Keywords
multifetal pregnancy - twin pregnancy - caesarean section - postpartum hemorrhage
Selection of Surgical Technique
Selection of Surgical Technique
Indications of Caesarean Delivery for Twin Pregnancy
Twin pregnancy is associated with increased perinatal mortality than singleton pregnancy
because of complications during birth. Higher rates of adverse perinatal outcome have
been reported for the twin pregnancy at full or near term if born by vaginal (VD)
versus caesarean delivery (CS).[1] But there was no clear evidence of differences between planned VD and CS for maternal
death or serious morbidity (risk ratio [RR] = 0.86, 95% confidence interval [CI]:
0.67–1.11), and there was no significant difference for perinatal or neonatal death
or serious neonatal morbidity between planned VD and CS (RR = 1.15, 95% CI: 0.80–1.67).[2] However, monochorionic, monoamniotic twins are avoided VD because of anxiety for
tangled umbilical cords. Currently, if the operator is not experienced in vaginal
breech delivery, CD is performed even for singleton pregnancy. Additionally, breech–vertex
presentation is capable of occurring interlocking. It is generally performed in planned
CD in which the first twin is in nonvertex presentation. Although there is no evidence
that VD of fetus in vertex presentation weighing less than 1,500 g is associated with
any increased risk of perinatal mortality, planned CD is recommended for low–birth
weight twin and preterm delivery prior to 34 weeks' gestation. If the first twin is
in vertex presentation and fetuses weighing at least 1,500 g or reaching at least
32 weeks' gestation, a low 5-minute Apgar's score occurred less frequently by planned
CS.[3] In twin pregnancy, between 32 0/7 and 38 6/7 weeks of gestation, with the first twin in the vertex presentation, planned CD did
not significantly decrease or increase the risk of fetal or neonatal death or serious
neonatal morbidity, as compared with planned VD.[4] Indications of CD is given in [Table 1].
Table 1
Indications of cesarean delivery for twin pregnancy
|
Chorionicity
|
Monochorionic monoamniotic twin
|
|
Gestational age (wk)
|
<32
|
|
Presentation
|
The first twin in the nonvertex presentation
|
|
Estimated fetal weight (g)
|
<1,500
|
|
Weight discordancy > 25%
|
|
Present of cesarean delivery indications for singleton pregnancy
|
|
Shortage of human resources, materials, and informed consents
|
(Reproduced with permission from Tanigaki S, Iwashita M. Multifetal pregnancy. In:
Hiramatsu Y, Konishi I, Sakuragi N, Takeda S, eds. Mastering the Essential Surgical
Procedures OGS NOW, No.3. Cesarean Section (Japanese). Tokyo: Medical View; 2010:
56–63. Copyright © Medical View).
Timing of Planned CD
Minakami et al reported that the incidence of stillbirth and early neonatal death
gradually declined until 37 to 38 weeks' gestation and then increased. So, limiting
the estimated date of delivery from 37 to 38 weeks may be appropriate in multifetal
pregnancies.[5] Luke reported that in the United States, the lowest fetal death rates in twin pregnancies
occurred at 36 to 37 week's gestation, too.[6] On the other hand, there were significantly many neonates with respiratory disorders
in which those have undergone CD labor before 38 weeks' gestation than those after
38 weeks' gestation.[7] In this article, it is noted that avoiding CD until the onset of labor or until
after 38 weeks' gestation should be considered. As gestational weeks progress, the
risk of preterm delivery is sharply increases. The odds ratio for delivery within
1 week in multifetal pregnancies compared with singleton pregnancies was 5.9 (95%
CI: 5.4–6.5) at 22 weeks' gestation and 13.7 (95% CI: 13.1–14.2) at 33 weeks' gestation.[8] Thus progressing weeks lead to the increasing possibility of emergency CD. In addition,
women pregnant with multifetal pregnancy have significantly greater and more severe
pregnancy-related complications, such as hypertensive disorder of pregnancy, HELLP
syndrome (hemolysis, elevated liver enzymes, low platelet count), cardiomyopathy,
thrombosis, and others. Therefore in multifetal pregnancy, waiting after 38 weeks'
gestation essentially requires close fetal and maternal surveillance to identify if
those pregnancies may benefit to extend a gestational period. It is important to construct
the system that an emergency CD can perform anytime.
