Fetal Stage

Abstract: This report considers the equine intrauterine conceptus from the time of entry from the oviduct as a blastocyst to expulsion as a foal. A series of events involving physical interactions between the uterus and conceptus will be highlighted, and the associated morphologic and physiologic aspects will be considered. Most of the events were discovered and characterized by transrectal ultrasonic imaging and transcervical endoscopic viewing. Certain aspects of the phenomena have been reviewed for embryos,1‐3 fetuses,4 and both stages.5,6 The term embryo is well engrained and will be used in reference to the entire early conceptus.5 The terms embryonic vesicle and embryo proper will also be used when needed to emphasize or distinguish between the entire conceptus and the forerunner of the fetus, respectively. The embryo terms will be used only to Day 39 (Day 0=ovulation). From Day 40 to parturition, the terms fetus or fetal stage will be used. The choice of Day 40 as the transition day facilitates categorizing and discussing the phenomena highlighted in this paper. The beginning of umbilical cord formation, completion of replacement of the yolk sac with the allantoic sac, and the beginning of fetal activity (head nods) are on approximately Day 40. Equine theriogenologists and biologists should be deliberate in using the terms embryo and fetus. For example, the terms embryo mobility versus fetal mobility and embryo reduction versus fetal reduction involve distinctly different mechanisms for embryos versus fetuses.

Abstract: Objective: The transcription factors GATA-1 and GATA-4 have been implicated in the regulation of testicular development and function. Their cofactors FOG-1 and FOG-2 are expressed in the gonads, but their cell-specific and developmental expression in the testis remains unresolved. Therefore, we analyzed GATA-1, GATA-4, FOG-1 and FOG-2 expression in detail, from undifferentiated male urogenital ridge to adult testis. Methods: Immunohistochemistry and in situ hybridization were applied on mouse testicular samples. Results: GATA-4 and FOG-2, but not GATA-1 or FOG-1, were expressed as early as in the male urogenital ridge. FOG-2 expression was localized in the Sertoli cells at embryonal day 12.5 (E12.5), but it diminished with advancing fetal testicular development. In E17.5 testis, FOG-2 was present only in the testicular capsule and a subset of fetal Leydig cells. FOG-1 was expressed from E15.5 Sertoli cells onwards, whereas GATA-1 was not detected during the fetal period at all. In the postnatal testis, FOG-2 was abundantly expressed immediately after birth, but in adult testis its expression was predominantly restricted to stage VII ‐ XII seminiferous tubules. Stage specificity was also found for FOG-1, which, similarly to GATA-1, was abundantly expressed in stage VII ‐ XII tubules during adulthood. Conclusions: Our results indicate that FOG-2, in addition to GATA-4, has a role in early gonadal development and sexual differentiation, and FOG-1 at later fetal stages, while GATA-1 executes its action postnatally. The findings suggest that, in contrast to the hematopoietic system and the heart, GATA-1 and GATA-4 do not use FOG-1 and FOG-2 respectively as their only cofactors during the early stages of testicular development.

Abstract: Objective To characterize the types of genetic abnormalities and their prevalence in early pregnancy loss at different developmental stages. We hypothesized that the prevalence of genetic abnormalities in pregnancy loss would differ across developmental stages. Methods Women with a pregnancy loss at < 20 weeks' gestation (n = 86) were enrolled at the time of diagnosis. Maternal tissue without a fetal component was found in 13 samples. Chromosomal microarray analysis (CMA) was performed on 74 samples (including two samples from a twin pregnancy); 15 were pre-embryonic (no visible embryo on ultrasound examination), 31 were embryonic (embryo; 6 + 0 to 9 + 6 weeks' gestation) and 28 were fetal (fetus; 10 + 0 to 19 + 6 weeks' gestation) losses. The twin pregnancy was found to be monochorionic diamniotic and was subsequently treated as a single sample in our analysis. Nine samples that underwent CMA were excluded from analysis because of 100% maternal-cell contamination. Results The overall prevalence of genetic abnormalities differed across developmental stages (9.1% pre-embryonic, 69.2% embryonic and 33.3% fetal; P < 0.01). This difference persisted when comparing pre-embryonic with embryonic samples (P < 0.01) and embryonic with fetal samples (P = 0.02) but not pre-embryonic with fetal samples (P = 0.12). Additionally, the prevalence of aneuploidy differed significantly across developmental stages (0.0% in pre-embryonic samples vs 65.4% in embryonic samples vs 25.9% in fetal samples, P < 0.001). Abnormalities were most common in embryonic cases, followed by fetal and then pre-embryonic. Maternal cell contamination (MCC) was noted in 47.4% of 46,XX cases assessed. Conclusions Genetic abnormalities detected by CMA are more likely to occur in the embryonic period than in pre-embryonic or fetal stages. MCC is common in early pregnancy loss and should be excluded when results demonstrate a 46,XX karyotype. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Abstract: Fetal intracranial tumors are rare and their evolution is usually poor. With routine use of antenatal ultrasound imaging, a larger number of such tumors have been diagnosed. During the period from January 1992 to January 2002, 18 cases diagnosed as intracranial tumors in the fetal stage were treated in the Neurosurgery and Obstetrics Departments of the Federal University of Sao Paulo and in the Fetal Medicine Service of the Maternity Hospital Santa Joana. The tumors most frequently found were those of the choroid plexus and teratomas. Out of those 18 cases, 11 patients presented with fetal hydrocephalus, and 5 of them, who were less than 34 weeks old (gestational age), underwent repeated cephalocenteses while awaiting better conditions for delivery. Two fetuses died while in utero before any intervention had taken place and 16 underwent craniotomy after birth. Twelve of those patients are still alive, 9 of whom are considered normal. The 3 others are slightly or moderately retarded.