HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Qidwai, G. I. Articles by Jacoby, A. F. Search for Related Content PubMed PubMed Citation Articles by Qidwai, G. I. Articles by Jacoby, A. F. Related Collections General gynecology General obstetrics Immunology Labor and operative obstetrics Medical complications of pregnancy

Obstetric Outcomes in Women With Sonographically Identified Uterine Leiomyomata

From the ¹Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, California.

	ABSTRACT

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
OBJECTIVE: To examine the association between leiomyomata and complications during pregnancy, delivery, and the puerperium.

METHODS: We conducted a retrospective cohort study comparing pregnancy outcomes in women with and without uterine leiomyomata who underwent routine second trimester obstetric ultrasonography and delivered viable infants at a single institution. Potential confounding variables, including maternal age, weight, ethnicity, parity, gestational age, epidural use, and labor induction, were controlled for using multivariate logistic regression techniques.

RESULTS: From 1993 to 2003, 15,104 women underwent routine second trimester prenatal ultrasonography, and 401 (2.7%) women were identified with at least 1 leiomyoma. By univariate and multivariate analyses, the presence of leiomyomata was associated with increased risks for cesarean delivery (adjusted odds ratio [AOR] 1.57, 95% confidence interval [CI] 1.16–2.13), breech presentation (AOR 1.64, 95% CI 1.11–2.40), malposition (AOR 1.59, 95% CI 1.18–2.15), preterm delivery (AOR 1.45, 95% CI 1.08–1.96), placenta previa (AOR 1.86, 95% CI 1.02–3.39), and severe postpartum hemorrhage (AOR 2.57, 95% CI 1.54–4.27). Premature rupture of membranes, operative vaginal delivery, chorioamnionitis, and endomyometritis were not associated with leiomyomata. Median length of labor was not different between the 2 groups. When compared with leiomyomata less than 10 cm in size, leiomyomata 10 cm or larger were associated with rates of cesarean delivery that were not statistically different (25% compared with 31%, P = .49).

CONCLUSION: Pregnant women with leiomyomata are at increased risk for cesarean delivery, breech presentation, malposition, preterm delivery, placenta previa, and severe post partum hemorrhage. Women with leiomyomata 10 cm or larger achieve a vaginal delivery rate of nearly 70%. These results are useful for preconception and prenatal counseling of women with leiomyomata.

LEVEL OF EVIDENCE: II-2

Leiomyomata have been associated with a number of pregnancy complications, including first trimester bleeding, miscarriage, preterm labor, premature rupture of membranes (PROM), placental abruption, pelvic pain, and intra-uterine growth restriction. During labor, leiomyomata have been linked with fetal malpresentation, labor dystocia, puerperal infection, operative vaginal delivery, cesarean delivery, postpartum hemorrhage, and retained placenta.^1–3,6,7

The location and size of leiomyomata has also been associated with adverse obstetric outcomes.^1–3,6,7 Leiomyomata greater than 3 cm in size have been linked to increased rates of malpresentation, preterm labor, abruption, pelvic pain, and cesarean delivery.¹

The goal of this study is to compare the obstetric outcomes in women with and without leiomyomata who underwent routine second trimester ultrasonography and delivered viable infants at a single institution. To diminish effects of confounding, we controlled for a number of factors. In addition, we analyzed the association between adverse obstetric events and leiomyoma size, number, and location.

	MATERIALS AND METHODS

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
This was a retrospective cohort study including all women who underwent routine second trimester ultrasonography and delivered at 24 weeks gestation or longer at the University of California, San Francisco from January 1, 1993, to December 31, 2003. Exclusion criteria included pregnancies with multiple gestations, intrauterine fetal deaths, and fetal anomalies as well as the absence of a second trimester sonogram and delivery at another institution. The University of California, San Francisco institutional review board approved the study protocol.

