HoldsUp

Huberman Lab · 2026-04-13 · Andrew Huberman (host), Natalie Crawford

How Women Can Improve Their Fertility & Hormone Health | Dr. Natalie Crawford

82 research-tied claims examined: 8 contradicted 9 overstated 8 context 53 supported 4 unverified

9 Overstated
0:24:17Natalie Crawfordoverstatedmoderate

In women who previously had a child and are conceiving with the same partner, monthly fecundability remains between 18% and 20% up until age 37 before dropping.

"But in the group who had a child before and were trying to conceive with the same partner, that number stayed between 18 to 20% up till age 37. And then it dropped." (said at 0:24:17)

While parous women attempting conception with a proven fertile partner consistently exhibit higher per-cycle fecundability than nulliparous women, prospective cohort studies and demographic analyses demonstrate that fecundability declines progressively starting in the late 20s and early 30s, rather than remaining constant at 18–20% until age 37. Although age 37 is well-recognized as a demographic and biological inflection point where ovarian follicle loss and the rate of fertility decline accelerate, claiming that per-cycle fecundability remains flat until age 37 overstates the stability of fertility across the early-to-mid 30s.

0:49:45Natalie Crawfordoverstatedmoderate

Approximately 50% of the time, investigation into a low AMH level reveals an underlying autoimmune disease.

"I sit across from women every day find out they have a low AMH, and I say this, like, let's do the investigation to see if we can find out why. Probably 50% of the time we find an autoimmune disease." (said at 0:49:45)

While autoimmunity is a recognized etiology and co-factor in diminished ovarian reserve (DOR) and premature ovarian insufficiency (POI), the claim that 50% of investigations into low anti-Müllerian hormone (AMH) reveal an underlying autoimmune disease is substantially overstated. Epidemiological and clinical cohort studies show that autoimmune disorders are diagnosed in approximately 5% to 25% of women with POI/DOR, and autoantibody positivity is typically present in roughly 10% to 38% of patients. In a large cross-sectional study of over 5,000 women (PMID 25948573), the prevalence of thyroid autoimmunity in women with low AMH/ovarian reserve was 12.1%, which was not significantly different from controls with normal ovarian reserve (10.3%).

1:33:47Natalie Crawfordoverstatedlow

Self-reporting poor sleep is associated with double the rate of infertility.

"And we see that if you say you have poor sleep, you have double the rate of infertility. If you just objectively say, "Yeah, I have poor sleep," you have double the rate." (said at 1:33:47)

The speaker claimed that self-reporting poor sleep is associated with double the rate of infertility. While some observational studies link sleep disturbances (such as perceived insufficient sleep or irregular sleep patterns) to reduced fecundability or lower IVF success rates, large prospective cohort studies and meta-analyses show that self-reported poor sleep quality is either not significantly associated with reduced fecundability or shows modest associations, nowhere near doubling the rate (a 2-fold increase or OR/RR of 2.0) of infertility. For example, a prospective cohort study of 10,475 women found no appreciable association between self-reported trouble sleeping and fecundability (fecundability ratio [FR] = 0.95, 95% CI: 0.82-1.10 for trouble sleeping most of the time compared to never; PMID: 40139814). Mendelian randomization also showed no causal association between genetic liability to insomnia and female infertility (PMID: 39990928). A systematic review and meta-analysis of IVF outcomes found that poor subjective sleep quality (PSQI > 5) was associated with only a modest or non-significant reduction in pregnancy odds under random-effects models (PMID: 41709190). Therefore, the claim that subjective poor sleep doubles the rate of infertility is overstated.

1:45:00Natalie Crawfordoverstatedlow

Randomized controlled trials demonstrate that supplementation with CoQ10, vitamin D, and omega-3 fatty acids is associated with improved reproductive outcomes in IVF.

"When we do randomized controlled trials though, which we often do in the IVF subset because we can look at more distinct criteria... we definitely see robust data that certain supplementation, CoQ10, vitamin D, omega-3 fatty acids, those are clearly associated with improved reproductive outcomes." (said at 1:45:00)

While randomized controlled trials and meta-analyses show potential associations and modest increases in surrogate endpoints (such as clinical pregnancy or embryo parameters) with certain supplements like CoQ10 and vitamin D, describing the RCT evidence as 'robust' and establishing that these supplements are 'clearly associated with improved reproductive outcomes' in IVF is an overstatement. Umbrella reviews and Cochrane systematic reviews evaluate the certainty of evidence for these nutrient supplements as low to very low, concluding that the available RCT evidence is insufficient to establish definitive clinical efficacy (e.g., live birth rates). For omega-3 fatty acids, randomized trial data specifically evaluating IVF reproductive outcomes remain limited and mixed.

  • partial: The Role of Nutrient Supplements in Female Infertility: An Umbrella Review and Hierarchica… (Nutrients 2024) · cited 14x in the literature
    "L-carnitine, coQ10, melatonin, myo-inositol, NAC and vitamin D increased clinical pregnancy rates in women with PCOS and/or undergoing MAR compared to placebo, standard or no treatment (odds ratio (OR) 11.14, 2.49, 1.66, relative risk (RR) 1.52, OR 2.15, and 1.49 respectively) with very low certainty evidence... The available evidence is insufficient to recommend nutrient supplementation to improve female infertility in women trying to conceive naturally and those utilising MAR." (abstract, results and conclusions, passage verified)
    pubmedfull study (doi)
1:54:00Natalie Crawfordoverstatedlow

Cannabis use impairs sperm production, decreases testosterone, and increases sperm DNA fragmentation, leading to higher miscarriage rates in female partners.

