Can Natural Killer Cells Cause Infertility or Miscarriage?
Release Date: 09/08/2025
Told Donor Eggs Were Your Only Option? Sarah's POI Story and What Her REI Never Tested For
Get Pregnant Naturally
Sarah Clark was told donor eggs were her only option. No second opinion. No workup. Just an IVF brochure pulled off the shelf. This is the story of what was actually going on, and what nobody looked for. At 28, Sarah was diagnosed with premature ovarian failure (now called premature ovarian insufficiency). Her OB/GYN handed her an IVF brochure during the appointment. She went to the REI, got on the donor egg list, and had both her kids through IVF with donor eggs. It took another decade before she discovered the underlying imbalances her REI never screened for: food sensitivities to dairy,...
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Why "Normal" Labs Aren't Optimized for Fertility | TSH, Ferritin, Glucose & IVF Failure
Get Pregnant Naturally
Your TSH is "normal." Your ferritin is "normal." Your glucose is "normal." And IVF still isn't working. Here's why normal lab ranges were never built for fertility and what optimal actually looks like. Most reference ranges are designed to flag disease in the general population, not to optimize egg quality, embryo competence, or implantation. That gap is where a lot of unexplained IVF failure, embryo arrest, and recurrent loss live. In this episode, Sarah Clark walks through the four biomarker categories most often dismissed as "fine" but influence cycle outcomes in women with diminished...
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The IVF Mistake That Causes Failed Cycles to Keep Repeating
Get Pregnant Naturally
If you're heading into another IVF cycle after a failed transfer, you're probably being told to trust the process and try again. But what if the process is the problem? In this episode, we get into how to tell whether your next cycle is actually different — or whether you're about to repeat the same outcome with a new protocol number. In this episode you'll learn: The three signs your last cycle wasn't fully interpreted, just failed Why changing the protocol doesn't always change the outcome What "unexplained" actually means and why it's often a gap, not a diagnosis How time pressure...
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Normal Semen Analysis but IVF Still Failing? What Wasn't Tested
Get Pregnant Naturally
Failed IVF with normal sperm? You're not alone, and the answer may be in what wasn't tested. DNA fragmentation and oxidative stress don't show up on a standard semen analysis. But they can drive fertilization failure, embryo arrest, and poor blastocyst development. If the male side was cleared after the basic parameters were evaluated, it may not have been fully evaluated. In this episode, you'll learn: What a semen analysis actually measures and what it leaves out Why normal parameters don't always translate to embryo development How DNA fragmentation and oxidative stress affect...
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Why a Good Embryo Doesn’t Implant in IVF (What’s Often Missed)
Get Pregnant Naturally
If your IVF transfer failed despite a good embryo, normal lining, and a smooth protocol, you may have been told it was “just bad luck.” But failed implantation with a euploid or high-quality embryo is not random. It often means key biological factors were never fully evaluated before the transfer. You followed the plan. The embryo looked good. The lining was “fine.” And it still didn’t work. This is where many people get stuck. Not because there are no answers, but because no one stepped back to assess the full picture before repeating another transfer. In this episode, we break down...
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Unexplained IVF Failure What Is Being Missed Before Your Next Cycle
Get Pregnant Naturally
Unexplained IVF failure happens when a cycle doesn’t work, and no clear cause is identified, but that doesn’t mean nothing is wrong. In many cases, it means the biology behind the cycle wasn’t fully evaluated. You did everything you were told to do. The protocol looked good. The embryos developed. The lining was fine. And it still didn’t work. Then you hear the word “unexplained.” That’s where many people get stuck. Not because there are no answers, but because no one has stepped back to assess the full picture. In this episode, we break down what unexplained IVF...
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Failed IVF Cycle: How to Audit What Went Wrong Before Trying Again
Get Pregnant Naturally
When an IVF cycle fails, the focus usually shifts to the next protocol. Different medications. Higher doses. Another retrieval. But an IVF cycle produces a huge amount of biological data that is rarely fully analyzed before repeating treatment. Ovarian response, egg maturity, embryo development, and the internal environment around transfer all provide important signals about what may be influencing the outcome. Yet many couples are encouraged to move forward with another cycle before those patterns are carefully reviewed. In this episode, we step back and walk through how to interpret a failed...
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Why Implantation Fails: Gut Health, Inflammation and the Vaginal Microbiome
Get Pregnant Naturally
Implantation failure is often blamed on the uterus. The lining. The timing. The transfer protocol. But implantation is not something the uterus decides on its own. Implantation is an immune event that reflects what is happening across the entire body. When inflammation, gut dysfunction, or microbial imbalance is present, the immune system may not shift into the receptive state required for implantation, even when embryos appear strong and transfers are performed correctly. In this episode we step back from the narrow focus on the uterus and explore how gut health, inflammation, and the vaginal...
