Since the 1960s there has been a worldwide increase in primary cesarean deliveries from 5% to 32%.1-3 North America has the second highest rate of cesareans in the world, which has resulted in high rates of repeat cesarean deliveries and worsening maternal morbidity including surgically-related infections, bowel and bladder injury, transfusions, hysterectomy, abnormal placentation, and cesarean scar pregnancy (CSP).3,4 While CSP is a rare outcome of pregnancies, and the incidence is not well known, there have been estimates based on different populations of 1:1800-1:2216.5,6 CSP has been associated with a history of prior cesarean that causes dehiscence of a portion of the uterine wall.5
CSP is considered an ectopic pregnancy and can carry very serious consequences, including hemorrhage, abnormal placentation, and uterine rupture.6 Due to the rarity of the condition and the possible serious consequences it requires specialized care to manage appropriately. The number of prior cesarean deliveries does not seem to correlate with risk of CSP and a meta-analysis found that 52% of such pregnancies were in women with one prior cesarean.7 This review examines the literature on CSP regarding pathophysiology, signs and symptoms, ultrasound diagnosis, management options, and future fertility for women with the condition.
To better understand CSP, an appreciation of placental development is important. As a brief overview, at the time of implantation, the blastocyst results in modification of endometrial stromal cells, which enhances the decidualization reaction. The decidua, in turn, is able to regulate endometrial receptivity to modulate architectural changes that facilitate immune and vascular cell function to further trophoblastic invasion.8 Trophoblasts continue to invade until meeting the decidua basalis in which a zone of fibrinoid degeneration is created, described as the Rohr stria and Nitabuch layer.8,9
Prior uterine scar tissue from a cesarean often results in absence of the decidua basalis or partial disruption with a faulty layer of fibrinoid degeneration.8 In the setting of CSP, the pregnancy is not surrounded by or implanting into the decidualized endometrium, but rather, embeds in fibrous scar tissue and myometrium.10,11 The pregnancy is abnormal from the moment of implantation and management requires careful consideration.
The authors report no potential conflicts of interest with regard to this article.
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- Jurkovic D, Hillaby K, Woelfer B, Lawrence A, Salim R, Elson CJ. First trimester diagnosis and management of pregnancies implanted into the lower uterine segment Cesarean section scar. Ultrasound Obstet Gynecol. 2003;21(3):220-227.
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- Godin PA, Bassil S, Donnez J. An ectopic pregnancy developing in a previous caesarean section scar. Fertil Steril. 1997;67:398.
- Weimin W, Wenqing L. Effect of early pregnancy on a previous lower segment cesarean section scar. Int J Gynecol Obstet. 2002;77(3):201-207.
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- Shufaro Y, Nadjari M. Implantation of a gestational sac in a cesarean section scar. Fertil Steril. 2001;75(6):1217.
- Pan Y, Liu M. The value of hysteroscopic management of cesarean scar pregnancy: a report of 44 cases. Taiwanese J Obstet Gynecol. 2017;56(2):139-142.
- Xiao Z, Cheng D, Chen J, Yang J, Xu W, Xie Q. The effects of methotrexate and uterine arterial embolization in patients with cesarean scar pregnancy: A retrospective case-control study. Medicine. 2019;98(11):e14913.
- Mara, M, Kubinova K, Maskova J, Horak P, Belsan T, Kuzel D. Uterine artery embolization versus laparoscopic uterine artery occlusion: The outcomes of a prospective nonrandomized clinical trial. Cardiovasc Intervent Radiol.2012;35(5):1041-1052.
- Monteagudo A, Cali G, Rebarbar A, et al. Minimally invasive treatment of cesarean scar and cervical pregnancies using a cervical ripening double balloon catheter: Expanding the clinical series. J Ultrasound Med. 2018;28(3):785-793.
- Grechukhina O, Deshmukh U, Fan L, et al. Cesarean scar pregnancy, incidence, and recurrence: Five-year experience at a single tertiary care referral center. Obstet Gynecol. 2018;132(5):1285-95.
- Api M, Boza A, Gorgen H, Api O. Should Cesarean scar defect be treated laparoscopically? A case report and review of the literature. J Minim Invasive Gynecol 2015 Nov-Dec;22(7):1145-1152.
- Maymon R, Svirsky R, Smorgick N, et al. Fertility performance and obstetric outcomes among women with previous cesarean scar pregnancy. J Ultrasound Med. 2011;30(10):1444.
- Cali G, Timor-Tritsch I, Palacios-Jaraquemada J, et al. Outcome of cesarean scar pregnancy managed expectantly: systematic review and meta-analysis. Ultrasound Obstet Gynecol 2018; 51: 169-175.