Ultrasonographic data were obtained by searching the University of California, San Francisco obstetric ultrasonography database, which contains information on the presence, size, number, and location of uterine leiomyomata. The leiomyoma group consisted of pregnant women with at least 1 leiomyoma measuring 1 cm or more. The control group was pregnant women without ultrasonographically detected leiomyomata. Obstetric data were retrieved from the University of California, San Francisco perinatal database and linked to leiomyoma data. Specific demographic and clinical information included maternal age, gestational age, parity, race or ethnicity, type of medical insurance, previous uterine surgery, fetal presentation, length of labor, mode of delivery, presence of placenta previa, placental abruption, preterm labor, PROM, chorioamnionitis, endomyometritis, and severe postpartum hemorrhage. Preterm delivery was defined as birth less than 37 weeks gestational age. Premature rupture of membranes referred to amniorrhexis at 37 weeks or longer gestational age before the onset of labor. Severe postpartum hemorrhage was defined as an estimated blood loss of 1,000 mL or more for a vaginal delivery and 1,500 mL or more for a cesarean delivery. The operative vaginal delivery rate was the proportion of women who delivered by low and outlet forceps or vacuum among the women who achieved a vaginal birth

The rates of obstetric outcomes were compared between the group of women with leiomyoma and the group of women without leiomyoma in a univariate model using the ² test for proportions, Student t test for means, and Wilcoxon’s rank sum test for median values. Subgroup analysis was performed based on leiomyoma size, number, and location. Multiple logistical regression analysis was used to adjust for confounding variables such as maternal age, maternal weight, ethnicity, parity, gestational age, epidural use, and labor induction. Cross-product terms to examine the interaction between predictor variables were created. Their contribution to the model was tested using the maximum likelihood ratio test. The cross-product terms remained in the model if they met statistical significance, defined as a P value less than .05. A statistical trend was defined as a P value between .05 and .1. The data were analyzed using STATA 7 software (StataCorp, College Station, TX).

	RESULTS

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
From January 1, 1993, to December 31, 2003, 15,104 women with a live, singleton pregnancy underwent routine second trimester ultrasonography and delivered at our institution. A total of 401 women (2.7%) had at least 1 uterine leiomyoma of 1 cm or more in size. Women with leiomyomata differed from those without leiomyomata in mean age, race or ethnicity, and insurance status (Table 1). Risk factors for leiomyoma included age 35 years or older, African-American race, private health insurance, and a history of diabetes mellitus or chronic hypertension (Table 2). Leiomyoma size ranged from 1 to 20 cm. Forty women had a leiomyoma of 10 cm or more in diameter, and 182 women had a leiomyoma less than 5 cm in diameter. Among the 321 women for whom information on number of leiomyomata was available, 217 women had 1 leiomyoma, 36 women had 2 leiomyomata, 23 women had 3 leiomyomata, and 45 women had 4 or more leiomyomata (Table 3).

The cesarean delivery rate for women with leiomyomata was 49.1% and 21.4% for the control group (P < .001) (Table 4). In addition, compared with the control group, the presence of leiomyomata was associated with higher rates of placenta previa (3.5% compared with 1.8 %, P = .021). This association persisted after controlling for prior cesarean delivery and myomectomy (3.8% compared with 2.0%, P = .028). The presence of leiomyomata was also associated with higher rates of preterm delivery (19.2% compared with 12.7%, P = .001), breech presentation (12.6% compared with 8.9%, P = .003), fetal malposition (24.1% compared with 15.7%, P < .001) and severe postpartum hemorrhage. (8.3% compared with 2.9%, P < .001). Conversely, rates of operative vaginal delivery, chorioamnionitis, PROM, and placental abruption were not significantly different between the 2 groups.

There was a statistical trend toward an association between endomyometritis and leiomyomata compared with the control group (5.5% compared with 3.6% P = .068); however, after controlling for mode of delivery, the association no longer existed (Table 4). Among the women who delivered vaginally, there was no statistical difference in the median length of the first and second stages of labor between women with and without leiomyomata.

