Author
Bowtie Team
Updated on
2025-08-11
Disclaimer: This article is translated with the assistance of AI.
Many women today rely on contraceptive pills for effective and reliable birth control. Available in pre-event and emergency forms, what’s the real difference? Dive into their mechanisms, proper usage, and potential side effects with the Bowtie team – your guide to smarter health choices!
How Oral Contraceptives Work
Oral contraceptives, also known as birth control pills, reduce a woman’s chance of getting pregnant through these key mechanisms:
- Contain synthetic hormones: Suppress ovulation in the ovaries
- Inhibit endometrial development: Prevent a fertilized egg from implanting
- Increase cervical mucus thickness: Make it harder for sperm to pass through the mucus into the uterus
Differences Between Contraceptive Pill Brands
Different brands of oral contraceptives feature varying synthetic hormone formulas and ingredients. They mainly fall into two categories: combined and progestogen-only. Many women opt for combined hormonal pills, while progestogen-only pills are better suited for breastfeeding mothers.
| Combined Hormonal Pills | Progestogen-Only Pills | |
| Ingredients | Estrogen and progestin | Progestin |
| Unintended Pregnancy Rate* | 0.3–9% | 0.3–9% |
| Suitable For | General women | Breastfeeding women |
- * The rate of unintended pregnancy for women after the first year of using this contraceptive method
21-Day vs 28-Day Packs: Differences & Usage
Combined hormonal pills come in 21-pill and 28-pill packs. The 21-pill pack consists entirely of hormone pills, while the 28-pill pack includes 21 hormone pills and 7 non-hormone (placebo) pills. Here’s how to take them differently:
- 21-Pill Pack: Start on the first day of your period, taking one pill daily at the same time until all 21 are finished—that’s one cycle.
After the 21st pill, your period usually starts in a day or two. Wait 7 days before starting the next pack, even if bleeding hasn’t stopped. - 28-Pill Pack: Begin on the first day of your period, taking one pill daily at the same time until all 28 are done—that’s one cycle.
Right after finishing the first pack, start the next one immediately.
If you’re starting the pill for the first time and begin on day 6 of your period or later, use extra protection like condoms during sex in the first week.
Who Should Avoid Birth Control Pills?
If you have any of the following conditions or characteristics, you should not take combined hormonal contraceptive pills:
- Suffering from thrombosis, breast cancer or genital cancers, severe liver disease, cerebrovascular or coronary artery disease, severe hypertension, diabetes, etc.
- Experiencing unexplained vaginal bleeding
- Suspected or confirmed pregnancy
- Currently breastfeeding
- Over 35 years old and a smoker
How Emergency Contraceptive Pills Work
If you’ve had unprotected sex and need emergency contraception, you can consult a doctor or visit the Family Planning Association for options. Taking emergency contraceptive pills is one method.
Emergency contraceptive pills, also known as the “morning-after pill,” use progestin or progesterone receptor modulators to inhibit ovulation or interfere with fertilization, preventing the fertilized egg from implanting in the uterus and reducing the chance of pregnancy.
Emergency contraceptive pills come in two types: “single hormone (progestin)” and “progesterone receptor modulator”:
| Single Hormone (Progestin) | Progesterone Receptor Modulator | |
| Time Limit for Taking | Within 72 hours after intercourse | Within 120 hours after intercourse |
| Failure Rate | 2-3% | 1-2% |
| Can It Be Taken While Breastfeeding? | Yes | Stop breastfeeding for 7 days after taking |
The effectiveness of single-hormone morning-after pills is affected by the timing; the later you take it, the higher the failure rate. Progesterone receptor modulators are not affected. However, according to research cited by the Family Planning Association, if emergency contraception fails, single-hormone pills have no impact on the fetus, but the effects of progesterone receptor modulators on the fetus are uncertain.
