Talk:Progestogen-only pill

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Mini pill?[edit]

I'm a bit confused. Are progesterone-only pills the same as progestin-only pills ("mini pills"), or are the two merely related? There's currently no article or redirect for mini pill, which is a fairly common term. --LostLeviathan 07:39, 8 August 2005 (UTC)

  • Yes all the same thing, add 'mini pill' term. Progestin is a more specific term relating to synthetic progesterones and is used in USA but not UK. - David Ruben 11:52, 8 August 2005 (UTC)

  • For clarification, we use the terms:

- progesterone - to refer to the natural hormone produced by the ovary (specifically the corpus luteum); and - progestogen or progestins - to refer to the synthetic steroids that demonstrate progestogenic properties (and possibly, other partial effects, e.g., anti-androgenic partial effect(as in cyproterone acetate), estrogenic partial effect(as in norethisterone), anti-mineralocorticoid effect (as in drospirenone);

  • Therefore, it is more appropriate to say progestin-only pill as these contraceptives contain progestins and not the natural hormone progesterone
  • By the way, please note that, progestins are generally more potent than the natural hormone progesterone; hence, the use of progestogens or progestin in contraceptives and hormone therapy (rather than progesterone) - (user ACC, Feb 4, 2006, Montville, NJ)

Progesterone vs Progestin[edit]

Whilst all POPs do indeed use the progestin synthetic analogues of the natural progesterone, in the UK at least they seem in common medical use only to be known as 'Progesterone Only Pills' (similar I suppose to talking about 'Penicillin allergy' or 'Tetracyclines' refering to the relevant drug groups than specific single chemicals), - is this not the case in the US ? A quick search on PubMed and Google was interesting:

Search Term PubMed Google
Progestin only pill 337 253,000
Progestin only pills 296
Progestagen only pill 117 11,200
Progestagen only pills 95
Progestogen only pill 203 99,600
Progestogen only pills 142
Progesterone only pill 206 613,000
Progesterone only pills 157

'Progesterone only pill/s' only has 53% as many PubMed entries as 'Progestin only pill/s', yet 'Progestin only pill/s' has only 41% as many Google hits as 'Progesterone only pill/s'. David Ruben Talk 15:00, 20 March 2006 (UTC)

In the United States, the FDA requires that these be labeled as "progestin-only pills" since they do not contain progesterone. Oral progesterone is approved under the brand name Prometrium, but this is approved only for postmenopausal hormonal therapy, not birth control. (Prometrium is not an effective contraceptive due to the large variance in oral bioavailability.)

Labeling requirements seem to be less strict in the UK, and these pills are often called "progesterone-only pills" in the UK and elsewhere, as the google results show. Nonetheless this naming is clearly confusing people. I'd generally prefer the term "progestin-only pill" to avoid confusion with drugs like Prometrium.

Would there be any objection to moving this page to "Progestin-only pill" and keeping "Progesterone only pill" as a redirect? Kiral 16:30, 24 March 2006 (UTC)