Although the total cesarean delivery rate for women with leiomyomata was 49.1%, a number of these women underwent cesarean delivery before the onset of labor. The indications for these cesarean deliveries included prior uterine surgery, fetal malpresentation, active herpes simplex lesions, placenta previa, and elective cesarean deliveries. To evaluate the effect of leiomyomata on patients who labored, a subgroup analysis was performed. Among the subgroup of labor-eligible women, there were consistently higher rates of cesarean delivery for the leiomyoma group compared with controls, regardless of parity (Table 5).

After controlling for potential confounders of obstetric outcomes using multivariate logistic regression techniques (Table 6), we were able to confirm the association between leiomyomata and an increased risk for cesarean delivery (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.28–2.11), malpresentation (OR 1.64, 95% CI 1.11–2.40), malposition (OR 1.59, 95% CI 1.18–2.15), preterm delivery (OR 1.45, 95% CI 1.08–1.96), severe postpartum hemorrhage (OR 2.57, 95% CI 1.54–4.27), and placenta previa (OR 1.86, 95% CI 1.02–3.39).

Among the 401 women with leiomyomata, 40 women (10%) had a leiomyoma of 10 cm or more in size. There were no differences between the groups with a leiomyoma of 10 cm or larger and a leiomyoma less than 10 cm in the overall cesarean delivery rate (60.9% compared with 47.8%, P = .097) and in the labor-eligible cesarean delivery rate (30.8% compared with 24.6%, P = .490) (Table 7). Leiomyoma 10 cm or larger were significantly associated with an increased rate of malpresentation compared with women with leiomyoma less than 10 cm (23.1% compared with10.4%, P = .022). Although placenta previa and PROM were more common among women with the largest leiomyomata, the differences were not statistically significant. Other obstetric outcomes such as malposition, preterm delivery, severe postpartum hemorrhage, operative vaginal delivery, placental abruption, and median duration of the first and second stages of labor were not associated with leiomyoma size by univariate or multivariate analysis.

When leiomyoma size was examined as a continuous variable in multivariate linear regression models, there was no statistically significant size associated with adverse obstetric outcomes. Similarly, the number of leiomyomata was not significantly associated with any of the examined outcomes (Table 3). There was insufficient data to perform statistical analysis on the effect of leiomyoma location.

	DISCUSSION

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Despite the frequency with which leiomyomata are encountered in pregnancy, there remains considerable uncertainty and controversy about their effect during the antepartum, intrapartum, and postpartum periods. The prevalence of leiomyomata in our cohort was 2.7%, similar to the prevalence reported in other studies, 0.1–3.9%. Because there is a national trend to delay child bearing until later in life, the prevalence of leiomyomata in pregnancy will likely increase. Earlier studies may have underestimated the prevalence because they relied on physical examination and visualization at cesarean delivery to identify leiomyomata.^1,6 More recent studies have employed ultrasonography for detection but have used it selectively, scanning only women with pregnancy complications or advanced maternal age.³ Our study investigated perinatal outcomes of a large cohort of women all of whom underwent second trimester obstetric ultrasonography.

As described in other studies, the presence of leiomyomata was associated with advanced maternal age, African-American race, diabetes mellitus, and chronic hypertension.^8,9 Unlike other studies, we did not find an association between leiomyomata and parity.⁸

In our study, leiomyomata were significantly associated with placenta previa and preterm delivery, but not with placental abruption or PROM. Other studies have suggested an association between leiomyomata and placental abruption, especially leiomyomata located beneath the placenta. In a large population-based study, Coronado et al⁶ documented a nearly 4-fold increase in placental abruption among leiomyoma subjects compared with the controls (1.8% compared with 0.6%, OR 3.9). Similarly, Rice et al¹ published a retrospective review of 93 women with uterine leiomyomata documented by antenatal ultrasonography. Of the 14 patients with 1 or more leiomyomata in a retroplacental location, 8 (57%) subsequently developed placental abruption, which contributed to 4 fetal deaths. In contrast, the 79 women without retroplacental leiomyomata had a placental abruption incidence of 2.5%. On the contrary, Davis et al⁷ published a study of 85 women with leiomyomata and 85 matched controls. There were no reported cases of placental abruption among the 55 women with leiomyomata in direct contact with the placenta.

