Age, oestradiol and blastocysts can predict success in natural cycle IVF-embryo transfer

Extended embryo culture is effective for patients of an advanced maternal age

The aim of this study was to determine the effectiveness of extended embryo culture in advanced maternal age (AMA) patients (37–43 years). In this retrospective analysis, 21,301 normally fertilized zygotes from 4952 couples were cultured until the blastocyst stage. Blastocyst development, including kinetics and morphology, transfer rate, implantation and live birth rates, were measured. In AMA patients, the blastocyst rate was significantly decreased as compared to that in younger women. On day 5, blastocysts underwent growth retardation in AMA patients, which was highlighted by a decreased rate of full/expanded blastocysts. Organization of the cells (trophectoderm and inner cell mass) was unaffected by age. However, in AMA patients, a ‘good’ morphology blastocyst had a decreased probability to implant compared with an ‘average’ morphology blastocyst in younger women. While the rates of blastocyst transfer and useful blastocysts were similar to younger patients, in AMA patients, both implantation and live birth rates were significantly reduced. Our results support the idea that extended embryo culture is not harmful for AMA patients. However, embryo selection allowed by such culture is not powerful enough to avoid chromosomal abnormalities in the developed blastocysts and therefore cannot compensate for the effect of a woman’s age.

Advantages of the two-step embryo transfer strategy in human IVF/ICSI cycles

The aim of this study was to evaluate the advantages of the two-step embryo transfer (ET) strategy combining a day 2/3 ET with a day 5/6 blastocyst transfer. In an observational comparative study, 400 infertile women were enrolled from two assisted reproductive technology (ART) units according to inclusion criteria: age below 42 years and at least three embryos obtained on day 2 thus allowing an extended in vitro culture. Two groups were defined according to the ET strategy adopted: group 1 had a two-step ET; and group 2 had a day 2/3 ET with (subgroup 2a) or without (subgroup 2b) blastocysts cryopreserved on day 5/6. Live birth rate was significantly higher in group 1 than in subgroups 2a and 2b (36.5% versus 29.4% and 13.4%, respectively; p < 10(-3)). Multiple pregnancy rates were comparable between groups. After adjusting on major prognostic factors, the two-step ET strategy was still associated with a significantly higher live birth rate than the day 2/3 ET (OR = 2.23; 95% CI: 1.32-3.77). The two-step ET provides better live birth rates than the cleavage-stage ET. It does not increase multiple pregnancy rates if the number of embryos transferred is limited. It also prevents cycle loss when embryos fail to develop into blastocysts.

Slow oocyte freezing and thawing in couples with no sperm or an insufficient number of sperm on the day of in vitro fertilization

BACKGROUND

The clinical results of in vitro fertilization of slowly frozen-thawed oocytes are known to be significantly worse than those obtained by fresh oocytes. Little is known about the factors affecting the clinical outcome of frozen-thawed oocytes. The aim of this retrospective study was to explore the role of oocyte cryopreservation in the group of patients with no available sperm on the day of in vitro fertilization. Additionally, the effects of the female serum FSH level and sperm quality on the clinical outcome of frozen-thawed oocytes were evaluated.

METHODS

Oocytes were slowly frozen and thawed in 22 infertile couples with no sperm or insufficient number of sperm on the day of in vitro fertilization (IVF). In 9 couples with severe azoospermia or oligoasthenoteratozoospermia frozen-thawed oocytes were fertilized by autologous sperm of bad quality when available (Group 1). In 13 couples with non-ejaculation due to psychological stress on the day of classical IVF or severe azoospermia frozen-thawed oocytes were fertilized by autologous or donated sperm of normal quality (Group 2). Oocytes were thawed in 23 cycles and microinjected by the autologous or donated sperm, when available. The clinical outcome of intracytoplasmic sperm injection--ICSI (fertilization, blastocyst, and pregnancy rates) was compared to the outcome of fresh oocytes of the same group of patients; additionally, the female serum FSH level and the sperm quality were compared.

RESULTS

In all couples, 70.5% of oocytes survived the freeze-thaw procedure. After ICSI, 61.5% of thawed oocytes were fertilized. Twenty one% of embryos developed to the blastocyst stage. The pregnancy rates per embryo transfer and freeze-thaw cycle were 33.3% and 17.4%, respectively. All pregnancies ended in the birth of a baby without congenital anomalies. In patients with severe azoospermia or oligoasthenoteratozoospermia there was no statistically significant difference in pregnancy rates per cycle obtained by thawed oocytes vs. fresh oocytes in previous ICSI cycles (14.2% vs. 13.6%) but there was a higher proportion of abnormal, non-cleaved or triploid zygotes when frozen-thawed oocytes were microinjected (33.3% vs. 11.8%; P < 0.01). The female serum FSH levels did not affect the survival and fertilization of frozen-thawed oocytes, but in patients with increased serum FSH level no pregnancies were achieved. After the complete freeze-thaw cycle, there was a significantly higher fertilization rate and tendency to higher pregnancy rates per thawing cycle after the microinjection of autologous or donated sperm of normal quality than autologous sperm of poor quality.

CONCLUSION

The slow oocyte freezing and thawing is a valuable method when no or insufficient number of sperm are available on the day of in vitro fertilization. The quality of sperm is an important factor affecting the clinical outcome achieved by frozen-thawed oocytes.