All 89 quotations, and where each one came from

“Frankly, I said these things to my patients without knowing all the facts. I was just repeating what I learned—that is, to be skeptical of combination therapy, and only vaguely knowledgeable about what thyroid extract is.”

Antonio C. Bianco, Rethinking Hypothyroidism (University of Chicago Press, 2022)

“Before I became aware of the controversies surrounding therapy for hypothyroidism, I would just dismiss these complaints and renew the prescription with what I thought was an appropriate dose of T4; I would not renew a prescription for T3 or thyroid extract, to the frustration of many.”

Antonio C. Bianco, Rethinking Hypothyroidism (University of Chicago Press, 2022)

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“My approach to symptomatic patients with hypothyroidism, which in retrospect seems insensitive, was not unique.”

Antonio C. Bianco, Rethinking Hypothyroidism (University of Chicago Press, 2022)

“There were discussions and some resistance about a live debate with patients. Physicians are not used to this; I heard, 'We can only invite patients we trust.'”

Antonio C. Bianco, Rethinking Hypothyroidism (University of Chicago Press, 2022)

“On a scale of 0 to 10 (10 being the maximum), patients returned a median score of 5 to 6 when asked about their satisfaction level with treatment. We were surprised to see that they also returned a score of 5 to 6 when asked about their current physicians. Patients revealed that they had changed physicians multiple times, some up to ten times.”

Antonio C. Bianco, Rethinking Hypothyroidism (University of Chicago Press, 2022)

“One comment indicative of refusal to acknowledge fault was: 'Oh yes, we knew about this—there is nothing new in this survey. These represent the emotionally unstable patients with hypothyroidism.'”

Antonio C. Bianco, Rethinking Hypothyroidism (University of Chicago Press, 2022)

“A major reckoning is in order, and, in my view, apologies as well.”

Antonio C. Bianco, Rethinking Hypothyroidism (University of Chicago Press, 2022)

“Before 12 weeks of gestation, a time when the fetal thyroid begins to concentrate iodine and synthesize T4, the fetus is entirely dependent on maternal transfer of thyroid hormones. Brain development begins during this period of fetal dependency in the first trimester and continues throughout pregnancy and on into infancy.”

ACOG Committee Opinion No. 381, Subclinical Hypothyroidism in Pregnancy (Oct 2007)

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“The prevalence of subclinical hypothyroidism could be anticipated to be between 2% and 5% of women screened.”

ACOG Committee Opinion No. 381, Subclinical Hypothyroidism in Pregnancy (Oct 2007)

“However, data indicating fetal benefit from thyroxine supplementation in pregnant women with subclinical hypothyroidism currently are not available.”

ACOG Committee Opinion No. 381, Subclinical Hypothyroidism in Pregnancy (Oct 2007)

“Without evidence that identification and treatment of pregnant women with subclinical hypothyroidism improves maternal or infant outcomes, routine screening for subclinical hypothyroidism currently is not recommended.”

ACOG Committee Opinion No. 381, Subclinical Hypothyroidism in Pregnancy (Oct 2007)

“A decision-analytic model compared the incremental cost per quality-adjusted life-year (QALY) gained among the following: 1) universal screening, 2) high-risk screening, and 3) no screening. Screening consisted of a first-trimester thyroid-stimulating hormone level and antithyroid peroxidase antibodies. Women with abnormal results underwent further testing and, when indicated, levothyroxine therapy.”

Dosiou, Barnes, Schwartz, Negro, Crapo & Stagnaro-Green, J Clin Endocrinol Metab 2012

“Risk-based screening and universal screening were both cost-effective relative to no screening, with incremental cost-effectiveness ratios (ICERs) of $6,753/QALY and $7,138/QALY, respectively. Universal screening was cost-effective compared with risk-based screening, with an ICER of $7,258/QALY.”

