PLACENTA "A", 420 GRAMS (51-75TH PERCENTILE):
The term fetus papyraceus is used to describe a flattened, mummified fetus associated with a viable twin or multiple gestation. Intrauterine fetal demise of a twin after eight weeks gestational age with retention of the fetus for a minimum of 10 weeks results in mechanical compression of the small fetus such that it resembles parchment paper. Prior to eight weeks gestational age the only evidence of an intrauterine death of a twin may be a cyst on the fetal surface of the surviving twin placenta.
The reported incidence is 1:12,000 live births and ranges between 1:184 and 1:200 twin pregnancies. In most cases death occurs in the second trimester between the third and fifth month. Virtually all occur before the seventh month allowing enough intrauterine retention time to elapse in order for mummification to occur. In our case the estimated gestational age at the time of fetal demise was 14 weeks.
The appearance of a calcified fetus or lithopedion may be evident if maturation is advanced. This can occur if there is retention of the fetus for many months beyond the average gestation. It is important to remember that a lithopedion does not need to be a twin. In one reported case, a 94-year-old woman was found to have a lithopedion, probably present for approximately 61 years.
Causative factors have been debated in the literature and in many cases remain unknown. The role of velamentous cord insertion has been postulated. A case of lethal nuchal cord was reported to result in fetus papyraceus. Others have seen this phenomenon occurring more often with monozygotic twin pregnancies versus dizygotic. No association with maternal age, parity nor gravidity has been noted. In our case, a cause was not identified.
In many cases of fetus papyraceus there are no complications to the mother or to the surviving twin, as was the situation described in the case presented here. However, multiple reports have shown that complications can and do occur. The maternal complications include severe unexplained postpartum maternal hemorrhage and maternal infection. Complications to the surviving infant include prematurity, dystocia presentation, intrauterine growth retardation and even death. Congenital anomalies which have been reported include intestinal atresia, gastroschisis, absent ear, aplasia cutis, central nervous system damage and anomalies of the heart. Some or all of these anomalies can be attributed to thrombi or other clotting factors from the dead fetus embolizing to the live twin and producing vascular occlusive lesions.
Because of possible complications, more attention has been paid to the intrauterine diagnosis of fetus papyraceus by serial ultrasound examinations. Signs and symptoms of note which may be present include rapid uterine growth followed by slow or normal growth, vaginal bleeding, acute illness, sudden lower abdominal pain and amniotic fluid leakage. The development or disappearance of toxemia may suggest death of a fetus or necrosis of the placenta.
Contributed by Patricia A. Aronica, M.D. and Dale S. Huff, M.D.