GN 301 Module 2: Prenatal Testing and IVF

Pregnancy Procedures

Describe the processes of Ultrasound, CVS, amniocentesis and cell-free DNA testing.

Ultrasound

In ultrasounds, sound waves are used to form pictures inside the body.

  • You can observe the development of a fetus, check for spine defects, head size, and confirm due dates.
  • You can find out when your baby is due or if they have any spinal deformities.
  • There are no known risks to this procedure. \n

Amniocentesis

In amniocentesis, a needle is put through the stomach which sucks amniotic fluid from the fetus.

  • The amniotic fluid extracted can tell if the fetus has any chromosome abnormalities or genetic disorders.
  • You can find out if your fetus has any chromosomal abnormalities or genetic disorders with genetic testing.
  • However, there is a risk of miscarriage, bleeding and infection because of the needle insertion.

CVS

In CVS (Chorionic Villus Sampling), chorion is taken from a fetus’s genotype by inserting a needle into the womb.

  • Cells are checked from the placenta to detect chromosomal abnormalities.
  • You can find out if your baby has any chromosomal abnormalities.
  • There is a risk of miscarriage, bleeding, and infection because you’re inserting the needle into the womb.

Cell-Free DNA Testing

In cell-free DNA testing, blood is taken from the mother’s arm.

  • You are able to see microdeletion or microduplication in bin count.

  • You can find out whether your baby will have genetic disorders like Down Syndrome or trisomy 18.

  • There are no known risks to this procedure.

  • Why might one or another procedure be used?

You might want to use ultrasounds or cell-free DNA testing if you’re worried about keeping your baby safe and want to avoid risks. However, if you’re concerned about your baby having a genetic disorder, you may want to try CVS or amniocentesis because these can show you your baby’s genotype before they are born.

List several genetic disorders that are screened for at birth

  • Sickle cell disease
  • Phenylketonuria (PKU)
  • Hypothyroidism
  • Galactosemia

IVF

  • What does IVF stand for?

    • in vitro fertilization

  • What does PGD stand for?

    • preimplantation genetic diagnosis

  • When might some choose to use one/both of these?

    • If someone was having trouble getting pregnant, she might want to try in vitro fertilization, where an embryo is directly implanted in the womb.
    • PGD is used before the transfer so you would know whether the embryo had any genetic disorders before implantation.

  • What is a first cycle embryo?

    • An embryo that has not been frozen and has just been produced.

Discuss the medical guidelines for IVF.

  • Previous success with IVF
  • Morphologically good quality eggs
  • Excess embryos preserved
  • First cycle embryos