MYOMA AND

PREGNANCY

Nomenclature

Fibroid--------Fibroids

Myoma--------Myomata

Fibromyoma—Fibromyomata

Leiomyoma---Leiomyomata

Fibroids (leiomyomas) are benign smooth

muscle cell tumors of the uterus.

Although they are extremely common,

with an overall incidence of 40% to 60%

by age 35 and 70% to 80% by age 50, the

precise etiology of uterine fibroids

remains unclear.

Described based on location in theuterus: Intramural: develop from withinuterine wall, do not distort uterinecavity, <50% protruding into serosalsurface

Submucosal: develop from myometrialcells just below endometrium, oftenprotrude into and distort uterine cavity

Subserosal: originate from serosalsurface of uterus, >50% protrudesout of serosal surface

Cervical: located in the cervix,rather than uterine corpus

The diagnosis of fibroids in

pregnancy is neither simple nor

straightforward. Only 42% of large

fibroids ( 5 cm) and 12.5% of

smaller fibroids (3-5 cm) can be

diagnosed on physical examination.

The ability of ultrasound to detect

fibroids in pregnancy is even more

limited (1.4%-2.7%) primarily due to the

difficulty of differentiating fibroids from

physiologic thickening of the

myometrium.

Reflecting the growing trend of

delayed childbearing, the incidence

of fibroids in older women

undergoing treatment for infertility is

reportedly 12% to 25%.

Despite their growing prevalence,

the relationship between uterine

fibroids and adverse pregnancy

outcome is not clearly understood.

the majority of fibroids (60%-78%) do

not demonstrate any significant change

in volume during pregnancy.

22% to 32% of fibroids increase in

volume & the growth was limited almost

exclusively to the first trimester,

especially the first 10 weeks of

gestation.

In the second trimester, small fibroids

grow whereas large fibroids (> 6cm)

remain unchanged or decrease in size

but all decrease in size in the third

trimester.

The majority of fibroids show no

change during the puerperium,

although 7.8% will decrease in volume

by up to 10%.

Pain

Pregnancy loss

Preterm labor and

birth

Placental

abruption

Placenta previa

PPH

Dysfunctional

labor

Malpresentation

Malposition

Cesarean delivery

The risk and type of complication appear to be

related to the: 1. Size, 2. Number, and 3. Location of the myomas.

If the placenta implants over or in close proximity to a myoma, there may be an increased risk of:

1. Miscarriage.2. Preterm labour.3. Abruption. 4. Prelabour rupture of membranes.5. Intrauterine growth restriction.

Fibroids located in the lower uterine segment may increase the likelihood of :

1. Fetal malpresentation,

2. Caesarean section, and

3. Postpartum hemorrhage.

American Journal of Obstetrics & Gynecology, Vol. 198, PC Klatsky et al, “Fibroids and

reproductive outcomes: a systematic literature review from conception to delivery," pp. 357-

366.

Most common

complication.

Causes

Red degeneration.

Tortion.

Impaction.

Theories.

rapid fibroid growth results in the tissue

outgrowing its blood supply

change in the architecture (kinking) of

the blood supply to the fibroid leading

to ischemia and necrosis

the pain results from the release of

prostaglandins from cellular damage

within the fibroid.

Multiple fibroid increase risk.

Submucosal or interstitial.

Unclear mechanism??

Increase uterine contractility.

Compressive effect.

Affection of blood supply to

developing placenta.

More common if the placenta

implants close to the fibroid.

Evidence not consistent across the

literature

Increased risk if placenta is adjacent to

or overlies a fibroid

Decreased oxytocinase activity higher

oxytocin levels premature contractions .

Fibroid uteri are less distensible, once

uterus grows to a certain point

contractions.

Conflicting evidence

Submucosal, retroplacental & volumes

> 200 cm3 are independent.

Abnormal placental perfusion:

decreased blood flow to endometrium

overlying fibroid placental ischemia,

decidual necrosis abruption (?)

Placenta previa is a less common

outcome and was positively

associated with fibroids in 2

studies (Qidwai IG et al 2006,

Vergani P et al 2007 ).

Two other studies found no

association with placenta previa,

making this association difficult

to ascribe to fibroids as

advanced maternal age and prior

uterine surgery were not

considered (Coronado GD et al

2000, Vergani P et al 1994)

Although cumulative data and a

population-based study suggested

that women with fibroids are at

slightly increased risk of delivering a

growth-restricted infant, these

results were not adjusted for

maternal age or gestational age.

Rarely, large fibroids can compress

and distort the intrauterine cavity

leading to fetal deformities.

A number of fetal anomalies have

been reported in women with large

submucosal fibroids, including

dolichocephaly , torticollis and limb

reduction defects. (Chuang J et al 2001)

Increases risk 13% vs

4.5%. (Klatsky PC et al

2008)

Risk factors :

Large fibroids.

Multiple fibroids.

Fibroids in the lower

uterine segment

Greater risk: retroplacental or

cesarean delivery.

Decreased force and coordination of

contractions uterine atony

Be prepared.

Retained placenta was more common in

women with fibroids, but only if the

fibroid was located in the lower uterine

segment.

Varying evidence

Decreased force of contractions

Asymmetric wave of contractile

force across uterus

Consistent evidence.

48.8% versus 13.3%.(Klatsky PC et al 2008)

Location in lower

uterine segment due

to higher risk of

malpresentation,

dysfunctional labor &

abruption.

Despite the increased risk of

cesarean, the presence of

uterine fibroids—even large

fibroids —should not be regarded

as a contraindication to a trial of

labor.

Rare.

However, several studies have reported that

antepartum myomectomy can be safely

performed in the first and second trimester

of pregnancy.

Acceptable indications include intractable

pain from a degenerating fibroid or from

tortion.

Obstetric and neonatal outcomes in

women undergoing myomectomy in

pregnancy are comparable with that

in conservatively managed women

except increasing rate of C.S. (De

Carolis S et al 2001, Celik C et al

2002)

Well-substantiated risk of severe

hemorrhage requiring blood

transfusion, uterine artery ligation,

and/or puerperal Hysterectomy.

It should only be performed if

unavoidable to facilitate safe delivery

of the fetus or closure of the

hysterotomy. Pedunculated subserosal

fibroids can also be safely removed.

Myomectomy remains the standard of

care for treating symptomatic fibroids

in women desiring fertility & this item

regard as relative contraindication of

uterine artery embolization.

Nevertheless, successful pregnancies

have been reported.

the outcomes of pregnancies suggest a

modest trend toward increasing risk of

preterm delivery, postpartum hemorrhage,

and abnormal placentation.

Sixty eight percent of the patients

underwent C.S.; however, the majority of

these cesareans were elective without a

trial of labor.

(Walker WJ et al 2006, Pron G et al 2005)