Neonatal Complications at Delivery

The transition from intrauterine to extrauterine life depends on physiologic changes that occur at the time of birth. Most of the time, this happens without difficulty. About 85% of term infants will begin breathing within 30 seconds of life, and 10% will breathe after drying and stimulation, leaving about 5% to need extra intervention (American Academy of Pediatrics [AAP], 2021).

Fetal circulation is unique. Before birth, the placenta provides gas and nutrient exchange for the fetus from the maternal circulation. The blood from the mother and fetus do not mix, so exchange occurs by diffusion (Saha, 2023). Blood is transported between the fetus and the placenta through the umbilical cord, which consists of 2 arteries and 1 vein (Marty et al., 2023).

Image 1:
Cross Section of the Umbilical Cord

The placenta has the lowest vascular resistance and receives 40% of the fetal cardiac output. This leads to low systemic pressure within the circulation. The fetal lungs are filled with fluid and have the highest vascular resistance, receiving less than 10% of the fetal cardiac output.Two right-to-left shunts occur in the fetus because there is high pulmonary vascular resistance and low systemic pressure (Fernandez, 2024; Anthony & McKinlay, 2022). During fetal development, a small opening called the foramen ovale is normally present in the wall between the right and left atria of the heart (Mayo Clinic, 2022). The fetus also has a ductus arteriosus, an artery connecting the aorta and the pulmonary artery. The ductus allows blood to detour away from the lungs before birth (Fernandez, 2024).

Image 2:
Fetal Circulation Anatomy

Blood is oxygenated in the placenta. From the placenta, oxygenated blood flows through the umbilical vein into the fetus's abdomen. The majority of this blood flows through the ductus venosus into the inferior vena cava and then into the right atrium. The oxygenated blood is then shunted from the right atrium to the left atrium. A small amount of blood does flow into the pulmonary artery and lungs. Blood travels to the left ventricle and then enters into the coronary arteries and aorta, bypassing the lungs. The oxygenated blood then enters the fetal systemic circulation (Elshazzly et al., 2023; Anthony & McKinlay, 2022).

Image 3:
Flow of Fetal Circulation

As soon as the newborn has their first cry, breath, or the cord is clamped at delivery, rapid physiologic changes occur for the neonate to have a successful transition. Alveolar fluid clearance must occur for lung aeration. Labor contributes to this change. The initial effective breaths of the neonate create high transpulmonary pressures, which drive out alveolar fluid from the air spaces into pulmonary vasculature. The physical pressure on the infant's chest wall during delivery may also help this process. This fluid is cleared partially within a few minutes and should clear completely within 24 hours.

With the first breath, intrathoracic pressure falls and allows for lung expansion (Fernandez, 2024). When the umbilical cord is clamped, the placenta is removed from neonatal circulation, which causes a rise in neonatal systemic blood pressure. This clamping decreases right-to-left shunting at the ductus arteriosus, which results in increased left-to-right shunting. This shunting creates increased blood flow through the pulmonary arteries and lungs. There is an increased ventricular stroke volume which increases cerebral oxygen saturation. These changes stimulate the closure of the ductus arteriosus (Saha, 2023). While most of the changes occur shortly after birth, the full transition can take up to 6 weeks after birth (Saha, 2023).

At every delivery, there should be at least one provider whose only responsibility is the newborn, and this provider should have the skills to initiate resuscitation. There should also be an immediately available provider to carry out full neonatal resuscitation, including intubation and medications. Equipment needed for resuscitation should also be available at every delivery (AAP, 2021).

The most widely used training program is the neonatal resuscitation program (NRP) which was developed by the American Academy of Pediatrics (AAP) and the American Heart Association (AHA) as a training program teaching principles and skills (AAP, 2021; American Heart Association [AHA], 2023). NRP is appropriate for nurses, doctors, nurse practitioners, and respiratory therapists. Institutions should have a policy that states which staff must have this training (AAP, 2021).

NRP guides the healthcare personnel on how to provide resuscitation as soon as the need is determined. During the first minute of life, all newborns are assessed to determine the need for care. The initial steps are to dry and stimulate the infant, warm the infant (and maintain body temperature), and position the airway and clear secretions. If the baby is term gestation with good tone and breathing or crying, the infant may stay with the mother and continue evaluation. Resuscitation should begin if the infant has apnea, gasping, or a HR below 100 bpm.

NRP teaches an algorithm to be used during resuscitation (AAP, 2021). The algorithm is complex and tells the person using it to warm, dry, and stimulate the infant. Then if the infant is not breathing, is gasping, or has a heart rate < 100, positive pressure ventilation (PPV) should be started. If the PPV does not work, there are steps to do, including repositioning the mask, giving chest compressions, and administering epinephrine. The NRP class teaches the step-by-step algorithm and the skills to perform in order to the most up-to-date evidence based research.

Information regarding the NRP course, the AAP algorithm, as well as access to the NRP materials are available here.

Newborns will be born without complications up to 85% of the time. It is important for nurses who attend births to understand what can cause complications at delivery and how to care for neonates requiring assistance. If a fetus is known to have problems that will complicate delivery, it is best to discuss this case in an interdisciplinary group before delivery. This group can develop a plan and be ready for complications at birth.

• American Academy of Pediatrics. (AAP). (2021). Textbook of Neonatal Resuscitation, (8th Ed). Visit Source.
• American Heart Association. (AHA). (2023). Fetal circulation. American Heart Association (AHA). Visit Source.
• Anthony, R. & McKinlay, C. (2022). Adaptation for life after birth: A review of neonatal physiology. Anaesthesia and Intensive Care Medicine, 24(1), 1-9. Visit Source.
• Elshazzly, M., Anekar, A. A., Shumway, K. R., & Caban, O. (2023). Physiology, newborn. In StatPearls. StatPearls Publishing. Visit Source.
• Fernandez, C. (2024). Physiologic transition from intrauterine to extrauterine life. UpToDate. Retrieved January 31, 2024. Visit Source.
• Mandy, G. (2023a). Overview of short-term complications in preterm infants. UpToDate.  Retrieved January 31, 2024. Visit Source.
• Mandy, G. (2023b). Neonatal complications of multiple births. UpToDate. Retrieved January 31, 2024. Visit Source.
• Marty, M., Kerndt, C., & Lui, F. (2023). Embryology, fetal circulation. In StatPearls. StatPearls Publishing. Visit Source.
• Mayo Clinic. (2022). Patent foramen ovale. Mayo Clinic. Visit Source.
• Saha, U. (2023). Changes in the newborn at birth: Fetal-to-newborn transition. Clinical Anesthesia for the Newborn and the Neonate. Springer, Singapore. Visit Source.