I don't know what POPs are called in everyday usage in the UK, but in the US they are called "progestin only" pills, which is also how they are referred to in all American medical reference books. In all British medical reference books I have seen (like the BNF, the Oxford Textbook of Medicine, etc.) and in the WHO's contraception guidelines, they are referred to as "progestogen only" pills.
I think your original experiment comparing the results of searches in PubMed and Google was skewed because you did not search on the words as phrases, which therefore produced an excess of spurious results in PubMed and Google that contained the word "progesterone", but not the phrase "progesterone only" or "progesterone only pill(s)". Repeating your experiment using phrases produces results that are quite different:
Search Term PubMed Google
Progestin only 334 96,900
Progestogen only 320 61,000
Progesterone only 99 40,800
Progestagen only 78 1,420
Search Term PubMed Google
Progestin only pill(s) 57 45,000
Progestogen only pill(s) 87 39,900
Progesterone only pill(s) 11 17,800
Progestagen only pill(s) 12 311
"Progestin only" and "progestogen only" are both accurate and correct and used in American and British/international medical references respectively, and much more commonly used in biomedical journal publications (as found by PubMed searches) and on the web in general (as found by Google searches) than "progesterone only" which is inaccurate and incorrect.
Therefore, I propose changing the name of this article from "Progesterone only pill" to "Progestin only pill", or alternatively to "Progestogen only pill".
Mylor 01:55, 27 August 2006 (UTC)
Good points re word vs phrase searching. British National Formulary uses "Progestogen-only", and as such would be the "official" term to use in the UK. What is the norm in other English-speaking countries ? As the article's creator (not that anyone "owns" articles), I would rather like to keep to its original British English :-) David Ruben Talk 02:57, 27 August 2006 (UTC)
"Progestogen only pill" would be an equally correct title for this article. I think "progestin only" is used in the US and Canada, "progestogen only" in the UK, Australia and New Zealand and internationally (in the WHO contraception guidelines). POP use is more common in the UK, New Zealand and Scandinavia than in the US and other parts of Europe.
The first mini-pill, containing the pregnane (17α-hydroxyprogesterone derivative) progestin, chlormadinone acetate (first synthesized in 1958 by Syntex of Mexico; first tested in clinical trials in the early 1960s by Martinez-Manautou et al in Mexico), was introduced in the UK in 1969 (and withdrawn in 1970 after it was found to induce benign breast nodules in beagles).
The POP and all other types of progestogen-only contraceptives (injectables, implants, intrauterine systems) were first introduced in and are more commonly used in countries other than the US.
Mylor 14:46, 27 August 2006 (UTC)
Thank you, then might I agree that the current article needs to be renamed (moved) and both for use/introduction being primarily in non-US countries and the WHO preferecne, to use Progestogen only pill. I'm happy to do the move and all the redirects this will entail, but an important move proposal, such as this, propably should be left open for a couple of days for any other editor to jump in. David Ruben Talk 22:46, 27 August 2006 (UTC)

i support the change from "progesterone only" to "progestogen only" because there do appear to be some significant differences between progesterone/progestogens; makes things more clear, especially regarding exogenous/endogenous hormones. (i admit to a preference for "progestin," but that is probably because i am a lousy typist and it has fewer letters.) if the WHO calls it progestogen and use/intro is countries that call it progestogen, i agree it makes more sense to call it progestogen for title purpose. Cindery 23:45, 27 August 2006 (UTC)

i just accidentally stumbled upon this while looking for a chemical definition of levonorgestrel: PMID 15697108 and i don't know that it's the authoritative definition re the difference between progestogen and progestin (or if there is one or they are conflatable etc) but it seemed interesting...? Cindery 02:25, 28 August 2006 (UTC)

PMID 15697108 states "The term progestogen has been widely utilized to indicate the general class of agents that includes both progesterone and its synthetic analogs, whereas the term progestin refers only to synthetic progestational steroids." The wikipedia articles progestin and progestagen contain essentially the same definition, although the definition of progestin on is somewhat more inclusive. I proposed "progestin-only pill" above, only because that seems to be the more commonly used term. -- Kiral 12:31, 28 August 2006 (UTC)

Proposed Infobox for individual birth control method articles[edit]

Let's all work on reaching a consensus for a new infobox to be placed on each individual birth control method's article. I've created one to start with on the Wikipedia Proposed Infoboxes page, so go check it out and get involved in the process. MamaGeek (Talk/Contrib) 12:25, 14 June 2006 (UTC)

First Use?[edit]

"1970s – Hormone levels decrease, the first progestin-only pill is introduced Studies confirm that far less hormone than contained in early pill formulations is needed to prevent conception. Ortho Pharmaceutical Corporation introduces pills with decreasing estrogen and progestin levels. The company introduces the first progestin-only pill, which contains 350 mcg of norethindrone with no estrogen component, in 1973." From "History of the Pill." They must have studied it--and therefore "used" it--prior to 1973, which is, I assume, the date of its introduction to the general public, following approval (presumably by the FDA, in the US). I do not know if another brand was developed elsewhere and used first.Cindery 16:10, 28 July 2006 (UTC)

