Cesarean Section Scar Niche: The Impact on ART Outcome

Study Overview
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Brief Summary
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To evaluate the impact of the presence of cesarean section niche and its characteristics on the outcome of ART cycles.

Detailed Description
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The incidence of Cesarean section (CS) is increasing worldwide, with a corresponding increase in its associated complications. The well-known complications are infection, hemorrhage, and increased risk of obstetric complications in subsequent pregnancies, like morbidly adherent placenta, cs scar pregnancies and uterine rupture. In addition, some studies emphasize the effect of cesarean sections on reduced fertility. A meta-analysis reported that a Caesarean section reduces the probability of subsequent pregnancy by 10%, compared with a previous vaginal delivery. The cesarean section niche is defined as an indentation of the uterine myometrium of at least 2 mm at the site of the caesarean scar. The most common symptom of niche is abnormal uterine bleeding. Meanwhile, other symptoms include dysmenorrhea, chronic pelvic pain, dyspareunia, and sub-fertility/infertility. The detection of a cesarean section niche depends on the operator and the diagnostic method used. This can be 2D, 3D transvaginal sonography, sonohysterography or hysteroscopy. Regarding ART, the presence of cs niche was reported to reduce the chances of embryo implantation, and increase the rate of spontaneous miscarriages, especially if the implantation is close to it or in the niche. The presence of a niche may increase the difficulty of embryo transfer procedure, clinicians need to be aware of its presence and the transfer should be done under ultrasound guidance to ensure the catheter bypasses the niche and enters the uterine cavity. Still the impact of c.s niche and its characteristics on outcome of ART is not clear.

Official Title
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Cesarean Section Scar Niche: The Impact on Assisted Reproductive Technology Outcome

Conditions
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ART, Cesarean Section

Intervention / Treatment
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* Diagnostic Test: cs niche group


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Aged from 18 - 37 years old. Having a history of one or more previous CS with ultrasonographic visible cesarean section niche (for the group with cs scar niche), which is regarding to European Niche Taskforce is an indentation of the uterine myometrium of at least 2 mm at the site of the CS scar (Jordans et al., 2019). A normal uterus with no anomalies or pathologies. At least one good-quality embryo available for transfer. Exclusion criteria: Younger than 18 or older than 37 years old. Congenital uterine abnormality or pathology. Presence of a hydrosalpinx. ICSI cycles with TESE samples.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 37 Years

Sexes Eligible for Study
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Female

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| cases with cs niche<br>133 cases with cs niche undergoing ART will be included. Pituitary suppression will be achieved by long or antagonist protocol. For long protocol, GnRH agonist will be administered for 10-14 days starting from mid-luteal phase of preceding cycle. After confirmation of down regulation, gonadotropins will be given from second or third day of cycle in a daily dose of (150-300 IU). Gonadotropins therapy will be tailored according to age, BMI, antral follicle count, antimullerian hormone and previous response. In antagonist protocol, gonadotropins will be given from second or third day of cycle in a daily dose of (150-300 IU). GnRH antagonist will be adjusted according to patient response. On the 5th -6th day of stimulation, sonography will be performed and repeated every 1-3 days with regular estradiol assessment. When at least 3 follicles reach ≥ 17 mm in mean diameter, trigger will be given. Oocytes pick up will be performed 34-36 hour after triggering. | Diagnostic Test: cs niche group<br>* A niche is formally defined by the European Niche Taskforce as an indentation of the uterine myometrium of at least 2 mm at the site of the CS scars. A niche can be sub classified as follows: Simple niche Simple niche with one branch Complex niche (with more than one branch). The following measurements will be taken: Length. Depth. Width. RMT (residual myometrium thickness). AMT (adjacent myometrium thickness). Distance between the niche and the VV (vesico-vaginal) fold. Distance between the niche and the external os. We will also comment on the position of the uterus (AVF or RVF), presence or absence of intra cavitary fluid and its thickness.<br>|
| cases without cs niche<br>133 cases without cs niche undergoing ART will be included. Pituitary suppression will be achieved by long or antagonist protocol. For long protocol, GnRH agonist will be administered for 10-14 days starting from mid-luteal phase of preceding cycle. After confirmation of down regulation, gonadotropins will be given from second or third day of cycle in a daily dose of (150-300 IU). Gonadotropins therapy will be tailored according to age, BMI, antral follicle count, antimullerian hormone and previous response. In antagonist protocol, gonadotropins will be given from second or third day of cycle in a daily dose of (150-300 IU). GnRH antagonist will be adjusted according to patient response. On the 5th -6th day of stimulation, sonography will be performed and repeated every 1-3 days with regular estradiol assessment. When at least 3 follicles reach ≥ 17 mm in mean diameter, trigger will be given. Oocytes pick up will be performed 34-36 hour after triggering. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The effect of cesarean scar niche and its characteristics on ongoing pregnancy rate of ART cycles. | Ongoing pregnancy: defined as a viable intrauterine pregnancy of at least 12 weeks duration confirmed on an ultrasound scan | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical pregnancy | Clinical pregnancy: A pregnancy diagnosed by ultrasonographic visualization of one or more gestational sacs. | 6 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cesarean Section niche, ART