Pre-implementation genetic diagnosis: Improving pregnancy rate in IVF

Pre-implementation genetic diagnosis: Improving pregnancy rate in IVF

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During the recently concluded World Fertility Congress in New Delhi, India and the Association of Fertility and Reproductive Health meeting in Port Harcourt, Rivers State, we presented a review of our current technique on Preimplantation Genetic Testing for chromosomal abnormalities, now called (PGT-A) and Preimplantation Genetic Testing for single gene diseases (such as sickle cell anaemia), now termed (PGT-M). This publication will highlight the results of PGT-A and PGT-M at Medical Art Center, Lagos.

For all cases, the patients went through standard assisted reproductive procedures. These included controlled ovarian stimulation, ultrasound monitoring of recruited follicles and ultrasound guided egg retrieval. This was followed by intracytoplasmic sperm injection, a procedure whereby a single sperm is injected into a single egg to facilitate fertilisation and subsequent embryo development.

Furthermore, the embryos were cultured to the blastocyst stage in our incubators. Assisted hatching was the performed on the morning of day five or evening of day four. The outer part of each blastocyst called trophectoderm was biopsied with the assistance of laser. Blastocysts were converted immediately after biopsy.

About five to six cells from over 144 cells in each blastocyst were placed in a special tube, properly labelled and numbered. The DNA content in these cells was then amplified to obtain a reasonable quantity for the genomic analysis of the 24 chromosomes.

Once results were ready, the genetically normal embryos were warmed for transfer in subsequent cycles. Pregnancy tests were performed 14 days after embryo transfer. For full details of the processes involved, you can refer to our earlier publications on March 15, 2016.

In the PGT-A group, a total of 193 embryos (63.9 per cent) were biopsied. About 89.6 per cent of the biopsied embryos had results with 55.5 per cent normal embryos. Clinical pregnancy rate was 46.2 per cent and implantation rate was 50 per cent. All recorded pregnancies were carried to term. There was no miscarriage recorded in this group. This buttresses the fact that the transfer of chromosomally normal embryos minimises the risk of early pregnancy loss.

For PGT-M group, a total of 59 embryos (50.4 per cent) were biopsied. About 89.8 per cent of the biopsied embryos had results with 73.6 per cent unaffected embryos and 26.4 per cent affected embryos. Clinical pregnancy rate was 50 per cent and only 50 per cent recorded pregnancies were carried to term.

When we compared the clinical pregnancy rates from both the PGT-A and PGT-M groups, which were 46.2 per cent and 50 per cent respectively, to global pregnancy rates, which is 25 per cent, we showed that IVF, in conjunction with pre-implantation genetic testing, significantly improved clinical pregnancy rates and invariably live birth rates. Some of the factors we found to have helped our success rates include proper planning, ensuring good oocyte and sperm yield with the use of orthomolecular supplements and Modern Mayr type of regeneration and detoxification. Furthermore,  a day five Biopsy with FET has significantly increased our success rate as a result of high embryo survival after both procedures.

Pre-implantation genetic testing is a well-established procedure globally for chromosomal aneuploidies and single gene disorders. We are proud to be a leading centre for this in West Africa.  These are the first reported pregnancies in Nigeria after trophectoderm biopsy and vitrification. With the advent of new testing protocols in PGD, the demand for trophectoderm biopsy has greatly increased. Our retrospective study illustrates the feasibility of trophectoderm biopsy in a developing country like ours and also highlights the importance of having a very good embryo cryopreservation system.



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