Total cortisol in amniotic fluid and fetal lung maturation

Area of Science:

• Reproductive Biology
• Endocrinology
• Neonatal Medicine

Background:

• Cortisol plays a crucial role in fetal development and maturation.
• Assessing fetal lung maturity is vital for managing high-risk pregnancies.

Purpose of the Study:

• To investigate the relationship between amniotic fluid cortisol levels and gestational age.
• To explore the correlation between amniotic fluid cortisol and fetal lung maturation indicators.
• To determine if amniotic fluid cortisol can predict post-term pregnancies.

Main Methods:

• Radioimmunoassay was used to measure total cortisol in 48 amniotic fluid samples.
• Samples were collected throughout normal pregnancy stages.
• Correlation analysis was performed with lecithin/sphingomyelin ratio and incidence of respiratory-distress syndrome.

Main Results:

• Cortisol levels were below 40 ng/mL before 34 weeks.
• Mean cortisol levels increased 2.4-fold between 35-40 weeks compared to 20-34 weeks.
• Levels exceeding 120 ng/mL were exclusively found in pregnancies >40 weeks.
• A strong positive correlation (r=0.83) was observed between cortisol and lecithin/sphingomyelin ratio.
• No respiratory-distress syndrome occurred when amniotic fluid cortisol >60 ng/mL.

Conclusions:

• Total amniotic fluid cortisol levels increase with gestational age, particularly after 34 weeks.
• Elevated amniotic fluid cortisol is associated with fetal lung maturation.
• Amniotic fluid cortisol may serve as a biomarker for identifying post-term pregnancies and predicting fetal lung maturity.