Once the baby takes the first breath, a number of changes occur in the infant's lungs and circulatory system: Increased oxygen in the lungs causes a decrease in blood flow resistance to the lungs. Blood flow resistance of the baby's blood vessels also increases. Fluid drains or is absorbed from the respiratory system.
What is the process of fetal circulation?
Fetal Circulation. The blood that flows through the fetus is actually more complicated than after the baby is born ( normal heart ). This is because the mother (the placenta) is doing the work that the baby’s lungs will do after birth. The placenta accepts the bluest blood (blood without oxygen) from the fetus through blood vessels...
What happens to the blood that flows through the fetus?
The blood that flows through the fetus is actually more complicated than after the baby is born ( normal heart ). This is because the mother (the placenta) is doing the work that the baby’s lungs will do after birth.
What happens to the baby's heart at birth?
At birth, major changes take place. The umbilical cord is clamped and the baby no longer receives oxygen and nutrients from the mother. With the first breaths of air, the lungs start to expand, and the ductus arteriosus and the foramen ovale both close. The baby's circulation and blood flow through the heart now function like an adult's.
How long does it take for blood to stop flowing afterbirth?
As a consequence, afterbirth, blood begins to flow backward from the aorta into pulmonary artery through ductus arteriosus. However, after only a few hours the muscle wall of the ductus arteriosus constricts markedly and within 1-8 days, the constriction is usually sufficient to stop all blood flow.
What happens when a baby's blood pressure increases?
An increase in the baby's blood pressure and a significant reduction in the pulmonary pressures reduces the need for the ductus arteriosus to shunt blood. These changes promote the closure of the shunt. These changes increase the pressure in the left atrium of the heart, which decrease the pressure in the right atrium.
What happens to the lungs after birth?
With the first breaths of life, the lungs begin to expand. As the lungs expand, the alveoli in the lungs are cleared of fluid. An increase in the baby's blood pressure and a significant reduction in the pulmonary pressures reduces the need for the ductus arteriosus to shunt blood. These changes promote the closure of the shunt. These changes increase the pressure in the left atrium of the heart, which decrease the pressure in the right atrium. The shift in pressure stimulates the foramen ovale to close.
What part of the fetus does the blood flow to?
In the fetus, the placenta does the work of breathing instead of the lungs. As a result, only a small amount of the blood continues on to the lungs. Most of this blood is bypassed or shunted away from the lungs through the ductus arteriosus to the aorta. Most of the circulation to the lower body is supplied by blood passing through the ductus arteriosus.
How does blood enter the heart?
Inside the fetal heart: 1 Blood enters the right atrium, the chamber on the upper right side of the heart. When the blood enters the right atrium, most of it flows through the foramen ovale into the left atrium. 2 Blood then passes into the left ventricle (lower chamber of the heart) and then to the aorta, (the large artery coming from the heart). 3 From the aorta, blood is sent to the heart muscle itself in addition to the brain. After circulating there, the blood returns to the right atrium of the heart through the superior vena cava. About two thirds of the blood will pass through the foramen ovale as described above, but the remaining one third will pass into the right ventricle, toward the lungs. 4 In the fetus, the placenta does the work of breathing instead of the lungs. As a result, only a small amount of the blood continues on to the lungs. Most of this blood is bypassed or shunted away from the lungs through the ductus arteriosus to the aorta. Most of the circulation to the lower body is supplied by blood passing through the ductus arteriosus. 5 This blood then enters the umbilical arteries and flows into the placenta. In the placenta, carbon dioxide and waste products are released into the mother's circulatory system, and oxygen and nutrients from the mother's blood are released into the fetus' blood.
What is the purpose of shunts?
The purpose of these shunts is to bypass certain body parts ? in particular, the lungs and liver ? that are not fully developed while the fetus is still in the womb. The shunts that bypass the lungs are called the foramen ovale, which moves blood from the right atrium of the heart to the left atrium, and the ductus arteriosus, ...
How does the fetal circulatory system work?
The fetal circulatory system uses two right to left shunts, which are small passages that direct blood that needs to be oxygenated.
What is the umbilical cord?
The fetus is connected by the umbilical cord to the placenta, the organ that develops and implants in the mother's uterus during pregnancy. Through the blood vessels in the umbilical cord, the fetus receives all the necessary nutrition, oxygen, and life support from the mother through the placenta. Waste products and carbon dioxide from ...
How does blood flow to the fetus?
