Embryonic morphological development is delayed in pregnancies ending in a spontaneous miscarriage

Area of Science:

• Reproductive Medicine
• Embryology
• Ultrasound Technology

Background:

• Pregnancies ending in miscarriage often exhibit smaller embryos and slower heart rates.
• Early embryonic morphological development is a key indicator of pregnancy viability.

Purpose of the Study:

• To investigate differences in embryonic morphological development between ongoing pregnancies and those ending in miscarriage.
• To assess the association between delayed embryonic development and miscarriage risk.

Main Methods:

• Prospective cohort study of 644 women with singleton pregnancies.
• Serial three-dimensional transvaginal ultrasound scans to assess Carnegie developmental stages.
• Linear mixed models and logistic regression used to analyze data, adjusting for confounders.

Main Results:

• Pregnancies ending in miscarriage showed significantly delayed Carnegie stages (βCarnegie = -0.824, P < 0.001), with a 4.0-day delay in reaching final stages.
• Smaller crown-rump length (CRL) and embryonic volume (EV) were associated with miscarriage (P=0.049 and P=0.027, respectively).
• Each delayed Carnegie stage increased miscarriage odds by 1.5% (ORCarnegie = 1.015, P=0.028).

Conclusions:

• Delayed embryonic morphological development, assessed by Carnegie stages, is a significant predictor of miscarriage.
• Embryonic morphology may serve as a future biomarker for estimating pregnancy viability and risk of recurrent pregnancy loss.
• Timely identification of miscarriage through embryonic development assessment can improve patient counseling and supportive care.