Author Information
Bang
N*, Panchbudhe S**, Satia MN***.
(*
Third Year Resident, ** Assistant Professor, *** Professor. Department of
Obstetrics and Gynecology, Seth GS Medical
College & KEM Hospital , Mumbai ,
India
Abstract
These pregnancies are
seen more frequently than in the previous decades due to fertility enhancing
technologies. These have lead to a marked increase in twins and triplets. 77%
of triplets are due to fertility treatment and also as more women are waiting
later in life to attempt pregnancy. Older women have higher chance of multiple
gestation than younger women due to increased level of follicle stimulating
hormone.[1] In this era of
advanced medical technology, although multiple births have improved outcome,
they are still associated with complications. We hereby report a case of
spontaneously conceived monochorionic triamniotic triplet gestation with two
out of three fetuses having multiple abnormalities and poor fetal outcome. The
patient was booked at 17 weeks of gestation with triplet pregnancy with fetus A
anencephalic, fetus B normal and fetus C acardic fetus. This patient was
managed in the antenatal ward, but spontaneously aborted at 23 weeks of
gestation.
Introduction
Multifetal gestation
includes twins, triplets, quadruplets and higher multiples. Spontaneously
conceived triplet gestation is seen in 1 in 8000 pregnancies.[2] The
incidence of multiple births is rising over the last two decades in contrast to
Hellin’s rule which previously existed in nature. The fate of multiple
pregnancy largely depends upon the chorionicity or the type of placentation
whether it is monochorionic, dichorionic or so on. Monochorionic twins are at
additional risk for complications due to placental angioarchitecture such as
severe discordant malformations, twin reversed arterial perfusion sequence
(TRAP), selective intrauterine growth retardation or twin-to-twin transfusion
syndrome. The management is further complicated by presence of abnormal
fetuses. Selective reduction of multifetal pregnancy can be done by
radiofrequency ablation and other modalities. The decision is taken by
comparing the medical risks of multifetal pregnancy, the possible benefits of
multifetal pregnancy reduction and the complex ethical issues regarding
multifetal pregnancy reduction.
Case Report
A 37 year old woman,
married for 9 years, third gravida with previous one full term normal delivery and one abortion presented at
17 weeks of gestation with monochorionic
triamniotic triplet gestation. Her general condition and systemic
examination revealed no abnormality. On per abdominal examination the uterus
was 24 weeks in size with multiple fetal parts felt and there was no uterine
activity. Per vaginal examination revealed that the cervix was closed and
uneffaced. A second trimester ultrasonography (USG) performed was suggestive of
single anterior placenta with fetus A showing absent calvarium and poorly
formed brain tissue above the orbits suggestive of anencephaly of 18 weeks.
Fetus B was also of 18 weeks gestation and appeared normal with no obvious
malformation. Fetus C was of 16 weeks with well developed lower thoracic and
lumbar spine with well developed lower extremities with umbilical artery flow
and with absent heart, upper extremity and skull suggestive of acardiac fetus.
She had come for selective reduction of abnormal fetuses. Fetal Medicine
expert’s opinion was taken in view of above USG findings and she was given the
option of radiofrequency ablation for better survival and prognosis of Twin B.
The patient and relatives were counseled about the advantages, complications
and cost factor of radiofrequency ablation. In view of high cost associated
with the procedure they decided for continuation of the pregnancy. The patient
was advised to follow up regularly in
antenatal clinic and was advised to take hematinics and calcium.
Figure 1. USG picture
showing acardiac fetus.
Figure 2. USG picture
showing anencephalic fetus.
Figure 3. Umbilical
artery flow on Doppler study in acardiac fetus.
Figure 4. USG picture
showing normal fetus with acardiac fetus.
Figure 5. Placental
vascular anastomoses on Doppler flow study.