Blood flow in the unborn baby follows this pathway: 1 Oxygen and nutrients from the mother's blood are transferred across the placenta to the fetus through the umbilical cord. 2 This enriched blood flows through the umbilical vein toward the baby’s liver. There it moves through a shunt called the ductus venosus. 3 This allows some of the blood to go to the liver. But most of this highly oxygenated blood flows to a large vessel called the inferior vena cava and then into the right atrium of the heart.
What happens to the blood in the fetal heart?
Here is what happens inside the fetal heart: When oxygenated blood from the mother enters the right side of the heart, it flows into the upper chamber (the right atrium). Most of the blood flows across to the left atrium through a shunt called the foramen ovale.
What happens to the umbilical cord at birth?
Then the cycle starts again. At birth, major changes take place. The umbilical cord is clamped and the baby no longer receives oxygen and nutrients from the mother. With the first breaths of air, the lungs start to expand and the ductus arteriosus and the foramen ovale both close.
How is the unborn baby connected to the placenta?
The unborn baby is connected to the placenta by the umbilical cord. All the necessary nutrition, oxygen, and life support from the mother’s blood goes through the placenta and to the baby through blood vessels in the umbilical cord.
What is the placenta during pregnancy?
Since the fetus doesn’t breathe air, their blood circulates differently than it does after birth: The placenta is the organ that develops and implants in the mother's womb (uterus) during pregnancy. The unborn baby is connected to the placenta by ...
Where does the blood flow from the lungs to the placenta?
Instead, it bypasses the lungs and flows through the ductus arteriosus into the descending aorta, which connects to the umbilical arteries. From there, blood flows back into the placenta. There the carbon dioxide and waste products are released into the mother's circulatory system. Oxygen and nutrients from the mother's blood are transferred ...
Where does blood flow to the unborn?
Blood flow in the unborn baby follows this pathway: Oxygen and nutrients from the mother's blood are transferred across the placenta to the fetus through the umbilical cord. This enriched blood flows through the umbilical vein toward the baby’s liver. There it moves through a shunt called the ductus venosus.
What happens when the umbilical cord is cut?
When the umbilical cord is cut, no more blood flows through the umbilical arteries and veins. The remenant of the umbilical vein becomes the round ligament of the liver and the ductus venosus becomes the ligamentum venosum. The umbilical arteries become the medial umbilical ligaments.
What causes the septum primum to close?
The increased left atrial pressure and decreased right atrial pressure (due to decreased pulmonary resistance) forces blood against the septum primum causing the foramen ovale to close. This action functionally completes the separation of the heart into two pumps–right and left sides of the heart.
What changes occur in the fetal circulation after birth?
Changes of fetal circulation after birth (in the newborn) The initial inflation of the lungs causes important changes in the circulatory system. It reduces the resistance to blood flow through the lungs resulting in increased blood flow from the pulmonary arteries. Consequently, an increased amount of blood flows from the right atrium to ...
What is the function of the umbilical vein?
In the fetal circulation system, the umbilical vein transports blood rich in O 2 and nutrients from the placenta to the fetal body. The umbilical vein enters the body through the umbilical ring and travels along the anterior abdominal wall to the liver.
What is the role of maternal blood in the development of a fetus?
Throughout the fetal stage of development, the maternal blood supplies the fetus with O 2 and nutrients and carries away its wastes. These substances diffuse between the maternal and fetal blood through the placental membrane. They are carried to and from the fetal body by the umbilical blood vessels.
Why does blood enter the pulmonary circuit?
Only a small volume of blood enters the pulmonary circuit because the lungs are collapsed, and their blood vessels have a high resistance to flow. This blood is enough to the lung tissue. Most of the blood in the pulmonary trunk bypasses the lungs by entering a fetal vessel called the ductus arteriosus, which connects the pulmonary trunk to ...
Which arteries are affected by increased blood flow?
Consequently, an increased amount of blood flows from the right atrium to the right ventricle and into the pulmonary arteries and less blood flows through the foramen ovale to the left atrium. In addition, an increased volume of blood returning from the lungs through the pulmonary veins to the left atrium, which increases the pressure in ...
What changes take place in the fetal circulation of blood at birth?
In this article we will discuss about the changes that take place in the fetal circulation of blood at birth: 1. Primary Changes in Pulmonary and Systemic Vascular Resistance 2. Closure of the Foramen Ovale 3. Closure of the Ductus Arteriosus 4. Closure of the Ductus Venosus.
Why does the ductus wall close?
The cause of closure is due to increased oxygenation of the blood flowing through the ductus. The degree of contraction of the smooth muscle in the ductus wall is highly related to the availability of O 2. Bradykinin constricts umbilical vessels and ductus arteriosus while dilating the pulmonary vascular bed.
