Birth control for over 35. Birth Control Options for Women Over 35: Choosing the Right Method
Can women over 35 safely use birth control pills. What are the best contraceptive options for women in their late 30s and 40s. How does age affect birth control choices. Are there health risks associated with birth control after 35.
Understanding Birth Control Needs for Women Over 35
As women enter their late 30s and 40s, their birth control needs may change. However, age alone doesn’t necessarily dictate which contraceptive methods are suitable. Dr. Kate White, director of the Fellowship in Family Planning at Boston Medical Center, emphasizes that healthy women of any age can use most forms of birth control.
Despite this, it’s crucial to consider various factors when choosing a contraceptive method after 35. These include overall health, lifestyle, future pregnancy plans, and potential risk factors.
Why is birth control still important after 35?
Many women mistakenly believe they no longer need contraception as they approach their 40s. However, Dr. Mary Jane Minkin, clinical professor at Yale University School of Medicine, advises against abandoning birth control until full menopause is confirmed. This means waiting for an entire year without menstrual periods before discontinuing contraception.
Available Birth Control Options for Women Over 35
Women over 35 have access to a wide range of contraceptive methods, including:
- Birth control pills (combination and progestin-only)
- Intrauterine devices (IUDs)
- Birth control injections
- Contraceptive implants
- Transdermal patches
- Vaginal rings
Each method has its own set of benefits and potential risks, which should be carefully considered in consultation with a healthcare provider.
Are birth control pills safe for women over 35?
Birth control pills can be safe for many women over 35, but certain factors may influence their suitability. Women who smoke or have specific health conditions may need to explore alternative options. Low-dose and progestin-only pills are available and may be more appropriate for some women in this age group.
Assessing Individual Risk Factors
When choosing a contraceptive method after 35, it’s essential to evaluate personal risk factors. Dr. Wendy Askew, an OB-GYN in San Antonio, Texas, emphasizes the importance of weighing the health-related risks of contraception against the increased risks associated with pregnancy after 35.
How does smoking affect birth control choices?
Smoking significantly impacts birth control options for women over 35. The combination of hormonal contraceptives and smoking increases the risk of blood clots and high blood pressure. Women who smoke should avoid estrogen-containing contraceptives and consider alternative methods.
What about the risk of blood clots?
Some contraceptive methods, particularly those containing estrogen, may increase the risk of blood clots. Women with a higher risk of thrombosis should discuss this with their healthcare provider and consider progestin-only or non-hormonal options.
Health Conditions and Contraceptive Choices
Certain health conditions may influence the selection of birth control methods for women over 35. These include:
- High blood pressure
- Long-standing diabetes
- Migraine headaches with aura
- History of certain cancers
Women with these conditions should work closely with their healthcare providers to find the most suitable contraceptive option.
Does birth control affect cancer risk?
The relationship between birth control and cancer risk is complex. While some oral contraceptives may slightly increase the risk of breast cancer, they may also reduce the risk of ovarian and uterine cancer. Dr. Askew notes that the benefit of preventing an unwanted pregnancy often outweighs the slight cancer risk associated with contraceptives.
Long-Acting Reversible Contraceptives (LARCs) for Women Over 35
Long-acting reversible contraceptives, such as IUDs and implants, are increasingly popular among women over 35. These methods offer several advantages:
- High efficacy rates
- Long-term protection
- Convenience and low maintenance
- Reversibility when pregnancy is desired
Are IUDs a good option for women over 35?
IUDs can be an excellent choice for women over 35. Both hormonal (e.g., Mirena, Liletta) and non-hormonal (e.g., Paragard) options are available. IUDs provide long-term contraception without the need for daily attention and can be easily removed when pregnancy is desired.
Considering Future Fertility in Contraceptive Choices
Women in their late 30s and 40s should consider their future family planning goals when selecting a birth control method. This consideration is particularly important given the natural decline in fertility that occurs with age.
Which birth control methods are best for preserving fertility?
