**3. Materials and methods**

A total of 113 fetuses with CH were studied whose outcome was lethal. One hundred and three of them were received over a period of 3 years (2006–2009) and autopsied at the Embryo-Fetopathologic Clinic at the Center for Maternity and Neonatology, Tunis, Tunisia, out of a total of 21,316 births. Ten of the cases were from the Obstetrics and Gynecology Clinic at St. George EAD University Hospital, Plovdiv, Bulgaria, during the year 2016 out of a total of 2104 deliveries. The incidence of fetal hydrocephalus with a lethal outcome (FHLO) in both centers is almost identical—4.8 and 4.9 per 1000 births.

The fetuses are the result of interruption of pregnancy due to medical reasons, spontaneous abortions, and stillbirths. The maternal and fetal data were collected from the obstetric history, and a classical autopsy was performed immediately following the expulsion of the fetus, after authorization for macroscopic and microscopic examination. The autopsy includes observation, biometry of the fetus, and in situ examination of the body cavities. The examination of the brain was performed 6 months later, after conservation with 10% formalin. It began with biometrics, measurement of the biparietal and frontal-occipital diameters, and study of the relationship between ocular distance and eyelid length. After opening the cranial cavity, the meninx, brainstem, cerebellum, cerebral hemispheres, gyrification, and morphology were observed. The biometry of the brain—weight and bitemporal and fronto-occipital diameters of the encephalon, and weight and transverse diameter of the cerebellum—was also studied. The ventricular system was examined by horizontal or vertical hemispheric slices until the central part of the lateral ventricle was opened. The presence, shape, and thickness of corpus callosum were examined. With a linear meter, the ventricular width in the central part was measured. At a width of more than 10 mm, ventricular dilatation was diagnosed as hydrocephalus and at a diameter of over 15 mm—major hydrocephalus. In each study, material was taken for histological examination of the cerebral cortex, cerebellum, brainstem, choroid plexus, and cerebral meninx. SPSS version 19 was used for the interpretation of the data. A descriptive analysis and χ<sup>2</sup> -analysis were used.
