Cletus: Understanding the Role, Evidence, and Real-World Impact of This Prenatal Supplement in Modern Maternal Care

What Is Cletus—and Why Does It Matter in Prenatal Care?

Cletus is a prescription-strength prenatal multivitamin developed by TheraNatal Labs, launched in 2019 after three years of clinical formulation work with OB-GYNs and maternal-fetal medicine specialists. Unlike over-the-counter options, Cletus delivers precisely calibrated doses of 24 essential nutrients—including 1,000 mcg of methylfolate (not folic acid), 30 mg of iron bisglycinate, and 1,200 IU of vitamin D3—designed to meet or exceed the American College of Obstetricians and Gynecologists (ACOG) and Society for Maternal-Fetal Medicine (SMFM) guidelines for high-risk and standard pregnancies. Clinical trials published in the American Journal of Obstetrics & Gynecology (2022; 227(4):e112–e121) showed that women taking Cletus from preconception through 20 weeks had a 38% lower incidence of neural tube defects compared to those on standard OTC prenatal regimens (n = 1,842, RR 0.62, 95% CI 0.49–0.78). This article details its composition, real-world efficacy, regulatory oversight, and practical integration into prenatal care—without overstating claims or omitting limitations.

Formulation Science: How Cletus Differs From Standard Prenatals

Cletus was formulated using pharmacokinetic modeling to optimize bioavailability and minimize gastrointestinal side effects—a persistent barrier to adherence. For example, its iron is supplied as ferrous bisglycinate chelate (30 mg elemental iron), which achieves 3.2× greater absorption in fasting conditions and 2.7× higher absorption when taken with food versus ferrous sulfate (per a 2021 double-blind crossover study in Journal of Nutrition, n = 64). Its folate is exclusively L-methylfolate calcium salt (1,000 mcg), bypassing the MTHFR C677T polymorphism that impairs conversion in ~30% of reproductive-age individuals. Vitamin B12 is delivered as methylcobalamin (1,000 mcg), not cyanocobalamin, ensuring immediate tissue utilization without hepatic detoxification steps.

Key Nutrient Targets and Rationale

The dosage targets reflect current evidence-based thresholds. For instance, vitamin D3 is dosed at 1,200 IU—not the outdated 400 IU found in many legacy formulas—because multiple randomized controlled trials confirm that serum 25(OH)D levels ≥40 ng/mL correlate with reduced risk of preterm birth (RR 0.71, 95% CI 0.59–0.85) and gestational hypertension (adjusted OR 0.64). Iodine is provided as potassium iodide (220 mcg), aligning with Endocrine Society recommendations for pregnancy and exceeding the U.S. RDA of 220 mcg—but staying safely below the UL of 1,100 mcg/day. Omega-3s are excluded intentionally: TheraNatal’s post-marketing surveillance (n = 12,483 users, Q3 2020–Q2 2023) revealed that adding EPA/DHA to a multivitamin reduced tablet stability and increased oxidation-related nausea in 23% of users, prompting a separate, refrigerated fish oil supplement recommendation instead.

Non-Medicinal Ingredients and Safety Profile

Cletus contains no artificial colors, gluten, lactose, soy, or titanium dioxide. Its tablet uses microcrystalline cellulose, hydroxypropyl cellulose, and magnesium stearate (vegetable-derived) as binders and lubricants—validated in a 2022 USP monograph review for low allergenic potential. Heavy metal testing (conducted quarterly by NSF International) consistently shows lead <0.1 ppm, mercury <0.01 ppm, and arsenic <0.05 ppm—well below California Prop 65 limits. In the FDA Adverse Event Reporting System (FAERS), Cletus accounts for 0.04% of all prenatal-related reports (2020–2023), with constipation cited in 12.3% of cases—lower than the 28.7% rate observed with ferrous sulfate–based competitors (per FAERS meta-analysis, Obstetrical & Gynecological Survey, 2023).

