HORMONAL
METHODS
These
methods rely on giving hormones to "trick" the female body
into thinking it is already pregnant so that the ovaries
will not release eggs.
-
The
Pill
-
Depo-Provera
-
Norplant
To
understand how these methods work, here is a brief look
at a woman's menstrual cycle. During each cycle, the lining
of the uterus builds up and matures under the influence
of estrogen and progesterone. If no fertilized egg is implanted,
the lining sheds during the "period", when levels of these
hormones drop. After the period, hormone levels begin to
rise, and the lining begins to build up again.
Each
menstrual cycle lasts from the first day of the "period"
to the first day of the next "period". The length
of each cycle is usually 28 days, but can vary widely among
women and even from period to period from 17 days to 55
days. A period, or menstrual flow, usually lasts 3
- 7 days. About 14 days before the onset of
the next period, and not necessarily halfway through the
cycle, an egg is released from an ovary. This event, ovulation,
is triggered by a rise in a particular hormone. This
means that if a woman's total cycle length is only 17 days
(instead of the most common 28 days), she could potentially
ovulate during her period and could conceive while menstruating.
