1, TOMASZ GOŹDZIEWICZ2, MARCIN RAJEWSKI5,
JANA SKRZYPCZAK2, GRZEGORZ H. BRĘBOROWICZ1
Abstract
Objective: The aim of this study is to evaluate pregnancy outcome after 41 weeks, depending on management:
induction of labor or expectant management. Material and methods: We enrolled a total of 81 patients in 41
weeks of gestation. Simple randomization assigned 37 patients to group A (expectant management) and 44 to
group B (active management). There were two protocols for clinical management: induction of labor at 41 g.a.
and expectant management up to 42 g.a. Results: There were 18.18% assisted vaginal births in the case of the
induction of labour compared to 2.78% of births in expectant management group (p = 0.03). The number of
cesarean sections was higher in case of an expectant management, but the difference was not statistically significant. No infant was admitted to the NICU and there were no stillbirth. Conclusions: After 41 weeks of gestation
in low-risk pregnancies expectant management with appropriate fetal surveillance and induction of labor seems
to be the appropriate management.
Key words: induction of labor, postterm pregnancy, cesarean section, stillbirth
Introduction
Induction of labor in developed countries is carried
out in approximately 20% of pregnancies [1]. It is indicated when delivery may be beneficial to either mother
or baby. Generally, it is performed in the case of postterm pregnancy (especially after 41 weeks of gestation),
when continuation of pregnancy increase the risk of neonatal morbidity [2]. However, the best moment of induction remains controversial. Early induction may result in
increased number of failures of the procedure and higher rate of cesarean section. On the other hand, the risk
of complications for both the mother and the fetus/newborn increases with gestational age [3]. Number of induction of labor is increasing rapidly throughout the
world. In the United States in 1990 it was carried out for
9.5% and in 2006 for 22.5% of all pregnancies [4]. Several independent studies showed recently that the risks
of continuing pregnancy after the estimated delivery
term for the fetus [5-10] and for the mother [11-15] is
greater than estimated before. Perinatal mortality (defined as the intrauterine fetal death and early death of
the neonates) at 42 weeks of gestation is two fold higher
than at 40 weeks of gestation (4-7, respectively, compared to 2-3 per 1000 births) and four fold higher in 43
weeks of gestation and a five to seven times in 44 weeks
of gestation [5-7, 16]. These studies also show that the
risk of neonatal morbidity increases significantly after 40
1
2
weeks of gestation [7]. Many serious complications such
as meconium aspiration syndrome, neonatal acidosis,
low Apgar scores, oligohydramnios, macrosomia (which
entails an increased risk of injuries during delivery), is
much more common in infants born after 41 weeks of
pregnancy [17, 18]. Postterm pregnancy is also an independent risk factor for neonatal encephalopathy [19]
and mortality in the first year of life [5, 7]. Too little
attention is often paid to the increased risk of complications in the mother in late pregnancy. This risk is
associated with an increased incidence of cervical dystocia (9-12% compared to 2-7% in pregnancies at term),
severe perineal trauma (third- and fourth-degree perineal
laceration, resulting from the increased incidence of fetal macrosomia and operational vaginal deliveries) and
cesarean section [8, 11, 12]. In addition, the pregnancy
continued beyond 40 weeks is associated with an increased risk of adverse effects on the emotional state of
patients such as strong anxiety and frustration [20].
On the other hand, there is a lot of data suggest that
the full-term infants born between 37+ 0 weeks of gestation and 38 + 6 weeks of gestation are characterized by
increased morbidity and mortality compared to full-term
infants born after 38 + 6 weeks of gestation [21, 22].
The aim of the study is to evaluate the obstetrical
results in pregnancies after 41 weeks, depending on the
Department of Perinatology and Gynecology, Poznan University of Medical Sciences, Poland
Division of Reproduction, Poznan University of Medical Sciences, Poland
102
A. Szpera-Goździewicz, T. Goździewicz, M. Rajewski, J. Skrzypczak, G.H. Bręborowicz
type of management: induction of labor or expectant management.
Material and methods
The research was conducted at the Department of
Perinatology and Gynecology and in the Division of Reproduction of Poznan University of Medical Sciences in
the years 2010-2012. The study was approved by the Bioethics Committee of the Poznan University of Medical
Sciences (No. 964/10). Each patient received detailed information about the study and signed an informed consent
to participate in the project on a properly prepared form.
Enrollment of patients was based on:
1) Determining the estimated date of birth on the basis
of the date of the last menstrual period revised by
CRL measurement during the first ultrasound examination (< 10 weeks gestation).
