The question women ask most often is 
“Which birth control method is best?” 

There is no single best answer 
but there is a method that is “right for each person’s body and lifestyle.” 

At Femily Wellness Clinic 
many patients are undecided between 4 main methods, including: 

• Birth control pills 

• Intrauterine device (IUD) 

• Contraceptive implant 

• Contraceptive injection 

This article explains them in detail and straightforwardly 

1️⃣ Birth control pills (oral contraceptive pill) 

How it works 

Estrogen + progestin 
prevents ovulation and thins the uterine lining 

Effectiveness 

• When used correctly: >99% 

• In real life (with occasional missed or late pills): about 91% 

Advantages

• More regular menstrual cycles 

• Reduces menstrual pain 

• May improve acne in some people 

Disadvantages 

• Must be taken every day 

• Nausea during the first few weeks 

• Risk of forgetting to take it 

• Some medical conditions mean it should not be used 

Suitable for

• Women who are disciplined and want to control their menstrual cycle 

  
  

2️⃣ Intrauterine device (Intrauterine Device: IUD) 

There are 2 types: 

• Copper IUD (hormone-free) 

• Hormonal IUD 

Effectiveness 99% 

Advantages 

• No need to remember it every day 

• Lasts 3–10 years 

• Fertility returns quickly after removal 

Disadvantages

• Must be inserted and removed by a doctor 

• Some people have spotting during the first few months 

Suitable for

• Women who want long-term contraception 

• The hormonal IUD is especially good at reducing heavy periods 

3️⃣ Contraceptive implant (Implant Contraception) 

Inserted under the skin of the upper arm 
continuously releases progestin hormone 

Effectiveness 

99% (very high) 

Advantages 

• Lasts 3-5 years 

• Ideal for people who are forgetful 

Disadvantages 

• Spotting is common 

• Must be inserted and removed by a doctor 

Suitable for

• For busy working adults, the implant is a very popular option because it is convenient and reliable 

4️⃣ Contraceptive injection 

 Contraceptive injection delivers hormones into the body through the muscle 
to prevent ovulation and thin the uterine lining 

There are 2 commonly used main types: 

1. Injection every 1 month 

2. Injection every 3 months  

🔹 Monthly injection (Combined Injectable) 

Contains 
estrogen + progestin 

Highlights 

• Menstrual cycles often remain close to normal 

• Less spotting than the 3-month injection 

• Hormones are similar to combined oral contraceptive pills 

Points to consider 

• Requires a monthly injection 

• Not recommended for people at risk of blood clots, such as heavy smokers or those over 35 with other risk factors 

🔹 Every-3-month injection (DMPA – Progestin only) 

Contains only progestin 

Highlights 

• No estrogen needed 

• Suitable for people who cannot use combined hormonal contraception 

• Only 4 injections per year (every 3 months) 

Points to consider

• Periods may stop 

• Spotting is common during the first few months 

• After stopping, it may take several months for ovulation to return 

• If used long term, bone health should be assessed as appropriate 

According to the guidelines of 
World Health Organization 
and American College of Obstetricians and Gynecologists 
long-term DMPA use is acceptable in people without contraindications, but patients should be counseled about its effects on bone density before making a decision 

How to choose 

In working adults who want regular periods 
the monthly injection is often more satisfying 

But for those who are breastfeeding or cannot use estrogen 
the 3-month injection is the better option 

The most important thing is to explain “abnormal bleeding in the early period” clearly 
because many people stop using it out of concern, even though it is a common side effect that usually improves over time 

Summary of choices 

• Want regular periods → Monthly injection 

• Cannot use estrogen / breastfeeding → Every-3-month injection 

• Do not want frequent periods → Every-3-month injection 

The choice should be made with a doctor to assess individual risk factors 

So which one is “best”? 

No method is the best it should be assessed based on: 

• Age 

• Underlying medical conditions 

• Whether the person smokes 

• When they want to have children 

• Whether they have menstrual problems 

According to the guidelines of 
American College of Obstetricians and Gynecologists 
Long-Acting Reversible Contraception (LARC), such as IUDs and implants, is recommended as a first-line option for women without contraindications 

Frequently asked questions

Does the implant cause weight gain?
Some people may gain a little weight, but not everyone

Does IUD insertion hurt?
You may feel brief cramping; it only takes a few minutes

After stopping injections, is pregnancy delayed?
It may take 6–12 months for the menstrual cycle to return to normal

What should I do if I forget one pill?
It depends on which week of the pack you are in; please read the label or consult a doctor

Summary 

If you want maximum convenience → implant or IUD 
If you want menstrual cycle control → pills 
If you do not want estrogen → injections, implant, or IUD 

The most appropriate choice should be made with guidance from a specialist doctor 

Written by 

Dr. Vichdet Vichchulda 
Obstetrics and Gynecology Specialist 
Currently pursuing subspecialty training in Maternal-Fetal Medicine at King Chulalongkorn Memorial Hospital 

Research published in the International Journal of Transgender Health 

References 

1. American College of Obstetricians and Gynecologists (ACOG). Long-Acting Reversible Contraception Practice Bulletin. 

2. World Health Organization. Medical eligibility criteria for contraceptive use. 

3. Williams Obstetrics, 26th Edition.