BALTIMORE – Less than half of the pregnant patients who met the criteria for thyroid screening were actually screened by their clinician, according to a retrospective cohort study presented at the annual clinical and scientific meeting of the American College of Obstetricians and Gynecologists in Baltimore. Those who met criteria and did receive screening had higher live birth rates and lower miscarriage rates than those who met the criteria but did not undergo screening, the study found.
“These results suggest that improving thyroid screening adherence may lead to improved pregnancy outcomes,” lead author Allan Dong, MD, of Advocate Lutheran General Hospital in Des Plaines, Ill., told attendees. “However, following targeted screening guidelines can be difficult for clinicians. In practice, universal screening for diabetes and pregnancy may provide more comprehensive screening coverage and potentially lead to improved outcomes.”
Instead of universal screening for thyroid disease, ACOG and the American Thyroid Association recommend targeted screening of high-risk patients, though ATA’s criteria are substantially broader than ACOG’s. But, Dr. Dong told attendees, “guidelines are only beneficial if they are followed appropriately,” and Ob.Gyns. have limited time to screen for risk factors in the midst of other clinical priorities. So he aimed to learn whether Ob.Gyns. were following the guidelines of either organization in screening people at higher risk for thyroid disease.
Dr. Dong and his coauthor, Melisa Lott, DO, reviewed the charts of all 1,025 patients who presented at their institution for new obstetrical visits in 2020 to determine which ones had risk factors that would qualify them for screening under ATA or ACOG guidelines. ACOG’s screening criteria included having a personal or family history of thyroid disease or type 1 diabetes, or there being clinical suspicion for thyroid disease. ATA’s screening criteria included the following:
- Personal or family history of thyroid disease.
- History of head or neck radiation.
- History of a prior thyroid surgery.
- Over age 30.
- Any autoimmune disease.
- A body mass index greater than 40 kg/m2.
- History of pregnancy loss, preterm delivery, or infertility.
- Recently used amiodarone lithium or iodine-based contrast.
- Lived in an area of known iodine deficiency.
- Clinical suspicion of thyroid disease.
ATA screening criteria identified four times as many patients requiring screening than did ACOG criteria, Dr. Dong noted. Of the 198 patients who met ACOG’s criteria, 43.9% were screened with thyroid function testing. Meanwhile, 826 patients – including all those who met ACOG’s criteria – met ATA’s criteria for screening, but only 13.1% of them underwent thyroid function testing.
Live birth rates were significantly higher among patients who met ATA criteria and were screened (92.6%) than among patients who met ATA criteria but were not screened (83.3%, P = .006). Similarly, the miscarriage rate was 4.6% in patients who met ATA criteria and were screened, compared to 12.4% in patients who met the criteria but did not undergo thyroid function testing (P = .009).
“A similar difference, although not statistically significant, was noted when comparing patients who were screened appropriately per ACOG criteria with those who met criteria for screening but were not screened,” Dr. Dong told attendees. “However, our study was underpowered to detect this difference due to the lower number of patients who meet criteria for screening under ACOG guidelines.”
The researchers did not find any significant difference in preterm delivery rates.
Anna Whelan, MD, of Women & Infants Hospital of Brown University, Providence, R.I., was not involved in the study but viewed the poster and pointed out that many of the patients, if seen by a primary care provider prior to pregnancy, would likely have been screened by their PCP. The rate of underscreening therefore suggests that patients “are not getting good, consistent primary care because there’s a lack of primary care physicians,” Dr. Whelan said in an interview.
In addition, she added, “maybe not all obstetricians and those providing care, such as midwives and other providers, are aware of the [ATA] guidelines on who should be screened.” She added that additional education about thyroid screening guidelines might be helpful for providers.
Dr. Dong reported being a stock shareholder in 3M, AbbVie, General Electric, Johnson & Johnson, Medtronic, Pfizer, and Viking Therapeutics. Dr. Whelan had no disclosures.