For women who may want to conceive in the future, reversible methods such as IUDs, implants, and most hormonal contraceptives are good options. Dr. White advises against using Depo-Provera injections for women planning future pregnancies, as fertility may take longer to return after discontinuation.
Non-Hormonal Birth Control Options
Some women over 35 may prefer or require non-hormonal contraceptive methods. These options include:
- Copper IUDs
- Barrier methods (condoms, diaphragms, cervical caps)
- Fertility awareness methods
- Sterilization (for women certain they don’t want future pregnancies)
Non-hormonal methods can be particularly suitable for women with certain health conditions or those who experience side effects from hormonal contraceptives.
Is the copper IUD a good choice for women over 35?
The copper IUD (Paragard) can be an excellent option for women over 35 who prefer or require non-hormonal contraception. It provides long-term protection without affecting hormone levels and can be removed when pregnancy is desired.
Navigating Perimenopause and Contraception
As women approach menopause, their contraceptive needs may change. During perimenopause, the transitional phase before menopause, women may experience irregular periods and hormonal fluctuations but can still become pregnant.
How long should women continue using birth control during perimenopause?
Women should continue using contraception until they have gone a full year without a menstrual period, which marks the official onset of menopause. Some women may choose to use hormonal contraceptives during this time to help manage perimenopausal symptoms while still preventing pregnancy.
Choosing the right birth control method after 35 requires careful consideration of individual health factors, lifestyle needs, and future family planning goals. Women should work closely with their healthcare providers to select the most appropriate contraceptive option. Regular check-ups and open communication about any changes in health or concerns are essential for ensuring the continued safety and effectiveness of the chosen method.
As women navigate their reproductive health journey beyond 35, they have a wealth of contraceptive options available. By staying informed and proactive about their birth control choices, women can effectively manage their fertility while prioritizing their overall health and well-being. Remember, the best contraceptive method is one that aligns with individual needs, preferences, and health considerations.
Birth control for women over 35 (or 40)
If you’ve recently celebrated a milestone birthday, have you given any consideration to the type of birth control you’re using?
In general, birth control for women over 40 is not much different from birth control for women over 35. If you’re happy with the current method of contraception that you’ve been using, and you’re in good health overall, there’s really no reason to switch just because there’s another candle on your birthday cake.
“There is nothing about age alone that says you can’t use a particular kind of birth control,” explains Kate White, MD, MPH, director of the Fellowship in Family Planning at Boston Medical Center. “If you are healthy at any age, you can use anything.”
Some of your choices include:
- Birth control pills: You can take a combination pill, which contains both estrogen and progestin, or a progestin-only pill. Both come in low-dose versions, and combination pills also come in extended-cycle versions.
- IUDs: Intrauterine devices are a popular form of long-acting reversible contraceptive, or LARC. Some, like the Mirena or Liletta IUDs, are hormonal forms, while others, like the Paragard IUD, are copper.
- Injections: If you choose the birth control shot, called Depo-Provera, you receive an injection of progestin every three months to prevent pregnancy.
- Implants: Another long-acting reversible contraceptive, the implant releases progestin into your body for three years from its place in your upper arm.
- The patch: Stick on your skin for three weeks, then remove. Apply a new one each month.
- Vaginal ring: These are flexible, removable rings that contain both estrogen and progestin.
But one thing you can’t afford to do is to ignore the whole issue. “Don’t give up on the conception until you know you’re fully menopausal,” says Mary Jane Minkin, MD, clinical professor of obstetrics, gynecology and reproductive sciences at the Yale University School of Medicine.
That means you need to go for an entire year with no menstrual periods before you bid farewell to birth control for good.
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Look at your own risk profile
As you weigh your options, there are some health issues to consider, in your late 30s and throughout your 40s. What do you need to think about when choosing a contraceptive method? You need to weigh health-related risks of contraception against the increased risks associated with a pregnancy after 35—including an unplanned pregnancy, says Wendy Askew, MD, an OB-GYN in San Antonio, Texas. These risks exist for women under age 35, too, but are much lower.
