Lect 8: In vitro Fertilization Flashcards
What is Infertility?
the inability to conceive within 12 months without contraception
Common causes of male infertility
low sperm count
problems with quality of sperm
motility issues
genetic mutation of sperm
Common causes of female infertility
failure to ovulate regularly or at all
low supply of egg-producing follicles
blocked or damaged Fallopian tubes
uterine problems (fibroids, polyps)
Ovarian Reserve
peaks in early fetal life (5-7 millon gametes at 20 wks of birth)
by the time you reach puberty you are down to 400,000
fertility can begin to decline by age 27
significant decline seen at age 35 and >
by age 45 spontaneous pregnancy are rare
Treatment of Infertility
- ovulation induction
- reproductive tract surgery (for damaged tubes)
- intrauterine insemination (IUI)
- assisted reproduction (IVF, GIFT)
Intrauterine insemination (IUI)
Two techniques: to concentrate sperm
swim up specimen
column technique
Prostaglandins
don’t take Ibuprofin can retard ovulation
What is the purpose of Down regulation of the Hypothalamic-Pituitary-ovarian axis (HPO)
during the menstrual cycle the brain knows when th one follicle is matured and is ready to extrude it. However, they want more than one egg so they give meds to bypass this axis
What is the Long protocol?
given GnRH agonists
What is the short protocol?
given GnRH antagonists
Controlled ovarian hyperstimulation?
to get as many eggs
What are some examples of apecialized ancillary IVF procedures?
Assisted embryo hatching Intra Cytoplasmic Sperm Injection (ICSI) Preimplantation Genetic Diagnosis Oocyte and Embryo Cryopreservation Oocyte and Embryo Donation Gestational Carriers (Surrogacy)
Mullerian agenesis
the Mullerian ducts are two tubes that fuse together to form the fallopian tubes, uterus and upper vagina. They have ovaries and can produce eggs that can be transferred to a surrogate
H-P-O Axis
arcuate nucleus produces GnRH which secrete it in pulses. Starts during puberty at night. This gets released and stimulates the gonadotrophins (FSH, LH). LH stimulates Theca cells to produce androgens and FSH will stimulates the granulosa cells to upregulate aromatase which converts androgens (testosterone to beta-estradiol). Need both cells types. They feedback on the brain to have –/+ impact
H-P-O down regulation & suppression
GnRH agonists you get a flare effect but overtime it gets desensitized where there is activity to stop the production of LH & FSH
==>long protocol
H-P-O down regulation & suppression
GnRH antagonist are competitive inhibitors of the receptor causing immediate block of FSH & LH
==>short protocol
GnRH Analogs
can make antagonist or agonist
hCG Trigger
bombarding the ovaries with lots of FSH to produce as many eggs as possible. Need hCG because it binds to the same receptor as LH does. LH surge causes ovulation. hCG mimics LH surge inducing ovulation. Then you retrieve this egg. hCG is also produced by the embryo as well. hCG has a longer half life due to sailic acid (a sugar molecule)
Oocyte insemination (2)
- standard oocyte insemination
2. ICSI- direct injection of the sperm into the oocyte allowing them to combine and divide
Oocyte insemination - blastocyst
After the cell divides you transfer anywhere between the 4-8 cell stage. Blastocyst is a day 5 embryo. Day 6 it implants. Problem is that if you are Day 3 and the embryo is moving along nicely yo may not get to blastocyst stage and have no embryo. It depends on the amount of eggs that the person has to work with
ICSI
directly injecting the sperm into the egg
==>2PN stage (two pronuclei stage one from mom and one from dad)
Embryo Transfer
directly injecting the egg the egg into the uterus under ultrasound
Options for Excess Embryos
freeze embryos
donate for research/stem cells
embryo adoption
discard
Limiting Factor
is the age of the egg, not the mother
PGD- preimplanatation genetic
to see if you have any genetic disorders
Three parent Embryos
using mitochondrial nucleus adding to an normal cell. Transplant that nucleus to another cell than fertilizing that egg with a sperm
Artifcial Gametes
using stem cells to become sperm and eggs and combine then to make an individual
Oncofertility
noble.
