Open Journal of Obstetrics and Gynecology, 2012, 2, 213-219 OJOG
http://dx.doi.org/10.4236/ojog.2012.23043 Published Online September 2012 (http://www.SciRP.org/journal/ojog/)
Twin gestation: Is induction of labor possible in highly
selected cases?
R. E. Mbu1, J. Fouedjio1, Y. Fouelifack2, J. T. Ngo Batta3, F. N. Tumasang2, S. N. Ako2,
R. N. Tonye2, M. B. Mbu4, R. J. I. Leke5
1Division Department of Obstetrics and Gynecology, Faculty of Medicine and Biomedical Sciences, University of Yaounde I,
Cameroon and the Maternity Unit, Central Hospital, Yaounde, Cameroon
2Maternity Unit, Central Hospital Yaounde, Yaounde, Cameroon
3Faculty of Medicine and Biomedical Sciences, University of Yaounde I, Yaounde, Cameroon
4Biostatistics and Epidemiology Unit, Ministry of Secondary Education, Yaounde, Cameroon
5Department of Obstetrics and Gynecology, Faculty of Medicine and Biomedical Sciences, University of Yaounde I, Yaounde,
Cameroon
Received 12 April 2012; revised 16 May 2012; accepted 31 May 2012
ABSTRACT
Induction of labor has been in practice for several
decades but the decision to induce labor in multifetal
gestations has not been accepted by many practitio-
ners in contemporary obstetrics. The aim of this
study was to compare maternal and fetal outcomes
among women with uncomplicated twin gestations
who were induced at term and those who were not. It
was a cross-sectional analytic study that lasted ten
years, (1st January 2000 to 31st December 2009 inclu-
sive) at the maternity of the central hospital, Yaounde,
Cameroon. 158 women were enrolled, 79 were in-
duced and 79 went into labor spontaneously. Mater-
nal and fetal outcomes, duration of labor, the preva-
lence of caesarean section were compared in the two
groups. The average age of the women in the groups
was 26, 75 ± 3.65 years (range 15 - 41 years). For
those who were induced, indication was premature
rupture of membranes in 44 (56%) of cases. The
characteristics of induced and none induced women
were similar, except for the number of antenatal
consultations (P ≤ 0.001). There was a significant dif-
ference in the duration of labor in the two groups (6
hrs versus 9, 75 hrs; P ≤ 0.001). The overall rate of
vaginal delivery in the two groups was 87, 97% (n =
139), 88.87% in the group that was induced versus
86.07% in the group that labor was spontaneous (OR
1, 22; 95% IC 0, 51-2, 92; P ≤ 0.90). With respect to
primary outcomes, there were no statistically signifi-
cant differences between the group that labor was
induced and that which labor was spontaneous. The
prevalence of caesarean delivery was similar in the
two groups (10%, 12% vs 13%, 92%; OR 0%, 7%;
95% IC 0, 27-1, 85; P ≤ 0.50). The main indications
for caesarean section were acute fetal distress and
failed induction. The first and fifth minute APGAR
scores less than 7 in the first twins delivered in the
two groups were similar. The 312 children delivered
in both arms did not show any complications at birth.
However, there were 3 neonatal deaths (1 vs 2). There
were no cases of uterine rupture or maternal deaths
among the 156 women. Induction of labor may be
proposed to women with uncomplicated term twin
gestations with specific indications. Induction in these
highly selected cases does not impute any additional
risks but close monitoring of labor is very necessary.
Keywords: Induction; Twins; Rupture
1. INTRODUCTION
Induction of labor denotes artificial provision of uterine
contractions for reasons that may be related to the fetus
or to the pregnant woman with the intention to deliver
the feto-placental unit [1-3]. Induction is usually pro-
grammed at term, at post term or remote from term [3,4].
