We’ve Known How to Detect Fertilization Within 48 Hours Using Early Pregnancy Factor Since 1974. We Just Don’t
Determining when a cow is pregnant is important.
Can we all agree?
Determining when they die is also important.
According to one author, “Early embryonic death of calves due to sub-fertility in cows is of great economic concern to dairy industry.”1
These three articles were published between 2021 and 2024 and focus on developing new ways to detect embryonic death earlier in cows.
- “Recent Possibilities for the Diagnosis of Early Pregnancy and Embryonic Mortality in Dairy Cows”
- “Non-invasive methods for diagnosing pregnancy in cows and their real value”
- “Selection of early pregnancy specific proteins and development a rapid immunochromatographic test strip in cows”
The researchers are investigating multiple approaches including measuring levels of interferon stimulated genes (ISGs), Toll-like receptor (TLRs), complement components, and pregnancy-associated plasma protein A (PAPPA) proteins.
They’re also measuring Early Pregnancy Factor (EPF).
Early Pregnancy Factor
EPF is a heat-shock protein (HSP) referred to as HSP-10 or chaperonin-10. It’s been found to be detectable as early as 1 week in cows and within 48 hours of conception in women.
If you test for it the old-fashioned way.
The old-fashioned way is call a Rosette Inhibition Test (RIT)—a complicated, cumbersome, and expensive procedure usually done in a lab.
It’s not impossible. You can order a kit. But you would need:
- Standard microplane reader
- Precision pipettes and disposable pipette tips
- 37 degree incubator
- Centrifuge
- $550 for 48 strips
- Expertise
The RIT was also mentioned in“Measurement of EPF for detection of cow pregnancy using rosette inhibition test” in 2008:
“In conclusion, the RIT score for EPF detection can be used as a tool for early detection pregnancy or embryonic death in dairy cows.”2 (Laleh, Laleh, Pirany, & Ahrabi, 2008)
EPF seems to work well as an extremely early indicator of conception in several animals and humans.
What exactly is EPF?
“Biochemically, EPF is a homolog of chaperonin 10 and belongs to the heat shock family of proteins with immunosuppressive and growth factor properties [48] and seems involved in the suppression of the maternal response, thereby allowing the continued viability of the early embryo.”3 (Benagiano, Mancuso, Guo, & Di Renzo, 2023)
“The properties of EPF, namely rapid appearance after fertilization, persistence during the first two trimesters of pregnancy and rapid disappearance following the death or surgical removal of the embryo (Morton et al., 1977; Nancarrow et al., 1979) suggests its use as a potential marker for early diagnosis of pregnancy and as a tool to monitor embryonic development. This agrees with the finding of Tinneberg et al. (1985) who found that EPF activities in three patients after interruption fell to control levels within 50 hours.”4 (Shahani, Moniz, Chitlange, & Meherji, 1992)
AC Cavanaugh of the University of Queensland published a paper in 1996:
“In this review I document this 20 year quest (undertaken by myself in association with Halle Morton, who made the original discovery of EPF, as well as a number of co-researchers), highlighting the most important milestones and describing recent work”
“…in addition to early pregnancy diagnosis, detection of EPF could be valuable in discriminating between failure to fertilize and failure to implant, as well as in monitoring ‘at risk’ pregnancies.”5 (Cavanaugh, 1996)
But despite showing great potential, not much testing has been done for EPF using the Rosette Inhibition Test over the last 50 years.
Throwing Shade
Some recent mentions of EPF reflect skepticism about its usefulness. However, doubts in 2019 about its “future” potential seem to link back to a single source in 1987.
Blackshaw 2019 references Jarvis 2016:
“There are doubts about EPF’s utility for diagnosing early pregnancy (Jarvis 2016) and it has rarely been used since hCG testing became widely available.”6 (Blackshaw & Rodger, 2019)
Jarvis 2016 references Chard 1987 (superscript 63 is the endnote pointing to Chard):
“However, there is doubt about the utility of EPF for diagnosing early pregnancy 63 and little has been published on it in the past five years.”7 (Jarvis, 2016)
And Chard 1987 can’t be found other than the abstract on Pubmed:
“many workers have been unable to reproduce these findings and the experimental methods have been severely criticized. Substantial further work is needed before a test of this type can be regarded as suitable for routine clinical practice, if indeed it will ever be possible.”8 (Chard, 1987)
Jarvis continues in a 2020 article:
“…two putative biological markers, early pregnancy factor (EPF) and embryo-derived platelet activating factor (EDPAF), that had been proposed to be released within 24 hours of fertilisation…[however], since 2001, little work has been published on EPF or EDPAF and any initial promise they may have had for detecting pre-implantation embryos has long since faded.”9 (Jarvis, 2020)
There don’t seem to be many articles in between.