Smoking
If you’re 35 or older and you smoke, it’s time to bid farewell to your birth control pills. Smoking raises your risk of cardiovascular disease anyway. But the combination of hormonal birth control and smoking can increase your risk of blood clots and high blood pressure.
Blood clots
If you are at increased risk for certain conditions like blood clots, your doctor may steer you away from certain contraceptive options. For example, combination birth control pills contain both estrogen and progestin and may raise your risk for developing blood clots. The birth control injection known as Depo-Provera is better known for being linked to an increase in bone loss over time. It does not contain estrogen, but some women may develop thrombosis after taking it.
Certain health conditions
You might also want to avoid methods containing estrogen if you have high blood pressure, or if you’ve had diabetes for at least 20 years. Migraine headaches with aura might be another possible contraindication, says Dr. White.
Cancer
The risk of developing cancer, however, is murky. Your risk of developing cancer increases with age. There may be a small possibility of an increased risk of breast cancer associated with some oral contraceptives, but it may be offset by a reduced risk of other types of cancer, like ovarian and uterine cancer. And as Dr. Askew notes, the benefit of preventing an unwanted pregnancy may very well outweigh the slight risk. Women with a family history of a particular genetic mutation for breast cancer could still consider looking at other options, though.
Choosing the best birth control method
In your late 30s and 40s, you should ask yourself—and be honest about the answer—if you are planning to have any children in the future.
- Yes, I am planning to have children. If the answer is yes, you can go with just about any method, except Depo-Provera. According to Dr. White, it can take a while for your fertility to return after going off Depo-Provera, and if you’re in your late 30s or 40s, you don’t have a lot of time to spare.
- Maybe I will have children. “If you think so, IUDs and implants can be great because it can give you years of not having to think about birth control while still reserving the option, in case you’re not 100% sure,” says Dr. White.
- No, I do not plan on having children. “If you know you are done having kids, think about [surgical] sterilization,” suggests Dr. White. However, if you and your partner don’t want to go that route, you can continue using a pill, a LARC, or other method, as long as you don’t have any health issues that would be problematic.
Birth control for women over 40 can help you manage symptoms of perimenopause that you’re experiencing. Talk to your doctor if you’re concerned about symptoms like hot flashes, night sweats, and vaginal dryness and discuss what methods might be best for you. If you don’t have any contraindications, a method containing estrogen, like a combination birth control pill or ring, might help you manage some of those symptoms, notes Dr. Minkin. And if you’re involved with a new partner, don’t forget to use condoms—you can get a sexually transmitted infection at any age.
Keeping your options open
Based on your health or other needs, some birth control options may be better than others for you in your 40s and 50s. Plus, new ones may be in the works. “It’s always good to re-evaluate because there are always new developments that come on the scene,” says Dr. Minkin.
For example, the U.S. Food and Drug Administration approved a new vaginal ring called Annovera in 2018. Unlike NuvaRing, the other vaginal ring on the market, it can be used for an entire year. You still have to remove it each month, but you don’t have to get a new one each month from the pharmacy.
And don’t be afraid to try something else if your current method doesn’t work for you and your particular needs. “It’s trial and error with birth control,” Dr. Askew says.
Risks of oral contraceptive use in women over 35
Review
. 1993 Dec;38(12 Suppl):1030-5.
M A Stenchever
1
Affiliations
Affiliation
- 1 Department of Obstetrics and Gynecology, University of Washington, Seattle 98195.
PMID:
8120860
Review
M A Stenchever.
J Reprod Med.
1993 Dec.
. 1993 Dec;38(12 Suppl):1030-5.
Author
M A Stenchever
1
Affiliation
- 1 Department of Obstetrics and Gynecology, University of Washington, Seattle 98195.
