Comparison of birth control methods: Difference between revisions
→Effectiveness of various methods: multiplication might not be all one might do (e.g. if one estimated the amount of correlation), restore part about when likely to use EC |
m [Pu405]Add: author-separator, display-authors, jstor, author2, author3, last4, first4, last5, first5, last6, first6, last7, first7, last8, first8, last9, first9. Tweak: author, title. Combined duplicate references. You can use this bot yo |
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Higher levels of user commitment are required for other methods.<ref name=WHOTable>{{cite report|title = Helping women understand contraceptive effectiveness | author = Kathleen Henry Shears, |
Higher levels of user commitment are required for other methods.<ref name=WHOTable>{{cite report|title = Helping women understand contraceptive effectiveness | author = Kathleen Henry Shears, |
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Kerry Wright Aradhya | url = http://www.fhi.org/NR/rdonlyres/eoabicg5w53xarcybsiefba5ruvr6r2dnkws7vj2hr3ndzv225gkvw2oxtkdlxzcl5yr3q3iok4kid/Mera08091.pdf | date = july 2008 | publisher = Family Health International}}</ref> Barrier methods, coitus interruptus, and spermicides must be used at every act of intercourse. Fertility awareness-based methods may require daily tracking of the menstrual cycle. The actual failure rates for these methods may be much higher than the perfect-use failure rates.<ref name="trussell2007" |
Kerry Wright Aradhya | url = http://www.fhi.org/NR/rdonlyres/eoabicg5w53xarcybsiefba5ruvr6r2dnkws7vj2hr3ndzv225gkvw2oxtkdlxzcl5yr3q3iok4kid/Mera08091.pdf | date = july 2008 | publisher = Family Health International}}</ref> Barrier methods, coitus interruptus, and spermicides must be used at every act of intercourse. Fertility awareness-based methods may require daily tracking of the menstrual cycle. The actual failure rates for these methods may be much higher than the perfect-use failure rates.<ref name="trussell2007" /> |
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==Side effects== |
==Side effects== |
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Some methods may be used simultaneously for higher effectiveness rates. However, mathematically combining the rates to estimate the effectiveness of combined methods can be inaccurate, as the effectiveness of each method is not necessarily independent, except in the perfect case.<!-- |
Some methods may be used simultaneously for higher effectiveness rates. However, mathematically combining the rates to estimate the effectiveness of combined methods can be inaccurate, as the effectiveness of each method is not necessarily independent, except in the perfect case.<!-- |
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--><ref>{{cite journal |author=Kestelman P, Trussell J |title=Efficacy of the simultaneous use of condoms and spermicides |
--><ref>{{cite journal |author=Kestelman P, Trussell J |title=Efficacy of the simultaneous use of condoms and spermicides | journal = Fam Plann Perspect | volume = 23 | issue = 5 |pages=226–7, 232 |year=1991| pmid = 1743276 | doi = 10.2307/2135759 |publisher=Family Planning Perspectives, Vol. 23, No. 5 |jstor=2135759}}</ref> |
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If a method is known or suspected to have been ineffective, such as a condom breaking, [[emergency contraception]] may be taken up to 120 hours after [[sexual intercourse]]. Emergency contraception should be taken shortly before or as soon after intercourse as possible, as its efficacy decreases with increasing delay. |
If a method is known or suspected to have been ineffective, such as a condom breaking, [[emergency contraception]] may be taken up to 120 hours after [[sexual intercourse]]. Emergency contraception should be taken shortly before or as soon after intercourse as possible, as its efficacy decreases with increasing delay. |
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| "the implant" || style="background:#e0ffff" | {{sort|000.05|0.05}} || style="background:#e0ffff" | {{sort|000.05|0.05}} || Progestogen || Subdermal implant || style="background:#e0ffff"| {{sort | 03.000 | 3 years}} |
