Methods of contraception

Among the existing contraceptive methods, more than 50% of couples choose reversible contraceptive methods, and sterilization, as a permanent method of contraception, is used by more than 1/3 of couples
.

Pregnancy termination by professional medical institutions is relatively safe, but it is a less frequently used method

1.
Barrier contraception

1.
Barrier contraception

Barrier contraceptive methods (such as condoms, contraceptive diaphragms, cervical caps) and spermicides are simpler, reversible and have fewer side effects than hormonal methods
.

But its effectiveness highly depends on compliance and correct usage

For the prevention of sexually transmitted infections (STI), female barrier methods include diaphragms, cervical caps and contraceptive sponges

2.

Surgical interruption of female fallopian tubes or male vas deferens to prevent fertility

There are many methods of tubal ligation, all of which are effective.
The 10-year cumulative pregnancy rate is 1.
85 per 100 women
.

However, when pregnancy occurs, the rate of ectopic pregnancy is as high as 30%

Vasectomy is a very effective outpatient procedure with very low risk
.

Azoospermia may be delayed by 2 to 6 months, and other forms of contraception must be taken before 2 azoospermic ejaculation occurs

Three, intrauterine contraceptive device

Three, intrauterine contraceptive device

IUD inhibiting pregnancy through multiple mechanisms, mainly through the through foreign matter (copper IUD) intrauterine aseptic inflammation plays a spermicidal or releasing progestin (progesterone implant, Mirena)
.

IUD can play a highly effective role without causing systemic metabolic effects, and it does not require continuous power to ensure efficacy after an implanted device

Aseptic inflammation caused by a foreign body in the uterine cavity (copper IUD) has a spermicidal effect or releases progesterone (progesterone implant, Mirena)

Four, hormone method

Four, hormone method

( 1 ) Oral contraceptives

( 1 ) Oral contraceptives

Oral contraceptives have become the most widely used hormonal contraceptives due to their convenience and effectiveness
.

It works by inhibiting ovulation, changing cervical mucus, and changing the endometrium

It can artificially synthesize estrogen and progesterone by inhibiting ovulation, changing cervical mucus, and changing the endometrium.

( 2 ) Other methods

( 2 ) Other methods

  The weekly contraceptive patch (Ortho Evara) is feasible and the effect is similar to that of oral contraceptives
.

Approximately 2% of the patches adhered to each other, and the proportion of women with skin reactions was similar
.
Women weighing 90 kg have a reduced effect
.
The amount of estrogen delivered is equivalent to 4 g of ethinyl androsterol oral contraceptives, which increases the risk of VTE and needs to balance the potential benefits of women who successfully use other methods
.
The monthly contraceptive estrogen and progesterone injection (Lunellee) is highly effective, with a failure rate of <0.
2% in the first year, but its effectiveness decreases in obese women
.
It can cause irregular bleeding, which decreases over time
.
Fertility quickly recovered after stopping
.
A monthly vaginal ring (Nuva ring) is placed in the vagina during sexual intercourse and can also be used for contraception
.
Its effectiveness is high, with a failure rate of 0.
7% in December
.
Ovulation begins in the first recovery cycle after stopping
.

( 3 ) Long-acting contraceptives

( 3 ) Long-acting contraceptives

   Long-acting progesterone preparations play a role mainly by inhibiting ovulation, changing the endometrium and cervical mucosa, reducing implantation and sperm transport
.
Long-acting medroxyprogesterone acetate (Depo-Provera, DMPA) is the only available injection preparation in the United States, effective for 3 months, and it takes 12 to 18 months for reproductive function to recover after stopping
.
Currently DMPA can be injected subcutaneously (SC) and intramuscularly
.
Irregular bleeding, menopause, and weight gain are the most common side effects
.
This kind of contraceptive is especially suitable for women who have contraindications for estrogen-containing contraceptives (such as migraine attacks, anaemia, fibroids)
.

Inhibit ovulation, change the endometrium and cervical mucosa, and reduce implantation and sperm transport.

( 4 ) Contraception after sexual intercourse

( 4 ) Contraception after sexual intercourse

  Regardless of time, the monthly probability of pregnancy is 8%, but the possibility varies significantly, and the ovulation period can be as high as 30%
.
To ensure sex, contraceptive methods after intercourse include the following:

1.
Implant a copper IUD within 5 days to prevent pregnancy through spermicidal, and the effectiveness is 99% to 100%; implantation is usually optional in family planning clinics
.

2.
Oral antiprogestin (Ulipristal acetate, a single dose of 30 mg available worldwide, or mifepristone, a single dose of 600 mg, not available in the United States) prevents pregnancy by delaying or preventing ovulation; the most used within 72 hours after sexual intercourse Good, no more than 120h at the latest, 98%～99% effective, prescription drugs
.

3.
Levogestrel (a single dose of 1.
5 mg) can delay or prevent ovulation, which is ineffective after ovulation
.
Should be taken within 72 hours of unprotected sexual intercourse, the effective rate is 60% to 94%, non-prescription drugs
.

Combinations of estrogen and progesterone have not been recommended
.
Pregnancy testing is not required before using the oral method, but pregnancy must be excluded before the IUD is implanted
.
Risk factors for failure of oral medications include near ovulation and use after unprotected intercourse
.
In addition, obese and overweight women have an increased risk of pregnancy using levynorgestrel for contraception after intercourse, and obese women have an increased risk of using antiprogestins
.

5.
The influence of obesity on contraceptive choices

5.
The influence of obesity on contraceptive choices

   Although obesity can lead to decreased fertility, most obese women can become pregnant
.
Obese women use intrauterine contraception more effectively than oral or transdermal methods
.
The WHO guidelines do not restrict the use of intrauterine contraception, DMPA, and progesterone-only drugs (grade 1) for obese women (BMI ≥ 30 kg/m2) who do not have drug problems, while methods containing estrogen increase the risk of thromboembolic diseases (drug stickers).
Agent, ring) is considered to be level 2 (the advantage usually exceeds the theoretical or proven risk)
.
There are no restrictions on the choice of contraceptive methods after bypass surgery, but postoperative malabsorption makes the effectiveness of combination preparations and progesterone preparations relatively low
.

Intrauterine contraception

Original source:

Dennis L.
Kasper, Anthony S.
Fauci, Stephen L.
Hauser, et al, HARRISON'S PRINCIPLES OF INTERNAL MEDICINE, 19th Edition.

Dennis L.
Kasper, Anthony S.
Fauci, Stephen L.
Hauser, et al, HARRISON'S PRINCIPLES OF INTERNAL MEDICINE, 19th Edition.
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