Distortions in fetal growth standards

Area of Science:

• Perinatology
• Neonatal research
• Biostatistics

Background:

• Existing fetal growth standards include data from neonates who did not survive.
• These non-survivors are often growth-retarded, potentially skewing standard measurements.
• Maternal bleeding in early pregnancy can be misidentified as the last menstrual period, affecting gestational age assessment.

Purpose of the Study:

• To develop improved fetal growth standards using data exclusively from surviving infants.
• To address and correct for errors in gestational age determination caused by misidentified maternal bleeding.
• To create more accurate and reliable fetal growth references.

Main Methods:

• Analysis of existing fetal growth standards to identify errors.
• Development of new standards using data solely from surviving neonates.
• Application of the probability plot method to differentiate measurement clusters based on gestational age, correcting for misidentified maternal bleeding.

Main Results:

• New fetal growth standards were created using measurements from survivors only.
• The probability plot method successfully separated measurement clusters, identifying and excluding data influenced by misidentified early pregnancy bleeding.
• The new standards exhibit significantly smaller standard deviations around mean values compared to older standards.

Conclusions:

• Revised fetal growth standards based on survivors provide a more accurate representation of typical fetal development.
• Correcting for misidentified last menstrual periods through probability plotting enhances gestational age accuracy.
• The reduced variability in the new standards offers a more precise tool for clinical assessment of fetal growth.