Editing GroES (section)

== Clinical utility ==

=== Pregnancy testing ===

It has been suggested that EPF could be used as a marker for a very [[early pregnancy test]], and as a way to monitor the viability of ongoing pregnancies in livestock.<ref name="sheep1979" />  Interest in EPF for this purpose has continued,<ref>{{cite journal | vauthors = Sakonju I, Enomoto S, Kamimura S, Hamana K | title = Monitoring bovine embryo viability with early pregnancy factor | journal = The Journal of Veterinary Medical Science | volume = 55 | issue = 2 | pages = 271–4 | date = Apr 1993 | pmid = 8513008 | doi=10.1292/jvms.55.271| doi-access = free }}</ref> although current test methods have not proved sufficiently accurate for the requirements of livestock management.<ref name="pig">{{cite journal | vauthors = Greco CR, Vivas AB, Bosch RA | title = [Evaluation of the method for early pregnancy factor detection (EPF) in swine. Significance in early pregnancy diagnosis] | journal = Acta Physiologica, Pharmacologica et Therapeutica Latinoamericana | volume = 42 | issue = 1 | pages = 43–50 | year = 1992 | pmid = 1294272 }}</ref><ref>{{cite journal | vauthors = Sasser RG, Ruder CA | title = Detection of early pregnancy in domestic ruminants | journal = Journal of Reproduction and Fertility. Supplement | volume = 34 | pages = 261–71 | year = 1987 | pmid = 3305923 }}</ref><ref>{{cite journal | vauthors = Gandy B, Tucker W, Ryan P, Williams A, Tucker A, Moore A, Godfrey R, Willard S | title = Evaluation of the early conception factor (ECF) test for the detection of nonpregnancy in dairy cattle | journal = Theriogenology | volume = 56 | issue = 4 | pages = 637–47 | date = Sep 2001 | pmid = 11572444 | doi = 10.1016/S0093-691X(01)00595-7 }}</ref><ref>{{cite journal | vauthors = Cordoba MC, Sartori R, Fricke PM | title = Assessment of a commercially available early conception factor (ECF) test for determining pregnancy status of dairy cattle | journal = Journal of Dairy Science | volume = 84 | issue = 8 | pages = 1884–9 | date = Aug 2001 | pmid = 11518314 | doi = 10.3168/jds.S0022-0302(01)74629-2 | doi-access = free }}</ref>

In humans, modern [[pregnancy test]]s detect [[human chorionic gonadotropin]] (hCG).  hCG is not present until after implantation, which occurs six to twelve days after fertilization.<ref>{{cite journal | vauthors = Wilcox AJ, Baird DD, [[Clarice Weinberg|Weinberg CR]] | title = Time of implantation of the conceptus and loss of pregnancy | journal = The New England Journal of Medicine | volume = 340 | issue = 23 | pages = 1796–9 | date = Jun 1999 | pmid = 10362823 | doi = 10.1056/NEJM199906103402304 | doi-access = free }}</ref>  In contrast, EPF is present within hours of fertilization.  While several other pre-implantation signals have been identified, EPF is believed to be the earliest possible marker of pregnancy.<ref name="mice" /><ref>{{cite journal | vauthors = Straube W | title = [Early embryonal signals] | journal = Zentralblatt für Gynäkologie | volume = 111 | issue = 10 | pages = 629–33 | year = 1989 | pmid = 2665388 }}</ref>  The accuracy of EPF as a pregnancy test in humans has been found to be high by several studies.<ref>{{cite journal | vauthors = Smart YC, Roberts TK, Fraser IS, Cripps AW, Clancy RL | title = Validation of the rosette inhibition test for the detection of early pregnancy in women | journal = Fertility and Sterility | volume = 37 | issue = 6 | pages = 779–85 | date = Jun 1982 | pmid = 6177559 | doi = 10.1016/S0015-0282(16)46338-7 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Bessho T, Taira S, Ikuma K, Shigeta M, Koyama K, Isojima S | title = [Detection of early pregnancy factor in the sera of conceived women before nidation] | journal = Nihon Sanka Fujinka Gakkai Zasshi | volume = 36 | issue = 3 | pages = 391–6 | date = Mar 1984 | pmid = 6715922 }}</ref><ref>{{cite journal | vauthors = Straube W, Tiemann U, Loh M, Schütz M | title = Detection of early pregnancy factor (EPF) in pregnant and nonpregnant subjects with the rosette inhibition test | journal = Archives of Gynecology and Obstetrics | volume = 246 | issue = 3 | pages = 181–7 | year = 1989 | pmid = 2619332 | doi = 10.1007/BF00934079 | s2cid = 20531983 }}</ref><ref>{{cite journal | vauthors = Fan XG, Zheng ZQ | title = A study of early pregnancy factor activity in preimplantation | journal = American Journal of Reproductive Immunology | volume = 37 | issue = 5 | pages = 359–64 | date = May 1997 | pmid = 9196793 | doi = 10.1111/j.1600-0897.1997.tb00244.x | s2cid = 71525444 }}</ref>

