Many times patient’s ask why we as Fertility specialists can’t find a reason for their lack of success. Genetic factors, lifestyle and age are just a few influences for successful pregnancy.
Consider what has to work properly:
- The hormones that stimulate egg and sperm development must be made in the brain and released properly
- The egg and sperm must be present in sufficient numbers and be chromosomally normal
- The egg and sperm must be able to develop to maturity
- The uterine lining (endometrium) must be receptive to estrogen and progesterone
- The uterus must be normally shaped and free of disease
- The Fallopian tubes must be free of disease and open
- The cervix must produce receptive mucous at the time of ovulation
- In the woman, the brain must release a sufficient surge of the LH hormone to stimulate the final maturation of the egg
- The follicle (eggs develop in structures called follicles in the ovaries) must rupture and release the egg (ovulation)
- Intercourse needs to occur near the time of ovulation
- Sperm must be deposited into the vagina, survive their brief visit to the vagina, enter the cervical mucous, swim to the Fallopian tubes and “find” the egg
- The Fallopian tube must “pick up” the egg and support the egg , sperm and embryo
- The sperm must be able to get through the cells that surround the egg (cumulus cells) and bind to the shell (zona pellucida) of the egg
- The sperm must undergo biochemical reactions and release their DNA package (23 chromosomes) into the egg
- The sperm and egg must each contain only 1 copy of the needed 23 chromosomes
- The fertilized egg must be able to divide
- The early embryo must continue to divide and develop normally
- Proper gene expression and imprinting must occur
- After 3 days, the tube should have transported the embryo into the uterus
- The follicle(s) that release the egg(s) must convert to the corpus luteum cyst(s) and continue to produce the hormones necessary to support and nourish the endometrial lining
- The endometrial lining of the uterus must be properly developed and receptive
- The embryo must develop to a Blastocyst
- The Blastocyst must hatch from it’s shell (zona pellucida)
- The hatched Blastocyst must attach to the endometrial lining and “implant”
- Early embryonic and fetal development must then follow….
Wow, that’s a lot. There is so much more we do not currently understand. Much of what must happen is still beyond our ability to observe and understand. Even with the amazing treatments we now have, there are factors well beyond our control.
A healthy child is truly a miracle. The good news is that miracles happen all the time!