Final answer:
Persistent oligohydramnios in the second trimester typically carries a poor prognosis due to the high risk of developing complications such as limb contractures and hypoplastic lungs, which can be fatal.
Step-by-step explanation:
Persistent oligohydramnios in the second trimester, regardless of the cause, generally carries a poor prognosis. This condition refers to having too little amniotic fluid, which can result in several complications for the developing fetus such as limb contractures, clubbing of the feet and hands, and potentially fatal hypoplastic lungs. Hypoplastic lungs are underdeveloped lungs that cannot support life effectively, and their development is closely linked to the volume of amniotic fluid surrounding the fetus during pregnancy.
It is important to note that there are varying degrees of oligohydramnios, and in some cases, the situation might be less severe. However, because oligohydramnios can indicate other underlying issues, the prognosis is usually considered to be poorer than normal when it is identified. This is why close monitoring by healthcare professionals is crucial.