Rates of induction vary depending on the norms and
procedures elaborated by each health facility but these
rates tend to be on the increase nowadays [5-7]. Some
important aspects to evaluate before induction are the
state of the cervix, fetal weight and the bony pelvis. Spe-
cific paraclinical assessment of the cervix by cervi-
cotonometry that measures the distensibility of the cervix
now exist but simple evaluation using Bishop’s score still
has a place in our daily practice [5,6,8]. Indications for
induction have been of old and have not shown signifi-
cant variation. Obstetric indications include premature
rupture of membranes (PROM), intrauterine fetal demise,
post term, placental abruption among many others that

R. E. Mbu et al. / Open Journal of Obstetrics and Gynecology 2 (2012) 213-219 214
are part of our daily practice. Induction has also been
carried out for medical reasons such as diabetes mellitus
and hypertensive disorders [9-14]. In our context, induc-
tion may follow the request made by the woman, her
husband or family. This approach is in practice in some
developed countries [14]. Contraindications to induction
group all contraindications to normal vaginal delivery
but may be related also to the techniques used. Methods
of induction in a typical developing world setting like
ours are juxtaposed, beginning from mechanical induc-
tion using large capacity Foley’s catheters or laminaria
tents, to surgical induction by amniotomy, membrane
sweeping and to medical induction using oxytocin or
prostaglandins or a combination of two or all these indi-
cations [15-20]. It is common practice to begin with one
method and progress to a combination of methods. Ma-
ternal and fetal monitoring is very important all through
induction irrespective of the method used or grade or
technical level of the maternity where induction is being
carried out [21-23].
For several decades, only singleton pregnancies have
been induced. In our daily practice, the decision to in-
duce twin gestations has not been accepted by many and
a review of the relevant literature does not give us suffi-
cient data to support those who are for or those who are
against. Up to date, studies on the subject have mitigat-
ing conclusions [9-23]. However induction in highly
selected cases of twin gestations may not be specifically
disadvantageous to mothers nor their fetuses.
2. OBJECTIVES
This study was designed to evaluate maternal and fetal
outcomes in highly selected cases of twin gestations
where labor was induced based on the hypothesis that
labor may be the same as in none induced cases that ex-
hibit similar characteristics and are in the same environ-
ment.
3. POPULATION AND METHODS
It was a cross-sectional analytic study that lasted ten
years (1/1/2000-31/12/2009) at the maternity of the
Yaounde Central Hospital, Cameroon. Included were all
consented cases of uncomplicated twin gestations re-
ceived during the study period with or without indica-
tions for induction at term (37 - 42 completed weeks)
and with the first fetus in vertex presentation. 79 of them
who presented with indications for induction were con-
sidered those with risk factors and the comparative group
was made up of an equal number of women with similar
characteristics who went into labor spontaneously. They
were matched for age gravidity and parity.
Complete clinical evaluation was carried out in all the
cases. For those who were induced; we used 5 IU of
oxytocin (Syntocinon®) in 500 ml of 5% glucose inserted
through one of the large veins in the left fore-arm using a
large bore intravenous catheter. We started induction at
10 drops per minute and increased by 5 drops every 30
minutes until there were good contractions (3 contrac-
tions every 10 minutes lasting 40 - 45 seconds). For both
groups, vital signs, fetal heart tones and uterine contrac-
tions were recorded every thirty minutes and vaginal
examination every two hours. These recordings were
transferred to the partogram when cervical dilatation was
four centimeters and monitoring on the partogram con-
tinued until delivery. After delivery of the first twin, we
carried out Leopold’s maneuvers to be able to detect the
position and lie of the second twin and if presentation of
the latter was vertex or breech, we ruptured the mem-
branes and allowed labor to progress. When it was
breech, we applied Mauriceau or Bracht methods for the
aftercoming head following Lovset’s maneuvers. If the
second twin was transverse, we performed podalic ver-
sion and breech extraction. The third stage of labor was
managed actively.
3.1. Variables Compared
Maternal variables were parity, gravidity, duration of
labor, rate of vaginal delivery, the prevalence of caesar-
ean section, post-partum hemorrhage, uterine rupture,
cervical tear. Fetal variables were acute fetal distress,
first and fifth minute Apgar scores and fetal demise.
