Thin
Endometrial
Lining
During Fertility Treatment
Some women encounter thin endometrial lining and abnormal
pattern during natural cycles or during fertility treatment.
The implantation of embryos is impaired in women with thin
lining and abnormal pattern. Abnormal lining can lead to
recurrent implantation failure in young women undergoing IVF
after repeated transfer of good quality embryos.
The thickness of the lining appropriate for implantation is
commonly defined at 7 to 13mm measured on vaginal ultrasound.
The most receptive pattern of the lining of the uterus is a
tri-laminar pattern (three line pattern) without little
homogenous pattern when visualized shortly before ovulation
(pattern 1 and 2 of the photo, Fanchin et al 2000).
Causes for Abnormal Endometrial lining
during Fertility Treatment
The two most common abnormalities encountered are
a. Fluid inside the Cavity: fluid may accumulate inside the
cavity due to stenosis (narrowing) of the cervix probably
because of prior surgery or leak of fluid from a blocked
dilted fallopian tube (hydrosalpinx).
b. Thin lining and /or abnormal pattern of endometrium.
Possible causes
1. Acquired (Asherman Syndrome): prior D&C (termination of
pregnancy), uterin surgery (e.g fibroid surgery) or
tuberculosis in women from certain geographical locales. All
work through the formation of scar tissue inside the uterus.
2. Idiopathic: no prior cause is identified.
Evaluation of The Uterine Cavity
Proper evaluation of the uterine cavity and lining is an
integral component of fertility evaluation and monitoring is
also essential during treatment. Methods of evaluation include
i. Vaginal ultrasound for the thickness and pattern during the
follicular and luteal phases of the menstrual cycle
ii. Evaluation of the cavity of the uterus using HSG
(hysterosalpingogram), saline sonography (water sonogram) or
hysteroscopy. Saline sonography is the most invasive and is a
very accurate method for evaluation of the cavity and identify
if a lesion arising from the wall of the uterus projects into
the cavity.
iii. MRI: magnetic resonance imaging can accurately identify
abnormalities in the wall of the uterus; fibroids,
adenomyosis, congenital anomalies (septum, bicornuate, T shape
uterus)
iii. Endometrial biopsy: rarely indicated. The lining of the
uterus is sampled and with special stain to detect chronic
infection. The value of this testis questionable.
Treatment of Abnormal Endometrial Lining
Many treatments are available to normalize the cavity of the
uterus and improve the lining
1. Excision of hydrosalpinx: a dilated blocked fallopian tube
especially those seen on ultrasound should be excised to avoid
leak of fluid into the uterus. This has the potential of
doubling the implantation rate of embryos. Laparoscopy can be
used to remove dilated tubes in a minimal access day surery
2. Asherman syndrome: operative hysteroscope can be used to
accurately cut the scar tissue and allow the surrounding
healthy lining to cove the row area. The lining is treated
with estrogen after surgery to promote healing
3. Uterine fibroids and polyps and spetum can be removed using
operative hysteroscope.
4. Antibioitics to treat chronic inflammation of the lining of
the uterus are seldom effective.
5. During IVF if the lining is not favorable all embryos can
be frozen. In subsequent cycle, the lining is prepared with
estrogen as long as needed till adequate thickness and pattern
is achieved. Progesterone is then started and embryos are
thawed in the appropriate time and transferred into the
uterus.
6. Sildenafil (viagra) can be given as vaginal tablets but its
value is questionable.
7. Gestational carriers can be used if all other methods fail.
Meticulous attention to the condition of the lining and cavity
of the uterus is important during fertility treatment of the
uterus. Endoscopic surgery and hormone preparation can improve
the majority of the linings and increase the chance for embryo
implantation