Fresh and Frozen-Thawed Embryo Transfer Compared to Natural Conception: Differences in Perinatal Outcome.

BACKGROUND/AIM: To compare the pregnancy outcome of singletons conceived after transfer of cryopreserved and thawed embryos (frozen embryo transfer [FET]) to singletons conceived after fresh embryo transfer (fresh ET) and natural conceived singletons. METHODS: Using a retrospective data analysis on a study population consisting of 1,261 singletons born after FET and 2,519 singletons born after fresh ET between 2006 and 2015. The control group consisted of singletons born after natural conception. Main outcome measures consisted of birth weight (in grams), gestational age, preterm birth (<37 weeks of gestation), being large for gestational age (LGA, above 90th weight percentile adjusted for gestational age) and Apgar scores. RESULTS: Babies born after FET had an increased risk of high birth weight (adjusted OR [AOR]) 2.92; 1.503-3.482) and being LGA (AOR fresh ET vs. FET 1.47; 1.210-1.787) compared to singletons born after fresh ET, as well as higher birth weights compared to natural conceived children. CONCLUSIONS: Singletons born after FET have a higher risk of high birth weight and being LGA compared to singletons after fresh ET and compared to natural conceived singletons. We assume that the freezing process might be the underlying cause.

The position of transferred air bubbles after embryo transfer is related to pregnancy rate.

OBJECTIVE: The possibility to visualize the transfer air bubbles is one of the main benefits of ultrasonographic-guided embryo transfer. The objective of this study was to analyze the relation between the position of the air bubbles and pregnancy rates. DESIGN: Prospective data-analysis. SETTING: University fertility clinic. PATIENT(S): IVF and intracytoplasmic sperm injection patients. INTERVENTION(S): Transabdominal ultrasonographic guidance at embryo transfer. MAIN OUTCOME MEASURE(S): Pregnancy rate, length endometrial plate, distance catheter to fundus, distance air bubbles to fundus. RESULT(S): Analysis of 367 consecutive ultrasonographic-guided embryo transfers following IVF or intracytoplasmic sperm injection treatment. Both absolute and relative position of the air bubbles were significantly closer to the fundus in patients who became pregnant compared with patients who did not become pregnant. When the relative position of the air bubbles was in the fundal half of the endometrial plate pregnancy rates were significantly higher compared with the lower half of the endometrial plate, 43.0% and 24.4%, respectively, P=.002. Multiple regression analysis revealed the relative position as an independently associated determinant for pregnancy. CONCLUSION(S): The position of the air bubbles after embryo transfer is related to pregnancy rate; the highest pregnancy rates are found when the air bubbles end up closer to the fundus.

Ultrasonographic-guided embryo transfer does not enhance pregnancy rates compared with embryo transfer based on previous uterine length measurement.

OBJECTIVE: To compare pregnancy rates (PRs) after ultrasound-guided embryo transfer and embryo transfer based on ultrasonographic length measurement. DESIGN: Prospective intervention group combined with retrospective control group. SETTING: University fertility clinic. PATIENT(S): Patients undergoing IVF and intracytoplasmic sperm injection. INTERVENTION(S): Transabdominal ultrasonographic guidance at embryo transfer. MAIN OUTCOME MEASURE(S): Pregnancy and implantation rates. RESULT(S): In 367 ultrasound-guided embryo transfers clinical PR, ongoing PR, and implantation rate were 35.1%, 31.1%, and 24.3%, respectively. In 363 embryo transfers based on previous ultrasonographic length measurement, the rates were 33.9%, 29.5%, and 24.2%, respectively. There were no statistical significant differences between the groups. CONCLUSION(S): Ultrasonographic guidance does not show any benefit in terms of PR and implantation rate compared to previous ultrasonographic length measurement, an other precise and atraumatic transfer technique.