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Isabela Nelly Machado 1,2 and Sílvia Dante Martinez 1 and Ricardo Barini 1
Recommended by K. Chan and N. A. Ginsberg
1, Fetal Medicine Program, Department of Obstetrics and Gynecology, School of Medicine, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
2, Department of Obstetrics and Gynecology, UNICAMP, Rua Alexander Fleming, 101, Cidade Universitária, 13083-970 Campinas, SP, Brazil
Received 29 September 2011; Accepted 18 October 2011
1. Introduction
Anencephaly is a neural tube defect (NTD) caused by a failure of closure in the cranial neuropore between the third and fourth week of gestation (23rd and 26th embryonic day), resulting in the absence of a major portion of the brain, skull, and scalp [1]. The brain lacks part or the entire cerebrum, and the remaining brain tissue is often exposed to injury from amniotic fluid. The precise etiology of anencephaly and other NTDs is unknown; however, socioeconomic status, environmental conditions, and the genetics of both population and familial ancestry are indicated [2-4]. The prenatal detection of anencephaly through the antenatal ultrasound is virtually 100% [5].
After the periconceptional folic acid supplementation, the prevalence of anencephaly-affected pregnancies declined worldwide, but no significant change in prevalence was observed in the subsequent years [6, 7]. Its actual prevalence is estimated in 1/1000 pregnancies [8], but because of the option of pregnancy termination after prenatal diagnosis, the exact incidence is not easily accessed.
Anencephalic newborns are not viable or treatable, and so, it is classified as a lethal neural tube defect. Although stillbirth is a common outcome of fetal anencephaly, some affected fetuses are born alive with a rudimentary brain. Lacking a functioning cerebrum, they are incapable of consciousness and of experiencing pain, although the brain stem may support reflex actions such as breathing, and occasionally responses to sound or touch [8]. Some rudimentary lower brain development is usually present with a small proportion of neonates surviving a few days; however, the timing of death shows marked variation in published records.
The aim of this study was to describe the obstetric and perinatal outcome of a group of pregnancies complicated by an anencephalic fetus, in an attempt to provide obstetricians important tools for a more detailed discussion about prenatal management with the affected families.
2. Materials and Methods
A...