What causes blood to flow backwards through the foramen ovale?
Closure of the Foramen Ovale: The low right atrial pressure and the high left atrial pressure that occur secondarily to the changes in pulmonary and systemic resistances at birth cause blood now to attempt to flow backward through the foramen ovale, i.e. from left atrium into right atrium.
How long does it take for blood to stop flowing through the pulmonary artery?
However, after only a few hours the muscle wall of the ductus arteriosus constricts markedly and within 1-8 days, the constriction is usually sufficient to stop all blood flow. This is called functional closure of the ductus arteriosus. Then, during the next 1-4 months the ductus arteriosus ordinarily becomes anatomically occluded by growth of fibrous tissue into its lumen.
How much portal pressure does the ductus venosus contract?
However, within 1-3 hours, the muscle wall of ductus venosus contract strongly and closes this venue of flow. So, portal venous pressure rises from ‘0’ to 6-10 mm Hg, which is enough to force blood flow through the liver sinuses.
What happens to the blood vessels in the lungs when they are expanded?
Immediately on expansion, these vessels are no longer compressed and the resistance to blood flow decreases several fold . Also in fetal life, the hypoxia of the lungs causes considerable tonic vasoconstriction of the lung blood vessels, but vasodilatation takes place when aeration of the lungs eliminates the hypoxia.
How does loss of blood flow through the placenta affect pulmonary vascular resistance?
This increases the aortic pressure as well as the pressure in the left ventricle and left atrium. Second, the pulmonary vascular resistance greatly decreases as a result of expansion of the lungs.
How does an obstetrician change the umbilical cord?
The obstetrician clamps and cuts the umbilical cord. This is one of the events that signals the astonishing change from fetal circulation to adult circulation. The placental flow stops instantly with the clamping of the cord. The umbilical arteries and vein are now disconnected. Air enters the lungs to expand the sacs, and breathing begins. All this causes blood flow to the lungs to increase as the vascular resistance in the lungs decreases. Pressure in the LA increases while the pressure in the RA decreases. This pressure change between the two atria causes the flaps of muscle around the FO, the hole that served as a shunt between them, to fold in so it functionally closes.
What does it mean when the obstetrician sits at the foot of the bed?
This signifies that the baby had had its first bowel movements in the womb during the stress of the delivery.
What happens to the shunts of the fetal circulation?
The shunts of the fetal circulation, the DV, DA and FO, begin to shut down functionally with that first breath. The inside of each of the two vessels is mostly obliterated by fibrous tissue growth in the first months of life, and they become ligamentous structures.
What is the life support of a baby?
The placenta is the life support of the baby. The kidneys and lungs (as well as digestive and immune systems) do not function at full throttle when the baby is in the womb. The placenta takes on the lion’s share of work for these organs, awaiting their maturation outside the womb.
What is the placenta?
The placenta is the life support of the baby. The transition of a baby from the warm comfort of the womb into this immense, noisy world is nothing short of phenomenal. Adult circulation, which begins when the baby takes its first breath, is very different from fetal circulation. In the womb, the baby, attached to the mother through the placenta, ...
What happens if a baby aspirates into the lungs?
If a baby aspirates this into its lungs it will compromise its breathing, and the transition from the womb to the outside world would be difficult.
Where does the blood return to the body?
The rest of the blood returns from the lungs by way of the pulmonary veins to the LA, then to the LV, which pumps it to the rest of the body, leaving the heart through the aorta. On the final passage, in the terminal aorta, a portion of the blood is diverted to the umbilical arteries, which return it to the placenta to pick up more oxygen and unload its carbon dioxide and other waste products. The other portion continues to the pelvis and lower extremities.
How long do you bleed after giving birth?
Lochia is typically heavier and dark red in color for up to 10 days after giving birth, and then transitions into lighter bleeding or spotting that can last for four to six weeks after delivery. You'll see the difference in the color as this starts to happen, from red to pink, then brown, and finally to a yellowish white.
When should you call your doctor about postpartum bleeding?
You should contact your doctor if you notice any of the following, which could be signs of an infection or another more serious condition such as postpartum hemorrhage:
What is a lochia?
What is postpartum bleeding or lochia? Vaginal postpartum bleeding, or lochia, is the discharge of blood and mucus that starts after delivery. Postpartum bleeding is normal and natural: Your body is ridding itself of all the extra blood, mucus and tissue it needed during pregnancy.
How to stop bleeding after postpartum?
