What is the potential risk of using NSAIDs in the third trimester?

Using NSAIDs (non-steroidal anti-inflammatory drugs) in the third trimester poses a significant risk of premature closure of the ductus arteriosus. The ductus arteriosus is a vital blood vessel in a fetus that connects the pulmonary artery to the aorta, allowing blood to bypass the lungs, which are not yet used for breathing during gestation.

In the later stages of pregnancy, particularly in the third trimester, the use of NSAIDs can inhibit prostaglandin synthesis. Prostaglandins play an important role in maintaining the patency of the ductus arteriosus. When NSAIDs are taken, the decrease in prostaglandin levels may lead to the early closure of this ductus, which can result in serious complications for the fetus, such as pulmonary hypertension and impaired blood flow.

Other potential adverse effects of NSAIDs, such as increased risk of bleeding or heightened nausea, while important considerations in general medication management, do not directly correlate to the critical cardiovascular implications associated with the premature closure of the ductus arteriosus. Enhanced uterine contractions are typically more associated with other classes of medications or procedures. Given these implications, awareness and caution regarding NSAID use in late pregnancy is paramount for fetal safety.