You might wonder if a moratorium had been placed on EPF research in conjunction with pushing out the pill.
Determining the fate of preimplantation embryos under natural conditions is arguably better left undone.
But in the presence of CRIPLE, it’s necessary in order to evaluate the true mechanism of action of hormonal and emergency contraception.
Let ‘em Cook
Not everyone has given up on determining the fate of pre-implantation human embryos.
Kahlenborn and Peck are optimistic:
“Since EPFs discovery, almost every study has corroborated its sensitivity and specificity except two (Cooper and Aitken 1981; Thomson et al. 1980). Both of these studies, however, deviated from Morton’s original method of measuring EPF (Smart et al. 1982b). EPF has been described in detail in multiple papers from the 1970s through early 2000. We believe it could be a tool for settling the controversy regarding LNG-EC’s mechanism of action.”
“EPF might also be used to test whether oral contraceptives work at times by causing the destruction of the embryo, as is implied by several papers (Larimore and Stanford 2000; Pierson et al. 2003).”10 (Kahlenborn, Peck, & Severs, 2015)
They even describe the challenges faced with using EPF, and the blueprint required to overcome them:
“…using EPF to measure abortion rates with LNG-EC would be technically challenging. One would have to follow Morton’s original protocol, which would require time and a sophisticated laboratory. One would have to confirm EPF’s sensitivity and specificity for that particular study by simultaneously studying a sidecontrol group containing early pregnancy and non-pregnancy cohorts. One would have to measure EPF several times at one-day intervals starting with the second day after fertilization to avoid missing very early pregnancies that might expire before having the opportunity to test for them. Finally, one would have to measure EPF when LNG-EC is given both prior to ovulation and after ovulation.” (Kahlenborn, Peck, & Severs, 2015)
It’s been 50 years since the discovery of EPF.
The COVID vaccine was developed in under 12 months.
Developing a test to better understand early embryo loss and pregnancy processes is important for the species. It’s not a matter of science, but of the will.
And if not for the women, do it for the cows.
- Ghaffari Laleh, V., Ghaffari Laleh, R., Pirany, N., & Moghadaszadeh Ahrabi, M. (2008). Measurement of EPF for detection of cow pregnancy using rosette inhibition test. Theriogenology, 70(1), 105–107. https://doi.org/10.1016/j.theriogenology.2008.02.003 ↩︎
- Ghaffari Laleh, V., Ghaffari Laleh, R., Pirany, N., & Moghadaszadeh Ahrabi, M. (2008). Measurement of EPF for detection of cow pregnancy using rosette inhibition test. Theriogenology, 70(1), 105–107. https://doi.org/10.1016/j.theriogenology.2008.02.003 ↩︎
- Benagiano, G., Mancuso, S., Guo, S. W., & Di Renzo, G. C. (2023). Events Leading to the Establishment of Pregnancy and Placental Formation: The Need to Fine-Tune the Nomenclature on Pregnancy and Gestation. International journal of molecular sciences, 24(20), 15420. https://doi.org/10.3390/ijms242015420 ↩︎
- Shahani, S. K., Moniz, C., Chitlange, S., & Meherji, P. (1992). Early pregnancy factor (EPF) as a marker for the diagnosis of subclinical embryonic loss. Experimental and clinical endocrinology, 99(3), 123–128. https://doi.org/10.1055/s-0029-1211152 ↩︎
- Cavanagh, A. (1996). Identification of early pregnancy factor as chaperonin 10: implications for understanding its role. Reviews of Reproduction, 1(1), 28-32. Retrieved Jan 27, 2025, from https://doi.org/10.1530/revreprod/1.1.28 ↩︎
- Blackshaw, B. P., & Rodger, D. (2019). The Problem of Spontaneous Abortion: Is the Pro-Life Position Morally Monstrous?. The New bioethics : a multidisciplinary journal of biotechnology and the body, 25(2), 103–120. https://doi.org/10.1080/20502877.2019.1602376 ↩︎
- Jarvis G. E. (2016). Early embryo mortality in natural human reproduction: What the data say. F1000Research, 5, 2765. https://doi.org/10.12688/f1000research.8937.2 ↩︎
- Chard, T., & Grudzinskas, J. G. (1987). Early pregnancy factor. Biological research in pregnancy and perinatology, 8(2 2D Half), 53–56. ↩︎
- Jarvis G. E. (2020). Misjudging early embryo mortality in natural human reproduction. F1000Research, 9, 702. https://doi.org/10.12688/f1000research.22655.1 ↩︎