PMID:
8120860
Abstract
Oral contraceptives are a reliable and convenient method of birth control. Nevertheless, physicians are reluctant to use them in women over 35 because of concerns about increased risks of cardiovascular disease, stroke and cancer despite evidence to the contrary. Well-designed studies have shown that the incidence of thromboembolic disease is related to the estrogen dose and that the risk of thromboembolism is highest in women who smoke. With current oral contraceptive formulations, there is no increased risk of cardiovascular disease or stroke in women without other risk factors. Oral contraceptives have been shown to protect against endometrial and ovarian cancer. The risk of breast cancer appears to be increased only minimally among current oral contraceptive users. Thus, oral contraceptives offer a safe and effective means of birth control in women over 35, especially in the absence of other risk factors.
PIP:
No one has yet conducted a definitive, prospective, controlled study in 35-50 year old women that examines the relationship between oral contraceptive (OC) use and thromboembolism, myocardial infarction (MI), stroke, and cancers of the breast and genital organs. The available data derive from large studies on women in all age groups. These studies, mostly from the US and the UK, demonstrate that older women are somewhat more likely to be at risk of thromboembolism, MI, and stroke. Yet, the risk does not tend to be limited to OC users and is likely associated with other risk factors for cardiovascular disease. The risk of thromboembolism is greatest in smokers. It is also associated with the estrogen dose, which is lower today than it was in the past (= or 50 mcg vs. = or 100 mcg). The relationship between breast cancer and OC use is not clear, but the data suggest that the risk of breast cancer is elevated slightly among current OC users. The data confirm, however, that OCs protect against endometrial and ovarian cancer. Since many women older than 35 years old need safe, reversible contraception, the US Food and Drug Administration Advisory Committee concluded that healthy older women with no risk factors can safely use OCs. Women who should avoid OCs include those with a hormone-related history of thromboembolism, coronary artery disease, hypertension, diabetes, and other conditions that might cause adverse effects. Women with a clear family history of endometrial or ovarian cancer could likely benefit from OC use. Prospective studies of such women who do use OCs should be conducted to determine whether the protective effects of OCs can be extended. If the results are favorable, providers can emphasize OC benefits rather than risks. OCs are safe and effective for women over 35 who have no risk factors.
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Contraceptives for women over 35
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Contraceptives for women over 35
Contents:
- Common methods of contraception after 35 years
Women over 35 who do not want to have a baby are interested in choosing the right contraceptive. And since many methods of protection against unwanted pregnancy have contraindications, their choice must be taken with the utmost care.
The most effective means of protection against pregnancy for women over 35 years of age are hormonal. In addition, they can delay the onset of menopause. It is necessary to select hormonal drugs only in the doctor’s office, who will prescribe the necessary tests and examinations.
Below are the most suitable hormonal contraceptives for this age:
- COCs (combined oral contraceptives) – at first glance it may seem that all these drugs are exactly the same and differ only in names. However, this is deeply misleading. COCs differ in the number of hormones that make up their composition. Women over 35 need to know that the fewer hormones contained in the pills, the better the body will tolerate them. 20 micrograms is the minimum possible dosage for middle-aged ladies.
- The patch is a great alternative for women with gastrointestinal problems. The hormones contained in the patch enter the body through the skin, thereby causing a minimum of side effects. The patch must be changed every 7 days for 3 weeks (for the 4th break).
- The intrauterine ring is another type of hormonal contraception. On the first day of menstruation, a woman inserts this ring into the vagina and leaves it for 3 weeks. During this period, the amount of hormones necessary to protect against pregnancy enters the female body.
Another popular method of contraception is the intrauterine device. The main advantages of this method are not only a high degree of protection against unwanted pregnancy, but also a long service life of the coil (more than 5 years).
The safest method of contraception is the barrier method. In addition to the usual condoms, this group includes cervical caps, suppositories, vaginal tablets and more.
However, women should not forget that whatever method of contraception they choose, first of all, it is necessary to consult a qualified specialist. Gynecologists of our clinics in Magnitogorsk and Chelyabinsk are always happy to assist in the selection of the most appropriate method of contraception for women. With extensive experience and all the necessary arsenal of equipment for analysis, we will help you choose the most relevant protection method just for you.
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There are contraindications. Specialist consultation is required.
