Fett broadens the scope of fertility challenges by turning her attention to the often-overlooked role of the immune system and uterine environment in implantation failure and recurrent pregnancy loss. While previous chapters focus largely on gamete quality, Fett argues that even chromosomally normal embryos can fail to implant if silent infections, endometriosis, or immune dysfunction are present—conditions that are surprisingly common, frequently undiagnosed, and sometimes entirely asymptomatic. Drawing from recent advances in reproductive immunology and endometrial testing, she introduces a range of diagnostic tools such as EMMA/ALICE microbiome tests, ReceptivaDX, and various antibody screenings to uncover hidden causes of infertility. Through studies showing dramatic increases in live birth rates after antibiotic or immunological treatment, Fett illustrates the tangible value of these tests, especially in cases of repeated IVF failure or pregnancy loss. Yet she also reveals the systemic inertia of modern medicine: Many clinicians hesitate to explore immune or microbial causes unless a patient has experienced multiple losses, reinforcing a model of care that is reactive rather than preventative.

This chapter not only demonstrates scientific rigor but also encourages readers to challenge conventional treatment pathways. Fett identifies a critical lag between emerging scientific evidence and mainstream clinical practice, urging readers to self-advocate in an environment where access to newer diagnostics remains uneven. However, the chapter is not without its weaknesses. It implicitly assumes that readers have access to fertility specialists, advanced testing, and the financial resources to pursue non-standard care, privileges not universally shared. Moreover, its recommendations lean on a biomedical model of fertility, sidelining social determinants like stress from systemic racism, lack of healthcare access, or reproductive coercion. That said, Fett’s meticulous breakdown of how conditions like endometritis, endometriosis, autoimmune antibodies, and clotting disorders can interfere with implantation offers clarity in a field often clouded by mystique or dismissal. Her coverage of controversial areas like natural killer cells, HLA matching, and experimental immunotherapies like IVIG and PRP is balanced, acknowledging limitations while still valuing individualized care. Comparatively, this chapter represents a nuanced update to older works like Dr. Alan Beer’s Is Your Body Baby-Friendly? but with far more emphasis on empirical evidence and less reliance on sweeping generalizations about immune dysfunction.

Fett’s writing is especially relevant in a fertility climate where reproductive technologies continue to advance rapidly while clinical protocols lag behind. Her work resonates with the cultural rise in patients taking control of their own reproductive narratives—researching, self-testing, and pressing for answers rather than accepting unexplained diagnoses. The chapter reflects a pragmatic shift in fertility literature: away from the sole focus on eggs and embryos and toward the complex, integrated systems that support implantation. In doing so, Fett invites readers not only to explore new possibilities for diagnosis and treatment but also to rethink the boundaries of what can and should be medically investigated before enduring repeated loss.

Chapter Lessons

• Even high-quality, chromosomally normal embryos may fail to implant due to undetected immune issues, infections, or inflammation in the uterus.
• Conditions like chronic endometritis, endometriosis, and abnormal immune responses are common and often asymptomatic, yet they can significantly affect fertility outcomes.
• Diagnostic tests such as EMMA, ALICE, ReceptivaDX, and various antibody screenings can uncover hidden causes of recurrent implantation failure or pregnancy loss.
• Although research supports immune-related treatments in select cases, many clinics remain hesitant to offer testing or intervention unless multiple IVF failures have occurred.

Reflection Questions

• If you have experienced unexplained IVF failure or pregnancy loss, how might this chapter change the kinds of questions you ask your doctor or the tests you request?
• Are there symptoms you have dismissed or been told were unrelated to fertility that might now seem worth exploring based on what you’ve learned about immune and uterine factors?