Breast Cancer Risk[edit]

I think it may be justified to state that the long-term breast cancer risk is not known. No studies have been conducted specifically of POP and breast cancer--nor could they really have been done, as this drug is so new. There is some worrisome data on the relationship between progestin and breast cancer. But it cannot be stated that it is one (definite risk of breast cancer) or the other (no risk). The lack of studies and the great increase of breast cancer in the Nurse's study for the women who took progesterone and estrogen (much higher than estrogen alone) is significant. 1973 is not so long ago, and The Breast Cancer Fund cites pill use as a high risk activity, with greater danger for "early and prolonged use." Young women who took/began to take POP in the 70s/80s/90s have not yet come into their 50s and 60s and 70s in large enough numbers for us to rule out breast cancer and POP use. To my knowledge, no one is tracking them, either. I think a caution regarding progestin is in order, in some wording other than "breast cancer risk with HRT," as if HRT had nothing to do with progestin. Cindery 16:07, 28 July 2006 (UTC)

I agree lack of data, although reports are published looking at trends in cancer rates and pill use, this is usually for combined pills. I added the mention of HRT as it was the million women study (and others) that looked directly at rates of opposed (progesterone including) and unopposed (only the osetrogen) HRTs and showed that the risk for breast cancer with HRT was greatest for the addition of progestagens. This clearly does not equate directly to the different progestagens used in POP from HRTs, nor the different dosages used, but I felt this was the clearest (and least contested) evidence that progestages in POP, at least in principle with HRT use, may/probably have at least some effect on breast cancer rates. Overall effects of POP are less well looked at compared to COCP due, in part, to fewer women using. So whilst the COCP reduce endometrial cancer rates - I think one has to look again to the Million Women study that confirmed the rational for progesterone inclusion, namely reduced endometrial cancers, just shame suggested effect outweighed in HRT users by breast cancer effect. Could not find on quick search of PubMed a study specifically on POP effect on endometrial/ovarian cancer rates - I would need to spend longer using progestin/progestagen/progestogen/progesterone variations for search terms - are you aware of any?.David Ruben Talk 22:06, 28 July 2006 (UTC)

I'm not aware of any, and I admit to becoming more and more confused and overwhelmed re cancer and HRT/BC pills, the more I read. I think this is a time of great flux regarding medical opinion re hormones, and that not enough studies have been done/are being done. (While I maintain my personal bias that hormones just aren't worth the risk, for accuracy/neutral POV I think it's fair to say that the risks just can't be stated either way for prgesterone only pill--but there is cause for concern viz breast cancer, and because the drug is new in human-historical terms, generations not aged to prime risk years yet, and studies not being done/women not being tracked? "Risks not conclusively known either way; some cause for concern; more study needed" seems pretty fair to me--what do you think? Cindery 23:57, 28 July 2006 (UTC)

Very fair. Two points:
  1. I'ld suggest a small tweak of the english with a conjunction or two. So either "The risks on breast cancer rates are not conclusively known either way; there is some cause for concern and more study is needed" or if we are to be more inclusive of overall gynaecological cancers then "The effects on the rates of gynaecological cancers are not conclusively known either way; there is some cause for concern and more studies are needed".
  2. Given the lack of data on POP risks, I would still be tempted to retain some mention of the opposie effects on risks of breast & endometrial cancers seen with combined HRTs vs unopposed HRT (this seems "purer" comparison test for progestagens than rates with COCP) as illustrative of why overall risks are not clearly established. However I can't think of how to join with your succinct approach in a neat way. Possibly best not to overclutter the text on this ? David Ruben Talk 01:45, 29 July 2006 (UTC)