| "the implant" || style="background:#e0ffff" | {{sort|000.05|0.05}} || style="background:#e0ffff" | {{sort|000.05|0.05}} || Progestogen || Subdermal implant || style="background:#e0ffff"| {{sort | 03.000 | 3 years}} |
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| [[Jadelle]]<ref group="ref">{{cite journal |author=Sivin I |
| [[Jadelle]]<ref group="ref">{{cite journal |author=Sivin I |title=The performance of levonorgestrel rod and Norplant contraceptive implants: a 5 year randomized study |journal=Hum. Reprod. |volume=13 |issue=12 |pages=3371–8 |year=1998 |pmid=9886517 |doi=10.1093/humrep/13.12.3371 |author-separator=, |author2=Campodonico I |author3=Kiriwat O |display-authors=3 |last4=Holma |first4=P |last5=Diaz |first5=S |last6=Wan |first6=L |last7=Biswas |first7=A |last8=Viegas |first8=O |last9=El Din Abdalla |first9=K}}</ref> (lower-dose) |
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| "the implant" || style="background:#e0ffff" | {{sort|000.05|0.05}} || style="background:#e0ffff" | {{sort|000.05|0.05}} || Progestogen || Subdermal implant ||style="background:#e0ffff"| {{sort | 05.000 | 5 years}} |
| "the implant" || style="background:#e0ffff" | {{sort|000.05|0.05}} || style="background:#e0ffff" | {{sort|000.05|0.05}} || Progestogen || Subdermal implant ||style="background:#e0ffff"| {{sort | 05.000 | 5 years}} |
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| || style="background:#e0ffe0" | {{sort|005.00|5}} || style="background:#dcdcdc" | {{sort|100.00|no data}} || Barrier + spermicide || Vaginal insertion || {{sort | 00.030 | Every act of intercourse}} |
| || style="background:#e0ffe0" | {{sort|005.00|5}} || style="background:#dcdcdc" | {{sort|100.00|no data}} || Barrier + spermicide || Vaginal insertion || {{sort | 00.030 | Every act of intercourse}} |
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| [[FemCap]] and spermicide<ref group="ref">{{cite web |url=http://www.femcap.com/clinician-protocol.php |title= |
| [[FemCap]] and spermicide<ref group="ref">{{cite web |url=http://www.femcap.com/clinician-protocol.php |title= Clinician Protocol |accessdate= |author= |last= |first= |authorlink= |coauthors= |date= |year= |month= |format= |work= |publisher=FemCap manufacturer |location= |pages= |language= |doi= |archiveurl= |archivedate= |quote= |dateformat=}}</ref> |
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Clinician Protocol |accessdate= |author= |last= |first= |authorlink= |coauthors= |date= |year= |month= |format= |work= |publisher=FemCap manufacturer |location= |pages= |language= |doi= |archiveurl= |archivedate= |quote= |dateformat=}}</ref> |
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| [[cervical cap]] || style="background:#ffffc0" | {{sort|007.60|7.6}} (estimated) || style="background:#dcdcdc" | no data || Barrier & spermicide || Vaginal insertion || {{sort | 00.030 | Every act of intercourse}} |
| [[cervical cap]] || style="background:#ffffc0" | {{sort|007.60|7.6}} (estimated) || style="background:#dcdcdc" | no data || Barrier & spermicide || Vaginal insertion || {{sort | 00.030 | Every act of intercourse}} |
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| "POP", "minipill" || style="background:#ffffc0" | {{sort|008.00|8}} || style="background:#e0ffff" | {{sort|000.30|0.3}} || Progestogen || Oral medication || {{sort | 00.010 | Daily}} |
| "POP", "minipill" || style="background:#ffffc0" | {{sort|008.00|8}} || style="background:#e0ffff" | {{sort|000.30|0.3}} || Progestogen || Oral medication || {{sort | 00.010 | Daily}} |
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| [[Ormeloxifene]]<ref group="ref">{{cite book |author=Puri V |
| [[Ormeloxifene]]<ref group="ref">{{cite book |author=Puri V |year=1988 |chapter=Results of multicentric trial of Centchroman |editor=Dhwan B. N., et al. (eds.) |title=Pharmacology for Health in Asia : Proceedings of Asian Congress of Pharmacology, 15-19 January 1985, New Delhi, India |location=Ahmedabad |publisher=Allied Publishers |author-separator=, |display-authors=1}}<br/> |
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{{cite book |author=Nityanand S |
