Beat The Heat SAVE 25% NOW
Medicine (MD/DO)
Anatomy & Embryology
Fetal Circulation
Postnatal Circulation

Master Postnatal Circulation with Picmonic for Medicine

With Picmonic, facts become pictures. We've taken what the science shows - image mnemonics work - but we've boosted the effectiveness by building and associating memorable characters, interesting audio stories, and built-in quizzing.

Postnatal Circulation

Recommended Picmonics

picmonic thumbnail
Fetal Circulation
picmonic thumbnail
Circle of Willis
picmonic thumbnail
Whole Blood Composition
picmonic thumbnail
Patent Ductus Arteriosus

Postnatal Circulation

Infant Circulation-symbol
Postnatal circulation begins when the infant breathes. There is decreased pressure in pulmonary vasculature, which leads to decreased right heart pressure. There is a relatively increased left atrial pressure, which causes the foramen ovale to close. Increased oxygen circulation in the infant leads to decreased prostaglandins, and these two factors result in a closed ductus arteriosus. A PDA can be closed with indomethacin, and the ductus arteriosus can be maintained with prostaglandin administration.
Infant Breathes
Infant Breathing

Immediately after delivery, the infant begins to breathe and cry, leading to lung expansion. It is for this reason mucous/fluid is suctioned from the oral cavity at birth, in order to prevent aspiration.

Decreased Pressure in Pulmonary Vasculature
Down-arrow Pressure-gauge in Lung Vessels

As the lungs expand with inhaled air, pulmonary vascular pressure decreases. This allows more blood flow to the lungs to promote gas exchange.

Decreased Right Heart Pressure
Down-arrow Right Heart Pressure-gauge

As pulmonary vascular pressure decreases, the right heart is no longer pumping against a high pressure system. Thus, right heart pressure is decreased compared to the left heart.

Increased Left Atrial Pressure
Up-arrow Left A-tree Pressure-gauge

As right heart pressure decreases, a disparity in right vs. left heart pressure is created. Comparatively, the left atrial pressure is now of higher pressure than the right atrium. Because of this, there is no longer a gradient for blood to pass into the left heart through the foramen ovale as it used to in the fetus.

Closes Foramen Ovale
Foreman Closing Oval-door

A disparity in atrial pressure leads to increased pressure in the left atrium vs. the right, halting the right-to-left atrial shunting which occured in the fetus. This forces the septum primum against the septum secundum, functionally closing the foramen ovale. In time the septa eventually fuse, leaving a remnant of the foramen ovale, the fossa ovalis.

Increased O2
Up-arrow O2-tank

Inhalation leads to increased oxygen content in left sided cardiac vessels. As the infant is now capable of creating its own oxygen supply, flow from the ductus arteriosus is no longer paramount for supplying the aorta with oxygenated blood. Furthermore, vasoconstriction is induced as higher arterial oxygen content releases endothelin, a local vasoconstrictor.

Decreased Prostaglandins
Down-arrow P-rasta-man

The placenta produces prostaglandins, which maintain prenatal patency of the ductus and, in early gestation, inhibit the ability of the ductus to contract in response to oxygen. The ductus arteriosus itself also produces prostaglandins and nitric oxide-like vasodilators. Postnatally, removal of placental prostaglandin and a decrease in the number of prostaglandin E2 receptors in the ductal wall occurs.

Closed Ductus Arteriosus
Closed-door on Duck Archer

During the postnatal period, final closure of the ductus arteriosus results from increased production of local vasoconstrictors (like endothelin) in response to higher arterial oxygen and decreased prostaglandins.

Open with Prostaglandins
P-rasta-man Opening-door

As prostaglandins are used for maintaining the ductus arteriosus, these are often used in patients with congenital heart defects. In severe congenital defects, the ductus arteriosus is the only way for the fetus to oxygenate tissues postnatally.

Closed with Indomethacin
Indigo-moth-man Closing-door

Indomethacin is an inhibitor of prostaglandin synthesis and is used to close a clinically significant PDA.


Take the Postnatal Circulation Quiz

Picmonic's rapid review multiple-choice quiz allows you to assess your knowledge.

It's worth every penny

Our Story Mnemonics Increase Mastery and Retention

Memorize facts with phonetic mnemonics

Unforgettable characters with concise but impactful videos (2-4 min each)

Memorize facts with phonetic mnemonics

Ace Your Medicine (MD/DO) Classes & Exams with Picmonic:

Over 1,910,000 students use Picmonic’s picture mnemonics to improve knowledge, retention, and exam performance.

Choose the #1 Medicine (MD/DO) student study app.

Picmonic for Medicine (MD/DO) covers information that is relevant to your entire Medicine (MD/DO) education. Whether you’re studying for your classes or getting ready to conquer the USMLE Step 1, USMLE Step 2 CK, COMLEX Level 1, or COMLEX Level 2, we’re here to help.

Works better than traditional Medicine (MD/DO) flashcards.

Research shows that students who use Picmonic see a 331% improvement in memory retention and a 50% improvement in test scores.