Case of the Week #534

O.V. Chursina*, O.L. Malmberg** and A.V. Zvereva**

Affiliations:
* Tula Regional Perinatal Center, Tula, Russia 
**  Medical Group Investment Perinatal Medical Center “Mother and Child”, Moscow, Russia

Posting Dates: April 8 - April 21, 2021

Case Report: A 28-year-old G3P2 woman with no past medical history presents for a routine first trimester ultrasound after spontaneous conception. Prior deliveries had been via caesarean section. There is no family history of inherited diseases.  An ultrasound examination at 11-12 weeks of pregnancy revealed the following findings:

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Image 1
Video 1
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Video 2
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At 20-21 weeks of gestation, we identified the following findings on the fetus located at the upper left corner of image 1 and video 1:

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Our ultrasound examination at 11-12 weeks of pregnancy revealed a dichorionic tetramniotic multiple pregnancy (Image 1, Video 1). Fetus A was associated with placenta 1, located along with anterior wall. The umbilical cord had an unremarkable attachment and contained 3 vessels. Fetus B (Image 2), C (Image 3), and D (Image 4) were supplied by placenta 2, located along the anterior and left lateral walls.  The umbilical cords of Fetuses B, C and D had a common attachment to placenta 2 (Image 5, Video 2). Fetal biometry and ultrasound findings are recorded in Table 1.

Table 1

We diagnosed a dichorionic, tetra-amniotic twins with Fetus B supplying two acardiac Fetuses C and D. The answer is twin reversed arterial perfusion (TRAP) syndrome.  The presence of a single corpus luteum in the right ovary was noted (not shown), which allowed the pregnancy to be regarded as a monozygous dichorionic tetra-amniotic quadruplet.

Follow up ultrasound examination at 14-15 weeks, 17-18 weeks, and 19-20 weeks did not reveal malformations in Fetuses A and B. Their sizes correlated with the gestational age. At the same time, growth of both amorphous fetuses was noted (Image 6).

At 20-21 weeks of gestation, heart chamber enlargements of fetus B was noted, tricuspid insufficiency and a slight accumulation of fluid in the pericardial cavity appeared (Video 3). Ejection fractions of the left and right ventricles were not changed. Overall, amorphous fetuses at this stage were regarded as hemodynamically significant, as expected in TRAP syndrome, and it was decided to carry out a selective reduction of fetuses C and D.

The interstitial laser ablation of the mediastinums of fetuses C and D was successively performed under aseptic conditions with ultrasound guidance. The criterion for the success of the procedure was the absence of blood flow in the major vessels of the acardiac fetuses. After the operation, two developing fetuses were identified in the uterine cavity. Ultrasound evaluation demonstrated that each fetus had cardiac activity with a regular rhythm, a normal amount of amniotic fluid, no structural anomalies, and fetal size corresponding to 20 weeks of gestation. Fetus A had an estimated fetal weight of 332g and a placenta measuring 24mm thick. Fetus B  had an estimated fetal weight of 368g and a placenta measuring 23mm thick.  In the uterine cavity, fetuses C and D measured 126 x 77 mm and 44 x 24 mm, respectively, without blood flow signals in the umbilical cords and internal structures (Image 7).

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Image 7: Amorphous fetuses after vascular coagulation

The patient was discharged in satisfactory condition with local follow up ultrasound examinations at 24-25 weeks, 28-29 weeks, 30-31 weeks and 32-33 weeks. The fetuses were seen to have normal growth (at 30 weeks 1300 g and 1450 g, respectively) and a normal amount of amniotic fluid. Both placentas had a diffusely heterogeneous structure due to small echogenic inclusions. Hemodynamic parameters of both fetuses were within normal limits.

At 32-33 weeks of gestation, intrauterine demise of fetus B was noted. The mother was asymptomatic. The estimated fetal weight was 1488 g. Secondary changes were noted including a double contour of the fetal head and abdomen, and enlarged intestinal loops. The placenta located along the anterior wall was diffusely heterogeneous, measuring 36 mm thick, with degree 2 of maturity. The amount of amniotic fluid was slightly reduced.

The size of fetus A corresponded to 31-32 weeks of gestation with an estimated fetal weight of 1798 g. Cardiac examination revealed a regular rhythm at 146 bpm. The placenta was diffusely heterogeneous, located along the left anterior lateral wall, measuring 35 mm thick, and with degree 2 of maturity. The amount of amniotic fluid was normal.

Amorphous fetuses were visualized, without blood flow in the umbilical cords and internal structures.

C-section was performed considering the prenatal death of fetus B in a pregnant woman with tetraamniotic, dichorionic pregnancy after selective fetocide of two amorphous fetuses. A surviving girl weighed 1800g with APGAR score of 7-8. The stillborn female fetus weighed 1550 g (Image 8). The afterbirth consisted of 2 placentas and closely spaced umbilical cords. The umbilical cords of amorphous fetuses C and D were located closer to the umbilical cord of fetus B. (Fig. 9)

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Image 8: Phenotype of fetuses A, B and C
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Image 9: The appearance and the location of the placentas and umbilical cords

According to the results of the postmortem report, fetal death occurred as a result of hypoxia and acute heart failure. The cause of intrauterine hypoxia was chronic placental insufficiency. Histological examination of the placenta revealed hemorrhages, pseudoinfarctions and edema of the umbilical cord and membranes without signs of inflammation.

The presented observation is undoubtedly an extremely rare pathology. The presence of 2 amorphous fetuses at once with dichorionic twins is a unique situation. This pregnancy posed a significant threat to the condition of the mother and fetuses due to possible complications as a result of multiple pregnancies in general, and because of the presence of reversed arterial perfusion syndrome. Intrauterine intervention (interstitial laser ablation of the mediastinum) made it possible to prevent the growth of amorphous fetuses, avoid decompensation of the donor fetus B in the second trimester of pregnancy and prolong pregnancy up to 32 weeks. Despite the antenatal death of fetus B, the outcome of pregnancy can be generally recognized as favorable: it ended with the birth of one healthy child. At the moment, the girl is 5 months old, growing and developing according to the age group.

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