Contraception: mechanisms and evidence
הוצג| English | משמעות |
|---|---|
| contraception/ˌkɒntrəˈsepʃn/ | מניעת הריון |
| barrier method/ˈbærɪə ˈmeθəd/ | שיטת מחסום |
What would explain this observation?
- Two methods can reduce pregnancy risk at different points in reproduction. Compare their mechanisms and evidence rather than assume one method answers every person’s needs.
Build the model
- The specification describes oral hormones inhibiting FSH so eggs do not mature, and slow-release progesterone injections, implants or patches inhibiting maturation/release.
- Condoms and diaphragms form barriers to sperm reaching an egg; spermicides kill or disable sperm.
- Timed abstinence avoids intercourse when an egg may be in the oviduct; sterilisation interrupts gamete transport.
- contraception 避孕: Methods used to prevent pregnancy.
- barrier method 屏障法: A method preventing sperm reaching an egg through a physical barrier.
Which explanation matches a barrier method?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
A barrier method physically blocks sperm from reaching the egg. It does nothing to eggs or hormones - cloning and hormone removal are unrelated fabrications.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Intrauterine methods include hormone-releasing devices and non-hormonal copper devices.
- The specification mentions prevention of implantation; the NHS reference explains copper’s main effect on sperm survival and fertilisation, with a possible additional implantation effect.
- Distinguish pregnancy prevention from protection against sexually transmitted infections.
- Evaluate use requirements, reversibility, evidence and values without inventing universal success rates.
In the lab: Use supplied fictional method comparisons with stated denominators and observation periods. Separate biological mechanism from practical use and ethical judgement. No classroom task should involve medical procedures, personal sexual histories or selecting a method for a student. Clinical clarification: Oxford University Hospitals, Copper IUD leaflet, page 5.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: a fictional one-year comparison records 6 pregnancies among 300 users under stated use conditions.
- The observed proportion is 2%, not 6%.
- It describes those data, not a real method’s published effectiveness.
- Different observation periods or typical/perfect use prevent a simple direct comparison.
Your turn: A fictional one-year record has 4 pregnancies among 200 users. Calculate the observed percentage.
A fictional one-year record has 4 pregnancies among 200 users. Calculate the observed percentage.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 2 %. Known: 4 pregnancies among 200 users in one year. Use percentage = pregnancies / users x 100. Observed percentage = 4/200 x 100 = 2%. This describes that record; published effectiveness needs typical and perfect use distinguished.
Check the conclusion and its limits
- A hormonal method does not necessarily protect against infection.
- A simplified calendar model cannot establish an individual safe interval.
- Scientific evidence informs effectiveness and risks, but choices also involve values, access and preferences.
Not true: Every pregnancy-prevention method also prevents all sexually transmitted infections. Barrier methods reduce both pregnancy and infection risk, but hormonal methods - pills, implants - act only on pregnancy. No pregnancy method other than barriers claims infection protection.
- The specification describes oral hormones inhibiting FSH so eggs do not mature, and slow-release progesterone injections, implants or patches inhibiting maturation/release.
- Intrauterine methods include hormone-releasing devices and non-hormonal copper devices.
- Watch for: A hormonal method does not necessarily protect against infection.
Barrier methods reduce both pregnancy and infection risk, but hormonal methods - pills, implants - act only on pregnancy.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
True. Barrier methods reduce both pregnancy and infection risk, but hormonal methods - pills, implants - act only on pregnancy. No pregnancy method other than barriers claims infection protection.
Methods used to prevent pregnancy: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
contraception means Methods used to prevent pregnancy.