Monique Bonavita Bueno, an embryologist from
Spain, attended the physicians’ roundtable recently organised in Lagos, by
Endometriosis Support Group (ESG) with the support of Nordica Fertility Centre,
Nigeria. In this interview with CHIOMA UMEHA, she speaks on sperm washing and
freezing as well as fertility preservation, their implications in fertility
treatment.
What is the link between sperm washing and sperm
freezing?
Sperm washing is the process in which individual
sperms are separated from the semen. Washed sperm is used in artificial
insemination using the intrauterine insemination (IUI) technique and in in
vitro fertilization (IVF).
Sperm washing involves removing any mucus and
non-motile sperm in the semen to improve the chances of fertilization and to
extract certain disease-carrying material in the semen. Sperm washing is a
standard procedure in infertility treatment. Sperm washing takes place in a
laboratory following sperm donation.
Sperm washing is done before sperm freezing. We
take the sample of a man’s (patient’s) sperm and wash it before freezing. So we
need to wash so will just keep the sperm to freeze.
How durable is the frozen sperm?
There is no limit for the freezing.
Can you explain the term, Preimplantation of
genetics diagnosis?
Preimplantation of genetics diagnosis (PGD) is a
genetic testing used to determine the embryos that carry a specific gene
mutation before the pregnancy occurs. While preimplantation genetics screening
(PGS) refers to removing one or more cells from an in vitro fertilization
embryo to test for chromosomal normalcy. PGS screens the embryo for normal
chromosome number. We can think of PGS as chromosome disorder screening on IVF
embryos. So PGS increase the chances for a healthy pregnancy.
What are the constraints?
There are no limitations, we have many good
reasons to do the PGD and PGS. Actually the main benefits of PGD are to prevent
the transmission of monogenic disorder by restoring the genetic quality of the
embryo while the PGS will steady the chromosomical quality of the embryo and
screen for equal embryo to be transferred. It would help in reducing the
miscarriage rate; it will increase the implantation rate and also the chances
of having a baby.
What is the requirement for those who wants to
undergo PGD and PGS?
Though anyone can undergo PGD and PGS, I will add
that it is common mainly among patients that have advanced in maternal age.
Women aged 37 and above: any IVF patient aged 37 or above may benefit from PGS,
provided that they produce five or more embryos.
Patients in their mid-thirties are more likely to
produce abnormal embryos so they are more likely to do the PGS that will
analyse and identify abnormal chromosomal abnormality and identify an equal
embryo to transfer to her uterus.
Preimplantation genetic diagnosis can benefit any
couple at risk for passing on a genetic disease or condition.
The following is a list of the type of individuals
who are possible candidates for PGD are: Carriers of sex-linked genetic
disorders; carriers of single gene disorders; those with chromosomal disorders;
women aged 35 and over. Others are: Women experiencing recurring pregnancy loss
and women with more than one failed fertility treatment.
PGD has also been used for the purpose of gender
selection.
However, discarding embryos based only on gender
considerations is an ethical concern for many people.
What are the advantages of PGD?
The following are considered benefits of PGD: PGD
can test for more than 100 different genetic conditions.
The procedure is performed before implantation
thus allowing the couple to decide if they wish to continue with the pregnancy.
The procedure enables couples to pursue biological
children who might not have done so otherwise.
What are the concerns of PGD?
The following are considered concerns or
disadvantages associated with the use of PGD: Many people believe that because
life begins at conception, the destruction of an embryo is the destruction of a
person.
While PGD helps reduce the chances of conceiving a
child with a genetic disorder, it cannot completely eliminate this risk. In
some cases, further testing is needed during pregnancy to ascertain if a
genetic factor is still possible.
Although genetically present, some diseases only
generate symptoms when carriers reach middle age. The probability of disorder
development should be a topic of discussion with the healthcare provider.
Keep in mind that preimplantation genetic
diagnosis does not replace the recommendation for prenatal testing.
What is egg bank and sperm bank?
Sperm bank or egg bank or cryo bank in general is
a facility that store human sperm, human eggs, garment in general from sperm to
egg donors to use by human or couple who need donor provider garments and to
achieve the pregnancy which they cannot using theirs.
Can you then define what fertility preservation
is?
Fertility preservation is the process of saving
eggs, sperm or embryo or ovarian tissue before they go into fertility damaging
treatment like cancer treatment so the person can still use their garment to
achieve pregnancy in the future. So women who want to delay motherhood can also
preserve their eggs, so she is able to use her eggs to have her own biological
child when she is ready.
A woman’s egg was preserved at 30 and now she is
40. How would you describe the success rate, how viable is it?
And as an experienced embryologist, you should be
sure of doing it in a perfect way so the patient can come at 30-years-old, then
returns when she is 40. If so, her egg will continue to be exactly the same quality.
How is the preservation done?
Currently we have a technique called
cryopreservation, and vitrification. Cryopreservation and vitrification are
methods used for preserving human germ cells. Thanks to them, germ cells may be
preserved in our cryobank for as long as several decades. The preservation
period depends on the agreement with the client.
The difference between cryopreservation and
vitrification is in the cell freezing rate.
Cryopreservation is a technique that utilises a
special medium to allow preservation in liquid nitrogen at a temperature of
-196°C.
Vitrification is a modern technique that rapidly
freezes reproductive cells to a temperature of -196°C, literally within
seconds. A special medium containing cryoprotectants is used during the process
to protect the cells against damage.
