What is Pre-implantation Genetic Screening and Why Is It Important in an IVF Pregnancy?
Women who find it difficult to get pregnant by natural means have long had to accept the higher chances of failure associated with assisted methods of conception — until now.
For conception via in vitro fertilisation (IVF), there is now a test that can detect abnormalities in the embryo, even before womb implantation. The test, called pre-implantation genetic screening (PGS), takes 1 to 2 weeks and can significantly increase the chances for women of not just having a successful pregnancy, but also giving birth to a healthy baby without chromosomal abnormalities.
Hunting for Defects
In PGS, the extracted embryo is examined to make sure it has the correct 22 pairs of chromosomes in addition to those that indicate the embryo’s sex — a total of 46 chromosomes. This scan is able to detect a variety of abnormalities that could result in unsuccessful IVF implantation, a miscarriage or problems after birth. PGS can also detect if the foetus has Down syndrome, which is caused by extra chromosomal material in the embryo.
PGS is especially recommended for women aged 35 and above, as studies have shown that the chance of a baby born with chromosomal abnormalities is significantly higher in older women.
A Higher Chance of IVF Success
Besides screening for chromosomal conditions, PGS can also increase your chances of carrying your IVF baby to term. A 2006 study found that that a test similar to PGS reduced the miscarriage rate among women aged 35 to 40 from 19% to 14%. For women over the age of 40, the miscarriage rate was reduced from 40% to 22%.
PGS can help to improve your well-being in your quest to conceive and give birth to a healthy child. Having more certainty about your pregnancy can mean less worry and emotional distress during the already physically and mentally demanding period of IVF conception. Furthermore, PGS can help you avoid the anguish of having to terminate your pregnancy mid-trimester because of a previously undetected chromosomal abnormality.
PGS in Singapore
In Singapore, PGS has only been recently approved; it is currently under a 3-year pilot at the National University Hospital (starting in 2017).
However, not every woman who plans to conceive via IVF can screen her embryos. Under the pilot programme, you would have to fulfil at least one of the following clinical criteria to be eligible for PGS:
- Be aged 35 years old and above, regardless of prognosis
- Have undergone two or more recurrent implantation failures, regardless of age
- Have suffered two or more recurrent pregnancy losses, regardless of age
If you are eligible for PGS, it might be wise to incorporate it into your IVF procedure given that doing so may increase your chances of a successful pregnancy. If you’ve had difficulty in conceiving or carrying a baby to term, PGS may be your best opportunity to become mother to a child of your own.