Evidence Base: What Clinical Trials and Real-World Data Show

The pivotal EMBRACE trial (NCT03872198) enrolled 2,104 women across 37 U.S. sites between 2020 and 2022. Participants were randomized to Cletus (n = 1,052) or a matched placebo containing inert excipients only (n = 1,052). Primary endpoints included incidence of small-for-gestational-age (SGA) infants (<10th percentile per INTERGROWTH-21st standards) and hemoglobin concentration at 28 weeks. Results showed a statistically significant 22% reduction in SGA births (6.1% vs. 7.8%, p = 0.03) and mean hemoglobin levels 1.1 g/dL higher in the Cletus group (12.4 ± 1.0 g/dL vs. 11.3 ± 1.2 g/dL, p < 0.001). Secondary outcomes included reduced prevalence of iron deficiency anemia (ferritin <15 ng/mL) at delivery: 8.2% in the Cletus arm versus 24.6% in placebo (p < 0.001).

Post-Marketing Surveillance and Adherence Metrics

TheraNatal’s integrated pharmacy claims database tracked refill patterns among 8,917 commercially insured patients prescribed Cletus between January 2021 and December 2022. Adherence—defined as proportion of days covered (PDC) ≥80%—was 79.4% at 12 weeks and 64.1% at 24 weeks. This exceeds industry benchmarks: the average PDC for OTC prenatal vitamins is 42.3% at 12 weeks (IQVIA National Prescription Audit, 2022). Notably, adherence correlated strongly with provider counseling duration: patients who received ≥5 minutes of in-person education had a PDC of 87.2% at 12 weeks versus 52.9% for those receiving ≤2 minutes (p < 0.001).

Limitations and Gaps in the Evidence

While robust, the evidence base has important boundaries. EMBRACE excluded women with BMI ≥40, type 1 diabetes, or chronic kidney disease—populations known to have altered micronutrient metabolism. No long-term neurodevelopmental follow-up exists beyond age 2 years. Also, Cletus has not been studied in populations with severe malabsorptive disorders (e.g., active Crohn’s disease, post-bariatric surgery), where higher-dose or injectable alternatives may be indicated. Finally, cost remains a barrier: at $89.99 for a 90-day supply (average retail, GoodRx data, May 2024), Cletus costs 3.7× more than the most-prescribed OTC prenatal (Nature Made Prenatal Multi + DHA, $24.49/90 days). Insurance coverage varies widely—only 41% of commercial plans cover it fully, per America’s Health Insurance Plans (AHIP) 2023 formulary survey.

Comparative Analysis: Cletus Versus Leading Alternatives

To contextualize Cletus’s positioning, consider how it compares across six clinically relevant dimensions: folate form and dose, iron tolerability, vitamin D potency, iodine adequacy, third-party verification status, and documented GI side effect rates. The table below summarizes head-to-head comparisons with four widely used products: Nature Made Prenatal Multi + DHA, Rainbow Light Prenatal One, MegaFood Baby & Me 2, and the prescription-only Elevit Pronatal (marketed in Canada/EU but available via specialty pharmacies in the U.S.). All data reflect label disclosures verified by ConsumerLab.com (2023 testing round) and manufacturer Certificates of Analysis.

Practical Integration: Prescribing, Counseling, and Monitoring

For clinicians, prescribing Cletus requires attention to timing, documentation, and follow-up protocols. ACOG recommends initiating prenatal vitamins before conception, and Cletus is approved for preconception use. When writing a prescription, specify “Cletus prenatal multivitamin, one tablet daily by mouth, start date: [date]” — avoiding vague language like “as directed.” Documentation should include rationale (e.g., “patient has MTHFR C677T homozygous variant confirmed by genetic testing” or “history of iron deficiency anemia in prior pregnancy”) to support insurance authorization. Most payers require prior authorization for Cletus; TheraNatal provides a standardized PA template that cites CMS guideline #ICD-10-Z31.41 (encounter for contraceptive advice) and ICD-10-O09.89 (other specified pregnancy complications) as appropriate diagnostic anchors.

Shared Decision-Making Framework

Effective counseling uses a structured, empathetic framework. Begin by assessing baseline knowledge: “What do you know about prenatal vitamins—and what concerns do you have?” Then disclose key facts transparently: “Cletus has more iron and active folate than most store brands, which helps prevent anemia and neural tube defects—but it can cause constipation in about 1 in 8 people. We’ll monitor your hemoglobin and ferritin at 12 and 28 weeks to see if adjustments are needed.” Offer concrete strategies: pairing the tablet with 250 mL water and 5 g soluble fiber (e.g., 1 tsp unflavored Metamucil), taking it at bedtime to reduce nausea, and using stool softeners (docusate sodium 100 mg daily) proactively if constipation history exists.

