In vitro fertilization pregnancy may cause fetal thymic volume involution: A case-control study

Area of Science:

• Obstetrics and Gynecology
• Fetal Medicine
• Reproductive Endocrinology

Background:

• The impact of assisted reproductive technologies on fetal development remains an area of active research.
• Specifically, the effect of in vitro fertilization (IVF) on fetal thymic volume is not well understood.

Purpose of the Study:

• To compare three-dimensional (3D) fetal thymus volumes between pregnancies conceived via IVF and those conceived spontaneously.
• To investigate potential associations between fetal thymus size and pregnancy complications in IVF cases.

Main Methods:

• A prospective case-control study involving 135 pregnant individuals was conducted.
• Fetal thymus volume was assessed using a virtual organ computer-assisted analysis system with advanced ultrasonography between 18-24 weeks gestation.
• Volumes were compared between IVF and spontaneous pregnancy groups.

Main Results:

• Fetal thymus volume was significantly smaller in the IVF group compared to the spontaneous conception group (p $$ 0.001).
• Pregnancy complications, including non-reassuring fetal health status and need for neonatal intensive care, were more frequent in the IVF group.
• The overall rate of pregnancy complications was significantly higher in the IVF group (p = 0.02).

Conclusions:

• Reduced fetal thymus size may represent a novel fetal complication associated with in vitro fertilization.
• These findings highlight the importance of monitoring fetal development in assisted reproductive technology pregnancies.