Pregnancy outcomes for women with large uterine fibroids

“We hypothesized that the mechanical ‘offloading’ of the cervix and exogenous progesterone supplementation may create a more favorable environment for pregnancy continuation in women with large uterine fibroids, compared with only medical or no management,” wrote the Russian authors.

The retrospective study consisted of 120 women, aged 18 to 45, with large UFs (≥8 cm) diagnosed in the first trimester, who underwent treatment in the regional perinatal center of the Omsk Regional Clinical Hospital in Russia between 2015 and 2019.

“The fibroids increased in size both during the first and second pregnancy trimester and showed histological signs of smooth muscle hypertrophy and edema, potentially progesterone receptor-mediated, or necrosis,” wrote the authors.

Large UFs in pregnancy were linked to a threatened pregnancy loss in 46.4% of women and pain in nearly 40% of women.

The women were divided into four groups: those who received both a cervical procedure (Arabin pessary or cervical cerclage) and micronized progesterone (n = 35); those who received the combination therapy, plus a myomectomy (n = 55); micronized progesterone only (n = 18); and no medical therapy during pregnancy (n = 12).

The combination of the cervical procedure and micronized progesterone reduced the rates of preterm delivery by 2.2-fold compared to progesterone-only and by 11.2-fold versus no medical management (χ 2 = 19.4; P = 0.0001).

There were no cases of miscarriage in either of the two combination therapy groups, compared to a miscarriage rate of 11.1% in the micronized progesterone-only group and 16.7% in the no medical therapy group.

In essence, all categories of preterm birth (very early, early and late) were less common in the two combination groups than the other two groups.

Term delivery occurred in 91.1% of women in the two combination therapy groups vs. 43.8% in the micronized progesterone-only group and 0% in the no medical therapy group.

However, fertility-preserving Cesarean deliveries were significantly more common in the two combination therapy groups: 96.3% vs. 68.3% in the micronized progesterone-only group and 20% in the no medical therapy group.

Hysterectomies were performed in 25% of the micronized progesterone-only group and in 60% of the no medical therapy group.

The investigators noted there is growing interest in the Arabin pessary for preventing preterm birth in high-risk women, starting in the second trimester. The advantages of combining the pessary with progesterone are also being explored.

For the current study, the authors confirmed that the optimal time for Arabin pessary placement is between 14 and 18 weeks of pregnancy, which is similar to other reports.

However, there is insufficient information in the literature about myomectomy during pregnancy, according to the authors, primarily because the procedure is considered high-risk for uterine scar rupture during the later stages of pregnancy.

Hence, the authors advocate that the risks and benefits of myomectomy during pregnancy be weighed on an individual basis by a multidisciplinary team. “The decision should take into account the myometrium thickness at the fibroid site to estimate the risks of pregnancy termination and uterine cavity penetration,” they wrote.

If performed, separate 8-shaped synthetic, self-dissolving sutures should be used to close the uterine wound to help prevent a subsequent uterine rupture.

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Barinov SV, Tirskaya YI, Lazareva OV, et al. Pregnancy outcomes in women with large uterine fibroids. J Matern Fetal Neonatal Med. Published online January 31, 2021. doi:org/10.1080/14767058.2021.1879044