Key Factors for In Vitro Fertilisation Success

Synchronisation between Embryo and Endometrium

One of the fundamental bases for successful IVF is the transfer of a high quality embryo with a normal genetic load (euploid) to a receptive and perfectly synchronised endometrium. During ovarian stimulation, high hormone levels can lead to desynchronisation between the embryo and the endometrium, which negatively impacts implantation rates.

Nowadays, deferred transfers are becoming increasingly common thanks to advances in embryo vitrification. According to recent data, 64.5% of transfers are performed deferred, compared to 35.5% fresh. This improves success rates by allowing the endometrium to return to an optimal state prior to transfer.

Maternal Factors: The Influence of Health Status

• Obesity: Although it does not directly affect egg quality or fertilisation rates, it is associated with an increased risk of miscarriage and obstetric complications. Women with a body mass index (BMI) greater than 30 have a 22% miscarriage rate following euploid embryo transfer.
• Maternal age: In the case of transferring a genetically normal embryo, the age of the mother does not have a significant impact on the outcome.
• AMH level: Although very high levels of anti-Müllerian hormone (>6.2 ng/ml) in women with polycystic ovary can complicate outcomes, in general, there is no direct relationship between moderate levels of AMH and worse outcomes.

Embryo Factors: Quality and Development

Embryo quality is crucial for IVF success. Transferring a single euploid embryo helps minimise risk and improves obstetric outcomes. In addition, embryo kinetics, or speed of development, is a key indicator: embryos that reach blastocyst stage on day 5 have higher success rates compared to those that achieve it on later days (day 6 or 7).

Uterine Factors: Preparation and Optimal Conditions

• Endometrial Thickness: A thickness of between 4 and 12 mm is sufficient to achieve good results if a euploid embryo is transferred. However, the endometrial pattern may influence the implantation rate.
• Adenomyosis: This condition reduces gestation rates by 30%. Treatments with GnRh analogues for 2-3 months have been shown to significantly improve the chances of success.
• Caesarean section scars: The presence of an isthmocele, fluid accumulation in the scar, can alter the endometrial microenvironment. In these cases, surgical correction is recommended before proceeding with the transfer.
• Natural Cycle vs. Substituted Cycle: Performing the transfer on a natural cycle, when the woman has regular cycles, reduces associated risks such as hypertension, pre-eclampsia and postpartum haemorrhage. This approach is safer for both mother and baby.

Treatment Optimisation at Clínica Fertia

At Clínica Fertia, we understand that each patient is unique. That is why we personalise assisted reproduction treatments to maximise the likelihood of success. We pay attention to factors such as embryo quality, uterine preparation and the specific characteristics of each patient, thus ensuring a comprehensive and effective approach.

Successful in vitro fertilisation treatments depend on multiple interconnected variables. An exhaustive evaluation of maternal, embryonic and uterine factors, combined with advanced technologies and personalised strategies, guarantees the best possible results. At Clínica Fertia, we work to make the dream of parenthood a reality.

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