The procedure of CD in twin pregnancy shows in [Fig. 1]. The CD does not change in even multifetal pregnancy. Each step after laparotomy
has few tips.
Fig. 1 Surgical steps. The procedures of caesarean section in twin pregnancy. PPH, postpartum
hemorrhage.
In-Depth Explanation
Myometrium Incision—Imaging of Uterine Rotation and Long U-Shaped Incision
In multifetal pregnancy, the uterus strongly leans to the right to put the uterus
which enlarged excessively in a pelvis (dextrorotation). The authors incise myometrium
after a pause, and then the round ligament and center of the uterus were confirmed
as well. There are lots of blood vessels including the cervix of uterus venous plexus
at the lateral wall of uterus that increase the risk of ureter injury ([Fig. 2A]).
Fig. 2 Myometrium incision with imaging of uterine rotation. (Reproduced with permission
from Tanigaki S, Iwashita M. Multifetal pregnancy. In: Hiramatsu Y, Konishi I, Sakuragi
N, Takeda S, eds. Mastering the Essential Surgical Procedures OGS NOW, No.3. Cesarean
Section (Japanese). Tokyo: Medical View; 2010: 56–63. Copyright © Medical View).
At lower uterine segment, transverse incision is used safely in most instances. In
the cases where uterine internal os opened and uterine effacement progressed, an appropriate
myometrial incision line progresses upward. The height of the vesicouterine pouch
may not be at appropriate line ([Fig. 2B]). If the pelvis is too deep and seems to be hard to operate, transverse incision
is performed without detachment of the peritoneum over the vesicouterine pouch.
The multifetal pregnancy has many cases that placenta is located at anterior wall
and may result placenta previa. There are lots of thick blood vessels. Ligation of
these is considered before the myometrium incision.
To extend a myometrium wound using a scissor is recommended after reach out at the
membrane. We insert Pean's forceps between a membrane and a myometrium or pull up
myometrium with a finger without rupture of the membrane. In addition, in case of
rupture of the membrane, the scissor does not injure the fetuses. The incision line
looks like U–shaped, near to V–shaped, and is longer than singleton pregnancy. U-shaped myometrium incision prevents injury to the vascular plexus of the uterine
lateral wall. Then move the scissor forward to the beginning of the round ligament
([Fig. 3]). Once the myometrium wound suturing is done, surprisingly it will not appear curved.
Using a scissor is easy to perform J- or L-shaped incision and can also avoid myoma of the uterus and thick vessels. One has
to learn to extend the wound with the help of finger properly. But in the case of
emergency, using a scissor is not recommended without having usual training.
Fig. 3 U-shaped myometrium incision using a scissor and Pean’s forceps forward to beginning
of the round ligament. (Reproduced with permission from Tanigaki S, Iwashita M. Multifetal
pregnancy. In: Hiramatsu Y, Konishi I, Sakuragi N, Takeda S, eds. Mastering the Essential
Surgical Procedures OGS NOW, No.3. Cesarean Section (Japanese). Tokyo: Medical View;
2010: 56–63. Copyright © Medical View).
Delivery of the First Twin—Is the Fetus Really the First Twin?
The second twin makes the delivery of the first twin difficult. A longer myometrium
incision is helpful. Do not rupture of the membrane immediately when membrane is visible.
In the case of multifetal pregnancy, the membrane which is easy to rupture may be
second twin’s membrane. If the membrane of the second twin is ruptured before the
first twin's delivery, operation of afterward is hard. Therefore, we have a pause,
too. Check the both twins and, if delivery is possible, rupture of that fetus's membrane.
Delivery of the Second Twin—Check the Presentation and Care of Entrapment
After the first twin's delivery, keep the membrane of the second twin. There is always
the risk that the second twin changes the presentation and the upper uterine segment
will clamp down and entrap the second twin.
At first check the presentation of the second twin before rupture of that fetus's
membrane. If the fetus is nonvertex, make intrauterine manipulation to footing presentation.
It is difficult to hold the fetal head, whereas it is easy to hold the foot by palpating
fetus's heel.