Dosiou, Barnes, Schwartz, Negro, Crapo & Stagnaro-Green, J Clin Endocrinol Metab 2012

“Even in a scenario that assumed no benefit of treating subclinical hypothyroidism, universal screening remained cost-effective.”

Dosiou, Barnes, Schwartz, Negro, Crapo & Stagnaro-Green, J Clin Endocrinol Metab 2012

“In a hypothetical scenario in which subclinical hypothyroidism has no adverse outcomes and does not get treated, and the only benefits of screening consist of detection and treatment of overt hypothyroidism and closer follow-up of detected anti-TPO antibody positive women, with more prompt diagnosis of PPT and overt hypothyroidism when they develop, our results were substantially similar to the base case.”

Dosiou, Barnes, Schwartz, Negro, Crapo & Stagnaro-Green, J Clin Endocrinol Metab 2012

“Universal screening was most cost-saving, providing an additional 14.1 quality-adjusted days and saving $1,533 compared with no screening.”

Dosiou, Barnes, Schwartz, Negro, Crapo & Stagnaro-Green, J Clin Endocrinol Metab 2012

“Universal screening is also highly cost-effective compared with screening of only high-risk women. … The medical community should seriously consider screening all pregnant women for AITD.”

Dosiou, Barnes, Schwartz, Negro, Crapo & Stagnaro-Green, J Clin Endocrinol Metab 2012

“…the committee acknowledges the important data confirming that such case finding will unfortunately miss 30% or more of women with overt or subclinical hypothyroidism.”

Endocrine Society clinical practice guideline, De Groot et al., J Clin Endocrinol Metab 2012

“…an ICER of $7,258 per QALY, well below the accepted threshold for cost-effectiveness of $50,000 per QALY.”

Dosiou, Barnes, Schwartz, Negro, Crapo & Stagnaro-Green, J Clin Endocrinol Metab 2012

“One task force member (CD) dissented from this recommendation, feeling that universal testing for maternal TSH and anti-TPO antibodies soon after pregnancy confirmation is warranted given the existing support for the obstetrical benefits of treatment, with minimal risk of harm with appropriate monitoring. There might be an additional benefit of treatment on fetal neurodevelopment, as shown in animal studies. Unfortunately, the timing of initiation of LT4 treatment after completion of the first trimester in the RCTs that examine child IQ as the outcome is a very serious design flaw that biases these studies to producing negative results, since they miss the relevant window of opportunity to influence neurodevelopment. Nonetheless, universal screening would allow identification and treatment of all women with overt hypothyroidism, which is prevalent in 0.3%–0.5% of pregnant women (259,260,583) and asymptomatic in about 70% of patients (606). It would also allow identification and selective treatment of women with autoimmune subclinical hypothyroidism, and appropriate close monitoring of euthyroid women with isolated thyroid autoimmunity, some of whom will develop hypothyroidism during gestation or PPT.”

ATA pregnancy guideline, Alexander et al., Thyroid 2017, below Recommendation 93

“Various studies have shown that risk factors recommended in the previous version of these guidelines would lead to screening of 55–78% of all pregnant women, while detection rates varied between 75% and 85% for overt hypothyroidism and between 54% and 60% for subclinical hypothyroidism.”

ATA pregnancy guideline, Korevaar et al., Thyroid 2026

“Importantly, if a screening paradigm is conclusively proved effective, universal screening of women in the first trimester has been shown to be cost effective.”

ATA pregnancy guideline, Alexander et al., Thyroid 2017

“Universal screening for thyroid disease during pregnancy should be performed.”

Title of Stagnaro-Green, Dong & Stephenson, Best Pract Res Clin Endocrinol Metab 2020

“Limited evidence concerning the impact of untreated and treated sub-clinical disease and thyroid autoimmunity has distracted from the core rationale for universal screening – the beneficial impact of detecting and treating overt thyroid disease. … universal screening for overt disease stands independently from that of subclinical and autoimmune disease. The time to initiate universal screening is now.”

