What is the most significant risk factor for clubfoot?

Choice A reason:

Small for gestational age (SGA) newborns are at risk for respiratory distress syndrome (RDS) and respiratory acidosis because they have immature lungs that produce less surfactant, which is needed to keep the alveoli open and prevent atelectasis. SGA newborns also have less glycogen stores, which can lead to hypoglycemia and impaired oxygen delivery to the tissues.

Choice B reason:

Maternal history of asthma is not a risk factor for RDS or respiratory acidosis in the newborn. Asthma is a chronic inflammatory disorder of the airways that affects the mother, not the fetus. Maternal asthma can cause complications such as preterm labor, preeclampsia, or intrauterine growth restriction, but it does not directly affect the fetal lung development or function.

Choice C reason:

Ventricular septal defect (VSD) is a congenital heart defect that causes a hole in the wall between the ventricles of the heart. This can result in increased pulmonary blood flow and pressure, which can lead to pulmonary edema and heart failure in the newborn. However, VSD does not cause RDS or respiratory acidosis, which are related to lung maturity and surfactant production.

Choice D reason:

Cesarean birth is not a risk factor for RDS or respiratory acidosis in the newborn. Cesarean birth can increase the risk of transient tachypnea of the newborn (TTN), which is caused by delayed absorption of fetal lung fluid. TTN usually resolves within 24 to 48 hours and does not cause a significant acid-base imbalance in the newborn.

Choice A reason:

Maternal/newborn blood group incompatibility is the most common cause of pathologic jaundice, which appears within the first 24 hours of life. This occurs when the mother's antibodies attack the newborn's red blood cells, causing hemolysis and increased bilirubin production. The excess bilirubin causes the yellowish discoloration of the skin and mucous membranes.

Choice B reason:

The absence of vitamin K is not related to jaundice but to hemorrhagic disease of the newborn. Vitamin K is essential for blood clotting and is given to newborns as an injection shortly after birth. Newborns are at risk of vitamin K deficiency because they have low levels of vitamin K in their bodies and breast milk, and their intestinal bacteria are not yet able to synthesize vitamin K.

Choice C reason:

Maternal cocaine abuse can cause many complications for the newborn, such as prematurity, low birth weight, neonatal abstinence syndrome, neurobehavioral problems, and congenital anomalies. However, it is not a direct cause of jaundice in the newborn.

Choice D reason:

Physiologic jaundice is a normal and benign condition that affects about 60% of term newborns. It occurs due to the immature liver's inability to metabolize bilirubin effectively. It usually appears after the first 24 hours of life and peaks around the third or fourth day. It does not require treatment unless the bilirubin level is very high or rising rapidly.