J Forensic Sci, Sept. 2004, Vol. 49, No. 5 Paper ID JFS2004027 Available online at: www.astm.org Marie-Dominique Piercecchi-Marti, 1,2 M.D., Ph.D.; Pascal Adalian, 1 Ph.D.; Agn` es Liprandi, 3 M.D.; Dominique Figarella-Branger, 3 M.D., Ph.D.; Olivier Dutour, 2 M.D., Ph.D.; and Georges Leonetti, 1,2 M.D., Ph.D. Fetal Visceral Maturation: A Useful Contribution to Gestational Age Estimation in Human Fetuses ABSTRACT: With regard to the law, estimating fetal age is essential to assess viability (after 20 weeks according to the WHO) and the proposed methods generally use long bone measurements. Here, we evaluated the accuracy of soft tissue maturational stage and compared it with long bone measurements. First, eight kinds of tissues or organs from 448 fetuses with known medical history were studied (macroscopically or histologically). We clearly demonstrated that adrenal glands and skin were very good age indicators, because some characteristics appeared only after 20 weeks. We established a linear regression with a 95% confidence interval of +/− 2.9 weeks. Second, we applied our original formula using femur measurement and we combined soft tissues and bones in a multiparametric regression. The confidence interval was reduced to +/− 2.5 weeks. We conclude that the pathologist must use both histological and anthropometric data to determine fetal age as accurately as possible. KEYWORDS: forensic science, fetus, visceral maturation, age estimation, femur Determination of age at death is one of the major preoccupations of forensic medicine. With regard to the French law, fetal age determination is extremely important to assess whether a fetus was or was not medically viable. The World Health Organization has set this viability threshold at 20 weeks gestation. This threshold is now considered as an indispensable juristic condition to qualify a homicide in courts. While age determination methods for adults are somewhat im- precise, those developed for non-matures show interesting deter- mination ranges (1). For fetuses, the proposed age determination methods are quite good but give wide confidence intervals for length of gestation (2). Moreover, some methods suffer from a lack of reli- ability (3). Methods generally take into account macroscopic or ra- diographic examinations, including measurements of body weight, crown-heel length, crown-rump length, length of the foot or of the ossified portion of the long bones (4–7). Each of these parameters is generally used to estimate fetal age by comparison with reference tables or regression equations proposed in the literature. Looking at these references, we observed that histological examination of tissues and organs is rarely done, even though the chronology of fetal tissue development is well established (8,9). This study had a dual purpose: firstly, we wished to determine the maturational level of eight tissues and organs sampled from 448 normal fetuses, on the basis of macroscopic or histological examination. The aim of this part of the study was to assess the usefulness of each tissue or organ in age assessment and especially in situating age around the threshold of 20 weeks. Secondly, we 1 Laboratoire de M´ edecine L´ egale, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France. 2 UMR 6578 CNRS, Universit´ e de la M´ editerran´ ee, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France. 3 Service d’Anatomie Pathologique et de Neuropathologie, CHU Timone, 264 rue Saint-Pierre, 13385 Marseille Cedex 5, France. Received 24 Jan. 2004; and in revised form 24 April 2004; accepted 24 April 2004; published 4 Aug. 2004. compared the estimated gestational age with that obtained by long bone measurement. Material A light microscopic study was performed on normal human fe- tuses ranging from 12 to 40 weeks gestation. Fetuses were chosen from anonymous fetopathological records, and we studied those whose cause of death was identified as in utero death or sponta- neous abortion. More than 2500 of the above-mentioned reports were studied (this sample corresponded to postmortem examina- tions performed between 1997 and 2000), and we selected 448 fetuses that were classified as “normal” according to the same cri- teria applied in our previous studies (10). Gestational age was based on maternal data (last menses: Naegele’s rule) and completed with ultrasound data obtained at 10 weeks gestation (this examination is obligatory under French law). We excluded all cases in which these two methods gave discordant age estimations, as well as those that were too poorly preserved. Methods We obtained seven different histological samples: skin (three samples, from the scalp, hand, and foot), thymus, lungs, thyroid gland, kidneys, and adrenal glands. The central nervous system was only macroscopically observed to estimate gestational age from Fees-Higgins and Larroche’s atlas (11). All samples were fixed in 10% formalin and embedded in paraf- fin; 5 μm sections were stained with hematoxylin-phloxine-safran for light microscopy. The examinations, both microscopic or macroscopic, were done to evaluate the degree of visceral maturation based on knowledge of the developmental chronology of fetal tissue:  Concerning the skin (example in Fig. 1), thymus, lungs (exam- ple in Fig. 3), thyroid and adrenal glands (Fig. 6), we observed Copyright C  2004 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. 1