Stagnaro-Green, Dong & Stephenson, Best Pract Res Clin Endocrinol Metab 2020

“The values range from 18% to 89%.”

Stagnaro-Green, Dong & Stephenson, Best Pract Res Clin Endocrinol Metab 2020

“Targeted screening, which is recommended by most professional associations, fails to detect a large proportion of pregnant women with thyroid disease. In fact, an increasing number of providers are performing universal screening for thyroid disease in pregnancy, contrary to society guidelines.”

Stagnaro-Green, Dong & Stephenson, Best Pract Res Clin Endocrinol Metab 2020

“While there is still debate regarding whether or not treating subclinical hypothyroidism decreases maternal/fetal adverse outcomes, the cost-effective studies demonstrate that universal screening is superior to targeted screening even if one assumes no benefit for identifying and treating subclinical hypothyroidism.”

Stagnaro-Green, Dong & Stephenson, Best Pract Res Clin Endocrinol Metab 2020

“There is insufficient evidence to recommend for or against universal TSH screening at the first trimester visit.”

ATA pregnancy guideline, Stagnaro-Green et al., Thyroid 2011

“Although agreeing with most of the recommendations, I present an alternative perspective on the normal range of TSH in pregnancy, management of women on levothyroxine preconception and universal screening for thyroid disorders during pregnancy.”

Stagnaro-Green, Nature Reviews Endocrinology 2017

“…I believe that the time for universal screening for thyroid disorders during pregnancy has come.”

Stagnaro-Green, Nature Reviews Endocrinology 2017

“This Viewpoint discusses these criteria and suggests that sufficient evidence exists for the institution of routine screening to detect and treat overt thyroid disease during pregnancy. However, there are insufficient data to support universal screening to detect subclinical hypothyroidism or the presence of thyroid antibodies.”

Stagnaro-Green, Viewpoint, JAMA 2015

“Treatment of overt thyroid disease is universally recommended, regardless of pregnancy status, and thus a placebo-controlled trial of the efficacy of treatment for overt thyroid disease during pregnancy is not required.”

Stagnaro-Green, Viewpoint, JAMA 2015

“In a sensitivity analysis, screening solely for overt hypothyroidism had a cost-effectiveness ratio of $6776/QALY … when compared with no screening and $7335/QALY when compared with targeted screening … For comparative purposes, the cost-effectiveness ratio for amniocentesis is $15,000/QALY and screening for gestational diabetes mellitus is $12,078/QALY.”

Stagnaro-Green, Viewpoint, JAMA 2015

“However, the lack of data regarding the treatment of subclinical hypothyroidism should not affect the decision to screen for overt thyroid disease.”

Stagnaro-Green, Viewpoint, JAMA 2015

“Other concerns regarding routine screening may include that the prevalences of diseases already screened for in pregnancy are extremely low; that once screening for thyroid disease has begun it will be impossible to discontinue …; or that possible medicolegal risks may arise for failure to screen.”

Stagnaro-Green, Viewpoint, JAMA 2015

“…only 26% (5 of 19) of the papers cited reported an upper limit of normal ≥ 4.0 mU/l, and in four of the five studies the population evaluated comprised less than 750 women. On the other hand, in the five largest studies cited (each including more than 5,000 pregnant women), only one reported an upper limit of normal exceeding 3.5 mU/l.”

Stagnaro-Green, Nature Reviews Endocrinology 2017

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“In essence, a universal TSH demarcation distinguishing the upper range of normal from the lower range of abnormal does not exist.”

Stagnaro-Green, Nature Reviews Endocrinology 2017

“However, these studies have some limitations, including that levothyroxine therapy is not initiated until the second trimester, thereby missing the critical time of neurodevelopment.”

