|
Human
chorionic gonadotropin is a hormone produced by the
human placenta. Its primary role is to support the corpus
luteum which secrets estrogen and progesterone. These
hormones are necessary to support a pregnancy during
the first trimester. hCG levels rise when pregnancy
is established and it is the hormone measured by pregnancy
urine test kits.
hCG
products such as Profasi and Pregnyl are derived from
human tissue. Ovidrel is a new pure product that is
derived from mammalian cell DNA technology. It is injected
subcutaneously facilitating patient administration.
hCG has one of the same biologic effects as leutinizing
hormone, namely to trigger ovulation. In a normal menstrual
cycle, the release of LH is triggered when hormones
(such as estrogen) reach the appropriate levels. This
is governed by hormonal relationships mediated though
the hypothalamic-adrenal-pituitary axis.
In
in vitro fertilization cycles, medications are used
to control how and when the follicles development. Different
drug protocols are individualized for each patient.
hCG is administered to stimulate the final maturation
of the eggs prior to egg retrieval. hCG must be administered
at the exact time specified by the reproductive endocrinologist
or his/her staff. Some IVF patients opt to keep a second
vial of Ovidrel available in case the first one is accidentally
broken.
Progesterone
is initially produced by the corpus luteum, a small
structure formed on the ovary when the egg is released
from the ovarian follicle. After about twelve weeks,
the placenta begins to produce progesterone. Progesterone
is vital to pregnancy support because it causes increased
vascularization (greater blood flow) and thickening
of the endometrium, which is the inner layer of the
uterus. If pregnancy does not occur, progesterone levels
fall triggering menstruation. Menstruation is essentially
"shedding" of the endometrial lining of the
uterus. These processes increase the ability of the
endometrium to provide vital nutrients to the developing
embryo.
Progesterone
is responsible for the temperature rise that is measured
by the basal body temperature chart. Progesterone
is sometimes used to treat a "luteal phase defect".
The luteal phase is the period between ovulation and
menses. Insufficient production of progesterone by the
corpus luteum might not provide adequate stimulation
of the endometrium to support a pregnancy. An endometrial biopsy is often taken to document a luteal
phase defect.
Progesterone is used in in vitro fertilization cycles
to insure adequate development of the endometrium. The
injectable form of progesterone provides the most predictable
blood levels and is often used in IVF. It is administered
by intramuscular injection and is painful.
Some
clinics are now using a gel form (Crinone) which is
administered intravaginally or specially compounded
suppositories may be prescribed. Progesterone
has many other uses not related to infertility treatment
some of which have dubious scientific support.
A qualified physician should be personally consulted
prior to the administration of any hormone product.
|
