Circumvallate placenta is a rare condition affecting about 1-2% of pregnancies, in which the amnion and chorion fetal membranes essentially "double back" on the fetal side around the edges of the placenta. After delivery, a circumvallate placenta has a thick ring of membranes on its fetal surface. Circumvallate placenta is a placental morphological abnormality associated with increased fetal morbidity and mortality due to the restricted availability of nutrients and oxygen to the developing fetus. Physicians may be able to detect a circumvallate placenta during pregnancy by using an ultrasound. However, in other cases, a circumvallate placenta is not identified until delivery of the baby. Circumvallate placenta can increase the risk of associated complications such as preterm delivery and placental abruption. Occasionally, a circumvallate placenta can also increase the risk of neonatal death and emergency caesarean section. Although there is no existing treatment for circumvallate placenta, physicians can attempt to minimize the effects of complications, if they occur, through frequent fetal monitoring and, if necessary, emergency cesarean section.In a circumvallate placenta, the chorionic plate, which forms the fetal surface of the placenta, tends to be smaller than the basal plate, which forms the maternal surface of the placenta. This results in the elevation of the placental margin and the appearance of an annular shape. The fetal surface is divided into a central depressed zone surrounded by a thickened white ring which is incomplete. The ring is situated at varying distances from the margin, or edges, of the placenta.
In addition to its medical use, testosterone undecanoate is used to improve physique and performance. The drug is a controlled substance in many countries and so non-medical use is generally illicit. Medical dosage
Testosterone undecanoate is used in androgen replacement therapy. It is specifically approved only for the treatment of hypogonadism. As an intramuscular injection, it is administered at a dosage of 1,000 mg once every 12 weeks. Conversely, oral testosterone undecanoate must be taken two or three times a day with food. Side effects
Side effects of testosterone undecanoate include virilization among others. Anaphylaxis
The Reandron 1000 formulation (Nebido in the United States) contains 1,000 mg of testosterone undecanoate suspended in castor oil with benzyl benzoate for solubilization and as a preservative, and is administered by intramuscular injection. As an excipient in Reandron 1000, benzyl benzoate has been reported as a cause of anaphylaxis (a serious life-threatening allergic reaction) in a case in Australia. Bayer includes this report in information for health professionals and recommends that physicians "should be aware of the potential for serious allergic reactions" to preparations of this type. In Australia, reports to the Adverse Drug Reactions Advisory Committee (ADRAC), which evaluates reports of adverse drug reactions for the Therapeutic Goods Administration (TGA), show several reports of allergic reactions since the anaphylaxis case from 2011. Pharmacology
Pharmacodynamics
Testosterone undecanoate is a prodrug of testosterone and is an androgen and anabolic–androgenic steroid (AAS). That is, it is an agonist of the androgen receptor (AR).