=== 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>

=== Infertility and early pregnancy loss ===

EPF is useful when investigating [[embryo loss]] prior to implantation.  One study in healthy human women seeking pregnancy detected fourteen pregnancies with EPF.  Of these, six were [[Spontaneous abortion|lost]] within ten days of [[ovulation]] (43% rate of early conceptus loss).<ref>{{cite journal | vauthors = Smart YC, Fraser IS, Roberts TK, Clancy RL, Cripps AW | title = Fertilization and early pregnancy loss in healthy women attempting conception | journal = Clinical Reproduction and Fertility | volume = 1 | issue = 3 | pages = 177–84 | date = Sep 1982 | pmid = 6196101 }}</ref>

Use of EPF has been proposed to distinguish infertility caused by failure to conceive versus infertility caused by failure to implant.<ref>{{cite journal | vauthors = Mesrogli M, Maas DH, Schneider J | title = [Early abortion rate in sterility patients: early pregnancy factor as a parameter] | journal = Zentralblatt für Gynäkologie | volume = 110 | issue = 9 | pages = 555–61 | year = 1988 | pmid = 3407357 }}</ref>  EPF has also been proposed as a marker of viable pregnancy, more useful in distinguishing ectopic or other nonviable pregnancies than other chemical markers such as hCG and [[progesterone]].<ref>{{cite journal | vauthors = Straube W, Loh M, Leipe S | title = [Significance of the detection of early pregnancy factor for monitoring normal and disordered early pregnancy] | journal = Geburtshilfe und Frauenheilkunde | volume = 48 | issue = 12 | pages = 854–8 | date = Dec 1988 | pmid = 2466731 | doi = 10.1055/s-2008-1026640 | s2cid = 260158786 }}</ref><ref>{{cite journal | vauthors = Gerhard I, Katzer E, Runnebaum B | title = The early pregnancy factor (EPF) in pregnancies of women with habitual abortions | journal = Early Human Development | volume = 26 | issue = 2 | pages = 83–92 | year = 1991 | pmid = 1720719 | doi = 10.1016/0378-3782(91)90012-R }}</ref><ref>{{cite journal | vauthors = Shu-Xin H, Zhen-Qun Z | title = A study of early pregnancy factor activity in the sera of patients with unexplained spontaneous abortion | journal = American Journal of Reproductive Immunology | volume = 29 | issue = 2 | pages = 77–81 | date = Mar 1993 | pmid = 8329108 | doi = 10.1111/j.1600-0897.1993.tb00569.x | s2cid = 22163702 }}</ref><ref>{{cite journal | vauthors = Shahani SK, Moniz CL, Bordekar AD, Gupta SM, Naik K | title = Early pregnancy factor as a marker for assessing embryonic viability in threatened and missed abortions | journal = Gynecologic and Obstetric Investigation | volume = 37 | issue = 2 | pages = 73–6 | year = 1994 | pmid = 8150373 | doi = 10.1159/000292528 }}</ref>

=== As a tumour marker ===

Although almost exclusively associated with pregnancy, EPF-like activity has also been detected in tumors of germ cell origin<ref>{{cite journal | vauthors = Rolfe BE, Morton H, Cavanagh AC, Gardiner RA | title = Detection of an early pregnancy factor-like substance in sera of patients with testicular germ cell tumors | journal = American Journal of Reproductive Immunology | volume = 3 | issue = 2 | pages = 97–100 | date = Mar 1983 | pmid = 6859385 | doi = 10.1111/j.1600-0897.1983.tb00223.x | s2cid = 33423830 }}</ref><ref>{{cite journal | vauthors = Mehta AR, Shahani SK | title = Detection of early pregnancy factor-like activity in women with gestational trophoblastic tumors | journal = American Journal of Reproductive Immunology and Microbiology | volume = 14 | issue = 3 | pages = 67–9 | date = Jul 1987 | pmid = 2823620 | doi=10.1111/j.1600-0897.1987.tb00122.x}}</ref> and in other types of tumors.<ref>{{cite journal | vauthors = Quinn KA, Athanasas-Platsis S, Wong TY, Rolfe BE, Cavanagh AC, Morton H | title = Monoclonal antibodies to early pregnancy factor perturb tumour cell growth | journal = Clinical and Experimental Immunology | volume = 80 | issue = 1 | pages = 100–8 | date = Apr 1990 | pmid = 2323098 | pmc = 1535227 | doi = 10.1111/j.1365-2249.1990.tb06448.x }}</ref>  Its utility as a tumour marker, to evaluate the success of surgical treatment, has been suggested.<ref>{{cite journal | vauthors = Bojahr B, Straube W, Reddemann H | title = [Case observations on the significance of early pregnancy factor as a tumor marker] | journal = Zentralblatt für Gynäkologie | volume = 115 | issue = 3 | pages = 125–8 | year = 1993 | pmid = 7682025 }}</ref>