Stagnaro-Green, Dong & Stephenson, Best Pract Res Clin Endocrinol Metab 2020

“Maternal TSH had an inverted U-shaped association with offspring total grey matter volume (p=0.007) and with cortical grey matter volume (p=0.022). … Analyses stratified for gestational age at blood sampling showed an inverted U-shaped association of maternal TSH with child total grey matter volume and cortical grey matter volume, which was most evident at 8 weeks gestation. After about 14 weeks of gestation, TSH was no longer associated with child brain morphology.”

Jansen, Korevaar, Mulder, White, Muetzel, Peeters & Tiemeier, Lancet Diabetes Endocrinol 2019

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“These novel findings suggest that embryonic brain development is particularly vulnerable to altered maternal thyroid function.”

Jansen, Korevaar, Mulder, White, Muetzel, Peeters & Tiemeier, Lancet Diabetes Endocrinol 2019

“The absence of association from the 14th week onwards is an important novel finding that should be considered during clinical risk assessment and when timing interventions during clinical practice, as well as in the design of future studies of the effects of levothyroxine treatment for mild thyroid disease in pregnancy.”

Jansen, Korevaar, Mulder, White, Muetzel, Peeters & Tiemeier, Lancet Diabetes Endocrinol 2019

“…some randomised controlled trials examining the effect of levothyroxine treatment of maternal subclinical hypothyroidism or hypothyroxinaemia in pregnancy on offspring IQ showed no beneficial effect. The initiation of treatment in these trials, with thyroid hormone replacement therapy starting between 13 and 18 weeks of gestation, was later than our estimated optimal timing.”

Jansen, Korevaar, Mulder, White, Muetzel, Peeters & Tiemeier, Lancet Diabetes Endocrinol 2019

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“Of concern to the task force is that the double-blind placebo control studies either recently completed, or presently underway, began screening and intervention after the first trimester. As such these studies will not be able to address the impact of LT4 treatment in the first trimester in women with SCH, isolated hypothyroxinemia, or thyroid antibody positivity on the mother and developing fetus. A trial that screens women preconception and then randomizes women with SCH or isolated hypothyroxinemia and TAb+ euthyroid women to either a treatment or no treatment arm is needed.”

ATA pregnancy guideline, Stagnaro-Green et al., Thyroid 2011

“The task force is aware of the difficulties inherent in performing such a trial, and the ethical challenges to be faced. Nevertheless, we believe that such a trial is feasible, can be ethically performed with appropriate study design and safeguards, and will yield invaluable information related to the optimal care of the pregnant women and the developing fetus.”

ATA pregnancy guideline, Alexander et al., Thyroid 2017

“Of concern to the task force is that most of the double-blind placebo-controlled studies either recently completed, or presently underway, began screening and intervention after the first trimester. As such, these studies will not be able to address the impact of LT4 treatment in the first trimester …”

ATA pregnancy guideline, Alexander et al., Thyroid 2017

“A RCT of early LT4 intervention (at 4–8 weeks) in women with either subclinical hypothyroidism or isolated hypothyroxinemia to determine effects on child IQ.”

ATA pregnancy guideline, Alexander et al., Thyroid 2017

“A randomized trial of early LT4 intervention (preconception or early pregnancy, i.e., 6–10 weeks' gestation) in women with either subclinical hypothyroidism or isolated hypothyroxinemia to determine effects on adverse pregnancy outcomes and child IQ.”

ATA pregnancy guideline, Korevaar et al., Thyroid 2026

“There are no data from randomized trials on early pregnancy LT4 treatment for isolated hypothyroxinemia.”

ATA pregnancy guideline, Korevaar et al., Thyroid 2026

“In women without known thyroid disease, it is suggested that TSH testing be offered upon a positive pregnancy test to those at increased risk of thyroid dysfunction during pregnancy.”

ATA pregnancy guideline, Korevaar et al., Thyroid 2026

“The risk factors that are considered an indication for thyroid function testing during pregnancy are not exhaustive. Furthermore, the use of this set of risk factors will not enable the identification of all women with thyroid dysfunction, specifically overt hypothyroidism.”