{{cite book |author=Nityanand S |year=1990 |chapter=Clinical evaluation of Centchroman: a new oral contraceptive |editor=Puri, Chander P.; Van Look, Paul F. A. (eds.) |title=Hormone Antagonists for Fertility Regulation |location=Bombay |publisher=Indian Society for the Study of Reproduction and Fertility |author-separator=, |display-authors=1}}</ref> |
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| "Saheli", "Centron" || style="background:#ffffc0" | {{sort|009.00|9}} || style="background:#e0ffe0" | {{sort|002.00|2}} || [[Selective estrogen receptor modulator|SERM]] || Oral medication || {{sort | 00.070 | Weekly}} |
| "Saheli", "Centron" || style="background:#ffffc0" | {{sort|009.00|9}} || style="background:#e0ffe0" | {{sort|002.00|2}} || [[Selective estrogen receptor modulator|SERM]] || Oral medication || {{sort | 00.070 | Weekly}} |
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| Condom || style="background:#ffddaa" | {{sort|015.00|15}} || style="background:#e0ffe0" | {{sort|002.00|2}} || Barrier || Placed on erect penis || {{sort | 00.030 | Every act of intercourse}} |
| Condom || style="background:#ffddaa" | {{sort|015.00|15}} || style="background:#e0ffe0" | {{sort|002.00|2}} || Barrier || Placed on erect penis || {{sort | 00.030 | Every act of intercourse}} |
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| [[Lea's Shield]] and [[spermicide]] used by parous<ref group="ref" name="lea">{{cite journal |author=Mauck C |
| [[Lea's Shield]] and [[spermicide]] used by parous<ref group="ref" name="lea">{{cite journal |author=Mauck C |title=Lea's Shield: a study of the safety and efficacy of a new vaginal barrier contraceptive used with and without spermicide |journal=Contraception |volume=53 |issue=6 |pages=329–35 |year=1996 |pmid=8773419 |doi=10.1016/0010-7824(96)00081-9 |author-separator=, |author2=Glover LH |author3=Miller E |display-authors=3 |last4=Allen |first4=Susan |last5=Archer |first5=David F. |last6=Blumenthal |first6=Paul |last7=Rosenzweig |first7=Bruce A. |last8=Dominik |first8=Rosalie |last9=Sturgen |first9=Kim}}</ref><ref name="lea" group="note">In the effectiveness study of Lea's Shield, 84% of participants were parous. The unadjusted pregnancy rate in the six-month study was 8.7% among spermicide users and 12.9% among non-spermicide users. No pregnancies occurred among nulliparous users of the Lea's Shield. Assuming the effectiveness ratio of nulliparous to parous users is the same for the Lea's Shield as for the Prentif cervical cap and the Today contraceptive sponge, the unadjusted six-month pregnancy rate would be 2.2% for spermicide users and 2.9% for those who used the device without spermicide.</ref><ref name="parous" group="note"/> |
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| || style="background:#ffddaa" | {{sort|015.00|15}} || style="background:#dcdcdc" | {{sort|100.00|no data}} || Barrier + spermicide || Vaginal insertion || {{sort | 00.030 | Every act of intercourse}} |
| || style="background:#ffddaa" | {{sort|015.00|15}} || style="background:#dcdcdc" | {{sort|100.00|no data}} || Barrier + spermicide || Vaginal insertion || {{sort | 00.030 | Every act of intercourse}} |
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Revision as of 12:48, 18 September 2011
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Different types of birth control methods have large differences in effectiveness, actions required of users, and side effects.
Ease of use
Different methods require different actions of users. Barrier methods, spermicides, and coitus interruptus must be used at every act of intercourse. The male condom may not be applied until the man achieves an erection. Barriers such as diaphragms, caps, the contraceptive sponge, and female condoms may be placed several hours before intercourse begins (note that when using the female condom the penis must be guided into place when initiating intercourse). The female condom should be removed before arising.[1] The other female barrier methods must be left in place for several hours after sex. Spermicides, depending on the form, may be applied several minutes to an hour before intercourse begins.
