The grades of evidence (I-III) and levels of recommendations (A-C) are defined at the end of "Major Recommendations" field.
The following recommendations and conclusions are based on limited or inconsistent scientific evidence (Level B):
- Testing for fetal lung maturity should not be performed, and is contraindicated, when delivery is mandated for fetal or maternal indications.
- Fetal pulmonary maturity should be confirmed before scheduled delivery at less than 39 weeks of gestation unless fetal maturity can be inferred from historic criteria.
- The probability of neonatal respiratory distress syndrome (RDS) is dependent on both the fetal lung maturity test result and the gestational age at which the fetal lung maturity test was performed.
- Fluorescence polarization assays (TDx FLM II) using a defined mature profile of 55 mg/g or greater is appropriate for the determination of risk of neonatal RDS in pregnancies of women with diabetes mellitus.
- Fetal lung maturity test results from amniotic fluid collected vaginally compared with those from fluid collected by transabdominal amniocentesis demonstrate that when results from fluid collected vaginally are mature, the results are reliable.
- Complications from third-trimester amniocentesis for fetal lung maturity are uncommon when performed with ultrasound guidance.
The following conclusions are based primarily on consensus and expert opinion (Level C):
- In general, the same threshold values for fetal lung maturity tests that predict low risk of neonatal RDS in pregnancies of women who do not have diabetes mellitus apply to pregnancies of women who have diabetes mellitus, whether it is gestational diabetes mellitus or pregestational diabetes mellitus.
- Data suggest that amniocentesis of both twins be performed when the gestation is between 30 0/7 weeks and 32 6/7 weeks of gestation. Amniocentesis of one twin appears to be sufficient when gestation is greater than 32 6/7 weeks.
- Prior to elective delivery, fetal lung maturity testing in twins with well defined gestational ages at 38 0/7 weeks or greater may not be necessary.
Definitions:
Grades of Evidence
I: Evidence obtained from at least one properly designed randomized controlled trial.
II-1: Evidence obtained from well-designed controlled trials without randomization.
II-2: Evidence obtained from well-designed cohort or case–control analytic studies, preferably from more than one center or research group.
II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments also could be regarded as this type of evidence.
III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
Levels of Recommendations
Level A - Recommendations are based on good and consistent scientific evidence.
Level B - Recommendations are based on limited or inconsistent scientific evidence.
Level C - Recommendations are based primarily on consensus and expert opinion.