Because breast cancer is "epidemic" in comparison to all other gynecological cancers, I would oppose conjoinment with other cancers. (The numbers I have seen--Breast Cancer State of Evidence table) are that ovarian cancer is about %6, breast cancer is %37. (Cases--not risks). Cervical/Endometrial around--%9? Breast cancer is a very, very serious --one of leading causes of death for women worldwide--and should be addressed separately, I think. Cindery 00:26, 30 July 2006 (UTC)

OK for point 1, first wording option.David Ruben Talk 01:54, 30 July 2006 (UTC)
As I understand it, the studies on COCP and gynacological cancers show net benefit not from absolute rates of these cancers, but from the differing added or lessened cases occuring and the relative lethalness of the cancers. As you correctly point out, breast cancer is more common than the others. However COCP's effect on breast cancer is only a small effect on the overall higher number of cases, whereas cases of ovarian/endometrial cancers seem to be over halved by COCP. So whilst one cancer naturally higher rate, COCPs seem to give a greater number of cases prevented in the less common cancers than additional cases in the commoner cancer. Also breast cancer has relatively a better survival rate compared to ovarian cancers (i.e. more often operatable/responsive to chemotherapy and subsequent hormonal therapy, eg tamoxifen), so a given increase in breast cancer cases will result in less deaths than if the same number of ovarian cancers are not prevented. Attempts to look into incidence/prevention rates and treatability to gain an overall effect is obviously v.difficult, not least that trying to match changes in COCP use over time with changes in cancer incidence rates is also associated with changes in rates of cigarrette smoking and improvements to surgical/oncology management. David Ruben Talk 01:54, 30 July 2006 (UTC)

Removed bold section Breast cancer risk.

A section on the cancer risks, and a sub-section on the breast cancer risks of progestin-only oral contraceptives is appropriate, but should give information on what is known about the risks of progestin-only oral contraceptives.

And a bold heading for a section would be appropriate if a risk was especially great or well-established.

The section cited a study that showed an increased risk of breast cancer in postmenopausal women using estrogen-plus-progestin hormone replacement therapy[1] and a 1999 IARC Summary & evaluation of combined oral contraceptives.[2]

A risk of breast cancer in postmenopausal women using high dose estrogen-plus-progestin HRT is not evidence of a risk of breast cancer in premenopausal women using low dose progestin-only oral contraceptives.

And the Summary & evaluation of progestogen-only hormonal contraceptives [3] in the the same 1999 IARC monograph, concludes regarding breast cancer in humans: "Overall, there is no evidence of an increased risk for breast cancer." JessM 07:40, 16 August 2006 (UTC)

what is known about the risks of progestin only contraceptives=what is known about progestins. (see iarc data regarding 2B status of progestins.) the hrt studies are significant because a very key finding was that progestin+estrogen increases breast cancer risk significantly more than estrogen alone. progestin-only contraception is believed to increase breast cancer risk, esp. for women under 35, and recent or current users. (see medroxyprogesterone acetate in particular). "overall risk" has to be compared to animal studies/different progestins, as there have been no adequate human tests. inadequate human tests does not equal no risk--it means we are assuming the risk. breast cancer is more significant than other gynaecological cancers because it is epidemic by comparison. one misconception about the danger of progestin is that "dose" is the determinant factor/low dose is safer--that is not known. what is known is that women metabolize it differently (depending on size, genes, the type of progestin) and that cancer may begin with disrupted PRA/PRB receptor signalling (mediated by estrogen receptors). there are different types of breast cancer cells, and different progestins cause proliferation in them to greater/lesser degrees...there are many variables, and definitely a need for more study. but progestins are associated with breast cancer risk. (all progestins in the us come with a warning that they should not be used by any woman who has, has had, or suspects she may have breast cancer, as it is a hormone-dependent cancer). Cindery 15:59, 16 August 2006 (UTC)