How to safely manage postpartum bleeding. For the first six weeks, use only pads, even if you need pads as thick as your baby's diapers. Don't use tampons, which can introduce bacteria into your still-recovering uterus and genital tract. Continue Reading Below.
What does a lochia smell like?
Lochia that has a foul smell (normal lochia should smell like a normal period) Faintness, breathlessness, dizziness or a racing heart. Nausea or vomiting.
What happens after a baby is born?
After your baby is born, it may seem as though all the symptoms you've been contending with over the last nine months or so will evaporate instantly. But you'll continue to experience a variety of symptoms during the postpartum recovery period, one of which is vaginal bleeding.
Is Lochia longer than menstrual cycle?
Lochia is typically heavier and (often much) longer-lasting than your menstrual cycle. It also has some components that you won't find in a basic menstrual period, like mucus and tissue from your uterus, mostly from where the placenta was attached.
What is fetal circulation?
As the fetus develops within the womb, fetal circulation is established during the early stages of development, allowing the growing fetus to receive the required oxygen and nutrients as well as dispose of waste products. This type of circulation refers to the circulatory system of a fetus which differs from postnatal circulation.
What is the patent ductus arteriosus?
Patent ductus arteriosus- During gestation, the fetal lungs are not inflating and therefore are not oxygenating the blood. The fetus is entirely dependent on the placenta for oxygenated blood (via the umbilical vein). As a result the oxygenated blood must pass from the right side of the heart, to the left side, or from the aorta to the pulmonary trunk (left ventricle outflow to the right ventricle outflow). The ductus arteriosus connects the aorta to the pulmonary trunk. Immediately after birth, the lungs inflate and the ductus arteriosus normally closes shortly after.
What are the three structures that are most important in the transitional circulation?
The three vascular structures most important in the transitional circulation are the ductus venosus, foramen ovale, and ductus arteriosus.
What is the ligamentum arteriosum?
Heart and ligamentum arteriosum in a cadaver: Ductus arteriosus connects the aortic arch with the left pulmonary artery. Once it closes during fetal life, it becomes the ligamentum arteriosum.
What is the difference between postnatal and fetal circulation?
This type of circulation refers to the circulatory system of a fetus which differs from postnatal circulation. Fetal circulation, unlike postnatal circulation, involves the umbilical cord and placental blood vessels which carry fetal blood between the fetus and the placenta. It is usually established in the fetal period ...
What happens when the sphincter contracts?
When the sphincter contracts, more blood is diverted to the portal vein and the hepatic sinusoids, and less to the ductus venosus. Although an anatomic sphincter in the ductus venosus has been described, its presence is not universally accepted.
What is the role of respiration in neonates?
Good respiration in the neonate depends on normal circulatory changes occurring at birth (transitional circulation), which results in oxygenation of the blood in the lungs when fetal blood flow through the placenta ceases. Prenatally, the lungs do not provide gas exchange and the pulmonary vessels are vasoconstricted.
Where does the ductus arteriosus send blood?
The ductus arteriosus sends the oxygen poor blood to the organs in the lower half of the fetal body. This also allows for the oxygen poor blood to leave the fetus through the umbilical arteries and get back to the placenta to pick up oxygen.
Why is the fetus more complicated than the heart?
This is because the mother (the placenta) is doing the work that the baby’s lungs will do after birth.
Where does the blood go when it goes through the placenta?
The placenta accepts the blood without oxygen from the fetus through blood vessels that leave the fetus through the umbilical cord (umbilical arteries, there are two of them). When blood goes through the placenta it picks up oxygen. The oxygen rich blood then returns to the fetus via the third vessel in the umbilical cord (umbilical vein). The oxygen rich blood that enters the fetus passes through the fetal liver and enters the right side of the heart.
What is the hole between the right and left atrium?
The hole between the top two heart chambers (right and left atrium) is called a patent foramen ovale (PFO).
Can a fetus survive a pregnancy?
Since the patent foramen ovale and ductus arteriosus are normal findings in the fetus, it is impossible to predict whether or not these connections will close normally after birth in a normal fetal heart. These two bypass pathways in the fetal circulation make it possible for most fetuses to survive pregnancy even when there are complex heart ...
Where does blood go in a fetus?
Blood coming back from the fetus’s body also enters the right atrium, but the fetus is able to send this oxygen poor blood from the right atrium to the right ventricle (the chamber that normally pumps blood to the lungs). Most of the blood that leaves the right ventricle in the fetus bypasses the lungs through the second of the two extra fetal connections known as the ductus arteriosus.