Fertility awareness-based methods require that users recognize fertility signs and abstain from intercourse or use other methods during their fertile time.
The lactational amenorrhea method (LAM) requires breast feeding at least every four to six hours.
Oral contraceptives require some action every day. Other hormonal methods require less frequent action - weekly for the patch, twice a month for vaginal ring, monthly for combined injectable contraceptive, and every twelve weeks for the injection Depo-Provera.
Implants, such as Implanon, provide effective birth control for three years without any user action between insertion and removal of the implant. Insertion and removal of the Implant involves a minor surgical procedure.
Intrauterine methods require clinic visits for removal and replacement (if desired) only once every few years (5-10, depending on the device).
Sterilization is a one-time, permanent procedure - after the success of surgery is verified, no action is usually required of users.
User dependence
Different methods require different levels of diligence by users. Methods that require a clinic visit less than once per year are said to be non-user dependent. Intrauterine methods, implants and sterilization fall into this category. For methods that are not user dependent, the actual and perfect-use failure rates are very similar.
Many hormonal methods of birth control, and LAM require a moderate level of thoughtfulness. For many hormonal methods, clinic visits must be made every three months to a year to renew the prescription. The pill must be taken every day, the patch must be reapplied weekly, or the ring must be replaced monthly. Injections are required every 12 weeks. The rules for LAM must be followed every day. Both LAM and hormonal methods provide a reduced level of protection against pregnancy if they are occasionally used incorrectly (rarely going longer than 4–6 hours between breastfeeds, a late pill or injection, or forgetting to replace a patch or ring on time). The actual failure rates for LAM and hormonal methods are somewhat higher than the perfect-use failure rates.
Higher levels of user commitment are required for other methods.[2] Barrier methods, coitus interruptus, and spermicides must be used at every act of intercourse. Fertility awareness-based methods may require daily tracking of the menstrual cycle. The actual failure rates for these methods may be much higher than the perfect-use failure rates.[3]
Side effects
Different forms of birth control have different potential side effects. Not all, or even most, users will experience side effects from a method.
The less effective the method, the greater the risk of the side-effects associated with pregnancy.
Minimal or no other side effects are possible with coitus interruptus, fertility awareness-based, and LAM. Following the rules for LAM may delay a woman's first post-partum menstruation beyond what would be expected from different breastfeeding practices.
Barrier methods have a risk of allergic reaction. Users sensitive to latex may use barriers made of less allergenic materials - polyurethane condoms, or silicone diaphragms, for example. Barrier methods are also often combined with spermicides, which have possible side effects of genital irritation, vaginal infection, and urinary tract infection.
Sterilization procedures are generally considered to have low risk of side effects, though some persons and organizations disagree.[4][5]
After IUD insertion, menstrual periods may be heavier, more painful, or both - especially for the first few months after they are inserted. However, some IUDs are designed to cause periods to become lighter or to cease completely.
Because of their systemic nature, hormonal methods have the largest number of possible side effects.[6]
Effectiveness calculation
Failure rates may be calculated by either the pearl index or a life table method. A "perfect-use" rate is where any rules of the method are rigorously followed, and (if applicable) the method is used at every act of intercourse.
Actual failure rates are higher than perfect-use rates for a variety of reasons:
- mistakes on the part of those providing instructions on how to use the method
- mistakes on the part of the method's users
- conscious user non-compliance with method.
- insurance providers sometimes impede access to medications (e.g. require prescription refills on a monthly basis)[7]
For instance, someone using oral forms of hormonal birth control might be given incorrect information by a health care provider as to the frequency of intake, or for some reason not take the pill one or several days, or not go to the pharmacy on time to renew the prescription, or the pharmacy might be unwilling to provide enough pills to cover an extended absence.
