What is the recommended management approach for a Thyroid Imaging Reporting and Data System (TI-RADS) 3 thyroid nodule in pregnancy?

Management of TI-RADS 3 Thyroid Nodules in Pregnancy

TI-RADS 3 nodules in pregnancy should be managed conservatively with ultrasound surveillance and selective fine-needle aspiration based on size thresholds, deferring any surgical intervention until the postpartum period unless cytology confirms malignancy with concerning features.

Risk Stratification and Initial Assessment

TI-RADS 3 nodules represent low-to-intermediate risk lesions with a malignancy rate of approximately 3-5% 1. The ultrasound pattern, rather than size alone, determines the risk of malignancy, but pregnancy introduces unique considerations that favor conservative management 1.

Key Ultrasound Features to Document

• Nodule size and growth pattern - measure maximum diameter in three dimensions 2
• Specific suspicious features - marked hypoechogenicity, microcalcifications, irregular margins, or taller-than-wide shape 1
• Relationship to surrounding structures - assess proximity to trachea and major vessels 1

Fine-Needle Aspiration Decision Algorithm

When to Perform FNA During Pregnancy

For TI-RADS 3 nodules ≥1.5 cm: Consider FNA during pregnancy, as this represents the standard size threshold for intermediate-risk nodules 2, 3.

For TI-RADS 3 nodules 1.0-1.5 cm: FNA can be deferred to the postpartum period unless the nodule demonstrates growth or develops additional suspicious features 1, 2.

For TI-RADS 3 nodules <1.0 cm: Do not perform FNA during pregnancy; monitor with ultrasound surveillance 1, 2.

FNA Technique Considerations

• Ultrasound-guided fine-needle aspiration is safe during pregnancy and should be performed when indicated 4, 5
• The cytological accuracy in pregnancy is comparable to non-pregnant patients, with benign cytology showing 100% concordance with histology 4

Cytology Results and Management Pathways

Benign Cytology (Most Common Outcome)

• No further intervention during pregnancy 4, 5
• Repeat ultrasound in the postpartum period (3-6 months after delivery) 5
• Thyroid function testing only if clinically indicated by symptoms 6

Malignant or Suspicious for Papillary Cancer

• Papillary cancer cytology: Surgery during the second trimester if diagnosed before 20 weeks gestation, or defer to early postpartum period if diagnosed after 20 weeks 4, 5
• Most thyroid cancers detected during pregnancy will not grow significantly during gestation and pose minimal risk to mother or fetus 5

Suspicious for Follicular Neoplasm

• Defer surgery to the postpartum period - follicular lesions have lower malignancy rates and do not require urgent intervention 4
• Continue ultrasound surveillance during pregnancy 5

Indeterminate Cytology

• Repeat FNA or defer definitive management to postpartum period 2, 5
• Molecular testing may be considered but is not specifically validated for pregnancy management decisions 2

Surveillance Strategy During Pregnancy

For nodules not undergoing FNA or with benign cytology:

• Perform ultrasound at initial detection and once during the second or third trimester 5
• Document any size changes or development of new suspicious features 5

Growth during pregnancy does not automatically indicate malignancy - physiological changes in pregnancy can affect nodule size 5.

Surgical Timing Considerations

Optimal Surgical Window

• Second trimester (weeks 14-24): Safest period for thyroidectomy if surgery cannot be deferred 4, 5
• Early postpartum period: Preferred timing for most cases, including confirmed malignancies without aggressive features 4, 5

Avoid Surgery When Possible

• Thyroidectomy during pregnancy carries higher risks than in non-pregnant women 5
• Most thyroid cancers, even when confirmed, can safely wait until postpartum without compromising maternal or fetal outcomes 5

Critical Pitfalls to Avoid

Do not perform routine TSH suppression therapy - levothyroxine suppressive therapy is not recommended for benign nodules and poses risks during pregnancy 2.

Do not biopsy nodules <1.0 cm unless they demonstrate highly suspicious features that would reclassify them to a higher TI-RADS category 1, 2.

Do not rush to surgery in the first or third trimester - the second trimester is the only appropriate surgical window if intervention cannot be deferred 4, 5.

Verify accurate TI-RADS classification - misclassification can lead to inappropriate management; if uncertain, re-evaluate using proper TI-RADS criteria 6.