The impact of menstrual cycle on the safety of elective thyroid surgery

The potential impact of the menstrual cycle on perioperative bleeding and surgical outcomes remains a topic of debate, yet limited evidence exists specifically for thyroid surgery in women of reproductive age. This study aimed to investigate the influence of menstrual cycle phase on the safety of routine thyroid surgery in women of reproductive age to provide evidence-based guidance for optimal surgical timing.

This retrospective descriptive study involved 318 women of reproductive age with regular menstrual cycles who underwent thyroid surgery. Patients were stratified by surgical extent into unilateral thyroid lobectomy and total thyroidectomy groups. Based on their menstrual cycle phase at the time of thyroid surgery, patients were further categorized into menstrual, follicular, and luteal phase groups. Clinical data were collected and analyzed to compare surgical safety outcomes across the different menstrual phases.

Baseline characteristics were largely comparable among the menstrual phase groups. While triiodothyronine levels, white blood cell counts, and absolute monocyte counts differed significantly among the menstrual phase groups (P<0.05), all values remained within the normal clinical reference ranges. In the total thyroidectomy group, 24-hour postoperative drainage volumes differed significantly across the menstrual phases (P<0.05). However, the absolute magnitude of this difference was small (median: 40 mL for all three groups), and no other intraoperative or postoperative variables differed significantly among groups (P>0.05). Multivariate analysis identified operative time as the sole independent risk factor for increased 24-hour postoperative drainage volume (β=1.33, 95% confidence interval: 0.61-2.06, P<0.001); notably, menstrual phase was not an independent predictor.

The menstrual cycle phase does not exert a clinically significant impact on the safety of routine thyroid surgery in women of reproductive age. These findings support that, under standard perioperative conditions including strict aseptic technique and meticulous surgical execution, performing thyroid surgery during menstruation is both safe and feasible.