The Fertility Clock No One's Checking

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Michael Bennett DDS, PhD, and Cathy Bennett MS

Good Morning.

You know the couple. Two or three years of trying. A stack of negative tests, then a fertility workup: hormone panels, an HSG, a semen analysis, maybe a round of Clomid or an IVF cycle that didn't take. Nobody in that workup ever asked either of them how they sleep.

That gap is the subject of this series. This is Part 1 of a three-part series on the airway's role in the family a couple is trying to build. Part 1 makes the case for screening before conception. Part 2 covers what an unscreened airway does during pregnancy. Part 3 covers the postpartum window that everyone assumes resolves on its own, and how to open a referral conversation with the reproductive and pelvic health clinicians in your community. Today, we start before the first cycle.

The 30-Second Version

• Infertility affects roughly 48.5 million couples worldwide, and sleep is essentially absent from the standard workup — obstructive sleep apnea (OSA) is not part of routine fertility screening on either side of the couple (Lazzeroni et al., 2026).

• In men, OSA blunts the GnRH-LH pulse and lowers testosterone independent of obesity, with semen quality declining in a dose-response relationship with OSA severity — and untreated OSA is associated with roughly 1.8x higher infertility risk in a Taiwanese cohort (Lazzeroni et al., 2026).

• In women, OSA is dramatically overrepresented in PCOS — 37% prevalence versus 6% in women without PCOS, and a composite odds ratio near 9.5 for OSA in PCOS across a recent meta-analysis (Abdul Jafar et al., 2025).

• OSA independently predicts worse ART outcomes — lower peak estradiol, fewer oocytes retrieved, and lower clinical pregnancy and live-birth rates in women undergoing IVF (Lazzeroni et al., 2026).

• The shared mechanism is intermittent hypoxia plus systemic inflammation (IL-6, TNF-α, CRP) disrupting the reproductive hormonal axis in both partners — this is a couple's issue, not a "her problem" or a "his problem."

• A five-minute airway screen at the first fertility visit costs nothing and, done early enough, changes the trajectory of care before a single cycle starts.

6-minute read.

Why this belongs in a dental newsletter

You are frequently the first clinician to see the airway problem. A reproductive endocrinologist doesn't screen for a narrow palate, a retruded mandible, or a Mallampati IV oropharynx; you do, as part of a routine exam, often years before that same patient sits down for a fertility consult. You are upstream of the workup that's currently missing this.

That's the opportunity in this series: not to treat infertility, that's never your scope, but to recognize the airway signs, ask one good question about trying to conceive, and make a referral that changes which specialists are in the room.

The two-way street: how OSA undermines fertility in him and in her

In men

OSA disrupts the hypothalamic-pituitary-gonadal axis, affecting GnRH release, LH surges, and testosterone levels, independent of obesity (Lazzeroni et al., 2026). Semen quality declines with OSA severity, and untreated OSA increases infertility risk by 1.8 times. OSA is also a risk factor for erectile dysfunction, impacting coital frequency.

Caveat: most of this evidence is cross-sectional. It shows a strong, consistent association and a plausible mechanism — not yet a randomized trial proving that treating OSA reverses infertility. Say it that way to patients.

In women

PCOS is a leading cause of ovulatory infertility, with a 2025 meta-analysis showing 37% of women with PCOS have OSA, compared to 6% without. OSA exacerbates insulin resistance and hormonal issues in PCOS, affecting fertility treatments. In IVF, OSA is linked to higher gonadotropin doses, lower estradiol levels, fewer oocytes, and reduced pregnancy and live-birth rates. Snoring, an OSA indicator, is associated with nearly three times higher odds of early pregnancy loss.

Caveat: same honesty applies here. These are strong associations from cohort and case-control data, not RCTs isolating OSA treatment as the variable that raises live-birth rates. The mechanism (hypoxia, inflammation, endocrine disruption) is sound; the proof that fixing the airway fixes the outcome is still being built.

What the evidence actually shows and what it doesn't yet

The honest summary: OSA is markedly overrepresented in the populations already struggling to conceive, on both sides of the couple, through a mechanism (hypoxia + inflammation + endocrine disruption) that is biologically coherent and consistent across studies. What's still missing is the interventional proof, large trials showing that CPAP or OAT before conception improves live-birth rates. That gap is exactly why the review's authors argue for integrating sleep screening into fertility workups rather than waiting for a couple to fail two or three cycles first (Lazzeroni et al., 2026).

Global OSA prevalence is estimated at nearly 1 billion people, with roughly 425 million moderate-to-severe cases, and in much of the world, under 10% of suspected cases are ever diagnosed. Women are especially underscreened in fertility evaluations, specifically. That's not a gap fertility medicine can close by itself. It needs dentistry in the room.

Here is an excellent video discussing the sleep-fertility link. Start at 4:10.

🦷 Clinical Corner: The Preconception Airway Screen

Your take-home this week — a one-page screen you can run at any hygiene or new-patient exam when a patient mentions they're trying to conceive (or you notice both partners are patients of record).

If two or more flags are positive: a home sleep apnea test referral and a note in the chart, phrased plainly — "Airway findings suggestive of possible sleep-disordered breathing identified during dental exam; patient reports actively trying to conceive; recommend HSAT and consideration in fertility workup."

Companion tool: we've built a fuller one-page version of this screen designed to hand directly to a reproductive medicine or OB partner — a shared instrument that opens the referral conversation rather than a one-way note. More on that in Part 3, when we cover exactly how to start that partnership.

A note on this issue's sponsor

Every stage of this series comes back to the same starting point: a clear, patent airway. Xlear's xylitol-based saline nasal care line supports the nasal-breathing foundation that any downstream airway or sleep work depends on — the same Tier 1 protocol we use at Advanced Dental Care before any conversation about OSA screening or treatment goes further.

Disclosure: Xlear is a paid sponsor of More Than Teeth. We feature only sponsors whose products meet our clinical protocols, and sponsorship does not influence our clinical recommendations.

Coach Cathy's Take

By Cathy Bennett, MS, NBCHWC

I've sat with more than one friend through the "why isn't this working" season of trying to conceive. It is one of the loneliest kinds of hard, a grief with no funeral, repeated every month.

What I want every reader to hear: nobody is saying poor sleep is "the reason." Infertility is rarely one thing. But sleep and airway health are two of the only levers a couple can start pulling today, before the next specialist referral, before the next round of testing — and they don't require anyone to feel like it's their fault.

If you're the clinician in the room when a patient mentions they're trying, that's not small talk. That's an opening. Take it gently, and take it seriously.

Next week: Part 2

The couple conceives. Nine months from now, an unscreened airway isn't a fertility question anymore — it's a maternal and fetal safety question. Part 2 covers OSA in pregnancy: why prevalence climbs every trimester, why preeclampsia and gestational diabetes risk climb with it, and why the standard screening tools you already know quietly stop working the moment a patient is pregnant.

References

1. Lazzeroni M, Lentini M, Maruca A, et al. The Global Burden of Obstructive Sleep Apnea on Fertility: Pathophysiology, Clinical Evidence, and Therapeutic Perspectives. Reprod Med. 2026;7(1):4. doi: 10.3390/reprodmed7010004

2. Abdul Jafar NK, Al Balushi A, Subramanian A, et al. Obstructive sleep apnea syndrome in polycystic ovary syndrome: a systematic review and meta-analysis. Front Endocrinol. 2025;16. doi: 10.3389/fendo.2025.1532519

Until next week,
Dr. Michael & Cathy Bennett
More Than Teeth | A Mission for Generational Health