Choosing a contraceptive based on age
Choosing a contraceptive method is a task that is best done together with a doctor. The main criteria are the effectiveness of contraception (how high the risk of becoming pregnant, despite the actions taken) and the convenience of the method used. You should also think about the side effects of the chosen method and the difficulty of abandoning the method, in case a woman wants to become pregnant. In general, the choice of contraceptive depends on the age of the woman.
16-19 years old
Hormonal contraception is recognized as the most suitable for this age.
Contraceptive pills. Photo: towfiqu999 / freepik.com
However, its use is considered justified under the following conditions:
- regular sexual life;
- the onset of the first menstruation at least two years ago;
- height not less than 160 cm;
- no obesity and serious heart and vascular disease.
The World Health Organization recommends combined birth control pills for adolescents. Three-phase (Trikvilar, Tri-regol, Triziston) and single-phase (Cilest, Femoden, Mercilon, Marvelon) preparations are best suited. They provide the least interference in the natural course of the processes occurring in the female body, and maintain the stability of the menstrual cycle.
19-35 years old
For women 19-35 years old , all means and methods of contraception are suitable, but intrauterine devices are considered the most optimal. This method is cheap and does not require the constant self-monitoring required when taking birth control pills.
Intrauterine device. Photo: freepik.com
At the same time, hormonal contraception remains one of the most effective and acceptable methods of preventing unwanted pregnancies. In addition, hormonal contraceptives also play an important role in the prevention of diseases such as menstrual irregularities, infertility, and endometriosis. At this age, doctors recommend using low-dose combined drugs as the safest.
35-45 years old
Intrauterine devices
Intrauterine devices at this age are preferred, but they are often contraindicated due to the presence of diseases of the cervix and body of the uterus (erosion, fibroids, etc.) in women.
Hormonal methods
Due to smoking, overweight, endocrinological diseases, the selection of hormonal contraceptives can be complicated.
When choosing hormonal methods of contraception (in the absence of contraindications and bad habits, such as smoking), preference should be given combined contraceptive pills of the latest generation and three-phase drugs (Femoden, Marvelon, Silest, Triquilar, Triregol, Triziston).
For women 35-40 years old, we can recommend not pills, but hormonal agents implanted under the skin and injected . The main advantage is that intramuscular administration (once every 3 months) or implantation under the skin (once every 3-5 years) requires much less self-control than daily pills. The most common drugs in this group are:0003
Depo-Provera. In addition to contraceptive action, this remedy reduces the risk of inflammatory diseases of the female genital organs, thrush (vaginal candidiasis), pathological changes in the mucous membrane of the uterus and mammary glands. Depo-Provera is used to treat endometriosis. Restoration of childbearing function after discontinuation of the drug occurs within 5-9 months.
Depo-Provera. Photo: Ciell / Wikipedia (CC BY-SA 2.5)
Norplant and Norplant-2 (capsules implanted under the skin of the shoulder through a small incision under local anesthesia). The contraceptive effect appears within a day after administration and lasts for 5 years (3 years when using the Norplant-2 system).
Surgical sterilization
Surgical sterilization may be an optimal option if the woman is determined not to have any more children. This method is popular in many countries of the world, but it is not yet widespread in Russia. This operation is carried out endoscopically (through a small skin incision with special instruments). However, remember that sterilization is an irreversible method of contraception and the subsequent restoration of natural reproductive function is almost impossible.
Photo: Genrix20061.mail.ru / Depositphotos
Over 45 years
Should I give birth?
After the age of 45, menopause occurs in women and ovarian function progressively decreases. Although the chances of getting pregnant are significantly reduced during this period of a woman’s life, pregnancy is not uncommon, as many women still ovulate regularly even at this age. However, pregnancy and childbirth in most patients occur against the background of various chronic diseases and disorders (cardiovascular diseases, diseases of the urinary system, liver, chronic inflammatory processes of the genital organs, uterine fibroids, prolapse of the uterus and vagina, etc.), which is extremely unfavorable affects the health of both mother and child.
