Scar Evaluation after Caesarean by Ultrasound Registry

While the caesarean section (CS) rate is increasing in most Western countries,
the long-term effects of this procedure are poorly studied. In this study we
will evaluate abnormal uterine bleeding, subfertility and uterine rupture after
CS.

Ultrasonography shows a niche at the site of the uterine caesarean scar in the
majority of women with a CS in the past history. A niche is a triangular,
anechoic area at the presumed site of incision. Our primary objective is to
develop an anatomical classification of niches and evaluate if this
classification can be related to the degree of abnormal uterine bleeding.
Our secondary objective is to demonstrate that the presence of a niche and
thickness of the lower uterus segment (LUS) during subsequent pregnancy, can
predict dehiscence or rupture of the uterus in women with previous caesarean
delivery.
As an addition, we want to evaluate if there is a relation between the presence
of a niche and subfertility. If this relation can be demonstrated, the
hypothesis will be tested that a niche negatively affects the endometrial
secretion pattern.

In an observational prospective cohort study, gel instillation
sonohysterography (GIS) is performed 6 to 12 months after CS to detect a niche.
The depth and shape, the thickness of the residual myometrium and the thickness
of the myometrium bordering the scar will be recorded in order to develop a
classification. Endometrial secretion will be obtained by performing
endometrial aspiration just before the GIS. Two blood samples will be taken for
anti-Müllerian hormone (AMH) serum level measurement and one spare sample for
stored serum. Women are asked to fill in a questionnaire and keep a diary card
to discover abnormal uterine bleeding. The questionnaire will be repeated every
year for the duration of 5 years and GIS will only be repeated if there is an
indication for sonohysterography. In case of secondary subfertility women will
be contacted by the investigator and receive additional questions.
In 6 women with niche and 6 women without niche, GIS will be repeated two more
times. Ultrasound images of the niche will be obtained in the follicular phase,
the phase around the ovulation and the luteal phase.
In case of subsequent pregnancy, transvaginal ultrasound will be performed
between 16 and 20 weeks* and between 36 and 38 weeks* gestation to detect the
presence of a niche and measure the thinnest zone of the LUS. The course of the
pregnancy and delivery are recorded. Special attention is paid to any sign of
uterine dehiscence or rupture.

Women with a history of caesarean section, without any fertility problems in
the past, and now visiting the outpatient clinic because of secondary
subfertility will undergo the same examinations: GIS, endometrial aspiration
and blood withdrawal. They will also be asked to fill in a questionnaire and to
keep a diary card to discover abnormal uterine bleeding.

The burden, associated with participation, includes a visit of the VU
University Medical Center to undergo GIS or transvaginal ultrasonography and
blood withdrawal. Endometrial aspiration will be performed during the GIS which
gives no additional inconvenience. The risk associated with GIS and
transvaginal ultrasound is very low. Furthermore, participants will be
requested to fill in a questionnaire on a yearly base, during a period of 5
years. In case of secondary subfertility women will receive additional
questions.
GIS will be repeated two more times in 12 volunteers.
The benefit of the SECURE-study is that women with complaints of abnormal
uterine bleeding might be diagnosed with having a niche. In case of a niche and
the presence of associated symptoms, further examination and treatment can
follow.