NK Cells, AMH, and Everything in Between: What You Need to Know When It Comes To TTC
If you’re trying to conceive (TTC) and constantly refreshing test results or chasing the next must‑do’ pre-screen (particularly if you’re on the IVF train), you’re not alone. It’s so easy to fall down the rabbit hole of hormones, immune panels, tubes, and sperm parameters — especially when you just want clarity and a baby. But here’s a grounded reminder: not every test is urgent, and not every result defines your fertility.
Let’s break it down in a way that feels practical, supportive, and rooted in evidence.
1) AMH Isn’t a “Fertility Scorecard”
Let’s get this out of the way: Anti‑Müllerian Hormone (AMH) is not a crystal ball for your fertility. Sure, it measures the number of small follicles in your ovaries — and yes, it’s useful in IVF to estimate egg response — but for natural conception? Not so much.
Low AMH ≠ “game over.” If you’re ovulating and cycling regularly, you can still get pregnant
AMH is more like a GPS for IVF than a countdown timer for natural conception
The takeaway? AMH tells you about ovarian reserve, not your body’s fertility potential for spontaneous pregnancy.
2) Progesterone and Cycle Tracking
A ‘Day 21 progesterone test’ aims to confirm ovulation, but (and this is IMPORTANT) - most women’s cycles aren’t textbook 28 days, so one snapshot can be misleading.
Progesterone peaks about 7 days after ovulation, not always on calendar day 21
If your blood draw isn’t perfectly timed, it can look like you didn’t ovulate when you actually did
Instead of trusting a single number, listen to your body:
Basal body temperature rises after ovulation
Cervical mucus transforms as your fertile window opens
Daily clues often give a fuller picture than one lab tube ever could.
Your body drops hints every day — temperature rises and cervical mucus changes can tell you more than a single blood test ever can.
3) NK Cells — Immune Testing (When It Actually Helps)
Natural killer (NK) cells, especially uterine NK cells (uNK), are immune system players that may influence implantation and early pregnancy. While NK testing isn’t for everyone, research suggests that it can be useful in certain situations. It’s important to know:
uNK cells interact with early embryo cells in the uterus
Abnormal uNK patterns are sometimes observed in recurrent implantation failure or miscarriage
Systematic reviews show insufficient evidence to recommend NK testing as a routine fertility step - but you are unique! And if your patterns suggest this might be at play, I’m going to recommend you look into this.
Context is key: NK testing isn’t for everyone, but when you’ve had repeated losses or implantation challenges, it can provide actionable insights.
4) Semen Analysis — Don’t Skip Him
Fertility is a team sport. A semen analysis is quick, often Medicare-covered, and gives insight into sperm count, motility, morphology, and DNA integrity.
Male factors contribute to around half of fertility challenges
Early detection saves time, money, and heartbreak. Skipping him is like trying to bake a cake when you’re not even sure you have flour. Why waste your time?
Things to note: Male factors are involved in about half of fertility issues — early detection can save months of stress and money.
5) Tests Are Tools — Not Final Answers
Think of fertility tests like maps, not magic balls. They point out potential roadblocks and help you plan, but they don’t predict your exact journey.
What really matters:
🌿 Lifestyle foundations: sleep, nutrition, stress support, gentle movement
🩺 Cycle awareness: understanding your patterns beyond simple lab results
🤝 Supportive care: practitioners who see you as a real human, not a spreadsheet or set of numbers
Final Thought
Tests can bring clarity, especially NK testing for repeated pregnancy loss or implantation challenges. But none define your fertility alone. Paired with lifestyle support and cycle awareness, they can all help turn frustration into actionable steps - and this is where the journey starts moving along.
Bottom line: One test, one number, or one scan does not define your fertility. Your journey is yours — and your body is far more capable than any lab can measure.
Further Reading:
The Value of Anti-Müllerian Hormone in the Prediction of Spontaneous Pregnancy: A Systematic Review and Meta-Analysis (source)
Serial progesterone levels more accurately predict the time of ovulation in subfertile women: a prospective cohort study (source)
The Role of Uterine Natural Killer Cells on Recurrent Miscarriage and Recurrent Implantation Failure: From Pathophysiology to Treatment (source)
Male Infertility (source)