Time al., 2014). Even thought, there was

Time lapse
imaging:

In order to find out a way of increasing the success
rates of IVF, scientists came across with an emerging tool that aims to
identify which cleavage-stage embryo has the lowest chance of having an
abnormal chromosomal number, called aneuploidy (Cetinkaya et al., 2015; Chawla et al.,
2015). Aneuploidy is found to effect up to 50% of all embryos in women passed their
44 years of age (Franasiak et al.,
2014). Those can reduce the chances of successful implantation of embryos, and
early miscarriage. Time lapse monitoring system (TLS) helps scientists to
potentially “screen” better quality embryos. 

How does it work:

This particular system, can either exists as a
combined time-lapse incubation system, or can be installed into an existing
embryo incubator (Armstrong et al.,
2014). Specialist software is needed for the images to be compiled, for the
creation of a time-lapse sequence of the development of the embryo, thus
negating the need for scientists to remove the embryos from the incubator in
order to perform morphological assessment (Conagham et al., 2013). This technology allows the retrospective and
recording analysis of temporal micro-kinetics variable, in a wide range of
culture conditions and clinical scenarios (Meseguer et al., 2011).

Is TLS really useful?

Despite the technology being novel, there is a large
number of fertility clinics worldwide that have been using this technique,
often adding on to the patients extra charges for its use. The first
meta-analysis of TLS (Polanski et al.,
2014), assessed its potential benefit inspired from an interim report of a
randomized controlled trial, with 62 patients included (Kovacs et al., 2017), as well as a non-inferiority
study consisted of 76 individuals (Kahraman et
al., 2012). Such studies agreed that TLS has no effects on the chances of
achieving clinical and ongoing pregnancy and requested for more valid evidence
(Polanski et al., 2014). Following a
paper about, whether morpho-kinetics improve reproduction outcomes compared to
incubation and selection based on embryo morphology (Rubio et al., 2014), a Cochrane report was published. This report
analyzed these three projects with a total of 997 patients (Armstrong et al., 2014). Even thought, there was
some flaws in the analysis, the conclusions were common to previous
meta-analysis, including insufficient evidence for differences in miscarriage,
live birth, clinical pregnancy or still birth in order to decide between TLS
and conventional incubation, and they all suggested for further studies. Following
a different study (Park et al., 2014),
a further analysis presented similar results, collected from 1358 patients,
reporting that: even though TLS has the potential in revolutionizing clinical
embryology, at present there are not enough quality data to support the use of
this technology in clinical matter for the selection of human preimplantation
embryos (Racowsky et al., 2015).

Later, two more relevant publications, one of them consisted
of 300 patients, considerably increased the number of cases of the overall number
(Goodman et al., 2016). After this, another
study was done including a total of 161 patients (Kovacs et al., 2017). Combining of all these five studies, the number of
all patients reaches 1637. The study including the most patients until now,
summarizes that TLS culture as well as selection, provides a superior ongoing
pregnancy rate and significantly fewer losses compared to the controls (Rubio et al., 2014).

Based on the results of these analysis, the
significant positive outcomes of TLS and its aid in selection of better embryos,
has been presented in a more recent cohort-controlled study, including 319
patients, it has been presented a 46% clinical pregnancy rate in TLS group
compared with a considerably lower 32% in the control group (Adamson et al., 2016). With those findings, the
study resulted that TLS adds helpful information to the traditional
morphological grading (Pribenszky et al.,
2017).

Summary:

In conclusion for embryo freezing, it has been shown
that there are no major differences between FET, and fresh ET. Cryopreservation
is relatively useful as second plan in case the couple decides to persuade a
second IVF process without going through ovarian stimulation process again. With
the cost of only one third of a fresh IVF treatment, embryo cryopreservation
presents to be a highly considerable alternative for couples deciding to have a
second baby through IVF, give the embryos to a donor program, or donate them
for research.

On the other hand, TLS even though is a very promising
technique with numerous potential advantages; up to date evidence from a number
of studies lacks in quality results, and it has been agreed that more studies
need to be made on this technology. It is believed that the current evidence is
insufficient to support the use of TLS technology with conventional evaluation
for selection of embryos. Further trials testing this technology are necessary.