Video Transcript
Most hormonal methods of
contraception are taken by females, and they prevent ovulation each month. Why is this effective at preventing
unwanted pregnancies? (A) If an egg, ovum, is not
released from the ovaries, any sperm entering the female reproductive system will
have nothing to fertilize. (B) If ovulation is prevented for
an extended period of time, the female will become infertile. (C) Preventing ovulation makes the
uterine environment too harsh for sperm to survive in. Or (D) this statement is incorrect;
preventing ovulation is not an effective way to prevent pregnancies.
This question asks about the
concept of hormonal methods of contraception. In order to answer the question
correctly, let’s recall how hormonal methods of contraception prevent
pregnancies.
In biological women, the menstrual
cycle and ovulation, the release of a mature egg, is regulated and stimulated by
many different hormones. Hormonal methods of contraception
attempt to manipulate these hormone concentrations in order to prevent
ovulation. If an egg were prevented from
release, there would be nothing for the sperm to fertilize.
Remember that in sexual
reproduction, both an egg and sperm must join together to form a zygote. In humans, this zygote can develop
into an embryo, which can implant into the uterus. This implantation, when successful,
results in a pregnancy. Hormonal contraception prevents
this by preventing the release of an egg in the first place.
Now that we have discussed the
method of ovulation and how hormonal birth control might counteract these effects,
let’s return to our question. The question asks why preventing
ovulation is an effective way to prevent pregnancy. We now know that it is effective
because if an egg, ovum, is not released from the ovaries, any sperm entering the
female reproductive system will have nothing to fertilize.