2) Assessment of general patient’s and fetus’ condition. Only low-risk pregnancies were enrolled.
3) Exclusion the patients with contraindications to induction of labor: the transverse or oblique presentation of the fetus, umbilical cord prolapse, classic caesarean section in history, placenta previa or vasa
previa, suspicion of fetal macrosomia on the basis of
clinical and ultrasound examination, any contraindication to vaginal delivery.
Simple randomization was performed in order to
classify patients into one of the clinical management protocols:
1) Active – administration gel containing prostaglandin
E2 (Prepidil gel) into the vaginal vault or cervical
canal or, where the cervical canal was open, put the
Foley catheter. The next day, in the absence of contractile activity, induction was carried out by oxytocin intravenous infusion until the completion of
delivery.
2) Expectant – waiting for spontaneous uterine contractions and observation of the patient and fetus to
completed 42 weeks of gestation. In the absence of
spontaneous contractile activity before the completed 42 weeks of gestation and the absence of indications for earlier delivery we implemented active
management. During the observation we performed
active supervision of the fetus – CTG tracing was
performed four times a day, the patient was watching the fetal movements and every other day ultrasound examination with Doppler umbilical vessels
and middle cerebral artery assessment and fetal biophysical profile was performed.
We enrolled into the study 81 patients in 41 weeks
of gestation and the same number of patients completed
the study. As a result of simple randomization the group
A (expectant management) consisted of 37 patients,
while group B (active management) was composed of
44 pregnant women. The average age of patients in
the group of expectant management was 28.97 years
(SD = 4.19), and in the group of active management 29.2
years (SD = 5.07). Mean gestational age at admission of
patients into the hospital in group A was 41 weeks +0.77
days (SD = 1.35), whereas in group B 41 weeks +0.45
days (SD = 1.06). The vast majority of patients were
nulliparous in each group (median of parity in each
group was 1 [min. 1, max. 4]) (Table 1).
Each patient had gynecological bimanual examination and ultrasound on admission to the hospital. In
group A median cervical dilatation was 1.0 cm (min 0,
max 3), and vaginal part of the cervix was mainly short
(59.46%) and in 40.54% formed, and in any case was
totally effaced. In Group B, median cervical dilatation
was also 1.0 cm (min 0, max 3), while the most common
form of vaginal part of the cervix was short (65.12%), in
32.56% formed, and in 2.33% was totally effaced.
Table 1. Patient characteristics, clinical and ultrasound examination results on admission to hospital
Expectant management N = 37
Mean, median or %
Active management N = 44
Mean, median or %
41 + 0.77
1.35 day
41 + 0.45
1.06 day
NS
Age (years)
28.97
4.19
29.2
5.07
NS
Dilation (cm)
1; 0-3
1; 0-3
NS
No effacement
40.54%
32.56%
NS
Medium effacement
59.46%
65.12%
NS
0%
2.33%
NS
Parity
Admission to hospital (g.a. + day)
1; 1-4
SD
p
SD
1; 1-4
NS
Cervical effacement:
Totally effacement
USG cervical length (mm)
27.69
8.25
25.62
8.5
NS
Management in pregnancy after 41 weeks of gestation
The average cervical length in transvaginal ultrasound
examination performed on the day of admission into the
hospital was 27.69 mm (SD = 8.25) in group A and 25.62
mm (SD = 8.5) in group B.
All the above features were not statistically different
between groups (Table 1).
The statistical analysis was based on the ShapiroWilk, Mann Whitney, two-sided Fisher and Pearson tests.
The analysis was performed using STATISTICA v. 10
software. The level of statistical significance was p < 0.05.
103
Results
In the group A (group of expectant management)
patients delivered at mean 41 weeks + 3.87 days (SD =
0.41). Regular contractions developed spontaneously 29
patients (77%), the other 8 (23%) needed induction of labour. In 3 cases induction was necessary because of
finished 42 g.a. The following 5 women had interrupted
expectant management due to oligohydramnion or abnormal biophysical test result. Induction was performed
at mean 41 weeks + 3.75 days (SD = 1.04).