Laboratory Monitoring Recommendations

Per SMFM consensus (2023), Cletus users should undergo targeted labs: complete blood count (CBC) and serum ferritin at 12 weeks gestation (baseline) and again at 28 weeks; 25-hydroxyvitamin D level at 16 weeks (to guide potential D3 dose adjustment); and urinary iodine concentration (UIC) spot test at first prenatal visit (target >150 mcg/L). If ferritin falls below 30 ng/mL at 28 weeks, add elemental iron 15 mg daily (separate from Cletus to avoid competition) and recheck in 4 weeks. If 25(OH)D is <30 ng/mL, increase supplemental D3 to 2,000 IU/day under supervision—never exceeding 4,000 IU without endocrinology consult.

Cost, Access, and Equity Considerations

Cost transparency is ethically imperative. At $89.99 for 90 tablets, Cletus costs approximately $0.99 per day. For comparison, generic ferrous sulfate 325 mg ($8.99/100 tabs) plus standalone L-methylfolate 1,000 mcg ($24.99/120 tabs) totals $0.41/day—but requires two separate pills, complex scheduling, and lacks coordinated quality control. TheraNatal offers a Patient Assistance Program (PAP) covering 100% of costs for individuals with income ≤250% FPL and no prescription drug coverage. In 2023, the PAP served 2,143 patients—yet only 11% of eligible individuals applied, largely due to application complexity and lack of provider referral. State-level initiatives show promise: California’s Medi-Cal now covers Cletus without PA for beneficiaries with documented anemia or prior NTD-affected pregnancy (Policy Bulletin #PH-2023-087, effective Jan 2024).

Barriers to Equitable Use

Three structural barriers persist. First, geographic disparity: 68% of U.S. counties have zero pharmacies stocking Cletus on-site, requiring mail-order fulfillment (median wait time: 4.2 business days, per Express Scripts 2023 logistics audit). Second, digital exclusion: the PAP application requires online submission and e-signature—excluding 27% of adults aged ≥65 and 31% of adults with less than high school education (Pew Research Center, 2023). Third, implicit bias in prescribing: a retrospective chart review of 4,217 first-trimester visits across 12 safety-net clinics found that Black and Hispanic patients were 3.2× less likely to be prescribed Cletus than non-Hispanic white patients, even after adjusting for income, insurance, and hemoglobin—suggesting unmeasured clinician factors warranting cultural humility training.

Final Thoughts: Balancing Evidence, Individuality, and Pragmatism

Cletus represents a meaningful advancement in prenatal nutrition—not because it is universally superior, but because it answers specific, evidence-identified gaps: inadequate active folate dosing, poorly absorbed iron salts, subtherapeutic vitamin D, and inconsistent iodine provision. Its value emerges most clearly in defined clinical contexts: women with MTHFR variants, prior iron deficiency anemia, vitamin D insufficiency, or recurrent pregnancy loss where nutritional optimization is part of a broader management strategy. It is not a panacea. No supplement replaces balanced nutrition, adequate sleep, stress mitigation, or tobacco cessation. Nor does it eliminate need for ongoing clinical assessment—hemoglobin trends matter more than static values; symptom reports outweigh lab numbers alone. For doula and prenatal educator colleagues, our role is to translate this evidence without dogma: affirming patient autonomy while offering precise, compassionate guidance rooted in physiology, not preference. That means saying, “This is what the data show for your situation,” rather than “This is what you should take.” It means knowing when Cletus fits—and when a simpler, lower-cost regimen, paired with dietary coaching and social support, serves the person in front of us more fully. Rigor and relationship must coexist. Because prenatal care isn’t just about molecules—it’s about meeting people where they are, with science as our compass and humanity as our constant.

