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One theory is that velamentous cord insertion may arise from the process of placental trophotropism, which is the phenomenon where the placenta migrates towards areas which have better blood flow with advancing gestation. The placenta grows in regions with better blood supply and portions atrophy in regions of poor blood flow.
There are three types of vasa praevia. In Type 1, there is a velamentous insertion with vessels crossing the cervix. In Type 2, the placenta is bilobed or has a succenturiate lobe, with unprotected vessels between the lobes. In Type 3, a portion of the placenta overlying the cervix has atrophied, leaving vessels at a margin exposed. [3]
The placenta (pl.: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation.It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal ...
Placental pathology (velamentous insertion, succenturiate lobes, bipartite i.e. bilobed placenta etc.) [13] Baby is in an unusual position: breech (buttocks first) or transverse (lying horizontally across the womb). Placenta praevia is itself a risk factor of placenta accreta. Alcohol use during pregnancy was previously listed as a risk factor ...
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. [1]
The placenta can be defined as an organ formed by the sustained apposition or fusion of fetal membranes and parental tissue for physiological exchange. [1] This definition is modified from the original Mossman (1937) [2] definition, which constrained placentation in animals to only those instances where it occurred in the uterus.
If placenta previa is present at the time of delivery, vaginal delivery is contraindicated because the placenta is blocking the fetus's passageway to the vaginal canal. Herpes simplex virus with active genital lesions or prodromal symptoms is a contraindication for vaginal delivery so as to avoid mother-fetal transfer of HSV lesions.
Studies on the evolution of the placenta have identified a variety of genetic and physiological processes that contribute to the origin and evolution of organs, these include the re-purposing of existing animal tissues, the acquisition of new functional properties by these tissues, and novel interactions of distinct tissue types.