**2. Placenta accreta, placenta increta, and placenta percreta**

Abnormal placental implantation (accreta, incretak, and percreta) is described using a general clinical term, respectively, morbidly adherent placenta (MAP) [2] or "abnormal invasive placenta" (AIP). If not diagnosed before delivery, MAP can lead to catastrophic postpartum hemorrhage, with life-threatening complications. Risk factors include increased maternal age, previous Cesarean delivery or myomectomy, multiparity, and previous intrauterine maneuvers (such as hysteroscopy and multiple dilatation and curettage [3]). The reported incidence ranges from 1:2500–1:7000 pregnancy in 2007 [4] to 1:533 deliveries in 2017 [3]. When the placental villi attach to the myometrium rather than the decidua, it is called placenta accreta; when the chorionic villi penetrate the myometrium, it is called placenta increta (e.g., **Figure 1**), whereas placenta percreta extends into the uterine serosa or adjacent organs (e.g., **Figure 2**). Placenta increta and placenta percreta are rare disorders, which represent <20% of the cases of placenta accreta [5]. These varieties can lead to more severe maternal complications (60% maternal morbidity [6], 7–10% maternal mortality [7]). The most important measure in decreasing these potentially fatal complications is the prenatal ultrasound diagnosis. In many cases, the patient's history is highly relevant. The key feature for early first-trimester diagnosis of MAP is an abnormal neovascularization in the ill-defined placental-myometrial junction detected in a color or power Doppler (2D or 3D) image [8], similar to the flow observed in an invasive mole, arteriovenous malformation, or retained products of conception. Other aspects can include focal or diffuse irregular lacunar lakes with turbulent flow typified by a high velocity (PSV, >15 cm/s) [9]. A higher number of lakes increase the risk of a presenting placenta accreta. The complete loss or disruption of the echolucent myometrial zone between the placenta and bladder is highly suggestive for MAP. When using color Doppler examination, the sensitivity and specificity of

the ultrasound scan can be as high as 80–90% and, respectively, 98% [10]. Magnetic resonance imaging can add accuracy to MAP diagnosis when assessing the lateral extension and penetration depth of the placenta. However, a majority of cases of MAP are diagnosed during the third stage of labor or during Cesarean section [9], and about 21% of cases of MAP are responsible for peripartum hysterectomy [11]. Overall, in suspected cases with this type of placental pathology, the best approach includes a multidisciplinary team with early planning for antepartum and intrapartum management, preferable than late planning [12]. Some groups recommend delivery at 34–35 weeks by performing preterm Cesarean section with the placenta left in situ [13]. Other several adjuvant techniques have been proposed, as methotrexate treatment and/or placement of internal iliac artery balloon catheters, for occlusion and/or arterial embolization [14]. The goal of the conservative approach of MAP is the attempt of gradual resorption of the placenta or delayed delivery of the placenta [15]. A good prognosis of MAP pathology is feasible, with improving maternal and fetal outcome, if diagnosis is timely and there is adequate preparation of the delivery. These are essential keys in the management of such cases [16].

**Figure 2.** Image of the uterus occupied by placenta percreta after postpartum hysterectomy due to important hemorrhagic

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http://dx.doi.org/10.5772/intechopen.75985

This type of obstetric pathology was firstly described in 1685 by Paul Portal, a French physician [17], as a major cause of hemorrhage, with a potentially life threat to the mother and the fetus. It was defined as the placenta that overlies entirely or partially the internal cervical os of the uterus. In complete praevia, the internal os is completely covered by the placenta (e.g., **Figure 3**). Placenta praevia is divided into *partial praevia* (a portion of the internal os is covered by the placenta),

**3. Placenta praevia**

complications.

**Figure 1.** Ultrasound color Doppler image of a case of placenta increta diagnosed in the early second trimester of pregnancy, associated with fetal demise. The surgical termination of pregnancy was performed under laparoscopic guidance, with no complications.

**Figure 2.** Image of the uterus occupied by placenta percreta after postpartum hysterectomy due to important hemorrhagic complications.

the ultrasound scan can be as high as 80–90% and, respectively, 98% [10]. Magnetic resonance imaging can add accuracy to MAP diagnosis when assessing the lateral extension and penetration depth of the placenta. However, a majority of cases of MAP are diagnosed during the third stage of labor or during Cesarean section [9], and about 21% of cases of MAP are responsible for peripartum hysterectomy [11]. Overall, in suspected cases with this type of placental pathology, the best approach includes a multidisciplinary team with early planning for antepartum and intrapartum management, preferable than late planning [12]. Some groups recommend delivery at 34–35 weeks by performing preterm Cesarean section with the placenta left in situ [13]. Other several adjuvant techniques have been proposed, as methotrexate treatment and/or placement of internal iliac artery balloon catheters, for occlusion and/or arterial embolization [14]. The goal of the conservative approach of MAP is the attempt of gradual resorption of the placenta or delayed delivery of the placenta [15]. A good prognosis of MAP pathology is feasible, with improving maternal and fetal outcome, if diagnosis is timely and there is adequate preparation of the delivery. These are essential keys in the management of such cases [16].