Effectiveness of various methods
The table below color codes the typical-use and perfect-use failure rates, where the failure rate is measured as the expected number of pregnancies per year per 100 women using the method:
Blue under 1% lower risk Green up to 5% Yellow up to 10% Orange up to 20% Red over 20% higher risk Grey no data no data available
In the User action required column, items that are non-user dependent (require action once per year or less) also have a blue background.
Some methods may be used simultaneously for higher effectiveness rates. However, mathematically combining the rates to estimate the effectiveness of combined methods can be inaccurate, as the effectiveness of each method is not necessarily independent, except in the perfect case.[8]
If a method is known or suspected to have been ineffective, such as a condom breaking, emergency contraception may be taken up to 120 hours after sexual intercourse. Emergency contraception should be taken shortly before or as soon after intercourse as possible, as its efficacy decreases with increasing delay.
Comparison table
This table lists the chance of pregnancy during the first year of use.
| Birth control method | Brand/common name | Typical-use failure rate (%) | Perfect-use failure rate (%) | Type | Implementation | User action required |
|---|---|---|---|---|---|---|
| Implanon[ref 1] | "the implant" | 0.05 | 0.05 | Progestogen | Subdermal implant | 3 years |
| Jadelle[ref 2] (lower-dose) | "the implant" | 0.05 | 0.05 | Progestogen | Subdermal implant | 5 years |
| Vasectomy[ref 1] | "male sterilization" | 0.15 | 0.1 | Sterilization | Surgical procedure | Once |
| Combined injectable[ref 3] | Lunelle, Cyclofem | 0.2 | 0.2 | Estrogen + progestogen | Injection | Monthly |
| Essure[ref 4] | "female sterilization" | 0.2 | 0.2 | Sterilization | Surgical procedure | Once |
| IUD with progestogen[ref 1] | Mirena | 0.2 | 0.2 | Intrauterine & progestogen | Intrauterine | 5 years |
| Tubal ligation[ref 1] | "female sterilization" | 0.5 | 0.5 | Sterilization | Surgical procedure | Once |
| IUD with copper[ref 1] | Paragard, Copper T | 0.8 | 0.6 | Intrauterine & copper | Intrauterine | 5 to 12+ years |
| LAM for 6 months only; not applicable if menstruation resumes[ref 1][note 1] | "ecological breastfeeding" | 2 | 0.5 | Behavioral | Breastfeeding | Every few hours |
| Depo Provera[ref 1] | "the shot" | 3 | 0.3 | Progestogen | Injection | 12 weeks |
| Lea's Shield and spermicide used by nulliparous[ref 5][note 2][note 3] | 5 | no data | Barrier + spermicide | Vaginal insertion | Every act of intercourse | |
| FemCap and spermicide[ref 6] | cervical cap | 7.6 (estimated) | no data | Barrier & spermicide | Vaginal insertion | Every act of intercourse |
| Combined oral contraceptive pill[ref 1] | "the Pill" | 8 | 0.3 | Estrogen & progestogen | Oral medication | Daily |
| Contraceptive patch[ref 1] | Ortho Evra, "the patch" | 8 | 0.3 | Estrogen & progestogen | Transdermal patch | Weekly |
| NuvaRing[ref 1] | "the ring" | 8 | 0.3 | Estrogen & progestogen | Vaginal insertion | In place 3 weeks / 1 week break |
| Progestogen only pill[ref 1] | "POP", "minipill" | 8 | 0.3 | Progestogen | Oral medication | Daily |
| Ormeloxifene[ref 7] | "Saheli", "Centron" | 9 | 2 | SERM | Oral medication | Weekly |
| Male latex condom[ref 1] | Condom | 15 | 2 | Barrier | Placed on erect penis | Every act of intercourse |
| Lea's Shield and spermicide used by parous[ref 5][note 2][note 4] | 15 | no data | Barrier + spermicide | Vaginal insertion | Every act of intercourse | |
| Diaphragm and spermicide[ref 1] | 16 | 6 | Barrier & spermicide | Vaginal insertion | Every act of intercourse | |
| Prentif cervical cap and spermicide used by nulliparous[ref 8][note 3] | 16 | 9 | Barrier + spermicide | Vaginal insertion | Every act of intercourse | |