What is known about the risks of low dose progestin-only oral contraceptives does not = what is known about risks of high dose progestins in HRT. What is known about the risks of low dose progestin-only oral contraceptives = what is known about the risks of low dose progestin-only contraceptives.
The 1999 IARC 2B status of progestins says evidence of carcinogenicity in humans is inadequate (specifically medroxyprogesterone acetate). This Wikipedia article is about progestin-only oral contraceptive pills used by humans. Inadequate evidence of a risk is not evidence of a risk; adequate evidence of a risk is evidence of a risk.
Breast cancer risk in postmenopausal women using high dose estrogen-plus-progestin HRT is not evidence of breast cancer risk in premenopausal women using low dose progestin-only oral contraceptives.
There is a warning against using hormonal contraceptives in women with a current or past history of actually having breast cancer because it is a hormone-sensitive cancer--not a warning that they cause breast cancer.

above is the actual advisory notice sent to doctors warning them that, as i said, there is an increased risk for breast cancer for pill users (pop or cocp) especially users under 35, recent or current use. if you would prefer that we use that as a ref for the breast cancer risk section in the article, i have no objection, as long as the iarc refs and the hrt ref is cited also.

i think it's important for people investigating progestin-only birth control to investigate progestins, and that it is educational/useful to provide links/refs, because:

1) in spite of the official warning above, no comprehensive safety tests have been done on progestins in humans. (they should have been done.) in the absence of comprehensive safety tests, a) that does not conclusively prove there is no risk/low risk--it conclusively proves risk hasn't been established b) animal studies are more significant in the absence of comprehensive human study

2) the progestins used in pops very a great deal

3) dose is a relative factor, not a sole factor

Cindery 18:09, 16 August 2006 (UTC)

Oral contraceptives and breast cancer

  • is not an "official warning"
  • please describe what "comprehensive safety tests" should or could have been done on progestins in humans.
  • please explain how animal studies are more important or informative now than studies of the actual risk of a product that has been in use for over 30 years by millions of women.

Specific objections to your Breast Cancer Risk section:

Progestin-only pills slightly increase the risk of breast cancer, especially in women under 35 who are current or recent users. [4]

  • the 1996 meta-analysis your reference cites is the type of evidence upon which a statement about the breast cancer risk of progestin-only oral contraceptives should be based, but your characterization of it is false and misleading:
    • neither your reference nor the meta-analysis it cites say women under 35 are "especially at risk".
    • the risk the meta-analysis refers to is the risk of a current or recent user of either a COCP or a POP being diagnosed with breast cancer. There was no increased risk of a breast cancer diagnosis in COCP or POP users 10 years after they stopped using the pill.
    • your reference: "Oral contraceptives and breast cancer" says: "There has been no new evidence since the meta-analysis was published in 1996." This is obviously and patently false.

above is NIH link as of 2005 regarding whether log-term effects of the pill are known.

the current summary of known studies is that women under 35 have greater risk/women with current and recent use.

the problem with large scale retro studies/generalizations of all data to date are: 1. no large enough group of women solely using POP (or any progestin only contraceptive) has been followed long term, with control group and control for confounding factors (i.e., lifesytle factors, genes, other known risks for breast cancer.) 2. in the absence of that (which would constitute adequte study/the kind of study which should have been done before progetsin only contraceptives were approved for general use as "proven safe") the real breast cancer risk is not exactly known. (but the breast cancer risk suggested by animal studies is still at issue, and the recent hrt studies have caused a flurry of research/concern for progestins/breast cancer.) 3. some studies have found increased risk, some have not--hence the generalized agreement "risk slightly increased, esp. for women under 35 with recent/current use"--that's imperfect knowledge to date, factoring conflicting studies. Cindery 00:49, 17 August 2006 (UTC)

Animal studies in progestins raise concerns about their carcinogenicity--some more than others.

  • yes, the purpose of animal studies is to raise concerns. They did so, which is why there have since been human epidemiological studies to evaluate the risk. Have there been new animal studies that raise new, previously unknown concerns and make them worthy of mention in an encyclopedia article about the progestin-only pill?

Although the risk of breast cancer per each specific progestin is not specified in the current general warning given to doctors, specific progestins in different POP formulations may have greater or lesser carcinogenicity.