Data from previous studies was inconsistent regarding an association between leiomyomata and PROM. Coronado et al⁶ described higher rates of PROM in the leiomyoma group (4.5% compared with 2.5%, OR 1.8); however, the gestational age at which PROM occurred was not stated. Other studies agreed with our finding that PROM was not associated with leiomyomata.^2,7,10

There was a positive association between placenta previa and leiomyomata. It is possible that prior uterine surgery, such as cesarean deliveries and abdominal myomectomies, acted as a confounder, causing a false association between the 2 conditions. However, subgroup analysis failed to show a difference in placenta previa rates between leiomyoma patients with and without prior uterine surgery.

We confirmed findings from previous studies that breech presentation and cesarean delivery are strongly associated with the presence of leiomyomata.^6,8 Coronado et al⁶ reported a 4-fold increase in malpresentation (12.6% compared with 3.0%, OR 3.98) and a 6-fold increase in cesarean deliveries (58.3% compared with 17.5%, OR 6.4) compared with controls. Sheiner et al⁸ described a nearly 7 times higher rate of cesarean delivery in the leiomyoma group after adjusting for maternal age, parity, gestational age, and breech presentation (57.7% compared with 10.8%, OR 6.7). Although mode of delivery was not statistically different between the leiomyoma and control subjects in the study by Exacoustos et al,² 12 of the 100 (12%) cesarean deliveries in the leiomyoma group had uterine atony and hemorrhage requiring cesarean hysterectomy. No cesarean hysterectomies were necessary in our cohort, although severe postpartum hemorrhage was positively associated with leiomyomata. To get a sense of the effect that leiomyomata may have on mode of delivery, if we consider the adjusted odds ratio for cesarean deliveries of 1.64 and a baseline cesarean delivery rate of 25%, for every 6 women with leiomyomata there would be 1 additional cesarean delivery performed. Applied to the U.S. population, if the prevalence of leiomyomata is similar to our population at 3%, then approximately 20,000 cesareans per year are attributable to leiomyomata.

Several studies have correlated leiomyoma size with risk for pregnancy complications and operative deliveries.^1,2 Although women with a leiomyoma 10 cm or larger had slightly higher rates of cesarean delivery compared with women with smaller leiomyomata, 70% of the labor-eligible subjects with a leiomyoma 10 cm or larger delivered vaginally. Our findings were similar to those of Exacoustos et al² regarding the lack of correlation between adverse obstetric events and the number of leiomyomata.

The biologic basis for the association between uterine leiomyomata and obstetric complications is unclear, although physical interference leading to decreased uterine distensibility or mechanical obstructions likely plays a role. It has been hypothesized that leiomyomata may interfere with uterine contractility; however, our data did not show differences in the lengths of first or second stages of labor or rates of operative vaginal delivery between patients with and without leiomyomata. Thus, while the strength of uterine contractility may vary, it does not seem to be the primary cause of the differences in clinical outcomes in patients with uterine leiomyomata.

This study was designed to improve upon several methodologic problems present in previous studies. Specifically, ascertainment bias was diminished by identifying the leiomyoma subjects from a large cohort of women undergoing routine second trimester obstetric ultrasonography rather than from a group of women selectively referred for ultrasonography due to obstetric complications. In addition, few published studies of leiomyomata and obstetric outcomes controlled for potential confounders by multivariate analysis.^6,8

Our study was not without limitations. Despite the high quality of the data gathered over 11 years, the study was still underpowered to examine relatively uncommon events such as placental abruption. Furthermore, retrospective studies can be complicated by missing and inaccurate data. However, among the variables analyzed, less than 1% were missing data. In addition, although we attempted to control for potential confounders, there may have been significant factors that we did not identify.

It is hoped that the results of this study will be clinically useful to physicians who provide preconception and prenatal care to women with leiomyomata. Although women with leiomyomata have higher rates of breech presentation and cesarean delivery compared with women without leiomyomata, even when a leiomyoma is 10 cm or larger, women have high rates of vaginal delivery. Clinicians should be prepared to manage severe postpartum hemorrhage after vaginal births and cesarean deliveries when leiomyomata are present. More studies are needed to clarify the association between leiomyomata and adverse obstetric outcomes such as placenta previa, preterm delivery, PROM, and placental abruption.

