A 29-year-old woman, gravida 2, para 0, was hospitalized for abdominal pain in the lower part of the abdomen with no apparent cause at 32+2 weeks of gestation. Ultrasound showed MC triplet gestation with a difference in fetal weight estimates (two fetuses at 32 weeks and the other at 31 weeks). Placental function ranged between grades I and II. The umbilical cord of one fetus was once around the neck. Umbilical artery Doppler and a non-stress test showed no unusual symptoms. No distinct evidence of FFTS was observed during the entire pregnancy. After the woman was diagnosed with threatened premature delivery, she was treated with phloroglucinol for tocolysis and dexamethasone for promoting lung maturation of the three fetuses. The next day, the woman complained of continuous abdominal distension, while her previous abdominal pain was relieved. An ultrasound examination on the fourth day showed two fetuses with a weight estimated for 33 weeks and the other for 32 weeks of gestation. The non-stress test indicated slight abnormality. Therefore, conservative medical care was continuously implemented. At 4:30 am on the fifth day, the three fetal heartbeats stopped and fetal movement ceased. Thereafter, the three deceased fetuses weighted 1700, 2100 and 1800 g when they were delivered by caesarean section.
An external examination showed that fetuses A and C were thin and pale, while fetus B was heavy and red (Figure 1). Observation of the internal organs showed that fetuses A and C suffered anaemic changes (Figure 2(A,C)). However, fetus B presented congestion and haemorrhage of the organs (Figure 2(B)). 
Examination of the MC placenta indicated that the umbilical cord of the recipient performed differently with the donor (Figure 3(A)). All three fetuses shared relatively symmetrical triple placental portions of the single placental disc. Two types of vascular anastomoses, including arterio-arterial anastomosis (AAA) and arterio-venous anastomosis (AVA), were observed in the placenta (Figure 3(B)). 
Microscopic examination of placental villi showed differences in anaemia and hyperaemia. We observed relatively large and immature villi with interstitial oedema in the anaemic area of the placenta (Figure 4(A,C)). In the hyperaemic area of the placenta, villi were mature with congestive interstitial telangiectasia. Furthermore, syncytiotrophoblast nuclei were degenerated, concentrated and gathered into multi-core nodules (Figure 4(B)). 
Laboratory studies showed that haemoglobin values of the fetuses were 58, 135 and 65 g/L for fetuses A, B and C, respectively.