| Today contraceptive sponge used by nulliparous[ref 1][note 3] | "the sponge" | 16 | 9 | Barrier & spermicide | Vaginal insertion | Every act of intercourse |
| Female condom[ref 1] | 21 | 5 | Barrier | Vaginal insertion | Every act of intercourse | |
| Symptoms-based fertility awareness[ref 1][note 5][note 6] | basal body temperature, cervical mucus | 25 | 3 | Behavioral | Observation and charting | "Throughout day" or "daily"[note 7] |
| Standard Days Method, CycleBeads & iCycleBeads[ref 1] | 12 | 5 | Behavioral | Calendar-based | Daily | |
| Knaus-Ogino method[ref 8] | "the rhythm method" | 25 | 9 | Behavioral | Calendar-based | Daily |
| Coitus interruptus[ref 1] | "withdrawal method", "pulling out" | 27 | 4 | Behavioral | Withdrawal | Every act of intercourse |
| Spermicidal gel, foam, suppository, or film[ref 1] | 29 | 18 | Spermicide | Vaginal insertion | Every act of intercourse | |
| Today contraceptive sponge used by parous[ref 1][note 4] | "the sponge" | 32 | 20 | Barrier & spermicide | Vaginal insertion | Every act of intercourse |
| Prentif cervical cap and spermicide used by parous[ref 8][note 4] | 32 | 26 | Barrier + spermicide | Vaginal insertion | Every act of intercourse | |
| None (unprotected intercourse)[ref 1] | 85 | 85 | n/a | n/a | n/a | |
| Birth control method | Brand/common name | Typical-use failure rate (%) | Perfect-use failure rate (%) | Type | Delivery | User action required |
Table notes
- ^ The pregnancy rate applies until the user reaches six months postpartum, or until menstruation resumes, whichever comes first. If menstruation occurs earlier than six months postpartum, the method is no longer effective. For users for whom menstruation does not occur within the six months: after six months postpartum, the method becomes less effective.
- ^ a b In the effectiveness study of Lea's Shield, 84% of participants were parous. The unadjusted pregnancy rate in the six-month study was 8.7% among spermicide users and 12.9% among non-spermicide users. No pregnancies occurred among nulliparous users of the Lea's Shield. Assuming the effectiveness ratio of nulliparous to parous users is the same for the Lea's Shield as for the Prentif cervical cap and the Today contraceptive sponge, the unadjusted six-month pregnancy rate would be 2.2% for spermicide users and 2.9% for those who used the device without spermicide.
- ^ a b c The word nulliparous refers to those who have not given birth.
- ^ a b c The word parous refers to those who have given birth.
- ^ No formal studies meet the standards of Contraceptive Technology for determining typical effectiveness. The typical effectiveness listed here is from the CDC's National Survey of Family Growth, which grouped symptoms-based methods together with calendar-based methods. See Fertility awareness#Effectiveness.
- ^ The term "fertility awareness" is sometimes used interchangeably with the term "natural family planning" (NFP), though NFP usually refers to use of periodic abstinence in accordance with Catholic beliefs.
- ^ Users may observe one or more of the three primary fertility signs. Basal body temperature (BBT) and cervical position are checked once per day. Cervical mucus is checked before each urination, and vaginal sensation is observed throughout the day. The observed sign or signs are recorded once per day.
Table references
- ^ a b c d e f g h i j k l m n o p q r s t u Trussell, James (2007). "Contraceptive Efficacy". In Hatcher, Robert A.; et al. (eds.). Contraceptive Technology (19th rev. ed.). New York: Ardent Media. ISBN 0-9664902-0-7.
{{cite book}}: Explicit use of et al. in:|editor=(help); External link in|chapterurl=|chapterurl=ignored (|chapter-url=suggested) (help) - ^ Sivin I; Campodonico I; Kiriwat O; et al. (1998). "The performance of levonorgestrel rod and Norplant contraceptive implants: a 5 year randomized study". Hum. Reprod. 13 (12): 3371–8. doi:10.1093/humrep/13.12.3371. PMID 9886517.
