Endometrial Dynamics and Pregnancy Outcomes in Assisted Reproductive Technologies

The endometrium undergoes a finely tuned sequence of morphological and functional changes under hormonal regulation, creating an implantation window essential for embryo acceptance. In assisted reproductive technologies (ART), variations in endometrial thickness, pattern and vascular perfusion have been shown to influence implantation rates, ongoing pregnancy and neonatal outcomes. While a thicker lining is generally associated with higher clinical pregnancy and live-birth rates, excessively thin or excessively thick endometria may disrupt uterine–embryo synchrony, impair placentation and increase risks of preterm birth, low birthweight or hypertensive complications. Emerging imaging techniques, such as three-dimensional Doppler and elastosonography, offer quantitative assessments of endometrial quality, yet standardisation remains a challenge. Optimising endometrial preparation protocols—whether natural cycles, hormone replacement or tailored luteal support—carries global significance for improving ART success and reducing obstetric morbidity.

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Endometrial Dynamics and Pregnancy Outcomes in Assisted Reproductive Technologies publication trend

The graph below shows the total number of articles in endometrial dynamics and pregnancy outcomes in assisted reproductive technologies across all publications each year (not limited to Nature Index journals).

Technical terms

Endometrial thickness: The measurement, in millimetres, of the uterine lining’s double-layered depth on transvaginal ultrasound.

Endometrial receptivity: The functional state of the endometrium when it is most favourable for embryo implantation, typically during a defined window of cellular and molecular changes.

Embryo transfer (ET): The procedure in which one or more embryos are placed into the uterine cavity during an ART cycle.

Frozen-thawed embryo transfer (FET): Embryo transfer performed using previously cryopreserved and subsequently thawed embryos.

Preterm delivery: Birth occurring before 37 completed weeks of gestation, associated with higher neonatal morbidity.

Hypertensive disorders of pregnancy (HDP): A spectrum of conditions including gestational hypertension and preeclampsia that can complicate pregnancy and affect maternal and fetal health.

References

1. Effect of endometrial thickness on obstetric and neonatal outcomes in assisted reproduction: a systematic review and meta-analysis. Reproductive Biology and Endocrinology (2023).
2. Endometrial thickness and early pregnancy complications after frozen-thawed embryo transfers. Frontiers in Endocrinology (2023).
3. The use of real time strain endometrial elastosonography plus endometrial thickness and vascularization flow index to predict endometrial receptivity in IVF treatments: a pilot study. BMC Medical Imaging (2023).