Introduction: The objective of this study was to investigate the size progression of uterine fibroids during pregnancy and examine the potential correlations with preterm labor, preterm delivery, intrauterine growth restriction and mode of delivery.

Method: A retrospective chart review was performed for a study population derived from existing charts and ultrasound images obtained in the Maternal Fetal Medicine department at Advocate Lutheran General Hospital from 2000-2010. Hospital records were also reviewed to determine gestational age at delivery and any complications during labor or post partum.

Result: Sixty-seven study patients were identified with sixty-six live births. One patient had a second trimester fetal demise. A statistically significant negative correlation was observed between the average diameter of the fibroid and gestational age at delivery; p=0.003. Statistically significant correlations were not seen for preterm delivery, mode of delivery and the number or growth of fibroids. 55.6% of patients showed growth of their fibroids during pregnancy, and 44.4% showed shrinkage or stayed the same. Two our of 2 patients with retroplacental fibroids had pregnancies complicated by intrauterine growth restriction. Younger patients were found to have preterm labor more often than older patients.

Conclusion: Uterine myomas increase the risk for preterm labor and preterm delivery. Retroplacental fibroids appear to increase the risk for IUGR. Larger fibroids are associated with increased risk of preterm delivery. Pregnancies complicated by fibroids should undergo increased surveillance for fetal growth and preterm labor.

Abstract:

Fibroids and Pregnancy: Association with Preterm Delivery and Fetal Growth

Susan Rim, MD; Barbara Parilla, MD; Brenna McCrummen, MD; Leticia Curran, RDMS; Nancy Davis, MA

Department of Obstetrics and Gynecology Advocate Lutheran General Hospital

Fibroids and Pregnancy: Association with Preterm Delivery and Fetal Growth

Susan Rim, MD; Barbara Parilla, MD; Brenna McCrummen, MD; Leticia Curran, RDMS; Nancy Davis, MA

Department of Obstetrics and Gynecology Advocate Lutheran General Hospital

Introduction:

Methods: A key word search of the Maternal Fetal Medicine ultrasound database was

performed for the years 2000-March 2010 for patients who were evaluated at Advocate Lutheran General Hospital and had at least 2 ultrasounds performed.

A chart review was performed to determine gestational age at delivery, admissions for preterm labor, ultrasound measurements of fibroids, fetal growth, and delivery information.

Also examined were evaluations for preterm labor with and without tocolysis, and whether preterm delivery occurred. Ultrasound reports were abstracted and the largest diameter for fibroid measurements noted. EFW was calculated for the last ultrasound done prior to delivery and/or actual birthweight recorded from the delivery record.

Conclusions:1. Uterine myomas increase the risk for preterm labor and preterm delivery.

2. Larger fibroids are associated with increased risk of preterm delivery.

3. Retroplacental fibroids appear to increase risk for IUGR.

4. Pregnancies complicated by fibroids should undergo increased surveillance for fetal growth and preterm labor.

5. Study limitations include small sample size, some ultrasound reports did not specify types of fibroid, multiple gestation pregnancies were included, and delivery information was not available for all patients.

