Bang N*, Panchbudhe S**, Satia MN***.
(* Third Year Resident, ** Assistant Professor, *** Professor. Department of Obstetrics and Gynecology, Seth GS
College & KEM Hospital, ) Mumbai,
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. 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.
Multifetal gestation includes twins, triplets, quadruplets and higher multiples. Spontaneously conceived triplet gestation is seen in 1 in 8000 pregnancies. 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.
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.
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. 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. 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. 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.
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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