ATA pregnancy guideline, Korevaar et al., Thyroid 2026

“In sensitivity analyses, even when the benefits of screening were limited to detection and treatment of overt hypothyroidism, screening was shown to be highly cost-effective at <$8000/quality-adjusted life year (QALY).”

ATA pregnancy guideline, Alexander et al., Thyroid 2017

“In developing the Guidelines, the task force frequently struggled with the paucity of high-quality double-blinded placebo-controlled trials in the field of thyroid and pregnancy. In fact, only a minority of the 97 recommendations (24%) in the present Guidelines were graded at the highest American College of Physicians Grading System level of evidence.”

ATA pregnancy guideline, Alexander et al., Thyroid 2017

“We conducted a randomized trial in which pregnant women at a gestation of 15 weeks 6 days or less provided blood samples for measurement of thyrotropin and free thyroxine (T4).”

Lazarus et al. (CATS), N Engl J Med 2012

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“A possible explanation for the negative results of our study is that screening was performed and levothyroxine therapy initiated too late in gestation to have a major influence on brain development (up to 20 weeks' gestation; median, 13 weeks 3 days). The timing of screening in our study was chosen because it is at this time that routine antenatal care in hospitals is initiated in the majority of women.”

Lazarus et al. (CATS), N Engl J Med 2012

“A limitation of the two trials is the relatively late time during gestation at which women were randomly assigned.”

Casey et al. (MFMU Network), N Engl J Med 2017

“Although we did not enroll women earlier than at 8 weeks of gestation in order to avoid enrolling women who might have an early miscarriage, we believe that these trials, which were performed at centers that were actively screening women on presentation for prenatal care, probably reflect what could be accomplished by means of routine thyroid screening during pregnancy in the United States.”

Casey et al. (MFMU Network), N Engl J Med 2017

“However, both the present trials and the CATS trial are limited by the late initiation of treatment. In the present trials, randomization did not occur until an average of 17 weeks of gestation, which is even later than in the CATS trial. … The findings of Casey et al. indicate that screening and treatment for subclinical hypothyroidism, if performed well into the second trimester of pregnancy, are unlikely to be beneficial.”

Cooper & Pearce, editorial, N Engl J Med 2017

“However, because more than 75% of women in the United States have their first prenatal visit before 12 weeks of gestation, earlier treatment appears to be feasible.”

Cooper & Pearce, editorial, N Engl J Med 2017

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“However, in post hoc analyses, we likewise did not find a benefit of screening and treatment in the subgroup of women who started treatment earlier, although it should be acknowledged that our trial was not powered for this assessment.”

Lazarus et al. (CATS), N Engl J Med 2012

“We also found no significant interaction according to the time of initiation of therapy (<17 weeks of gestation vs. ≥17 weeks of gestation).”

Casey et al. (MFMU Network), N Engl J Med 2017

“Based on prevalence and impact of overt thyroid disease in pregnancy, which is 1.15%, it is incumbent upon us to do universal screening whether or not the identification and treatment of subclinical hypothyroidism or thyroid autoimmunity has any beneficial effect.”

Stagnaro-Green, ENDO 2019 debate, as reported by HCPLive · transcript 09:39

“I am not making the argument that we should screen all women to diagnose and treat subclinical hypothyroidism. And I am not making the argument that we should screen all women to diagnose and treat women with autoimmune antithyroid disease. My argument is very simple. We have missed the forest for the trees. … So what we are really saying is we are trying to avoid uncertainty at all costs. We are putting our head in the sand. And we are saying we only want to diagnose that what we know how to handle.”

Stagnaro-Green, ENDO 2019 debate transcript · 36:12

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“I agree. Screening should be done preconception. As I've alluded to.”

Kristien Boelaert, ENDO 2019 debate transcript · 45:45

Transcript flag V6: verify against the recording before re-quotation.