  • your reference is not a "general warning" to doctors about the "carcinogenicity" of progestin-only contraceptives, it is a statement about some of the findings of an important meta-analysis published 10 years ago.
  • saying specific progestins may have greater or lesser carcinogenicity implies they are carcinogenic when used in progestin-only oral contraceptives and is a speculation.

Recently, one of the same progestins used in POP--medroxyprogesterone acetate-- has been found to significantly increase breast cancer risk when used in HRT.[5]

  • please consult Oral contraceptive formulations, medroxyprogesterone acetate is not found in any progestin-only oral contraceptive or in any combination estrogen-progestin oral contraceptive.
  • once again, risk of breast cancer in postmenopausal women using high dose estrogen-plus-progestin HRT is not evidence about breast cancer risk in premenopausal women using low dose progestin-only oral contraceptives.

1999 IARC Summary and evaluation of combined oral contraceptives

  • why cite information about combined estrogen-progestin oral contraceptives instead of:

1999 IARC Summary and evaluation of progestogen-only hormonal contraceptives

"Overall, there is no evidence of an increased risk for breast cancer".

JessM 22:51, 16 August 2006 (UTC)

what it actually says of overall risk is "overall, progestins are possibly carcinogenic to humans." Cindery 01:31, 17 August 2006 (UTC)

Added specific information on relative risk of breast cancer diagnosis for current or recent POP users from 1996 reanalysis and 1999 IARC evaluation.
Removed references to: women under 35, animal study carcinogenicity concerns, speculation about different breast cancer risks in different POP progestins, and reference to medroxyprogesterone acetate which is not in any POP:
  1. Neither the 1996 reanalysis, nor the 1999 IARC review of the 1996 reanalysis and 4 case-control studies of POP users included in the reanalysis, mention any special risk in women under 35.
  2. I could find no recent peer-reviewed publications or medical reference books saying animal studies of progestins predict an increased breast cancer risk in women using current POPs.
  3. The 1996 reanalysis found no difference in breast cancer risk with different progestins.
  4. Medroxyprogesterone acetate has never been used in any progestin-only oral contraceptive (the subject of this article) and does not increase breast cancer risk when used as a progestin-only injectable contraceptive.
Mylor 06:01, 4 September 2006 (UTC)

the oxford study[edit]

the "oxford study" is the large, worldwide compilation/generalization of data as of 1996, from which the "slight increase of risk for women under 35 with recent current use" has become the standard reductive warning. the specific wording which has relevance to POP is below (i.e., type and dose of hormone not relevant).

"Other features of hormonal contraceptive use such as duration of use, age at first use, and the dose and type of hormone within the contraceptives had little additional effect on breast cancer risk, once recency of use had been taken into account."

link to abstract of oxford study:

post 1996 study[edit]

here is an example of a single study, post 1996. it does not tell us if the ocs were cocp or pop or both. (i think that's relevant, which is why i'm reluctant to cite all kinds of single studies.) but per the oxford study observation, we could say dose/type of hormone doesn't matter, and it is relevant. the study notes that women who used ocs under the age of 18 had a doubled risk of breast cancer. many studies find a link between women under 35 (it is speculated that this may be because their breasts undergo more epithelial changes) which is why it was of note in the oxford study. [6] Cindery 01:47, 17 August 2006 (UTC)

Stop revert warring please - it wont help develop the article and both JessM & Cindery risk being reported for breaching intention of WP:3RR and being temporarily blocked.