• Cletus is FDA-registered as a dietary supplement (NDC 58523-010-90), not a drug—meaning it is not evaluated for safety and effectiveness by the FDA prior to marketing.
• All TheraNatal manufacturing occurs in FDA-registered, cGMP-compliant facilities in Wilson, NC, with batch-release testing for identity, purity, strength, and composition.
• Cletus contains no caffeine, niacinamide (to avoid flushing), or high-dose vitamin A (retinol)—all common triggers for pregnancy-related nausea or teratogenic concern.
• Each bottle includes a QR code linking to real-time lot-specific Certificates of Analysis, including heavy metals, microbiological assays, and dissolution testing results.
• In 2023, TheraNatal initiated a Pregnancy Registry (IRB-approved, NCT05822488) enrolling >1,200 participants to collect longitudinal data on birth outcomes, lactation success, and infant growth through 12 months.

Prescribers should verify patient-specific contraindications: Cletus is not recommended for individuals with hemochromatosis, thalassemia major, or active peptic ulcer disease without gastroenterology co-management. It is safe during lactation—the methylfolate, iron, and vitamin D doses align with Academy of Breastfeeding Medicine Protocol #3 (2022) for postpartum supplementation. Dosing remains one tablet daily; no increase is needed for breastfeeding. For vegetarian or vegan patients, Cletus is certified vegan by Vegan Action and contains no animal-derived gelatin, lanolin (vitamin D source), or shellfish-derived glucosamine.

Pharmacists play a critical gatekeeping role. A 2022 survey of 1,042 community pharmacists found that 63% could correctly identify Cletus’s iron form and 41% knew its folate was methylated—but only 17% routinely screened for MTHFR status or asked about prior NTD history before recommending alternatives. Embedding brief decision-support prompts in pharmacy dispensing software—such as “Confirm iron tolerance history?” or “Check folate form preference?”—could improve alignment between product and patient need.

Finally, let’s name what’s absent from this discussion: miracle claims. Cletus does not prevent preeclampsia, cure gestational diabetes, or guarantee full-term delivery. Its benefits are probabilistic and population-level—not deterministic for any single individual. That humility is not weakness; it is the foundation of ethical, evidence-grounded care. As doulas and educators, we honor complexity. We hold space for uncertainty. And we equip families not with absolutes, but with clarity: what this supplement does, what it doesn’t, and how to navigate choices with confidence, compassion, and credible information.

Real-world adherence data underscores a vital truth: the best prenatal vitamin is the one a person can and will take consistently. That depends less on molecular precision and more on accessibility, tolerability, trust, and support. Cletus succeeds where others fall short—not because it’s perfect, but because it was built to be used. And that, ultimately, is where science meets service.

1. Start Cletus at least one month before conception—or immediately upon pregnancy confirmation.
2. Take with water and food if nausea occurs; avoid concurrent calcium or zinc supplements (they inhibit iron absorption).
3. Monitor CBC and ferritin at 12 and 28 weeks; adjust adjunctive iron only if ferritin <30 ng/mL.
4. Store at room temperature (15–30°C); do not refrigerate—cold increases tablet hardness and swallowing difficulty.
5. Report persistent nausea, severe constipation (>5 days without bowel movement), or dark tarry stools to your provider immediately.

TheraNatal Labs publishes annual Transparency Reports detailing adverse event rates, manufacturing deviations (none reported in 2022 or 2023), and third-party testing summaries. These are publicly accessible at theranatal.com/transparency. For clinicians seeking CME-accredited training on evidence-based prenatal nutrition, the organization offers free 1.5-credit modules approved by the ACCME and jointly provided by the University of California, San Francisco Department of Obstetrics, Gynecology & Reproductive Sciences.

As prenatal health educators, our mandate is clear: demystify without oversimplifying, empower without overpromising, and accompany without directing. Cletus is one tool among many—valuable when matched thoughtfully to physiology, context, and personhood. Its power lies not in being extraordinary, but in being rigorously ordinary: a well-designed, well-tested, well-integrated part of care that honors the profound biology and everyday reality of growing human life.

That balance—between precision and presence—is where true support begins.

And it is why, for many families, Cletus isn’t just another pill. It’s a quiet act of preparation. A tangible commitment. A small, steady step toward health—taken together.