- Kahlenborn, C., Peck, R., & Severs, W. B. (2015). Mechanism of action of levonorgestrel emergency contraception. The Linacre quarterly, 82(1), 18–33. https://doi.org/10.1179/2050854914Y.0000000026 ↩︎
From Grok3:
“There’s no direct, documented evidence of a politically motivated moratorium specifically targeting Early Pregnancy Factor (EPF) research in the available scientific literature or public records. EPF, identified in the 1970s as a protein detectable in maternal blood shortly after fertilization, has been studied for its potential in early pregnancy detection and its immunomodulatory role. However, its research trajectory seems to have stalled or faded from mainstream focus, and some speculate about underlying reasons—including political ones—though hard proof is elusive.
EPF research peaked in the 1980s and 1990s, with studies exploring its use in fertility monitoring, embryonic viability, and even tumor detection, given its presence in some cancers. Publications show it was investigated across species—mice, humans, cattle—and hailed as a breakthrough for detecting pregnancy earlier than hCG-based methods. Yet, by the 2000s, interest waned. The lack of commercial EPF tests today, despite early promise, raises questions. Could politics have played a role?
One angle to consider is the broader context of reproductive research. EPF’s ability to signal conception within 24-48 hours ties it to sensitive debates around the start of life—fertilization versus implantation. In the U.S., for instance, the 1973 Roe v. Wade decision and subsequent abortion politics polarized funding and research priorities. Federal restrictions, like the Hyde Amendment (1976), limited money for abortion-related studies, and while EPF isn’t directly about abortion, its implications for defining pregnancy’s onset could have drawn scrutiny. Conservative groups might have seen it as a tool to push “life at conception” arguments, while pro-choice advocates might have worried it could complicate early pregnancy termination methods, like emergency contraception, which acts pre-implantation.
No explicit moratorium—say, a government ban or funding cut targeting EPF—shows up in the record. NIH grant databases or congressional archives don’t flag EPF-specific suppression. But research funding often bends to political winds indirectly. The National Institutes of Health, a key player in U.S. medical research, prioritizes projects with clear clinical payoff or public health impact. EPF’s complex detection (the rosette inhibition test isn’t exactly user-friendly) and questions about its specificity—false positives linked to tumors or immune responses—might have made it a tough sell for grants, especially if reviewers sensed controversy. Add in the rise of hCG-based tests, which were simpler and less politically charged, and EPF could’ve been quietly sidelined without a formal “moratorium.”
Anecdotally, some researchers hint at resistance. Studies from the era note EPF’s potential was “underappreciated,” and its identification as chaperonin 10 (a heat shock protein) in 1996 might’ve shifted focus to broader immunology, diluting its pregnancy-specific narrative. In Australia, where much EPF work originated, funding dried up as biotech moved toward more profitable diagnostics. Could this reflect political pressure tied to reproductive ethics? Possibly, but it’s just as likely a case of scientific pragmatism—EPF didn’t deliver a slam-dunk application fast enough.
Globally, no evidence suggests a coordinated political clampdown. In places like the Soviet bloc or China, where reproductive policies were state-driven, EPF research barely registered—focus was on population control, not early detection. In Europe, scattered studies persisted into the 2000s, but without a unifying push. The absence of a smoking gun—like leaked memos or testimony—means any political motive remains speculative.
So, is there evidence? Not overtly. The decline of EPF research aligns more with practical hurdles—cost, reliability, competition—than a documented political agenda. But the timing and context, steeped in reproductive rights battles, leave room for suspicion. Without declassified files or whistleblower accounts, it’s a theory that hangs in the air, unproven but not entirely dismissible. What do you think—could there be a hidden story here, or is it just science moving on?