Uterine myomas during pregnancy: a longitudinal sonographic study

To evaluate volumetric changes of uterine myomas (fibroids) during pregnancy.

This was an observational, longitudinal and prospective study of 38 consecutive Caucasian women with singleton pregnancies and a total of 42 uterine myomas, enrolled from a cohort of 1492 women who took part in our first-trimester Down syndrome screening program. Myoma volume was evaluated by ultrasound at 11-14, 20-22 and 32-34 weeks of gestation.

Mean myoma volume increased significantly throughout pregnancy. Taking a volumetric change of > 10% between gestational periods to be an increase in size, 71.4% of uterine myomas increased in size between the first and second gestational periods, while this percentage was slightly lower (66.6%) between the second and third periods. Logistic regression analysis revealed that greater maternal age was correlated with a reduction/no change in overall myoma size and multiparity was correlated with a decrease/no change between the first and second trimesters, while a higher prepregnancy maternal body mass index (BMI) was correlated with a volumetric increase between the first and second trimesters and a decrease/no change between the second and third trimesters.

Fibroids enlarge during pregnancy regardless of their initial size or local factors, and maternal age, prepregnancy BMI and parity are apparently correlated with these changes.