	Footnotes

 
Dr. Aaron Caughey is supported by the National Institute of Child Health and Human Development, Grant HD01262, as a Women’s Reproductive Health Research Scholar.

Corresponding author: Alison F. Jacoby, MD, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, 2356 Sutter Street, 6th Floor, San Francisco; e-mail: jacobya{at}obgyn.ucsf.edu.

doi:10.1097/01.AOG.0000196806.25897.7c

	REFERENCES

TOP ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
1. Rice JP, Kay HH, Mahony BS. The clinical significance of uterine leiomyomas in pregnancy. Am J Obstet Gynecol 1989;160:1212–6.[Medline]

2. Exacoustos C, Rosati P. Ultrasound diagnosis of uterine myomas and complications in pregnancy. Obstet Gynecol 1993;82:97–101.[Abstract/Free Full Text]

3. Katz VL, Dotters DJ, Droegemeuller W. Complications of uterine leiomyomas in pregnancy. Obstet Gynecol 1989;73:593–6.[Abstract/Free Full Text]

4. Burton CA, Grimes DA, March CM. Surgical management of leiomyomata during pregnancy. Obstet Gynecol 1989;74:707–9.[Abstract/Free Full Text]

5. Hasan F, Arumugam K, Sivanesaratnam V. Uterine leiomyomata in pregnancy. Int J Gynaecol Obstet 1991;34:45–8.[Medline]

6. Coronado GD, Marshal LM, Schwartz SM. Complications in pregnancy, labor, and delivery with uterine leiomyomas: a population-based study. Obstet Gynecol 2000;95:764–9.[Abstract/Free Full Text]

7. Davis JL, Ray-Mazumder S, Hobel CJ, Baley K, Sassoon D. Uterine leiomyomas in pregnancy: a prospective study. Obstet Gynecol 1990;75:41–4.[Abstract/Free Full Text]

8. Sheiner E, Bashiri A, Levy A, Hershkovitz R, Katz M, Mazor M. Obstetric characteristics and perinatal outcome of pregnancies with uterine leiomyomas. J Reprod Med 2004;49:182–6.[Medline]

9. Marshall LM, Spiegelman D, Barbieri RL, Goldman MB, Manson JE, Colditz GA, et al. Variation in the incidence of uterine leiomyoma among premenopausal women by age and race. Obstet Gynecol 1997;90:967–73.[Abstract]

10. Vergani P, Ghidini A, Strobelt N, Roncaglia N, Locatelli A, Lapinski RH, Mangioni C. Do uterine leiomyomas influence pregnancy outcome? Am J of Perinatol 1994;11:356–8.

This article has been cited by other articles:

				M. C. Alanis, A. Mitra, and N. Koklanaris Preoperative Magnetic Resonance Imaging and Antepartum Myomectomy of a Giant Pedunculated Leiomyoma Obstet. Gynecol., February 1, 2008; 111(2): 577 - 579. [Abstract] [Full Text] [PDF]

				E. Somigliana, P. Vercellini, R. Daguati, R. Pasin, O. De Giorgi, and P.G. Crosignani Fibroids and female reproduction: a critical analysis of the evidence Hum. Reprod. Update, September 1, 2007; 13(5): 465 - 476. [Abstract] [Full Text] [PDF]

				P. Vergani, A. Locatelli, A. Ghidini, M. Andreani, F. Sala, and J. C. Pezzullo Large Uterine Leiomyomata and Risk of Cesarean Delivery Obstet. Gynecol., February 1, 2007; 109(2): 410 - 414. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Qidwai, G. I. Articles by Jacoby, A. F. Search for Related Content PubMed PubMed Citation Articles by Qidwai, G. I. Articles by Jacoby, A. F. Related Collections General gynecology General obstetrics Immunology Labor and operative obstetrics Medical complications of pregnancy