Cytomegalovirus infection and fetal death in one monozygotic twin

Abstract

Congenital cytomegalovirus (CMV) infection is symp-tomatic in approximately 10% of infected neonates and isassociated with clinically significant brain damage andsensorineural hearing loss in almost one-half of those infected[1e3]. In addition, neurologic defects will eventually developin 8e13% of neonates with asymptomatic infections. Theprenatal diagnosis of congenital infection is possible; however,there has been much debate about the value of screening forfetal CMV infections. Although CMV-specific hyper-immunoglobulin therapy is possible for the prevention andtreatment against fetal CMV infections, no prenatal therapy orvaccine is currently available. There is no accurate means topredict the sequelae of primary infections. Up to 2% of allinfants excrete CMV, and attempts to identify and isolate theviral agent are expensive and impractical. Serologic screeningis not recommended by the American College of Obstetriciansand Gynecologists [4]. Screening for prenatal CMV infectionis not mandatory in Taiwan but is performed at the physician’sdiscretion and with the patient’s consent. Therefore, theprenatal suspicion and diagnosis of CMV is an enormousclinical challenge for obstetricians.Primary maternal CMVinfection during pregnancy leads tovertical transmission in around 30e50% of fetuses, and therate of transmission (0.2e1%) is far lower for mothers withsecondary infection relatively [5e7]. Only 10e15% ofnewborns of mothers with primary CMV infection duringpregnancy present the typical clinical findings of congenitalCMV [8e10]. Although the fetuses can be infected by CMVthroughout the whole pregnancy and several studies havesuggested that gestational age at infection has no apparentinfluence on the rate of transmission [11,12], an increased riskof transmission in late gestation was indicated by Bode´us et al[13] and Daiminger et al [14]. Furthermore, a greater risk ofsymptomatic fetal involvement was noted in infectionsoccurring during the first half of the pregnancy or near thetime of conception, whereas infections in the second halfresult in less sequelae [7,11]. The fetal damage is also moresevere in early primary infection than in late infection [7,9].Although all of the factors influencing the severity of CMVinfection are not known, maternal and fetal immune status andviral strain virulence are considered to play a significant role[15]. When CMV affects a twin gestation, both of the twinsusually have clinical or laboratory evidence of infection. Thedata in the literature pertaining to congenital CMVinfection intwins, however, are limited [16e21]. Twin gestations representan interesting model for CMV because of the same maternalinfluence. Moreover, congenital CMV in monozygotic twinshas rarely been reported [17]. Monozygotic twins are geneti-cally identical.We describe a unique case of congenital CMV in a mono-zygotic twin gestation, resulting in the intrauterine demise ofone fetus and the survival of the other fetus without compli-cations. We have followed the survivor for 8 years as of thiswriting. This case offers an opportunity to observe a differentcourse of CMV infection amongst twins.After a period of secondary infertility, a twin pregnancy wasachieved in a 38-year-old woman using clomiphene therapy.Duringtheregularprenatalexamination,shewasshowntohavegestational diabetes mellitus and noted to have the familiarmarker chromosome. Discordant intrauterine growth of thetwins was noted, beginning in the early second trimester, anda difference in the estimated body weight was also recordedbeginning in the late second trimester using ultrasound exami-nation.AlthoughtheDopplerexaminationoftheumbilicalcordflowandamnioticfluidvolumewerewithinnormallimits,afetaldemise was incidentally diagnosed at 36 weeks of gestationduring an ultrasound examination. A low segment cesarean