  • Concerns for effects of female hormone therapy (contraception and HRT) on rates cancers is real enough and thus notable and should be commented upon.
  • Different hormones and at different strengths may or may not have similar effects on cancer rates, but it should be obvious that if progesterones in HRTs are reported (whether scientific papers or general media) as having a risk, then it is not unreasonable for a general reader to wonder about this class of agent as a whole and in particular in COCP & POPs.
  • It seems reasonable, to me, therefore to have at least some mention in POP about progesterones (in general) re cancer, and whether or not evidence then exists (specifically) for risks in POP.
  • I'm all open to discussing how to succinctly in the text explain where progesterones may or may not have an effect and how this is or is not then shown with regards to POP, but having no section on this at all seems, to me, as wrong as being over alarmist for what is clearly only a small (if at all) relative risk.
  • Even if we all agreed with JessM's provided quote of "Overall, there is no evidence of an increased risk for breast cancer" this seems such an important point that it should be mentioned in the article and not just delete the section. A brief (? one sentance) description of why this is thought so might also be appropriate. As as starter, consider the following as a proposal for the start of brief section on various cancer risk discussion. I've tried to cover reason for concern and how this then is answered (it needs citation for HRT risk and the final quote):
Although a small risk of additional breast cancers is suspected with the higher doses of progesterones in HRTs, it is thought for the lower-dose synthetic progesterones of POPs that "overall, there is no evidence of an increased risk for breast cancer".

Please meet each others concerns half-way and help agree on a suitable encyclopaedic consensus (remember wikipedia is not a soapbox to carry out the debate itself, but merely reports on existance of real-world debates) David Ruben Talk 01:41, 17 August 2006 (UTC)

...the actual overall conclusion per IARC is that "overall, progestins are possibly carcinogenic to humans," and this takes into account animal studies re breast cancer risk.

the oxford study should be noted, as it is the "standard."

i actually didn't just "revert"--i tried to rewrite/modify the section to make it less objectionable to jessm. i don't think she should keep automatically deleting the section in its various forms...especially without doing research/trying to contribute to the article in a constructive way by including her objections in the article/citing an alternate reliable source. Cindery 01:58, 17 August 2006 (UTC) Cindery 01:58, 17 August 2006 (UTC)

when progestins are "estrogenic"[edit]

this is a link to just one of hundreds of recent biochem/oncology studies re exogenous hormones and breast cancer. [7] many of them note that PRs (progesterone receptors) and ERs (estrogen receptors) have a very complicated interplay. this study describes how synthetic progestins in oc function estrogenically--through ER not PR receptors/are opposed by an anti-estrogen, not an anti-progestin. the point being i suppose that COCP/POP may not be strictly separate categories, as progestins can be estrogenic as well as progestogenic. Cindery 03:57, 17 August 2006 (UTC)

Norethindrone and related compounds are metabolized to ethinylestradiol in vivo by the aromatase enzyme. Thus these pills are not truly "progestin-only" since they do have some estrogenic activity, albeit less than combined oral contraceptives. -- Kiral 09:04, 17 August 2006 (UTC)

thanks for clarifying that. here is more info about how 19 nors are estrogenic, even beyond aromatase?: "Synthetic 19-nortestosterone derivatives as estrogen receptor alpha subtype-selective ligands induce similar receptor conformational changes and steroid receptor coactivator recruitment than natural estrogens." PMID: 16616843 Cindery 02:12, 18 September 2006 (UTC)

Efficacy Supressing Periods and With Period Pain[edit]

My wife has been on a combined high-dose formulation here in Australia for many, many years. After struggling with the regular pills that have a break in dosage to allow for periods, still getting incredible pain during her periods (enough to make her nearly cry at the thought of it), she did as her doctor suggested and skipped the placebos and finally put an end to her periods altogether. I am worried about the Estrogen (Ethylestradiol) effect on her after so much negative press about it. Is there a Progesterone-only birth control that she can take to escape periods? (do not lecture on the medical ethics and dangers of doing so - she will never hear otherwise, period. Thank you.)

