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Antidepressants & Birth Defects / Paxil & VSD
Recent studies indicate that Paxil may cause cardiovascular defects in babies' hearts. The FDA has alerted pregnant women who take Paxil (paroxetine) in their first trimester of pregnancy that their babies risk of being born with holes in the heart, (conditions known as atrial and ventricular septal defects), is doubled. According to the FDA, "The early results of two studies showed that women who took Paxil during the first three months of pregnancy were about one and a half to two times as likely to have a baby with a heart defect as women who received other antidepressants or women in the general population. " Most of the heart defects reported in these studies were atrial and ventricular septal defects (holes in the walls of the chambers of the heart). In general, these types of defects range in severity from those that are minor and may resolve without treatment to those that cause serious symptoms and may need to be repaired surgically. A ventricular septal defect (or VSD) is a defect in the ventricular septum (the wall dividing the left and right ventricles of the heart). The ventricular septum consists of a muscular (inferior) and membranous portion (superior). The membranous portion (which is close to the atrioventricular node) is most commonly affected. Congential VSDs are collectively the most common congenital heart defect. Atrial septal defects (ASD) are a group of congenital heart diseases that involve the interatrial septum of the heart. The inter-atrial septum is the tissue that separates the right and left atria from each other. Without this septum, or if there is a defect in this septum, it is possible for blood to travel from the left side of the heart to the right side of the heart, or the other way around, resulting in mixing of arterial and venous blood. Since the right side of the heart contains venous blood with a low oxygen content, and the left side of the heart contains arterial blood with a high oxygen content, it is beneficial to prevent any communication between the two sides of the heart and prevent the blood from the two sides of the heart from mixing with each other. During development of the fetus, the inter-atrial septum develops to eventually separate the left and right atria. The foramen ovale remains open during fetal development to allow blood from the venous system to bypass the lungs and go to the systemic circuation. This is because prior to birth, the oxygenation of the blood is via the placenta and not the lungs. A layer of tissue begins to cover the foramen ovale during fetal development, and will close it completely soon after birth. After birth, the pressure in the pulmonary circulation drops, and the foramen ovale closes. In approximately 30% of adults the foramen ovale does not seal over. In this case, elevation of pressure in the pulmonary circulation (ie: pulmonary hypertension due to various causes, or transiently during a cough) can cause opening of the foramen ovale. This is known as a patent foramen ovale.
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FDA Drug Warning |