References:1. Ouyang DW, Economy KE, Norwitz ER. Obstetric complications of fibroids. Obstet Gynecol Clin N Am 2006; 33:153-169. 2. Klatsky PC, Tran ND, Caughey AB, Fujimoto VY. Fibroids and reproductive outcomes: a systematic literature review from conception to delivery. Am J Obstet Gynecol 2008; 198:357-366. 3. Katz VL, Dotters DJ, Droegemueller W. Complications of uterine leiomyomas in pregnancy. Obstet Gynecol 1989; 73: 593-596. 4. Qidwai GI, Caughey AB, Jacoby AF. Obstetric outcomes in women with sonographically identified uterine leiomyomata. Obstet Gynecol 2006; 107: 376-382. 5. Exacoustos C, Rosati P. Ultrasound diagnosis of uterine myomas and complications in pregnancy. Obstet Gynecol 1993; 82:97-101. 6. Coronado GD, Marshall LM, Schwartz SM. Complications in pregnancy, labor and delivery with uterine leiomyomas: a population-based study. Obstet Gynecol 2000; 95:764-769. 7. Sheiner E, Bashiri A, Levy Am, Hershkovitz R, Katz M, Mazor M. J Reprod Med 2004; 49: 182-186. 8. Neiger R, Sonek JD, Croom CS, Ventolini G. Pregnancy-related changes in the size of uterine leiomyomas. J Reprod Med 2006; 57:671-674. 9. Davis JL, Ray-Mazumder S, Hobel CJ, Baley K, Sassoon D. Uterine leiomyomas in pregnancy: a prospective study. Obstet Gynecol 1990; 75:41-44. 10. Ouyang DW, Norwitz ER. Management of pregnant women with leiomyomas. Up To Date 2008. 11. Cooper NP, Okolo S. Fibroids in pregnancy – common but poorly understood. Obstet Gynecol Survey 2005; 60:132-138. 12. Bulletti C, De Ziegler D, Polli V, Flamigni C. The role of leiomyomas in infertility. J Am Assoc Gynecol Laparosc 1999; 6:441. 13. Pritts EA. Fibroids and infertility: a systematic review of the evidence. Obstet Gynecol Surv 2001; 56:483. 14. Stenchever M, Droegemueller W, Herbst A, Mishell D. Comprehensive Gynecology 4th Ed. St Louis: Mosby 2001. 15. Rice JP. Am J Obstet Gynecol 1989; 160:1212-1216.

Results:Sixty-seven study patients were identified with sixty-six live births. One intrauterine fetal demise delivered at 22 weeks. Median age at delivery was 35.4 years, and median gestational age at delivery was 37.35 weeks. 22% had 1 fibroid, while 78% had multiple fibroids. 70.7% delivered by cesarean section, 29.3% delivered vaginally. Delivery information was not available for 9 patients. 2 patients had post-partum hemorrhages, with 1 cesarean hysterectomy due to PPH. 2 patients were identified with IUGR and both patients had retroplacental fibroids. One of these patients had oligohydramnios and abruption with delivery at 22 weeks. 35.7% were admitted for preterm labor, and overall 27.6% delivered preterm which is roughly a 2-fold increase over the background incidence of preterm delivery. 20.6% received indocin for tocolysis.

Average diameter of fibroids was 6.42cm, with 55.6% showing growth during pregnancy, while 44.4% showed shrinkage or stayed the same. Statistical significance was observed between size of fibroid and gestational age at delivery, i.e the larger the fibroid the earlier the delivery. Correlations were not seen for preterm delivery and number or growth of fibroids.

Table 1. Complications associated with fibroids in pregnancy.

Figure 1. Fibroids in early pregnancy.

Figure 3. Correlation between size of fibroid and gestational age at delivery.

Figure 2. Large fibroidsFigure 4. Retroplacental fibroids.

Fibroids are the most common benign tumor of the female genital tract, affecting 25-35% of reproductive age women. Their prevalence in pregnancy is between 0.1% to 12%. Fibroids have been correlated with many adverse obstetric outcomes (Table 1), but there is no uniform management of pregnant patients with fibroids; some receive routine care while others receive extensive surveillance with more frequent visits, ultrasounds and cervical examinations.

There is an increased risk of spontaneous abortion in the first trimester, especially for submucosal fibroids as they can distort the uterine cavity and vascular supply and interfere with normal placentation. Intramural fibroids can decrease implantation rate as well. Bleeding and abruption has also been associated with leiomyomas, with the highest risk being for patients with retroplacental fibroids, or fibroids larger than 7cm. Intrauterine growth restriction is a concern for patients with large fibroids as well. Preterm contractions and preterm labor may correlated with increasing size of fibroids though there is conflicting literature on the topic

The influence of pregnancy on fibroid growth is unclear in the literature, with some reporting growth in the first trimester and then a decrease in the third trimester, and some reporting no change. Our study addresses the questions raised in the current literature regarding obstetric outcomes, and growth of fibroids.