Editing GroES (section)

=== Birth control research ===

EPF may also be used to determine whether pregnancy prevention mechanism of [[birth control]] methods act before or after fertilization.  A 1982 study evaluating EPF levels in women with [[Intrauterine device|IUDs]] concluded that post-fertilization mechanisms contribute significantly{{quantify|date=August 2008}}  to the effectiveness of these devices.<ref>{{cite journal | vauthors = Smart YC, Fraser IS, Clancy RL, Roberts TK, Cripps AW | title = Early pregnancy factor as a monitor for fertilization in women wearing intrauterine devices | journal = Fertility and Sterility | volume = 37 | issue = 2 | pages = 201–4 | date = Feb 1982 | pmid = 6174375 | doi = 10.1016/S0015-0282(16)46039-5 | doi-access = free }}</ref>  However, more recent evidence, such as tubal flushing studies indicates that IUDs work by inhibiting fertilization, acting earlier in the reproductive process than previously thought.<ref name=CT-IUD>{{cite book |author=Grimes, David |year=2007 |chapter=Intrauterine Devices (IUDs) |editor=Hatcher, Robert A. |title=Contraceptive Technology |edition=19th rev. |location=New York |publisher=Ardent Media |isbn=978-0-9664902-0-6 |page=[https://archive.org/details/contraceptivetec00hatc/page/120 120] |display-editors=etal |chapter-url-access=registration |chapter-url=https://archive.org/details/contraceptivetec00hatc/page/120 }}</ref>

For groups that define [[beginning of pregnancy controversy|pregnancy as beginning with fertilization]], birth control methods that have postfertilization mechanisms are regarded as [[abortifacient]].  There is currently contention over whether [[hormonal contraception]] methods have post-fertilization methods, specifically the most popular hormonal method: the [[combined oral contraceptive pill]] (COCP).  The group Pharmacists for Life has called for a large-scale clinical trial to evaluate EPF in women taking COCPs; this would be the most conclusive evidence available to determine whether COCPs have postfertilization mechanisms.<ref>{{cite journal | author =  Lloyd J DuPlantis, Jr | title = Early Pregnancy Factor | publisher = Pharmacists for Life, Intl | year = 2001 | url = http://www.lifeissues.net/writers/dup/dup_01earlypregfacts.html | access-date = 2007-01-01 }}</ref>