If contraction ring may develop the upper uterine segment, a vertical uterine incision
is performed without hesitation. And uterine relaxation with 50 to 100 µg intravenous
nitroglycerine is considered. Because nitroglycerine takes 1 minute until an effect
is given, it is prepared before starting the operation and early decision is necessary.
Warnings
Prevention of Postpartum Hemorrhage
Women with multifetal pregnancy are at increased risk of postpartum hemorrhage (PPH).
As shown in [Table 2], causes of PPH in multifetal pregnancy.
Table 2
Causes of PPH in multifetal pregnancy
|
Uterine atony
|
Hyperextension of uterus
Fatigue of myometrium: long usage of tocolytic agent including of magnesium sulfate
to management preeclampsia
Placenta located in the lower uterine segment: huge size of placenta
|
|
Delay of myometrium suture
|
Delayed placenta delivery
|
|
High risk of complications
|
High risk of disorder of blood coagulation: GT, PIATD, HELLP syndrome, acute fatty
liver
|
Abbreviations: GT, gestational thrombocytopenia; HELLP, hemolysis, elevated liver
enzymes, low platelet count; PIATD, pregnancy-induced antithrombin deficiency; PPH,
postpartum hemorrhage.
(Reproduced with permission from Tanigaki S, Iwashita M. Multifetal pregnancy. In:
Hiramatsu Y, Konishi I, Sakuragi N, Takeda S, eds. Mastering the Essential Surgical
Procedures OGS NOW, No.3. Cesarean Section (Japanese). Tokyo: Medical View; 2010:
56–63. Copyright © Medical View).
Mainly PPH is caused by uterine atony. An oxytocin intravenous infusion or injection
is performed immediately after delivery of the second twin. So oxytocin should be
prepared before starting the CD. Urgent manual removal of placentas causes remained
placenta that can increase the amount of bleeding. After placenta delivery, uterine
posterior wall is confirmed that it does not have the adhesion. Then uterus pulls
up outside of the abdominal cavity ([Fig. 4]). The both uterine arteries are suppressed by the abdominal wall, and the bleeding
from the myometrial wound is reduced. In addition, because bleeding does not accumulate
in the wound, it is easy to get a field of vision and to myometrium suture. But it
is important to train myometrium suture at intra-abdominal space. Because the uterus
is huge or there are severe adhesions around the uterus, uterus cannot pull out the
outside of the abdominal cavity. If hemostasis is insufficient, insertion of a balloon
and gauze is recommended along with suture. Tourniquet technique to suppress uterine
cervix and parametrium is a simple and an effective maneuver ([Fig. 5]).
Fig. 4 Uterus is drawn the outside of the abdominal wall. (Reproduced with permission from
Tanigaki S. Iwashita M. Multifetal pregnancy. In: Hiramatsu Y, Konishi I, Sakuragi
N, Takeda S, eds. Mastering the Essential Surgical Procedures OGS NOW, No.3. Cesarean
Section (Japanese). Tokyo: Medical View; 2010: 56–63. Copyright © Medical View).
Fig. 5 Tourniquet technique. (Reproduced with permission from Dr. Shinji Tanigaki).
All bleeding may not be recognized in the operation field. Blood pressure and heart
rate or shock index(SI; the heart rate/systolic blood pressure) may not show a state
for the massive bleeding. We would like to cautious surgeons from losing the timing
of the blood transfusion.
Risk of Emergency Caesarean Section after Vaginal Delivery
In the vaginal birth of the multifetal pregnancy, emergency CD is necessary for delivery
of the second twin after VD of the first twin. The second twin does not fix in a pelvis
after the prompt delivery of the first twin, then descending umbilical cord, malrotation,
and abnormal presentation may occur. In addition, sustained bradycardia and abruption
of placentae with sudden uterine contraction can be caused. As per literature, 9.45%
of the second twin was performed emergency CD after VD of the first twin.[9] The risk of the second twin performed by emergency CD after VD of the first twin,
that is, vertex-vertex presentation, is approximately 7%. But vertex–nonvertex presentation
becomes higher with approximately 23% as for the risk.[10] The prevalence (low 5-minute Apgar's score, respirator management, and convulsions)
rises for the second twin, if an emergency CD was performed.[9]