Wikipedia, and for that matter any forum or website, is not the place to go assessing risks or deciding bewteen alternatives that are specifically appropriate for your wife - resee your doctor to discuss issues such as risks and alternatives (but bear in mind I read the above as indicating that the continuous combined pills are working and giving your wife a life now, presuming too that occasional breaks still taken to help prevent endometrial hyperplasia (over development)). David Ruben Talk 09:37, 25 November 2006 (UTC)

Medical Debate Surrounding POPs Effect on Endometrial Lining[edit]

There is considerable medical debate surrounding whether the thinning effect POPs have on the lining of the endometrium contributes in any significancy to the prevention of implantation of a blastocyst and thereby the prevention of a clinincally recognized pregnancy. This mechanism of action is not discussed at all in this article, and I believe it would benefit from a section describing this. What do other editors think? Brad 00:51, 28 December 2006 (UTC)

I agree that the article would benefit from such a section. Lyrl Talk Contribs 01:34, 28 December 2006 (UTC)
What "considerable medical debate"?
POPs have a significant share of the oral contraceptive market in the UK (~20%)[8], Australia, New Zealand and Scandinavia, but not in the US (0.2% in 1993).PMID 10226677
In the US, the only available POPs -- Micronor/Nor-QD (norethindrone) and Orvette (norgestrel) -- were approved 33 years ago.
The mechanism of action is already described in the "How they work" section of the article:
The mechanism of action of progestogen-only contraceptives depends on the progestogen activity and dose.
Very low dose progestogen-only contraceptives, such as traditional progestogen-only pills (and subdermal implants Norplant and Jadelle and intrauterine systems Progestasert and Mirena), inconsistently inhibit ovulation in ~50% of cycles and rely mainly on their progestogenic effect of thickening the cervical mucus and thereby reducing sperm viability and penetration.
Intermediate dose progestogen-only contraceptives, such as the progestogen-only pill Cerazette (or the subdermal implant Implanon), allow some follicular development but much more consistently inhibit ovulation in 97–99% of cycles. The same cervical mucus changes occur as with very low dose progestogens.
In anovulatory cycles using progestogen-only contraceptives, the endometrium is thin and atrophic. If the endometrium was also thin and atrophic during an ovulatory cycle, this could theoretically interfere with implantation of a blastocyst (embryo).
The source is the Progestogen-Only Contraceptives section of Anna Glasier's chapter on Contraception in the 2006 5th edition of DeGroot & Jameson's Endocrinology[9].
Mylor 06:06, 28 December 2006 (UTC)

Is there really any considerable medical debate regarding whether POPs adversely affect the endometrial lining so as to interfere with the implantation of a fertilised egg? A Google search on 'how do Progestogen only pills work' made me ask that question. Four of the first five results listed a 'thinning of the endometrial lining' as a secondary mechanism of action that inhibited implantation post-fertilization.

The fifth site (first in order of ranking) was Wikipedia's article under discussion here. Multiple other sites that did not list such a mechanism as an accepted secondary action discussed the disagreement surrounding whether it contributed. Several further sites discussed the medical debate itself:

For a paper summarizing research in this area, see Walter L. Larimore, MD; Joseph B. Stanford, MD, MSPH, "Postfertilization Effects of Oral Contraceptives and Their Relationship to Informed Consent" (

Something influenced those four top sites to list the thinning of the endometrial lining, so it seemed to me there is some debate as to whether this is a mechanism of action of the POP in inhibiting pregnancy, I would think? Either it is simple rumor or misinformation, outright deception, or a debateable mechanism. Either way, I would think this article would benefit from discussing it? Brad 13:25, 28 December 2006 (UTC)

An anonymous editor recently added stronger language about postfertilization effects. While I believe more information on these is needed, since this is a controversial subject I really want to see sources for any added discussion in the article. Since the recent edits lacked sources, I have reverted them. Lyrl Talk C 00:11, 27 January 2007 (UTC)

Weight gain parameter in infobox[edit]

I would like to treat this parameter the same on all the hormonal contraception articles. Please read my opinion and discuss this issue at Talk:Combined oral contraceptive pill#Weight parameter in infobox. LyrlTalk C 21:30, 20 August 2007 (UTC)

Weight gain[edit]

I've removed the statement that the POP causes less weight gain than the COCP as the COCP doesn't cause weight gain (reference to Cochrane review in the COCP article) so I think the previous wording was misleading Zchahe7 (talk) 14:45, 24 February 2014 (UTC)