The Prenatal Study Of The Development Of Intracranial Structures By Ultrasonography In Fetuses Conceived By Asisted Reproductive Technology

Purpose:1. To evaluate whether assisted reproductive technology(ART) wouldaffect the development of the central nervous system(CNS) or not in fetuses conceived byART, via monitoring the growth and development of intracranial structures of thesefetuses during second-trimester by ultrasonography and analyzing the incidence of CNSmalformations.2. To explore the clinical significance of prenatal diagnosis of absentcavum septum pellucidum(CSP) and cerebellar malformations by ultrasonography.Methods: All singleton pregnant fetuses were selected, who were undergoneprenatal utrasonographic screening during second-trimester and had regular prenatalexaminations in our hospital from January,2010to June,2012. Among these fetuses, therewere427fetuses conceived by ART and32859fetuses conceived naturally. The studywas divided into two parts.1. Seventy-two normal fetuses conceived by ART wereselected as experimental group during second-trimester, named ART group. And201normal fetuses conceived naturally were selected as control group, named NC group. Thewidth of cavum septum pellucidum、transverse diameter of cerebellum(TCD)、 depth ofcisterna magna(CM) and width of lateral ventricle were measured by ultrasonography foreach fetus in each group, respectively. The correlation of each parameter with thegestational age was analyzed and the parameters in two groups were compared.2. Bothfetuses conceived by ART and fetuses conceived naturally with CNS malformationsdiagnosed by ultrasonography were collected. The incidence of CNS malformations wascalculated, respectively and compared. Then the ultrasonographic characteristics ofabsence of CSP and Dandy-walker syndrome were analyzed retrospectively.Results:1. The parameters measured and compared in two groups①ART group:The width of CSP ranged from2.1mm to8.8mm, with a mean data (5.7±1.3)mm; TCD ranged from21.3mm to30.7mm, with a mean data(26.8±1.9)mm; the depth of CM rangedfrom2.1mm to9.0mm, with a mean data(5.4±1.2)mm; the width of lateral ventricle rangedfrom2.8mm to9.7mm, with a mean data(6.2±1.3)mm. Both width of CSP and TCD hadgood correlation to the gestational age(r=0.7841、 P<0.0001, r=0.7698、P<0.0001,respectively). They grew with the advancing gestational age. Neither depth ofCM nor width of lateral ventricle had significant correlation to the gestational age (bothP>0.05).②NC group: The width of CSP ranged from1.6mm to9.2mm, with a mean data(5.9±1.3)mm; TCD ranged from22.2mm to30.3mm, with a mean data(26.7±1.9)mm; thedepth of CM ranged from3.2mm to9.4mm, with a mean data(5.5±1.3)mm; the width oflateral ventricle ranged from2.3mm to9.7mm, with a mean data(6.4±1.5)mm. Both widthof CSP and TCD had a good correlation to the gestational age(r=0.7864、P<0.0001,r=0.6926、P<0.0001,respectively). They grew with advancing gestational age. Neitherdepth of CM nor width of lateral ventricle had significant correlation to the gestational age(both P>0.05).③The parameters in ART group had no significant difference from those inNC group (P>0.05).2. CNS malformations analyzed①In ART fetuses, there were5casesdiagnosed as CNS malformations by ultrasonography. The incidence of CNSmalformations was1.2%(5/427). There were3fetuses diagnosed as absence of CSP and1associated with Dandy-walker malformation(DWM). The other2cases were diagnosed asanencephaly and encephalocele, respectively.②In NC fetuses,296fetuses were diagnosedas CNS malformations. The incidence of CNS malformations was0.9%(296/32859).There were63fetuses diagnosed as absence of CSP and21fetuses were Dandy-walkersyndrome. In these fetuses there were2absent CSP fetuses associated with Dandy-walkersyndrome. The others were anencephaly, encephalocele, choroid plexus cyst, arachnoidcyst, etc.③There was no significant difference for incidence of CNS malformationsbetween ART fetuses and NC fetuses.Conclusions:1. Assisted reproductive technology doesn’t affect the development ofthe central nervous system in fetuses conceived by ART because the intracranial structuresgrew and developed normally in ART fetuses during second-trimester and the incidence ofCNS malformations was almost the same as NC fetuses’.2. CSP and cerebellum areconsidered as essential parts for prenatal evaluations of the fetal central nervous systemduring second-and third-trimester. Absence of CSP is always accompanied by an extremely wide spectrum of fetal neuroanatomic malformations, including prosencephalondiseases, intracranial midline anomalies, etc. While cerebellar malformations alwayspresent as Dandy-walker syndrome. Prenatal screening by ultrasound is of the choice fordetecting these malformations. It has great clinical significance for providing good prenataland postnatal care.