The Correlation Analysis Of Endometriosis And Placenta Previa In Assisted Reproductive Technology

Background:Endometriosis refers to the endometrium is active in the uterus to grow outside the area, and in the local growth, infiltration, and repeated bleeding. The exact mechanism of endometriosis is not clear so far. The traditional theory is menstrual blood reflux cultivation theory raised by Sampon, other theories included body cavity metaplasia theory, spread theory, theory of stem cells and so on. A newly formed theory is "in ectopic determinism".Infertility is the most serious and profound complication of endometriosis. Studies show that endometriosis attacks5%-20%fertility women, meanwhile, the incidence of endometriosis is25-40%in infertile women. The mechanism of endometriosis cause infertility is still unknown. Some researches reveal that endometriosis can destroy oocytes and affect early embryonic development. And pelvic adhesion caused by endometriosis will hinder the eduction, intake and operation of oocyte. Meanwhile, the decreased receptivity of endometrium may block embryonic implantation to bring out sterility. Assisted reproduction technologies is an important way to cure endometriosis patients with infertility and the obstetric outcomes get widespread attentions, especially the placenta previa is the hot issue in focus on research.Placenta previa is defined as the placenta attached to the lower uterine segment with the lower edge reaching or covering the intra-cervical mouth after the28th week of gestation.The incidence of placenta previa is0.63%in foreign countries while0.24%-1.57%in domestic reports. Traditional theories that the uterus intrauterine membrane pathological changes and all kinds of surgical damages including abortion, curettage, induced labor, ring taking-out and putting-in, hysteroscopy operation, cesarean section and so on are likely to cause varying degrees of endometritis or atrophic endometrium lesions. Uterine decidua vessels defects and poor placental blood supply caused chronic ischemia hypoxia. The placenta area expanded to absorb enough nutrition is prone to lead to placenta previa. Other factors such as assisted reproductive technology, advanced pregnant women, smoking, taking drugs, multiplets and placenta factors may increase the occurrence of placenta previa. Reports showed that pregnant women with endometriosis are increased to bring out placenta previa.ObjectiveTo investigate the relationship between placenta previa and endometriosis in women with assisted reproductive technology.Methodsa retrospective analysis reviewed2060cases with assisted reproductive technology between2008and2012in Women’s Hospital, School of Medicine, Zhejiang University. We reviewed the relationship between the factors such as maternal age, body mass index(BMI), parity, production time, number of abortion, previous caesarean section, endometriosis, ovarian dysfunction, male infertility and placenta previa.Results:Of the110women with Placenta previa, there was69cases were diagnosed endometriosis. We found that endometriosis (odds ratio=19.7;95%CI=0.5-300.6) have a positive relation with placenta previa. The high degree of endometriosis patients is more prone to have placenta previa (the Kendall correlation coefficient is0.274, Spearman correlation coefficient is0.281, all P<0.001).Conclusions:1. Women with endometriosis appear to face greater obstetric risks compared except infiltration with the general population. Endometriosis increased the incidence of placenta previa.2. In women with assisted reproductive technology, endometriosis is a high risk factor of placenta previa.3. The higher degree of endometriosis, the more possible of placenta previa.