Obstetricians often find themselves in clinical situations in which they have to ask the question, “Is delivery indicated for the benefit of the mother and/or fetus, or can this pregnancy be safely continued?” Many clinical scenarios pose risks that can be difficult to predict, even when using our best judgment and tools. Although it is not perfect, antenatal fetal monitoring is one such tool that we use in everyday practice to assess fetal health.1 It can help us to decide to deliver a preterm fetus if compromise is suspected, or reassure us that delivery can be safely delayed.
Amniocentesis for fetal lung maturity (FLM) assessment is another tool in our armamentarium that can help us decide which at-risk fetuses or mothers might be better delivered rather than subjected to continued expectant management. More specifically, if the risk of respiratory distress syndrome (RDS) is low (ie, FLM confirmed), delivery before fetal or maternal complications occurs becomes would be more likely. For example, risk of stillbirth and RDS is higher in patients with poorly controlled pregestational diabetes, making documentation of lung maturity an important management tool. Performing amniocentesis to assess FLM, however, has recently come under strong criticism.
Published in 2013, American College of Obstetricians and Gynecologists (ACOG) Committee Opinion No 560, “Medically Indicated Late-Preterm and Early-Term Deliveries,” reviewed evidence about neonatal morbidities associated with the late preterm (34–36 6/7 weeks) and early-term (37–38 6/7 weeks) pregnancy.2
In addition to major neonatal morbidities (such as RDS, intraventricular hemorrhage, and necrotizing enterocolitis), minor morbidities (such as temperature instability, hyperbilirubinemia, feeding difficulties, and admission to newborn intensive care units) were also considered. The two important and useful purposes that the document served were discouraging elective delivery prior to 39 weeks because of increased neonatal morbidity in these late-preterm and early term deliveries, even when lung maturity was documented and providing guidance and recommendations as to when pregnancies might be delivered in a setting complicated by selected medical or fetal complications.
The authors suggested that “amniocentesis for the determination of lung maturity in well dated pregnancies generally should not be used to guide the time of delivery.”2 However, we believe that the rationales cited were rather simplistic. If a patient needs to be delivered, then she should be delivered, regardless of fetal lung maturity. And if a patient doesn’t need to be delivered, then we should wait.