Table 2. Delivery and perinatal outcomes of pregnancies after 41 weeks of gestation depend on the management
G.a. + day of delivery
G.a. + day of induction of labour
Induction of labour
Prostaglandin E2
Prostaglandin E2 + Oxytocin
Prostaglandin E2 + Foley
Foley + Oxytocin
Prostaglandin E2 + Foley
+ Oxytocin
Induction of labour
Expectant management
(group B) N = 44
(group A) N = 37
p
Mean, median or % SD or min-max Mean, median or % SD or min-max
41 + 3.87
0.41
41 + 1.97
1.62
p < 0.001
41 + 3.75
1.04
41 + 0.9
1.35
p = 0.005
23%
100%
p < 0.001
37.5%
50%
NS
50%
43.19%
NS
12.5%
0%
NS
0%
4.3%
NS
0%
2.51%
NS
61.11%
36.11%
2.78%
56.82%
25%
18.18%
NS
NS
p = 0.03
Indications
to operative delivery:
– lack of progress of labour
– symptoms of fetal distress
– other
46%
46%
8%
42%
58%
0%
NS
NS
NS
Blood loss during labour (ml)
329
159
343
169
NS
Birth weight (g)
Male
Female
Ap 1’ (median, min-max)
Ap 5’ (median, min-max)
3637
63.89%
36.11%
10
10
426
396
6-10
7-10
3647
52.27%
47.73%
10
10
8-10
10-10
NS
NS
NS
NS
NS
pH UA
BE UA
pH UV
BE UV
7.28
!3.88
7.33
!3.35
0,08
3.57
0.08
3.31
7.26
!4.05
7.32
!4.22
0,09
3.16
0.07
2.66
NS
NS
NS
NS
0%
0%
NS
NS
Spontaneous labour
Cesarean section
Vacuum extractor
NICU admission
Intrauterine fetal death
0%
0%
104
A. Szpera-Goździewicz, T. Goździewicz, M. Rajewski, J. Skrzypczak, G.H. Bręborowicz
Preinduction of labour by prostaglandin E2 led to regular
uterine contractions without necessity of oxytocin infusion in 37.5% (n = 3) of patients. Next 50% of patients
(n = 4) needed following oxytocin infusion. The labour
finished in 61.11% spontaneously, in 36.11% by cesarean
section and in 2.78% by vacuum vaginal delivery. Mean
blood loss was 329 ml (SD = 159 ml). Mean birth weight
of infants was 3637 g (SD = 426 g), males were born more frequently (63.89%) and median Apgar score at 1 and
5 min was 10 points (1'-min 6, max 10, 5'-min 7, max 10).
Acid-base balance assessed in arterial and venous
cord blood after birth show table 2. The assessment of
maternal total blood counts showed no significant disturbances. In one case, the puerperium was complicated by
infection, which was diagnosed on the basis of clinical
symptoms.
In the group of active management (group B) patients delivered at mean 41 weeks + 1.97 days (SD =
1.62). Induction of labor was carried out in all of patients
(which was in line with assumptions) at 41 weeks ± 0.9
days (SD = 1.35). Preinduction of labour by prostaglandin E2 led to regular uterine contractions without necessity of oxytocin infusion in 50% (n = 22) cases. In next
43.19% (n = 19) patients, following oxytocin infusion was
necessary to develop contractions. The labour finished
in 56.82% spontaneously, in 25% by cesarean section and
in 18.18% by vacuum vaginal delivery. Mean blood loss
was 343 ml (SD = 169 ml). Mean birth weight of infants
was 3647 g (SD = 396 g), males were born more frequently (52,27%) and median Apgar score at 1 and 5
minute was 10 points (1'-min 8, max 10, 5'-min 10, max
10). One labour was complicated by post partum hemorrhage – patient required a transfusion of four units
of PRBC and 2 units of plasma.
Patients with active management delivered earlier
than women with expectant management, at 41 g.a. +
1.97 days vs 41 g.a. + 3,87 days, respectively (p < 0.001).
The frequency of cesarean section was higher in the
group of expectant management (36.11%) than in the active management group (25%), however the difference
was not statistically significant. The frequency of assisted vaginal delivery was higher in patients enrolled to
active management (18.18%) than expectant one (2.78%)
(p = 0.03). The indications to operative delivery were: lack
of progress of labour, symptoms of fetal distress and in
one case epileptic seizures. There were no differences in
neonatal outcome between both groups. None of infants
was admitted to neonatal intensive care unit (NICU) and
there was no intrauterine fetal demise. There were no
significant differences also in other factors (Table 2).
Discussion
Regulation of the Polish Minister of Health from
2010 obliges the obstetrician to admission of pregnant
women to the hospital in 41 weeks of pregnancy [23].
What optimal procedure should be implemented in such
a case, the induction of labor or waiting for spontaneous
uterine contractions to 42 weeks of pregnancy?
Induction of labor may be associated even with two
fold higher rate of cesarean sections. In a retrospective
analysis of 7804 pregnant women, induction after 41
weeks of pregnancy was performed in 1020 patients.