3.2. Statistical Analysis
Sample size estimation was based on the hypothesis that
normal delivery of twin gestations will reduce the rate of
caesarean deliveries by 50% (Po = 50% × P1). We col-
lected data using a questionnaire that was conceived,
pretested, corrected and adapted for the study. Epi Info
6.04 and Excel 2010 were used for analysis. With 1 in-
duced to 1 none induced case, a period of ten years was
required to recruit 156 cases needed to provide at least
90% power for a two sided test that would detect a
change when the two groups were compared. Associa-
tions were compared using Chi Square test with Yates
correction as applicable for smaller sample sizes. Based
on Woolf’s method, we calculated Odd Ratio with 95%
confidence intervals (95% CI) to measure the effect of
induction on variables
4. RESULTS
Women in their second and fifth pregnancies were more
represented as reported in Table 1 but this difference was
not statistically significant (OR 1.64; 95% IC 0.86 - 3.66;
P = 0.20). Fifty (63.29%) women in the group that was
induced had more than four antenatal consultations as

R. E. Mbu et al. / Open Journal of Obstetrics and Gynecology 2 (2012) 213-219 215
Table 1. Comparison of characteristics of induced versus none induced women.
Characteristics Induced None induced OR 95% IC X2 P
Gravidity 2 - 5 55 46 1.64 0.86 - 3.66 2.22 ≤0.20
Gravidity > 5 14 22 0.56 0.26 - 0.12 2.3 ≤0.20
Parity 2 - 5 63 60 1.25 0.59 - 2.65 0.33 ≤0.90
Parity > 5 11 7 1.66 0.61 - 4.53 1 ≤0.50
Gestational age 37 - 40 SA 76 72 2.46 0.61 - 9.88 1.71 ≤0.20
Gestational age > 40 SA 3 7 0.41 0.1 - 1.65 1.71 ≤0.20
ANC ≤ 4 29 42 0.51 0.27 - 0.96 4.32 ≤0.05
ANC > 4 50 27 3.32 1.73 - 6.37 13.4 ≤0.001
Duration of labor 4 - 8 59 21 8.15 4 - 16.6 36.56≤0.001
Duration of labor > 8 heures 20 58 0.12 0.06 - 0.24 36.56≤0.001
Normal vaginal delivery 68 66 1.22 0.51 - 2.92 0.16 ≤0.90
No maternal complications 64 62 1.77 0.54 - 2.55 0.16 ≤0.90
against 27 (34.18%) in the group that went into sponta-
neous labor (OR 3, 32; 95% IC 1, 73-6, 37; P = 0.001).
Majority of the women (n = 59 or 74.68%) who were
induced had shorter duration of labor (4 - 8 hours) as
against 21 women (26.58%) in the second group and this
difference was statistically significant (OR 8, 15; 95% IC
4-16, 6; P = 0.001). When duration of labor was greater
than 8 hours, women in the group that was not induced
was more represented (P ≤ 0.001).
Table 2 describes maternal and fetal complications
that appeared in equal proportions.
5. DISCUSSION
Maternal and fetal outcomes were evaluated in selected
cases of uncomplicated twin gestations with specific in-
dications for induction of labor. These outcomes were
matched against uncomplicated twin gestations where
labor occurred spontaneously.
Outcome measures that were compared were obstetric
characteristics such as gravidity, parity, gestational age at
induction, number of antenatal consultations, duration of
labor, and mode of delivery. Maternal and fetal compli-
cations were also compared.
A total of 158 women were enrolled, 79 in each arm.
They were aged between 18 - 44 years with an average
age 26, 75 ± 3.65 years. We found this to be in conso-
nance with published data [24]. Eighty (51%, 9%) were
married, 67 (42%, 40%) were of primary level of educa-
tion and equal proportions (42%, 40%) were full time
house wives. As regards past histories, 120 (75%, 94%)
and 126 (79%, 74%) respectively did not present any
medical or obstetric histories that necessitated particular
surveillance.
Premature rupture of membranes (PROM) was the
major indication for induction in 44 (56%) of the 79
women who were induced. Reviewing the relevant lit-
erature, PROM is found to be second to post term gesta-
tions when considering indications for induction of labor
in monofetal and as well as twin gestations [24-27]. Hy-
pertensive disorders of pregnancy have not been reported
in similar studies as indications for induction but 22.78%
(18 cases) of inductions in this series were due to pre-
eclampsia and eclampsia.
In a study carried out in the maternities of France be-
tween 2001 and 2002, 24.8% of inductions were for
medical reasons [28]. Medical indications constituted
15.18% of our inductions. There were 12 cases of post
term gestations and only 5 of them consented to induc-
tion. The rest did not because of fear or uncertainty of
outcome. The decision to induce in twin gestations has
been plagued with fear and uncertainty [28-31].
