Massive subchorionic thrombohematoma: termination should not be discouraged by antenatal diagnosis

Abstract

Sir, We read the article ‘Massive subchorionic thrombohematoma: a series of 10 cases’ by Fung et al. (1). Massive subchorionic thrombohematoma (MST) was frequently associated with fetal or neonatal death. Women with fetal/neonatal death (n=4) and with living infants (n=6) were delivered at median of 18 and 33 weeks of gestation, respectively (1), which suggests that delivery at an early gestational weeks may lead to a poor outcome, obliging physicians to make a difficult decision as to whether cesarean section (CS) should be performed in early gestation due to the deteriorating fetal condition. In a primiparous woman at 250/7 weeks, ultrasound revealed a subchorionic placental mass (91×57 mm) (Figure 1a). Oligohydramnios and absent umbilical artery endo-diastolic flow were observed. Estimated fetal weight was 400g. Magnetic resonance imaging revealed a large homogeneous mass between the placental parenchyma and the amniotic cavity (Figure 1b). We diagnosed this condition as MST. Fetal weight did not increase and no umbilical artery endo-diastolic flow was present. We informed the parents that fetal death might be imminent but that a fetal weight <500g may prevent intact survival, and they chose CS. At 27+1 weeks, the mother gave birth to an infant weighing 471g with Apgar scores 4/8 (1/5 min). A large thrombohematoma was observed between the chorionic plate and the placenta and was confirmed by histological examination. The baby has been growing well without neurological or respiratory defects. To our knowledge, this case is the earliest gestational week and the lightest weight of a viable infant that ever survived reported in the English literature. Ultrasound (a) and magnetic resonance imaging (b) at the 27th week of gestation. (a) Arrow indicates the homogeneous mass protruding into the amniotic cavity. (b) T2-weighted image indicates homogeneous mass (circled) protruding into the amniotic cavity (right arrow), indicating massive subchorionic thrombohematoma. Left arrow indicates the placenta, which has a more heterogenous density, making it discernible from thrombohematoma (circled). Kojima et al. (2) described a patient with MST: although the fetus showed various clinical signs indicative of fetal compromise similar to our case, termination was not performed and the fetus died in utero in the 32nd week, with a weight of 490g. The presence of MST may have prevented the decision to deliver. Although Fung et al. (1) questioned ‘whether antenatal diagnosis could improve fetal outcome’ in the Introduction, they did not directly answer this. Of 10 patients, eight were prenatally diagnosed and two were not: three (3/8=37%) and one (1/2=50%), respectively, had neonatal or fetal death. They stated, ‘fetal loss risk remains high even if an antenatal diagnosis can be made’. Antenatal diagnosis of MST may make physicians closely observe the patient and may lead to patient transfer to a tertiary center. In this sense, antenatal diagnosis may improve fetal outcome. Conversely, as Kojima et al. (2) illustrated, antenatal diagnosis may make physicians hesitate to decide on terminating the pregnancy, as the poor prognosis of MST has become well known. They ended the article with, ‘it is very difficult to determine a timing of termination in a severe case with MST’ (2). We cannot reach any conclusion regarding the timing of termination from our single experience. However, this case may provide an important clinical perspective. In MST, physicians should not abandon the possibility of infants’ survival even in an earlier gestational week and at a lighter weight. Delivery should not be discouraged. It is then a question which MST discourages delivery and which encourages it, and further study is needed.