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Why Your IVF Cycle Was Decided 90 Days Before It Started
Get Pregnant Naturally
Most couples do not walk into IVF lightly. By the time you reach a cycle, you have likely changed your diet, added supplements, tried acupuncture, adjusted your lifestyle, and done everything you were told might help. And yet, stimulation begins, and the outcome feels underwhelming. Here’s the biological reality: egg and sperm development are influenced during the 90 days before a cycle ever starts. Follicles recruited at stimulation were already developing months earlier. During that window, metabolic signaling, inflammatory load, hormonal communication, and stress physiology quietly set...
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Day 3 vs Day 5 Embryo Arrest: What the Timing Really Means
Get Pregnant Naturally
Poor embryo development is not random. And “it just didn’t work” is not an explanation. If your embryos stopped growing on Day 3 or Day 5, you’ve likely been told some version of the same thing. Bad luck. Egg quality. Try again. But Day 3 vs Day 5 embryo arrest are not interchangeable events. The timing carries biological clues. And when those clues are ignored, couples often repeat cycles without addressing what actually shaped the outcome. In this episode, we break down what early arrest, later arrest, and repeating arrest patterns may be signaling and how to think more clearly...
info_outlineIf you’ve been diagnosed with low AMH, high FSH, diminished ovarian reserve (DOR), premature ovarian insufficiency (POI), or have experienced recurrent pregnancy loss or failed IVF, you may be wondering if natural killer (NK) cells are playing a role.
In this episode, Sarah Clark, founder of Fab Fertile, explains what NK cells are, when testing may be helpful, and why many reproductive endocrinologists dismiss it. You’ll hear how functional fertility strategies, addressing inflammation, gut health, nutrient deficiencies, and immune balance; differ from conventional medicine and can improve egg quality, implantation, and pregnancy outcomes.
We also cover what progressive fertility clinics are doing, what the research says, and how to decide if immunotherapy or intralipids are right for you.
This episode is for you if you’ve had multiple implantation failures or miscarriages, feel dismissed by “normal” test results, and want evidence-based options to support your fertility journey.
🎧 Subscribe to Get Pregnant Naturally for evidence-based guidance on functional fertility, and share this episode with anyone on their fertility journey.
Not sure where to start? Download our most popular guide: Ultimate Guide to Getting Pregnant This Year If You Have Low AMH/High FSH it breaks everything down step by step to help you understand your options and take action
For personalized support to improve pregnancy success, book a call here.
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TIMESTAMPS
[00:00:00] Low AMH, DOR, pregnancy loss - when to look at natural killer (NK) cells
[00:02:00] Who should consider NK cell testing (recurrent miscarriage, failed IVF, autoimmune, inflammation)
[00:04:00] Why most clinics dismiss NK testing + controversy in reproductive immunology
[00:05:00] Functional fertility view: gut health, nutrient deficiencies, inflammation, toxins
[00:06:00] Vitamin D, magnesium, and environmental exposures linked to NK cell activity
[00:07:00] Functional Fertility steps before NK testing: diet, gut health, sleep, stress
[00:08:00] Stress and nervous system dysregulation as hidden fertility disruptors
[00:09:00] Why elimination diet beats trendy diets for fertility and inflammation
[00:10:00] Functional testing: GI-MAP, minerals, B vitamins, and methylation markers
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RESOURCES
Stop Ignoring hsCRP and the Role of Inflammation in Diminished Ovarian Reserve: https://fabfertile.com/blogs/podcasts/stop-ignoring-hscrp-and-the-role-of-inflammation-in-diminished-ovarian-reserve
How To Prevent and Reverse Autoimmune Disease and Get Pregnant: https://fabfertile.com/blogs/podcasts/how-to-prevent-and-reverse-autoimmune-disease-and-get-pregnant?_pos=4&_sid=c268f733d&_ss=r
Causes of Miscarriage Before 12 Weeks: What Most Doctors Miss: https://fabfertile.com/blogs/podcasts/causes-of-miscarriage-before-12-weeks-what-most-doctors-miss?_pos=12&_sid=0606f25e8&_ss=r
Improving Egg Quality and Fertility: The Gut Fertility Connection for Low AMH, High FSH, and Poor Egg Quality: https://fabfertile.com/blogs/podcasts/improving-egg-quality-and-fertility-the-gut-fertility-connection-for-low-amh-high-fsh-and-poor-egg-quality?_pos=8&_sid=6da5ed9f3&_ss=r
How Reproductive Immunology Therapies Can Improve Pregnancy Outcomes with Dr. Marco Mouanness: https://fabfertile.com/blogs/podcasts/how-reproductive-immunology-therapies-can-improve-pregnancy-outcomes-with-dr-marco-mouanness?_pos=1&_sid=8a12de180&_ss=r
Our favorite fertility tracker Inito (use code FABFERTILE15 to save 15)
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💛 Join my free Facebook group: Get Pregnant Naturally With Low AMH and/or High FSH: https://www.facebook.com/groups/451444518397946
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Please note we only promote products that Sarah Clark or her Fab Fertile team has tried and believes are beneficial for someone who is TTC. We may receive a small commission