The women who were induced had a median gravidity
of 3 with extremes of 2 - 7 pregnancies. In the group
where labor was spontaneous, the median gravidity was
4 with extremes of 2 - 7 pregnancies. Though more
women in the gravidity bracket G2-G3 were induced than
those who delivered spontaneously, this observation was
not significant (P ≤ 0.20). Between G2-G5, there was a
greater representation of parturient who were induced,
but again, this was not significant (P ≤ 0.20).
Median parity amongst the induced cases was 2 with
extremes of 2 - 5 and 42 cases were para 1 and 2. These
parities were similar among the women who were not
induced. Parity among women with twin gestations vary.
In some studies median pariy has been reported as 3 t

R. E. Mbu et al. / Open Journal of Obstetrics and Gynecology 2 (2012) 213-219 216
Table 2. Maternal and fetal complications.
Complications Induced None induced OR 95% IC X2 P
PPH 10 13 0.74 0.3 - 1,8 0,46 ≤0.50
Dynamic dystocia 2 4 0.49 0.09 - 2.76 0.69 ≤0.50
Cesarean section (%) 10.12 13.92 0.7 0.27 - 1.85 0.46 ≤0.50
Respiratory distress 1 2 0.5 0.04 - 5.55 0.34 ≤0.90
Asphyxia neonatorium 4 4 1 0.25 - 4.07
with extremes of 2 - 8. It has been reported that twin
gestations are found among women with higher parities
[32,33], but this observation was not noted in this study
In a Japanese study that compared induction and nor-
mal delivery in twin gestations, the average gestational
age at induction was 37 ± 0.4 weeks as against 39 ± 1.1
weeks among those who were not induced. Our average
gestational age at induction was 37 ± 0.9 weeks with
extremes of 37 - 41 weeks. This was a bit much earlier
than the women who were not induced (38 ± 1 week). In
general terms, 70% of women with twin gestations will
deliver between 35 and 37 weeks [33-35]. This differs
from our findings where 93, 7% (n = 148) of the women
had gestational ages that ranged between 37 - 40 weeks
at induction or spontaneous labor, 76 (51.35%) of them
in the group that was induced versus 72 (48.65%) in the
group that was not induced but this did not show any
significant statistical difference (OR 1, 44; 95% IC 0.44-
4.75; P ≤ 0.90).
There is insufficient literature on antenatal care as
concerns twin gestations which are considered high risk.
Majority of the women recruited in both arms were fol-
lowed-up by qualified attendants all through pregnancy.
148 of the 158 women received appropriate antenatal
care, though those who were induced had more antenatal
consultations than those who were not but there was sig-
nificant difference in the number and quality of antenatal
consultations in the two groups (OR 3.32; 95% IC 1.73 -
6.37; P ≤ 0.001). About ten women in the group that was
not induced did not have any antenatal follow-up (P ≤
0.01).
In a case control study of 81 twin gestations where 36
were induced with oxytocin, prostaglandins or laminaria
tents and 45 others delivered without induction, the dura-
tion of labor in the two groups were similar (6.5 ± 2.8 hrs
vs 6 ± 3.6 hrs) [36]. We found a difference in the dura-
tion of labor in the two groups, 6 hrs in the group that
was induced as against 9.75 hrs in the group that was not
induced, a difference of 3.75 hrs (P ≤ 0.001). In a study
carried out over four years but with a smaller sample size
where misoprostol was matched against oxytocin in in-
duction of twin gestations greater than 34 weeks, the
duration of labor in oxytocin group was 15.1 hrs [37].
In twin gestations, the mode of delivery depends on
several factors. These include gestational age at the time
of delivery, pregnancy related complications, states of
the fetuses (intra-uterine growth restriction for example).
In resource restricted settings where personnel do lack in
quantity and quality, vaginal delivery is recommended in
uncomplicated cases [38-40]. In this study, 139 women
(87.97%) delivered normally 68 of them (89.87%) in the
group that was induced and 66 (86.07%) in the group
that was not induced and this slight difference was not
significant statistically (OR 1, 22; 95% IC 0, 51-2, 92;
P≤ 0.90).
