Methods Used in In-vitro Fertilization

In-vitro fertilization (IVF) involves aspiration of contents from a woman’s fallopian tubes or uterus with a plastic catheter after natural ovulation and fertilizing the naturally ovulated ovum with semen. But different techniques are required for doing this simple process successfully. Some of the commonly used techniques of in-vitro fertilization include ovarian hyper-stimulation, egg retrieval, egg and sperm preparation, fertilization, embryo culture, embryo selection, embryo transfer etc.

Ovarian hyper-stimulation:

For IVF ovarian hyper-stimulation involves two different methods, a long duration method and a short duration method. Long duration method involves suppression or down regulation of pituitary ovarian axis by the prolonged use of a GnRH (gonadotropin releasing hormone) antagonist, which generally takes 10-14 days.

The short duration method involves stimulation of development of multiple follicles of the ovaries by use of fertility medications such as gonadotropins. Follicular growth should be checked by gynecological ultrasound.

Egg retrieval:

The egg retrieval method is done after ovulation is complete. If follicular maturation is adequate, hCG (human chorionic gonadotropin) is given (known as “trigger shot”), which will cause complete maturation of follicles and ovulation within 42 hours and eggs are recovered from ovary. A transvaginal technique is used for egg recovery under ultrasound guidance. Commonly 10-30 eggs are recovered in one single procedure.

Egg and sperm preparation:

Egg preparation is done after retrieval of eggs from ovary, in a laboratory for preparing fertilization. The eggs cleaned (striped) of any surrounding cells after identification. In the mean time sperms are prepared for fertilization by a technique called “sperm washing” which involves removing inactive cells and seminal fluid.

Fertilization:

This involves incubation of eggs and sperm together for 18 hours at the ratio of 1:75,000, i.e. one egg for 75,000 viable sperms. Normally egg(s) is fertilized within that time, i.e. 18 hours. But sometimes, e.g. in case of low sperm count or motility, a technique called ICSI (intra-cytoplasmic sperm injection) is used, which involve injection of single sperm directly into egg. After fertilization, the fertilized egg is placed into a special growth medium and left for about 48 hours until the egg consists of six to eight cells, this process is called embryo culture.

Embryo culture is done for all fertilized eggs, till they reach 6-8 cells. After embryo culture an embryo is selected for transfer into the uterus using a plastic catheter. The embryo selection and number of embryos transferred depends of the policies of different countries and different clinics.

This guest post is written by Jupitor Chakma who blogs in his Health Blog:  healthyone.org  and Net Health Site.