Tuesday September 24 2013
A post-fertilisation pill could work up to a month after sex
"'Once-a-month contraceptive pill is scientifically possible,” The Guardian says, covering a story that the Mail Online describes as “abortion by the back door”.
These headlines are not based on any new drugs, or even research. Instead they focus on a controversial opinion piece calling for research into creating a post-fertilisation contraceptive to be carried out.
The piece, published in the Journal of Family Planning and Reproductive Health Care, discusses possible future “post-fertilisation methods of birth control” that work to prevent implantation after a sperm and an egg have joined.
Current oral contraceptive pills, such as the combined or progestogen-only pill, primarily aim to prevent the sperm and egg from meeting in the first place.
Emergency contraception (the “morning after pill”) and intrauterine devices stop the egg from being fertilised or implanted into the womb and are effective for up to five days after intercourse. The researchers describe a pill that they envision would be effective for up to a month after intercourse.
Have scientists produced a contraceptive pill that works once a month?
No, this article is an opinion piece and does not provide evidence on the efficacy or acceptability of such a form of birth control. Headlines suggesting that a new pill has been developed are not accurate. There is no such pill licensed at the current time.
The piece briefly discusses the technical feasibility of developing such a form of birth control, and outlines expected areas of both support and opposition. The authors call for funding to pursue research into new birth control methods that would work after an egg has been fertilised.
The article, which suggests that such a birth control option is scientifically feasible, will likely find both opposition and support. And, perhaps most importantly, calls for legislators and policymakers to understand the evidence surrounding birth control options “in order to avoid bad decisions based on misinformation”.
What do the authors say about post-fertilisation contraception?
The article covers four main points:
- scientific feasibility – development of a birth control medicine after fertilisation of an egg is described as possible, if technically challenging
- sources of likely opposition – the authors suggest the development of such a birth control method would be held back by politics rather than science – they suggest that such options (especially those that would disrupt pregnancy after the fertilised egg has already implanted in the lining of the uterus) would face vehement opposition
- sources of likely support – the authors quote several potential sources of support, including that data indicates terminating a pregnancy is safer earlier in pregnancy. They also cite a 20-year-old survey that indicated that many women were likely to accept the idea of a post-fertilisation contraceptive pill
- call for research funding – finally, the article authors suggest that in the face of such potential political opposition, funding for such research will likely need to come from non-governmental donors
What is the need for a ‘post-fertilisation’ birth control?
In general, the combined oral contraceptive pill as we currently know it works by interfering with ovulation (stopping the ovaries releasing an egg each month) and preventing fertilisation of the egg (it makes cervical mucus thicker, which acts as a barrier to sperm). As discussed in this opinion piece, a post-fertilisation pill would disrupt the pregnancy process after the sperm and egg have come together.
When taken correctly (meaning regularly, without missing any pills), existing pre-fertilisation-combined hormonal contraceptive pills are over 99% effective at preventing pregnancy.
Other pre-fertilisation contraceptive methods – including other hormonal birth controls (such as the pill, the patch and the implant), as well as use of condoms and other barrier methods – vary in how they work and how well they work.
The authors suggest that a post-fertilisation pill would give women more birth control options and could be a “failsafe” if existing methods do not work. The article suggests that because a pill could potentially be taken monthly (or even less frequently) it would reduce the chances of unwanted pregnancy arising due to difficulties sometimes faced in getting hold of contraceptives before sex.
How could 'post-fertilisation' birth control become a reality?
The authors do not thoroughly address the technical details of “post-fertilisation” birth control, but suggest that progesterone receptor modulators may be one route. Progesterone receptors are proteins in women’s bodies that interact with progesterone. These modulators can disrupt the normal working of progesterone receptors.
They also suggest that combining progesterone receptor modulators with the hormone prostaglandin could – feasibly – lead to the termination of a pregnancy up to a month after intercourse has taken place by preventing the implantation of a fertilised egg into the uterus lining.
It is important to note that these are only suggestions and do not represent a “new contraceptive pill” as suggested by media headlines. There is currently no known research taking place into post-fertilisation contraception.
Also, significant research would be needed to establish the efficacy of such an approach, to say nothing of public discussion surrounding acceptability.
Would this be a form of abortion?
The ethics around this are complicated, but the authors report that current UK (and US) law defines pregnancy as beginning when a fertilised egg is implanted in the uterus.
By that definition, a potential birth control method that acted after egg fertilisation, but before implantation took place, would not legally be considered abortion (medically speaking, “termination of pregnancy”).
They point out that this legal definition is not considered stringent enough by some. It is almost certain that post-fertilisation/pre-implantation birth control methods would likely be considered abortion by some individuals, pressure groups and religious organisations.
Current emergency contraceptives (“morning after pills”) are believed to act primarily by preventing or delaying ovulation rather than acting post-fertilisation. However, other intrauterine devices such as the copper coil (which may be used both as emergency contraception and conventional contraception), are believed to act primarily post-fertilisation, preventing a fertilised egg from implanting in the lining of the uterus. In this respect there are therefore certain birth control methods already in current use that may also work post-fertilisation.
This article discusses potential post-fertilisation birth control methods that would work by disrupting pregnancy after fertilisation. Public, and even expert, opinion may be divided on whether this would be a technically considered a form of abortion or not, even if legally it is not.
How has the media covered ‘post-fertilisation’ birth control?
Media coverage of the opinion piece varied, with headlines from the Daily Mail suggesting that such a pill already exists (“new contraceptive pill that can be taken a month after sex is attacked by campaigners as ‘abortion by the back door’”), while The Guardian’s coverage makes clear from the headline that this is not the case and is a more appropriate portrayal of the article (“one-a-month contraceptive pill is scientifically possible, say experts”).
However, the Mail Online also sought out responses from groups who do not agree with the piece, whereas The Guardian only published the article author’s comments.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.