Preconception Nutrition Flashcards
Define infertility.
absence of production of children
Define infecundity
biological inability to bear children after 1 year of unprotected intercourse
Define miscarriage
generally, the loss of a conceptus in the first 20 weeks
aka: spontaneous abortion
Define endocrine
system of the body
ductless glands that produce secretions that affect bodily functions (testes, thyroid, adrenal, ovaries)
Define subfertility
reduced level of fertility characterized by unusually long time to conception (over 12 months) or repeated early pregnancy losses
Who is considered subfertile?
women who experience multiple miscarriages
women who ovulate infrequently
men with sperm abnormalities
What is the purpose of the menstrual cycle?
prepare an ovum for fertilization and the uterus for implantation by building up a supply of blood and nutrients in the walls of the uterus
What glands secrete the hormones the cause menstrual cycles?
pituitary gland, ovaries, hypothalamus
What are the phases of the menstrual cycle?
follicular - first 14 days
luteal - the last 14 days
What is GnRH?
gonadotropin-releasing hormone
secreted by the hypothalamus
What is FSH?
follicule and sperm stimulating hormone
secreted by the pituitary gland
prompts the growth and maturation of 6-20 follicles
its presence stimulates the production of estrogen
together they further stimulate the growth and maturation of follicles
What is LH?
luteinizing hormone
secreted by the pituitary gland
cause cells within the follicles to secrete progesterone
stimulates secretion of E, P and T and growth of the CL
What is the cycle of hormones at the beginning of the follicular phase?
estrogen –> GnRH –> FSH –> LH
What do estrogen and progesterone do?
prompt the uterine wall to store glycogen and other nutrients, expand the growth of blood vessels and connective tissue
When do blood levels of FSH and LH peak?
just prior to ovulation
the surge in LH causes on ovum to release from a follicle
What is the corpus luteum?
formed from the cells left behind in the follicle after ovulation
secretes large amounts of progesterone and some estrogen
hormones inhibit the production of GnRH so FSH and LH aren’t secreted which means the ova don’t mature and aren’t released
stimulates further development of the endometrium
provides nutrients to the fetus until the placenta forms
What happens if the ovum isn’t fertilized?
production of hormones by the corpus luteum declines
blood levels of estrogen and progesterone fall
removes the inhibitory effect on GnRH release
so the cycle can start over and uterine wall sheds its outer layer
What are prostaglandins?
substances that cause the uterus to contract and release the stored blood and nutrients
derived from essential fatty acids
What happens if the ovum is fertilized?
generally will implant in the uterus lining in 8-10 days
hormones secreted by the fertilized egg signal the corpus luteum to increase in size and to continue to produce E and P to maintain nutrient and blood supply
CL ceases to function in the first few months when it is no longer needed for hormone production
What glands secrete hormones in the male reproductive system?
pituitary gland, hypothalamus, testes
What triggers the production of testosterone in males?
GnRH –> FSH and LH –> testosterone
What does testosterone do?
stimulates the maturation of sperm (70-80 days)
source is mostly the testes
Where are mature sperm stored?
epididymis (tissue on top of the testes)
What is semen formed from?
sperm mixed with secretions from the testes, seminal vesicle, prostate, and bulbourethral gland
What is estrogen?
controls release of GnRH, stimulates thickening of uterine wall
source: ovaries, testes, fat cells, CL, placenta
What is progesterone?
source: ovaries and placenta
stimulates uterine lining buildup
helps stimulate cell division of fertilized ova
inhibits action of testosterone
What are sources of disruption in fertility?
adverse nutritional exposures contraceptive use severe stress infection tubal damage and other structural problems chromosomal abnormalities
How do these conditions modify fertility?
affect hormones that regulate ovulation
affect the presence and length of the luteal phase
sperm production
tubular passageways
What is PID?
pelvic inflammatory disease
generally caused by an infection from an STD or IUD
infection of parts of the female reproductive system
can cause scarring and blockage of fallopian tubes
What is endometriosis?
common cause of reduced fertility
presence of endometrial tissue in abnormal locations
How does nutrient intake and body fat primarily affect fertility?
altering the environment in which eggs and sperm develop
modifying levels of hormones
How does chronic undernutrition impact fertility?
reduces it only by a small amount
primary effect is small, frail babies
can greatly affect neonatal outcomes though