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In humans, the circulatory system is different before and after birth. The fetal circulation is composed of the placenta, umbilical blood vessels encapsulated by the umbilical cord, heart and systemic blood vessels. A major difference between the fetal circulation and postnatal circulation is that the lungs are not used during the fetal stage ...
Lastly cardiac output increases to nearly double what it was in utero. All of these cardiovascular system changes result in the adaptation from fetal circulation patterns to an adult circulation pattern. During this transition, some types of congenital heart disease that were not symptomatic in utero during fetal circulation will present with ...
According to a study conducted by Whitcome, et al., lumbar lordosis can increase from an angle of 32 degrees at 0% fetal mass (i.e. non-pregnant women or very early in pregnancy) to 50 degrees at 100% fetal mass (very late in pregnancy). Postpartum, the angle of the lordosis declines and can reach the angle prior to pregnancy.
The primitive heart within the first few days of contraction is best described as a peristaltic pump, however after three days the flow becomes pulsatile. [9] Pulsatile flow plays an important role in vascular remodelling, as flow patterns can affect the mechanotransduction of stress to endothelial cells. [7] [13]
Persistent fetal circulation is a condition caused by a failure in the systemic circulation and pulmonary circulation to convert from the antenatal circulation pattern to the "normal" pattern. Infants experience a high mean arterial pulmonary artery pressure and a high afterload at the right ventricle.
The umbilical artery regresses after birth. A portion obliterates to become the medial umbilical ligament (not to be confused with the median umbilical ligament, a different structure that represents the remnant of the embryonic urachus). A portion remains open as a branch of the anterior division of the internal iliac artery.
Umbilical cord compression can result from, for example, entanglement of the cord, [16] a knot in the cord, [16] or a nuchal cord, [16] (which is the wrapping of the umbilical cord around the fetal neck) [17] but these conditions do not always cause obstruction of fetal circulation. Velamentous cord insertion; Single umbilical artery; Umbilical ...
The unpaired umbilical vein carries oxygen and nutrient rich blood derived from fetal-maternal blood exchange at the chorionic villi.More than two-thirds of fetal hepatic circulation is via the main portal vein, while the remainder is shunted from the left portal vein via the ductus venosus to the inferior vena cava, eventually being delivered to the fetal right atrium.