The odds ratio of cesarean section was 2.03 at 41 weeks
compared to the induction of labor performed between
37-40 weeks of gestation, and the percentage of operations reached 38.5% [24]. Different results were obtained in a study assessing the induction of labor in the
Scottish population. Stock and colleagues analyzed the
course of 1 271 549 pregnancies in the years 1981-2007.
They compared expectant management with induction
of labor at 37-41 weeks of gestation. For patients in the
41 week of pregnancy induction of labor was associated
with a significantly lower percentage of cesarean and
vaginal operational labours. The odds ratio of cesarean
section in consequence of labor induction was 0.73 compared with expectant management procedure [25]. Cochrane Database contains a meta-analysis of 22 randomized
controlled trials, which also indicates a lower rate of
cesarean delivery for induction of labor (odds ratio 0.89)
[26]. In our study, the percentage of cesarean delivery
was also higher in the case of expectant management
and amounted to 36.11%, compared to the active management (25%), but these differences were not statistically significant. The frequency of operative vaginal delivery was significantly higher in the case of induction of
labor at 41 g.a. (18% vs 2.78%, p = 0.03). The main indications for operating births in each group was fetal distress and the lack of progress of labour.
Expectant management, especially after 41 weeks
of gestation is associated with an increased risk of perinatal mortality, which include the intrauterine death
and neonatal death up to 7 day of life. The results of the
Scottish population analysis indicate that waiting for
spontaneous uterine contractions were significantly
more often associated with perinatal mortality than for
induction of labor (22% vs 7% respectively) [25]. A metaanalysis included in the Cochrane database also shows
the reduction of perinatal mortality in the induction of
labor (odds ratio 0.30) [26]. There was no intrauterine
death of the fetus or newborn death in none of the
groups we studied.
Management in pregnancy after 41 weeks of gestation
We can used prostaglandin E2 or a Foley catheter to
preinduction of labor. Results of a randomized study
analyzing 824 pregnant women (PROBAAT study) who
undergo induction of labor in a median of 40 weeks of
gestation did not show significant benefits of any of the
above methods [28]. The results of our study indicate
mainly the use of Prostaglandins E2 to preinduction of
labor, which often was sufficient to induce regular uterine contractions without oxytocin infusion necessity.
Recommendations of the American Society of Obstetricians and Gynecologists does not indicate the optimal
management with postterm pregnancy. They allow expectant management and induction of labor. In the course of expectant management appropriate supervision
should be carried out by assessing fetal CTG records,
biophysical profile of the fetus and amniotic fluid volume
assessment. If there is evidence of fetal distress or decreased amniotic fluid volume expectant management
should be stopped and induction of labour shoud be carried out [27].
After 41 weeks of gestation in low-risk pregnancies
expectant management with appropriate fetal surveillance and induction of labor seems to be the appropriate
way to proceed. The decision on the method of procedure we may leave to the patient after a detailed discussion of the advantages and disadvantages of each.
References
[1] Mealing N.M., Roberts C.L., Ford J.B. et al. (2009)
Trends in induction of labour, 1998-2007: a populationbased study. Aust. N.Z.J. Obstet. Gynaecol. 49: 599-605.
[2] Gulmezoglu A.M., Crowther C.A., Middleton P. (2006)
Induction of labour for improving birth outcomes for
women at or beyond term. Cochrane Database Syst. Rev.
4: CD004945.
[3] Norwitz E.R., Snegovskikh V.V., Caughey A.B. (2007)
Prolonged pregnancy: when should we intervene? Clin.
Obstet. Gynecol. 50: 547- 57.
[4] Roos N., Sahlin L., Ekman-Ordeberg G. et al. (2010) Ma-
ternal risk factors for postterm pregnancy and cesarean
delivery following labor induction. Acta Obstet. Gynecol.
Scand. 89: 1003-10.
[5] Cotzias C.S., Paterson-Brown S., Fisk N.M. (1999) Pro-
spective risk of unexplained stillbirth in singleton pregnancies at term: population based analysis. BMJ 319:
287-8.
[6] Feldman G.B. (1992) Prospective risk of stillbirth. Obstet. Gynecol. 79: 547-53.
[7] Hilder L., Costeloe K., Thilaganathan B. (1998) Pro-
longed pregnancy: evaluating gestation- specific risks of
fetal and infant mortality. Br. J. Obstet. Gynaecol. 105:
169-73.
[8] Rand L., Robinson J.N., Economy K.E. et al. (2000) Postterm induction of labor revisited. Obstet. Gynecol. 96:
779-83.
