IVF lab procedures and techniques to boost the success rates

Inconsistent, sometimes unproven information and the price of laboratory IVF add-ons may cause confusion and may raise alarm in patients. Are there any chances to boost IVF success rates with use of LAB techniques and procedures? Or is it just false hope? Is it true that the more additional procedures we use, the more chances of success we have? These are the fundamental questions that Elena Gonzálvez Albaladejo, Head of the IVF laboratory at Phi Fertility, tried to answer in her webinar presentation.

Conditions in the IVF lab are sensitive

Elena starts with reminding us that embryos are very sensitive to the lab conditions. Over the years, IVF scientists have worked on improving lab conditions to make them imitate the female uterus and help embryos implant after the transfer. In order to achieve that goal, it is very important to closely control lab environment and pay attention to factors like humidity, oxygen, CO2 and luminosity. Additionally, there are all the new IVF techniques that can improve implantation rates. However, as Elena says, they can work differently for different patients.

Generally, the success of embryo implantation depends mainly on the quality of eggs and sperm. However, there are a lot of factors that may influence the mentioned quality and these include patient’s age, medical and family background, chronic diseases, wrong diet (overweight or malnutrition), stress, bad habits (smoking or drinking) or even environment pollution.

Moreover, the IVF lab is one of the most important issues in any IVF treatment. These are the lab incubators that are responsible for providing right conditions to the embryos. Controlling temperature and levels of CO2, O2 and humidity in the incubator is critical to the embryo culture. The correct incubation humidity is 95% and the ideal level of both CO2 and oxygen is 5%. Embryologist should also take care of good lab cleaning and they are recommended to wear sterile clothes and shoes. What is interesting, they are not allowed to wear make-up and perfume while performing lab procedures.

IVF Lab techniques to improve the success rates

Elena goes on to explain some IVF techniques that may improve the embryo quality. First of them is a time-lapse system – the incubator with integrated continuous embryo monitoring capabilities. It provides individualised and undisturbed incubation environment. Thanks to time-lapse, it is not necessary to remove the embryo from the incubator during the cultivation. The system takes photos and videos of the embryo development that embryologist can see on their computers. In result, an embryo experiences less fluctuations in temperature, humidity and pH. And what’s the most important, time-lapse can help embryologists to evaluate the embryos by indicating them with different colours. In this way, the embryologists can choose the best embryos to transfer.

Another IVF technique for improving the success rates is choosing the best day for an embryo transfer. Elena Gonzálvez Albaladejo says that a few years ago, it was common to transfer embryos on day 2, 3 or 4 of their development. However, it often turned out that some of them were not ready to implant as they had lower implantation potential. So in spite of the fact that earlier in the embryo culture process there are more embryos available, it does not mean that a patient is more probable to get pregnant. Instead, she may be subjected to more treatments, more costs and – consequently – more emotional stress.

Blastocyst transfer

Nowadays it is more usual to conduct the embryo transfer on day 5 or 6 of the embryo development. In fact, it is not earlier than on day 3 when the embryo starts to develop itself and show its true potential. Thanks to a later embryo transfer, embryologist can make sure that they use only really good embryos. Additionally, it allows them for choosing one embryo instead of two. This significantly decreases the risk of multiple pregnancies. Elena admits that the day embryologists choose for the embryo transfer depends on a patient’s individual case – but according to hers and her colleagues’ experience, it is generally recommended to conduct transfers on the last stages of embryo culture.

Embryo culture medium

The next important IVF lab factor that Elena discusses is embryo culture medium. There are 2 different types of such media: sequential and global. With the sequential medium, embryos are grown from day 1 to day 3 in a first growth medium and then, on day 3, they are moved to a second medium in which they stay up to day 5. On day 3, embryologists have to change the environment the embryos are being cultured in and because of that, the embryos remain outside their incubators for about 3 minutes. As it involves fluctuations in media conditions and greater light exposure, there is an increased risk of generating stress and free radicals.

The second type of embryo culture medium is the global one. It provides all the nutrients for embryo growth until day 5. Because an embryo stays in an incubator uninterrupted, its culture conditions are stable. According to Elena, embryologists, basing on their experience, always recommend global culture medium.

PGT-A, genetic diagnosis of embryos

PGT-A, pre-implantation genetic testing, is another technique that may significantly boost the success rates. Formerly known as PGS (preimplantation genetic screening), it is a genetic study of the embryo produced during IVF treatment to identify numerical chromosome aneuploidies (imbalances). One has to remember that all women are at risk of producing chromosomally abnormal embryos. PGT-A is especially indicated in case of advanced maternal age (38-40 years and above), repetitive miscarriages or IVF failures (two or more). However, as this is quite an invasive procedure (a biopsy) and it requires a significant number of good quality embryos to be tested, it is not recommended for everyone.

ICSI, IMSI, PICSI, Spermslow

As Elena mentioned at the beginning, the sperm quality also plays an important role in increasing the pregnancy rates. Fortunately, there are a lot of different IVF lab techniques that enable embryologists to select the best sperm. These include MACS (magnetic-activated cell sorting), SpermSlow, PICSI (phisiological ICSI), IMSI (Intracytoplasmic Morphologically Selected Sperm Injection) and Fertile Chip. All of them are recommended when sperm test results show low concentration or mobility, high level of fragmentation or bad morphology. The embryologists should evaluate each patient’s case individually and choose the best technique.

The last technique Elena focuses on in her webinar presentation is the embryo transfer medium, which is known under different names, such as e.g. EmbryoGlue® or UTM™. It is a hyaluronan-enriched medium that, thanks to its chemical composition, may help the embryo in its adherence to the uterus lining. It is especially recommended in patients with the history of repetitive miscarriages or implantation failures.

In conclusion, Elena highlights the importance of treating each patient as a single case. One should bear in mind that the embryo quality will not improve simply because all of the available IVF techniques were applied. A patient should always evaluate costs against real benefits and remember that the mentioned techniques are only as good as the experienced and professional staff using them.