Risk of abortion
Since most women are no longer going to have children by the age of 40-45, pregnancy is often interrupted by induced abortion. But abortion at this age is often complicated by inflammatory diseases of the genital organs, the development of uterine fibroids, endometriosis, the severe course of the menopause, and can provoke the development of cancer. Therefore, contraception is necessary at this age.
Photo: freepik.com
Competent contraception
The main difficulties in choosing methods of contraception in women over 45 years of age are associated with existing risk factors (overweight, smoking, concomitant diseases, etc.).
Intrauterine devices for women aged 45-50 years are often contraindicated due to various diseases (large uterine fibroids, pathological changes in the cervix, etc.).
Hormonal contraception is not only highly effective, but also has pronounced healing properties in a number of gynecological diseases. Women using this method are less susceptible to osteoporosis, ovarian and uterine cancer.
Combination contraceptive pills are contraindicated :
- Women who smoke heavily
- women who previously had cases of blockage (thrombosis) of various blood vessels (heart attacks, strokes, thrombophlebitis, etc.),
- for severe diabetes,
- in diseases of the liver, etc.
However, low-dose drugs of the latest generation (for example, Femoden, Marvelon, Silest, Triquilar, Triregol, Triziston) have much fewer side effects, so their use is not only possible, but also useful.
The use of mini-pills, injectables (injections), as well as agents implanted under the skin (Norplant) is promising. They do not increase the risk of thrombosis, do not change blood pressure, liver function, have a therapeutic effect in the presence of pathological changes in the mucous membrane of the uterine cavity, uterine myoma, endometriosis. However, the use of these drugs may lead to premature menopause.
Women with various general and gynecological diseases, who, due to health conditions, are prohibited from pregnancy, are especially indicated * surgical sterilization.**
References
- Tadele A., Berhanu M. Trends and factors influencing long-acting contraceptive utilisation among contraceptive users in Ethiopia: repeated cross-sectional study. // BMJ Open – 2021 – Vol11 – N1 – p.e037103; PMID:33441349
- Skracic I., Lewin AB., Steinberg JR. Types of Lifetime Reproductive Coercion and Current Contraceptive Use. // J Womens Health (Larchmt) – 2021 – Vol – NNULL – p.; PMID:33404346
- Pearce E., Jolly K. Emergency Oral Contraceptive Consultations in Pharmacies in a Rural Setting: An Epidemiological Analysis. // J Pharm Pract – 2020 – Vol – NNULL – p.8971
961698; PMID:329
- Demir O., Ozalp M., Sal H., Aran T., Osmanagaoglu MA. Evaluation of the frequency of coitus interruptus and the effect of contraception counseling on this frequency. // J Obstet Gynaecol – 2020 – Vol – NNULL – p.1-6; PMID:32543257
- Gyllenberg F., Saloranta T., But A., Gissler M., Heikinheimo O. Predictors of choosing long-acting reversible contraceptive methods when provided free-of-charge – A prospective cohort study in Finland. // Contraception – 2020 – Vol101 – N6 – p.370-375; PMID:32061566
- Mugore S. Exploring Barriers: How to Overcome Roadblocks Impeding the Provision of Postabortion Care to Young People in Togo. // Glob Health Sci Pract – 2019 – Vol7 – NSuppl 2 – p.S342-S349; PMID:31455629
- Gyllenberg FK., Saloranta TH., But A., Gissler M., Heikinheimo O. Induced Abortion in a Population Entitled to Free-of-Charge Long-Acting Reversible Contraception. // Obstet Gynecol – 2018 – Vol132 – N6 – p.1453-1460; PMID:30399102
- Liu J., Schatzkin E., Omoluabi E., Fajemisin M., Onuoha C., Erinfolami T., Ayodeji K., Ogunmola S., Shen J., Diamond-Smith N., Sieverding M. Introducing the subcutaneous depot medroxyprogesterone acetate injectable contraceptive via social marketing: lessons learned from Nigeria’s private sector.