The patient came in
active labor at 23 weeks of gestation. On examination her general condition was
fair, temperature was normal, pulse was 88 per minute and blood pressure 110/70
mm Hg. An abdominal examination showed a uterus of 28 weeks’ size with multiple
fetal parts felt. There was good uterine activity. Per vaginal examination
revealed that the cervix was 4 cm dilated, 60 percent effaced with first fetus
in complete breech presentation at station zero. Fetus A with anencephaly aborted
spontaneously. It weighed 275 g. Artificial rupture of membranes of the second
sac was done and Fetus B aborted. It weighed 395 g and had no obvious
congenital malformations on external examination. Fetus C got expelled en sac
along with the placenta. It was an acardiac triplet with well developed lower
extremities and thorax and absent skull, heart and upper extremities. Its
weight was 190 g. The placenta was
single with three cords.
Figure 6. Anencephalic fetus.
Figure 7. Acardiac fetus.
Figure 8. Normal fetus.
Discussion
The
type of placentation in multifetal gestation is predictive of many
complications and pregnancy outcome. It
depends upon the type of placentation whether the triplet pregnancy is trichorionic,
dichorionic or monochorionic. Trichorionic triplets have three foetuses with
separate placentas and amniotic cavities. Dichorionic triplets have a singleton
pregnancy with its own placenta along with monochorionic twins. Monochorionic
triplets have three foetuses with one common placenta and three separate
amniotic cavities as was seen in our case. Multiple pregnancy is associated
with higher risks and complications for both mother and babies as compared to
singleton pregnancies. Over 60 percent of twins and almost all higher order
multiples are premature. The expected average duration of pregnancy decreases
with increasing number of foetuses. The average duration of pregnancy is 35
weeks for twins, 32 weeks for triplets and 30 weeks for quadruplet. The risk of
spontaneous loss of entire pregnancy is 8% for twins, 15% for triplets and 25%
for quadruplets.[3] There is
additional risk of complications due to vascular anastomoses such as twin to twin transfusion syndrome and twin
reversed arterial perfusion syndrome, conjoint twins and discordant growth in
monochorionic triplets. The relative
risk of cerebral palsy in triplets is 12.7.[4] The risk of death by the age of one year is
seven times higher in twins and twenty times higher in triplets as compared to
singleton pregnancy.[5] TRAP sequence occurs in 1% of monochorionic
pregnancies and 1 in 35000 pregnancies overall. It has a normally developing
pump twin which supplies blood to the acardiac fetus which lacks functioning
cardiac system. The pump twin is at a very high risk of cardiac failure due to
excessive demand and if not treated, it will die in 50-75% cases. The acardiac
one is a parasitic twin that fails to develop a heart, arms and head and
receives blood supply from the host by means of umbilical cord. Its much like a
fetus –in- fetus, except that the acardiac twin is outside the hosts body.
Acardiac fetus can be of three types depending upon the growth of head and
other identifiable structures. Acardiac acephalus, as was seen in our case
shows failure of head growth. The other
two types are acardiac myelacephalus with partially developed head and
identifiable limbs and acardiac amorphous with no recognizable structure. The
use of radio-ablation needle to coagulate the blood in the acardiac twins
umbilical cord greatly increases the chances of survival of the pump twin to
about 80%. However there are no definitive guidelines in the management of
monochorionic higher order multiple pregnancies. It depends upon many factors
such as available facilities and equipments, financial resources, potential
litigations and patients influence which determines the management protocol.
References
- Lambalk CB, De Koning CH, Braat DD. The endocrinology of dizygotic twinning in the human. Mol Cell Endocrinol 1998; 145(1-2):97-102.
- Benirschke K, Kim CK. Multiple pregnancy. N Engl J Med. 1973; 288(24):1276-84.
- Pharoah PO. Risk of cerebral palsy in multiple pregnancies. Clin Perinatol 2006; 33:301–13.
- Evans MI, Britt DW. Multifetal pregnancy reduction: evolution of the ethical arguments. Semin Reprod Med 2010;28:295–302.
- Multiple gestation: complicated twin, triplet, and high-order multifetal pregnancy. ACOG Practice Bulletin No. 56. American College of Obstetricians and Gynecologists. Obstet Gynecol 2004;104:869–83.
Citation
Bang N, Panchbudhe S, Satia MN. Higher
Order Births with Acardiac and Anencephalic Fetuses with Poor Fetal Outcome.
JPGO 2014 Volume 1 Number 12 Available from: http://www.jpgo.org/2014/12/triplets-with-acardiac-and-anencephalic.html