105
[9] Yudkin P.L., Wood L., Redman C.W. (1987) Risk of unexplained stillbirth at different gestational age. Lancet 1:
1192-4.
[10] Yoder B.A., Gordon M.C., Barth W.H. Jr. (2008) Late- pre-
term birth: does the changing obstetric paradigm alter the
epidemiology of respiratory complications? Obstet. Gyne-
col. 111: 814-22.
[11] Campbell M.K., Ostbye T., Irgens L.M. (1997) Post-term
birth: risk factors and outcomes in a 10-year cohort of
Norwegian births. Obstet. Gynecol. 89: 543-8.
[12] Alexander J.M., McIntire D.D., Leveno K.J. (2000) Forty
weeks and beyond: pregnancy outcomes by week of gestation. Obstet. Gynecol. 98: 291-4.
[13] Caughey A.B., Musci T.J. (2004) Complications of term
pregnancies beyond 37 weeks of gestation. Obstet. Gy-
necol. 103: 57-62.
[14] Caughey A.B., Stotland N.E., Washington A.E. et al.
(2007) Maternal obstetric complications of pregnancy are
associated with increasing gestational age at term. Am. J.
Obstet. Gynecol. 196: 155. e1-e6.
[15] Caughey A.B., Bishop J. (2006) Maternal complications of
pregnancy increase beyond 40 weeks of gestation in low
risk women. J. Perinatol. 26: 540-5.
[16] Bakketeig L.S., Bergsjo P. (1989) Post-term pregnancy:
magnitude of the problem. [In:] Enkin M., Keirse M.J.,
Chalmers I., (eds.) Effective Care in Pregnancy and Childbirth. Oxford University Press, Oxford.
[17] Doherty L., Norwitz E.R. (2008) Prolonged pregnancy:
when should we intervene? Curr. Opin. Obstet. Gynecol.
20(6): 519-27.
[18] Caughey A.B., Snegovskikh V.V., Norwitz E.R. (2008)
Postterm pregnancy: how can we improve outcomes?
Obstet. Gynecol. Surv. 63: 715-24.
[19] Badawi N., Kurinczuk J.J., Keogh J.M. et al. (1998) Ante-
partum risk factors for newborn encephalopathy: the Western Australian case-control study. BMJ 317: 1549 -1553.
[20] Heimstad R., Romundstad P.R., Hyett J. et al. (2007)
Women’s experiences and attitudes towards expectant
management and induction of labor for post-term pregnancy. Acta Obstet. Gynecol. Scand. 86: 950-6.
[21] Engle W.A., Kominiarek M.A. (2008) Late preterm infants, early term infants, and timing of elective deliveries.
Clin. Perinatol. 35: 325-41.
[22] Reddy U.M., Ko C.W., Willinger M. (2006) ‘Early’ term
births (37-38 weeks) are associated with increased mortality. Am. J. Obstet. Gynecol. 195: S202.
[23] Rozporządzenie Ministra Zdrowia z 23 września 2010 r.
„Standardy postępowania oraz procedury medyczne przy
udzielaniu świadczeń zdrowotnych z zakresu opieki okołoporodowej sprawowanej nad kobietą w okresie fizjologicznej ciąży, fizjologicznego porodu, połogu oraz opieki nad
noworodkiem”.
[24] Ehrenthal D.B., Jiang X., Strobino D. (2010) Labor induc-
tion and the risk of a cesarean delivery among nulliparous
women at term. Obstet. Gynecol.116: 35-42.
[25] Stock S.J., Ferguson E., Duffy A. et al. (2012) Outcomes
of elective induction of labour compared with expectant
management: population based study. BMJ 344: e2838.
[26] Gulmezoglu A.M., Crowther C.A., Meddleton P. (2012)
Induction of labour for improving birth outcomes for
106
A. Szpera-Goździewicz, T. Goździewicz, M. Rajewski, J. Skrzypczak, G.H. Bręborowicz
women at or beyond term. Cochrane Database Syst. Rev.
6: CD004945.
[27] Matthew J. Neff. (2004) ACOG Releases Guidelines on
Management of Post-term Pregnancy. Am. Fam. Physician. 70: 2221-5.
[28] Jozwiak M., Oude Rengerink K., Benthem M. et al. (2011)
Foley catheter versus vaginal prostaglandin E2 gel for
induction of labour at term (PROBAAT trial): an openlabel, randomised controlled trial. Lancet 378: 2095-103.
J
Agata Szpera-Goździewicz
Department of Perinatology and Gynecology
Poznan University of Medical Sciences
60-535 Poznań, Polna 33, Poland
e-mail: [email protected]