“The intervention trials that have been done, you can see that treatment was actually started late. And, you know, I would agree that both the CATS trial and the Casey study treatment was started too late.”

Kristien Boelaert, ENDO 2019 debate transcript · 45:45

Transcript flag V6: verify against the recording before re-quotation.

“These studies are exceedingly difficult, and it's probably a bit of wishful thinking that we will get decent data from intervention studies where this has actually started early enough.”

Kristien Boelaert, ENDO 2019 debate transcript · 45:45

“So I know it is small numbers of patients but even in these 50 women, nearly 50 women that were treated, there was no difference. So again I put it to you, are we overegging things a little bit?”

Kristien Boelaert, ENDO 2019 debate transcript · 42:10

“Universal screening for thyroid disease in pregnancy is not recommended because identification and treatment of maternal subclinical hypothyroidism has not been shown to result in improved neurocognitive function in offspring.”

ACOG Practice Bulletin No. 148 (Apr 2015), Summary of Recommendations, Level A

“Universal screening for thyroid disease in pregnancy is not recommended because identification and treatment of maternal subclinical hypothyroidism has not been shown to result in improved pregnancy outcomes and neurocognitive function in offspring.”

ACOG Practice Bulletin No. 223 (2020), Summary of Recommendations, Level A

“Currently, there is no evidence that identification and treatment of subclinical hypothyroidism during pregnancy improves these outcomes.”

ACOG Practice Bulletin No. 148 (Apr 2015), discussion

Re-sourced: register had pointed to a secondary summary; the sentence is in PB 148 itself.

“The results of the CATS study and the 2017 Maternal–Fetal Medicine Units Network's Randomized Trial of Thyroxine Therapy for Subclinical Hypothyroidism or Hypothyroxinemia Diagnosed During Pregnancy trial demonstrate that screening and treatment of women with subclinical hypothyroidism during pregnancy does not improve the cognitive function of their children at age 3 years and 5 years, respectively.”

ACOG Practice Bulletin No. 223 (2020)

“Therefore, the American College of Obstetricians and Gynecologists, the Endocrine Society, and the American Association of Clinical Endocrinologists recommend against universal screening for thyroid disease in pregnancy and recommend testing during pregnancy only for women who are at increased risk of overt hypothyroidism.”

ACOG Practice Bulletin No. 223 (2020)

“The committee could not reach agreement with regard to screening recommendations for all newly pregnant women. Two versions are therefore presented.”

Endocrine Society guideline 2012, Recommendation 8.4a

“Some members recommended screening of all pregnant women for serum TSH abnormalities by the ninth week or at the time of their first visit.”

Endocrine Society guideline 2012, Recommendation 8.4a · version 1 (L.D.G., J.R., J.H.L., N.A., C.J.E.)

“Some members recommended neither for nor against universal screening of all pregnant women for TSH abnormalities at the time of their first visit. These members strongly support aggressive case finding to identify and test high-risk women… and they recognize that in some situations ascertainment of the individual's risk status may not be feasible. In such cases, and where the local practice environment is appropriate, testing of all women by wk 9 of pregnancy or at the first prenatal visit is reasonable.”

Endocrine Society guideline 2012, Recommendation 8.4a · version 2

“Universal screening for the presence of anti-TPO antibodies either before or during pregnancy is not recommended.”

Endocrine Society guideline 2012, Recommendation 8.3a

“Universal screening is not recommended for patients who are pregnant or are planning pregnancy, including assisted reproduction. Grade B, BEL 1”

AACE/ATA hypothyroidism guideline, Garber et al., Endocr Pract / Thyroid 2012, Recommendation 20.1.1

Located 30 Oct 2026; register had marked it missing.

“Levothyroxine should not be discontinued during pregnancy and hypothyroidism diagnosed during pregnancy should be promptly treated.”

