Growth trend of small uterine fibroids and human chorionic gonadotropin serum levels in early pregnancy: an observational study.

OBJECTIVE

To analyze the growth trend of small uterine fibroids during early pregnancy, evaluating the potential factors involved, with particular interest in hCG levels.

DESIGN

Observational study.

SETTING

Tertiary care university hospital.

PATIENT(S): Women who had an ultrasound diagnosis of small myomas (diameter, ≥10 mm and ≤50 mm) from January 2007 to December 2013, and who subsequently became pregnant within 1 year.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): Three additional ultrasound examinations were performed during early pregnancy (7-8, 10-13, and 20-22 complete gestational weeks, respectively) and the modifications in diameter and volume of each uterine fibroid were recorded. A serial evaluation of hCG serum levels from 5-12 weeks was performed.

RESULT(S): From the 109 women who fulfilled the study inclusion/exclusion criteria, a significant increase emerged, both for volume and diameter of the detected fibroids. Specifically, a median growth rate (GR) of 122% was observed during the interval of the first to the second ultrasound, whereas a median GR of 108% was detected during the interval between the second and the third ultrasound, and a median GR of 25% between the third and the fourth ultrasound. A significant positive correlation between hCG levels and diameter (R = 0.69) of myomas between 5 and 12 weeks emerged.

CONCLUSION(S): A remarkable nonlinear growth of small fibroids during initial pregnancy was observed, with a faster rate in the first trimester and a slowdown by midpregnancy. Those changes seem to be related to the similar increase of hCG levels until 12 weeks.