Introduction
Endometriosis is an oestrogen-dependent chronic inflammatory condition,
characterised by the presence of endometrial-like tissue outside of the
uterus.1 Three subtypes of endometriosis are
described: superficial peritoneal, ovarian (endometrioma), and deep
(infiltrating).2 The true prevalence of endometriosis
is unknown. It is estimated to affect between 6–10% of women of
reproductive age3 and is present in 50% of women with
infertility who have evidence of normal ovulation and normospermic
partners.4 In 50-60% of women, endometriosis is
associated with debilitating pelvic pain which can have an adverse
effect on quality of life.5 However, a proportion of
women are relatively asymptomatic and less likely to attend for
diagnostic tests or seek treatment.
The gold standard for diagnosis of endometriosis is histological
examination of lesions excised during surgery.6However, when surgery is used to detect endometriosis, long delays of up
to 7-8 years after onset of symptoms have been
reported.7 There are no accurate non-invasive
biomarkers for endometriosis and ultrasound or MRI are the only
diagnostic tests which could be used as alternatives to surgery.
Following recent advancements in technology and training, ultrasound is
widely acknowledged as the first line investigation of choice in women
with suspected endometriosis.8,9 A standardised
approach for ultrasound assessment is well described in a recent
consensus statement.10 Transvaginal ultrasound has
been shown to have good concordance with laparoscopy for the diagnosis
of deep endometriosis (kappa 0.76) and is highly reproducible for the
detection of endometriotic cysts and nodules.11,12However, ultrasound is not a sensitive tool for the diagnosis of
superficial endometriosis.11
Naftalin et al. found evidence of ovarian and/or deep endometriosis on
transvaginal ultrasound examination in 6.4% of women attending a
general gynaecology clinic.13 There have been no
studies on the prevalence of ovarian endometriomas and deep
endometriosis in pregnancy and there is no consensus regarding
specialist care for women with endometriosis in pregnancy. Recent
literature suggests that women with endometriosis have a higher risk of
spontaneous miscarriage, preterm birth, small for gestational age
babies, placenta praevia, antepartum haemorrhage, postpartum haemorrhage
and preterm birth.14,15 Exacoustos et al reported that
women with deep endometriosis have increased rates of Caesarean sections
and surgical complications.16 Imaging offers the
potential to diagnose endometriosis in early pregnancy and identify
women at higher risk of adverse pregnancy outcomes.
The aim of this study was to assess the prevalence of ovarian
endometriomas and deep endometriosis in women attending a dedicated
early pregnancy assessment unit.