"All cannabis use is hugely detrimental to sperm, for sure across the board, right? Both production, the quantity of sperm, testosterone production, also the quality of the sperm, specifically the DNA fragmentation inside the head of the sperm, to the degree that female partners who conceive from a male partner who's using cannabis have much higher miscarriage rates than partners who do not utilize cannabis." (said at 1:54:00)

While systematic reviews report that cannabis use is associated with adverse semen parameters (such as reduced sperm concentration, motility, and abnormal morphology), the speaker's sweeping assertion that 'all cannabis use is hugely detrimental across the board' overstates the clinical evidence. Specifically, human studies examining the effect of cannabis on testosterone levels show contradictory and inconclusive results rather than a definitive decline. Furthermore, evidence establishing that paternal cannabis use directly causes significantly higher miscarriage rates in female partners is limited, observational, and inconclusive.

2:00:25Natalie Crawfordoverstatedlow

Oral nicotine pouch usage significantly lowers sperm counts.

"It makes sense based on what nicotine does to your body and how it kind of changes your cellular response that it probably is impacting your egg quality also, even with these oral nicotine pouches, you know, that we're seeing everybody utilize. And it's tanking sperm counts. I mean, that one's really clear." (said at 2:00:25)

The speaker claims that oral nicotine pouches are 'tanking sperm counts' and that the effect is 'really clear.' While observational evidence in humans using smokeless tobacco (Swedish moist snuff/snus) shows an association with reduced total sperm counts (e.g., ~24% lower total sperm count in snus users), direct clinical studies specifically isolating modern tobacco-free oral nicotine pouches are limited, and the effect is not established as severely 'tanking' counts beyond modest observational differences. Thus, the claim is overstated.

1:53:41Andrew Huberman (host)overstatedmoderate

Approximately 15% of pregnant women in the United States report using cannabis in some form during pregnancy.

"what I found was that 15% of women in the United States report having used cannabis in some form or another while pregnant." (said at 1:53:41)

Nationally representative surveillance data in the United States indicate that self-reported cannabis use during pregnancy is substantially lower than 15%, generally falling between 4% and 7% (e.g., CDC PRAMS multi-state data reported 4.2% during pregnancy, and NSDUH 2021-2023 reported past-month use around 6.3% to 7.0%). While some individual regional clinic-based cohorts or biomarker validation studies report self-reported rates near 14% (e.g., a Michigan clinic cohort found 14.2% self-report and 19.1% on urinalysis), broad national self-report estimates do not reach 15%. Thus, characterizing 15% as the general proportion of pregnant women in the US reporting cannabis use is overstated.

2:19:21Natalie Crawfordoverstatedmoderate

The EARTH study demonstrated that higher exposure to endocrine-disrupting chemicals is associated with increased time to pregnancy and worse IVF outcomes, including fewer retrieved eggs, fewer embryos, and poorer sperm counts.

"There's now been robust data looking at, you know, one of the biggest cohort studies we have, and it's called the EARTH study, where they're looking at different environmental compounds on reproductive health and they're looking at cohorts of people trying to get pregnant naturally, and they did a sub-study looking at endocrine-disrupting chemicals specifically of those people who went on to do IVF and showed that those who had higher levels of endocrine-disrupting chemicals had a harder time getting pregnant even with IVF, and their IVF markers: fewer eggs retrieved, fewer embryos, poorer sperm counts." (said at 2:19:21)

The Environment and Reproductive Health (EARTH) Study is a prospective cohort of couples presenting to the Massachusetts General Hospital Fertility Center undergoing fertility treatments, rather than a natural pregnancy cohort with an IVF sub-study. While specific analyses in the EARTH study have reported associations between select endocrine-disrupting chemicals (EDCs, such as high-quartile DEHP exposure in earlier cohorts or specific phthalates with follicular fluid AMH) and certain reproductive markers, the overall body of evidence from the EARTH study found mostly null associations for BPA, parabens, and chemical mixtures with primary IVF outcomes (including embryo quality, fertilization rate, peak estradiol, and live birth rates). Claiming robust, uniform declines in egg retrieval, embryo numbers, sperm counts, and IVF success across EDC exposures overstates the nuanced and largely mixed or null findings of the study.

2:28:25Natalie Crawfordoverstatedlow

Higher dietary red meat intake is associated with poorer embryo development, worse IVF outcomes, and higher staging of endometriosis at surgery.

"Red meat's the really controversial one, and increased servings of red meat—of course dietary studies quartile it: lowest exposure, highest exposure—highest exposure groups had poor embryos develop, worse outcomes with IVF, and an increase in staging of endometriosis when they went to surgery." (said at 2:28:25)

The speaker bundles three claims regarding higher red meat intake: poorer embryo development, worse IVF outcomes, and higher surgical staging of endometriosis. Observational evidence (including systematic reviews and the Nurses' Health Study II prospective cohort) does link higher red meat consumption to an increased incidence/risk of laparoscopically confirmed endometriosis (RR 1.17 to 1.56 for highest vs. lowest categories). However, evidence is lacking or inconsistent to firmly demonstrate that red meat specifically increases laparoscopic surgical staging/severity or causes poorer embryo development and worse IVF outcomes. Asserting these specific IVF and surgical-stage associations as established facts overstates the observational epidemiological findings.

Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.