In a study carried out in Nigeria over ten months
where maternal outcome was evaluated among 71 women
who bore twin gestations, normal delivery was recorded
in 61.97% of the cases, a percentage we found lower
than what we obtained [39]. Several other studies have
reported vaginal delivery in twin gestations ranging from
68.4% to 82% [41-43]. Though these have all been small
series that used different methods of induction, they have
not shown any differences in the proportions of vaginal
deliveries in induced and none induced cases.
In the absence of induction, rates of cesarean deliver-
ies vary in different countries. In one hospital in Nigeria,
the rate of cesarean delivery was reported as 41.3% [39].
The prevalence of cesarean delivery in this study was
12.09% (10.12% in induced cases versus 13.92% in none
induced cases (OR 0, 7; 95% IC 0, 27-1, 85; P ≤ 0.50).
Similar findings have been reported [44-47].
The main indications for cesarean delivery were fetal
distress, dynamic dystocia, failed induction and retention
of the second twin. Though induction increases the inci-
dence of instrumental deliveries, we did not find any
difference in the proportion of women to whom delivery
was assisted instrumentally in the two groups (OR 1, 52;
95% IC 0, 25-9, 35; P ≤ 0.90).
The first minute APGAR scores for the first twins in
the two groups were better than those of the second twins
in all the 158 twin pairs. These tally with reports from
studies carried out in Nigeria where APGAR scores of
the first twins have been reported to be better than those
of the second twins. In the group that was not induced, 5
out of 79 first twins had poor APGAR scores in the 1st

R. E. Mbu et al. / Open Journal of Obstetrics and Gynecology 2 (2012) 213-219 217
minute and by the 5th minute; there was persistence of
poor APGAR scores in 2 of the twins. The median AP-
GAR score in the 1st minute for the whole study was 8
with extremes of 6 - 10; and in the 5th, the median AP-
GAR score was 9 with extremes of 9 - 10.
At birth, 155 first twins, that is, 98.10% had 1st minute
scores > 7. The prevalence of scores < 7 in the 1st twins
was 1.26% and 2%, 5% respectively for those whose
mothers were induced and those whose mothers were not
induced (P ≤ 0.90). For the second twins, scores < 7 in
the 1st minute were 7.6% and 6.3 % respectively but the
difference was not statistically significant (OR 1.22; 95%
IC 0.36 - 4.17; P ≤ 0.90). Similar studies have reported
no statistically significant differences in scores between
the two groups.
There was no difference in birth weights of twins in
both groups as has have been reported in literature [44].
In all the twin pairs, the average weight of the 1st twin
was 2713 kg ± 500 gm in the women who were induced
as against 2670 kg ± 460 gm in those who were not. For
the 2nd twins, the average weight was 2706 kg ± 510 gm
in induced cases and 2970 kg ± 420 gm in those who
were not induced. These results are like those found in
other reports where average weights of the 1st twins were
found to be 2412 ± 600 g and those of the 2nd twins as
2485 ± 630 g.
We recorded 88.88% live births. As a whole, a greater
proportion of the babies did not present any complica-
tions at birth, 148 (93%, 67%) in the group that was in-
duced versus 145 (91%, 17%) in the group that was not
induced. This difference was not significant statistically
(P ≤ 0.20) as found in a randomized study where induc-
tion was compared to spontaneous delivery in uncompli-
cated twin gestations at 37 weeks [45]. We recorded 8
cases of neonatal hypoxia due to low birth weight (LBW)
and delay in the delivery of the second twin, phenomena
found in twin gestations.
Most of the women 79%, 74% (n = 126) did not pre-
sent with intrapartum complications. There were 23
cases of post partum hemorrhage due to uterine atony, 10
in the group of women who were induced and 13 in the
second group but the difference was not statistically sig-
nificant (OR 0.74; 95% IC 0.3 - 1.8; P ≤ 0.50) similar to
reports of similar studies [46,47]. There were no cases of
uterine rupture.
6. CONCLUSION
Induction of labor in selected cases of twin gestations is
possible even in under privileged situations. If decision
to induce has been reached, maternal and fetal monitor-
ing remains basic in this approach. Induction should be
carried out only in centers with facilities for cesarean
delivery and blood transfusion. Women in this category
do not run special risks when compared to those whose
labor is spontaneous.
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