If you’re using hormonal contraception, you can take single-hormone morning-after pills. Taking progesterone receptor modulators may reduce the effectiveness of your hormonal method. Also, be careful not to take both single-hormone and progesterone receptor modulator pills in the same cycle, as it could harm your body.
How to Take Emergency Contraceptive Pills
Both single-hormone and progesterone receptor modulator pills come in a single-dose format. Single-hormone pills should be taken as soon as possible within 72 hours after intercourse, while progesterone receptor modulator pills should be taken within 120 hours.
Pros and Cons of Birth Control and Morning-After Pills
| Pros | Cons | |
| Birth Control Pills |
|
|
| Morning-After Pills |
|
|
Where to Buy Contraceptive Pills in Hong Kong?
Since every woman has a unique body, and different brands of contraceptive pills have varying formulas and ingredients, it’s best to consult a doctor or visit the Family Planning Association for advice. After an assessment and physical check-up by healthcare professionals, you can choose the most suitable contraceptive pill.
How Reliable Are Contraceptive Pills?
Birth control pills have a failure rate of about 0.3–9%, while morning-after pills have around a 2% failure rate. If women frequently use morning-after pills, the chance of pregnancy is higher than with other regular contraception methods, so they should only be used for emergencies and not as a replacement for birth control pills.
Other Contraception Methods
Besides taking contraceptive pills, you can also use the following methods for contraception:
- Contraceptive injection: Works on the same principle as pills but involves injecting artificial hormones into the body, typically once a month or every three months
- Intrauterine device (IUD): Long-term wear prevents fertilized eggs from implanting
- Condoms: Available for men and women, they prevent semen from entering the uterus
- Cervical cap: A hemispherical latex device placed in the vagina to cover the cervix, blocking sperm from meeting the egg; when used with spermicide, it kills sperm or reduces their mobility
Additionally, women can track their ovulation cycles for contraception. If both partners decide against having more children, permanent options like tubal ligation or vasectomy are available.
Do Birth Control Pills Need Daily Timed Intake?
Birth control pills must be taken at regular times to maintain and deliver their contraceptive effects; missing the schedule might reduce their effectiveness.
What If I Miss a Dose?
If you miss one pill, take it as soon as you remember, then continue with your regular schedule. If you miss two or more, seek advice from a healthcare professional.
Does Taking Birth Control Affect Fertility?
Under normal circumstances, fertility returns after stopping the pill, without affecting future pregnancies or fetal health.
How Long After Stopping to Get Pregnant?
It depends on individual factors like body constitution, genetics, and lifestyle. Most women can conceive 1-3 months after stopping, with the majority succeeding within a year.
Does Birth Control Cause Weight Gain?
Weight gain can stem from various causes like lack of exercise or increased appetite. Studies cited by the Family Planning Association show no evidence that birth control pills cause faster weight gain than in non-users.
Can Birth Control Treat Acne?
The estrogen in oral contraceptives can balance hormones, counteracting testosterone that causes acne, reducing sebum production and preventing clogged pores.
Can Birth Control Ease Period Pain?
For most women, consistent use of birth control pills can regulate periods, reduce menstrual flow, and alleviate cramps.
Other Topics
Blood HealthBowtie StoryBusinessCancerChinese MedicineCovidCustomer ReviewDeathcareDental HealthDigestive HealthDoctor SpecialistsDrugsEar, nose, and throatEndocrinology & DiabetesExercisingEye HealthFinanceFood & NutritionGroup Medical InsuranceHealthHealth GlossaryHeart HealthHospitalsHot TopicsImmigrationInsuranceKidney HealthKids HealthlearnLiver DiseaseLung & RespiratoryMedical Check UpsMen’s HealthMental HealthNervous SystemOrthopedicsOutpatient ServicesParentingPhysiotherapyPress ReleasePrevention/VaccinationProduct PhilosophyRealtyRheumatic DiseaseSeniors HealthSkin IssueSymptomsTreatment PlanUrology女性健康