{{cite journal}}: Unknown parameter|author-separator=ignored (help) - ^ "FDA Approves Combined Monthly Injectable Contraceptive". The Contraception Report. Contraception Online. June 2001. Archived from the original on October 18, 2007. Retrieved 2008-04-13.
- ^ "Essure System - P020014". United States Food and Drug Administration Center for Devices and Radiological Health.
{{cite web}}: Cite has empty unknown parameters:|month=,|dateformat=, and|coauthors=(help) - ^ a b Mauck C; Glover LH; Miller E; et al. (1996). "Lea's Shield: a study of the safety and efficacy of a new vaginal barrier contraceptive used with and without spermicide". Contraception. 53 (6): 329–35. doi:10.1016/0010-7824(96)00081-9. PMID 8773419.
{{cite journal}}: Unknown parameter|author-separator=ignored (help) - ^ "Clinician Protocol". FemCap manufacturer.
{{cite web}}: Cite has empty unknown parameters:|month=,|dateformat=, and|coauthors=(help) - ^ Puri V (1988). "Results of multicentric trial of Centchroman". In Dhwan B. N., et al. (eds.) (ed.). Pharmacology for Health in Asia : Proceedings of Asian Congress of Pharmacology, 15-19 January 1985, New Delhi, India. Ahmedabad: Allied Publishers.
{{cite book}}:|editor=has generic name (help); Invalid|display-authors=1(help); Unknown parameter|author-separator=ignored (help)
Nityanand S (1990). "Clinical evaluation of Centchroman: a new oral contraceptive". In Puri, Chander P.; Van Look, Paul F. A. (eds.) (ed.). Hormone Antagonists for Fertility Regulation. Bombay: Indian Society for the Study of Reproduction and Fertility.{{cite book}}:|editor=has generic name (help); Invalid|display-authors=1(help); Unknown parameter|author-separator=ignored (help)CS1 maint: multiple names: editors list (link) - ^ a b c Trussell, James (2004). "Contraceptive Efficacy". In Hatcher, Robert A.; et al. (eds.). Contraceptive Technology (18th rev. ed.). New York: Ardent Media. pp. 773–845. ISBN 0-9664902-6-6.
{{cite book}}: Explicit use of et al. in:|editor=(help)
[dead link].
References
- ^ Cates, Willard and Raymond, Elizabeth (2008). "Vaginal Barriers and Spermicides". In Hatcher, Robert A. et al. (eds.) (ed.). Contraceptive Technology (19th ed.). New York: Ardent Media Inc. ISBN 1-59708-001-2.
{{cite book}}:|editor=has generic name (help)CS1 maint: multiple names: authors list (link) - ^ Kathleen Henry Shears,
Kerry Wright Aradhya (july 2008). Helping women understand contraceptive effectiveness (PDF) (Report). Family Health International.
{{cite report}}: Check date values in:|date=(help); line feed character in|author=at position 24 (help) - ^ Cite error: The named reference
trussell2007was invoked but never defined (see the help page). - ^ Bloomquist, Michele (May 2000). "Getting Your Tubes Tied: Is this common procedure causing uncommon problems?". MedicineNet.com. WebMD. Retrieved 2006-09-25.
- ^ Hauber, Kevin C. "If It Works, Don't Fix It!". Retrieved 2006-09-25.
- ^ Staff, Healthwise. "Advantages and Disadvantages of Hormonal Birth Control". Retrieved 2010-07-06.
- ^ James Trussell, LL Wynn (January 2008). "Reducing unintended pregnancy in the United States" (PDF). Contraception (PDF). 77 (1): 1–5. doi:10.1016/j.contraception.2007.09.001. PMID 18082659.
{{cite journal}}: More than one of|number=and|issue=specified (help) - ^ Kestelman P, Trussell J (1991). "Efficacy of the simultaneous use of condoms and spermicides". Fam Plann Perspect. 23 (5). Family Planning Perspectives, Vol. 23, No. 5: 226–7, 232. doi:10.2307/2135759. JSTOR 2135759. PMID 1743276.