FDA review, Tirosint-SOL, NDA 206977 (2016), reviewers’ proposed Risk Summary

“Hypothyroidism during pregnancy is associated with a higher rate of complications, including spontaneous abortion, pre-eclampsia, stillbirth and premature delivery. Maternal hypothyroidism may have an adverse effect on fetal and childhood growth and development.”

FDA medical officer review, Synthroid NDA 21-402 · Jean Temeck, MD · 18 April 2002

Signed Jean Temeck MD, 4/18/02.

“For pregnant patients with pre-existing hypothyroidism, measure serum TSH and free-T4 as soon as pregnancy is confirmed and, at minimum, during each trimester of pregnancy.”

Synthroid prescribing information, NDA 21-402 (supplement 036)

“Among pregnant women who had their TSH measured in the first trimester, 62.8% had a TSH level greater than 2.5 mU/L, with 7.4% greater than 10 mU/L.”

Taylor et al., J Clin Endocrinol Metab 2014

“For women receiving LT4 preconception, a prospective, randomized study has provided evidence that supports a single dose-adjustment strategy… Dosage augmentation should occur as soon as possible when a missed menstruation or suspected pregnancy occurs, and this should be discussed with every patient in the prepregnancy setting.”

ATA pregnancy guideline, Alexander et al., Thyroid 2017

“The T4 dose usually needs to be incremented by 4 to 6 wk gestation and may require a 30% or more increase in dosage.”

Endocrine Society guideline, De Groot et al. 2012, Recommendation 1.2.4 · USPSTF level A

Located 30 Oct 2026; graded USPSTF level A.

“Inform patients that agents such as iron and calcium supplements and antacids can decrease the absorption of levothyroxine. Instruct patients not to take SYNTHROID tablets within 4 hours of these agents.”

Synthroid prescribing information, NDA 21-402 (supplement 036)

“Of the 10,680 pregnancies, 8774 (82.2%) had at least one TSH measurement … and 6707 (62.8%) had at least two TSH tests during pregnancy. … it is concerning that 17.8% did not.”

Lemieux et al., Thyroid 2021 (Alberta cohort)

“TSH in pregnancy below 0.10 mIU/L increased the odds of preterm delivery when compared with control pregnancies (adjusted odds ratio, 2.14 [95% confidence interval 1.51–2.78]).”

Lemieux et al., Thyroid 2021 (Alberta cohort)

“The data suggested a potential harm of overtreating pregnant women on thyroid replacement, as a TSH level below 0.10 mIU/L at any time during pregnancy was associated with a doubling of the odds of preterm delivery.”

Lemieux et al., Thyroid 2021 (Alberta cohort)

“…the majority of patients identified through any universal screening process have TSH concentrations between 2.5 and 5.0 mU/L—a population in whom a treatment benefit is not well established. Furthermore, such a strategy could have detrimental effects, labeling many patients with a biochemical abnormality, and in many cases leading to initiation of possibly inappropriate long-term treatment.”

ATA pregnancy guideline, Alexander et al., Thyroid 2017

“Maternal thyroxine is particularly critical early in pregnancy because the fetal thyroid gland cannot synthesize iodothyronines until after 10 weeks of gestation.”

Casey et al., Subclinical Hypothyroidism and Pregnancy Outcomes, Obstetrics & Gynecology 2005;105:239–245 · Introduction, p. 239 · DOI · PubMed

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“It may be that therapy beginning after 10 weeks of gestation would not eliminate any already established fetal neurodevelopmental impairment from hypothyroxinemia. Pop and colleagues have provided evidence that treatment may be ineffective only if given after this time.”

Casey et al., Subclinical Hypothyroidism and Pregnancy Outcomes, Obstetrics & Gynecology 2005;105:239–245 · Discussion, p. 244 · DOI · PubMed

Matched against the converted primary paper. Original page-image check remains outstanding. Casey et al. attribute the second sentence to evidence from Pop and colleagues; this entry does not independently verify Pop’s study.