Ultrasound Obstet Gynecol 2019; 54: 643–649 Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/uog.20244 Impact of placenta previa with placenta accreta spectrum disorder on fetal growth E. JAUNIAUX1 ,I.DIMITROVA2, N. KENYON3, M. MHALLEM4,N.A.KAMETAS2, N. ZOSMER2, C. HUBINONT4,K.H.NICOLAIDES2 andS.L.COLLINS3 1EGA Institute for Women’s Health, Faculty of Population Health Sciences, University College London, London, UK; 2Fetal Medicine Research Institute, King’s College Hospital, Harris Birthright Research Centre, London, UK; 3Nuffield Department of Women’s and Reproductive Health, University of Oxford, Oxford, UK; 4Department of Obstetrics, Saint Luc University Hospital, Universite´ Catholique de Louvain, Brussels, Belgium KEYWORDS: birth weight; fetal growth; increta; percreta; placenta previa accreta CONTRIBUTION and invasive (n = 47) PAS subgroups, and 146 women What are the novel findings of this work? with placenta previa without PAS disorder. There Placenta previa accreta does not impact on fetal growth. were 64 controls with a low-lying placenta. There was no significant difference in the incidence of ≤ th What are the clinical implications of this work? small-for-gestational age (SGA) (birth weight 10 As placenta previa accreta does not pose a risk to fetal percentile) and large-for-gestational age (LGA) (birth ≥ th development other than those linked to premature birth, weight 90 percentile) between the study groups. serial ultrasound examinations should not be required to Median gestational age at diagnosis was significantly evaluate fetal wellbeing in the second half of pregnancy lower in pregnancies with placenta previa without PAS = in women presenting with placenta previa accreta. disorder than in the low-lying placenta group (P 0.002). No significant difference was found between pregnancies complicated by placenta previa with PAS disorder and ABSTRACT those without for any of the variables. Median estimated fetal weight percentile was significantly lower in the adher- Objectives To evaluate fetal growth in pregnancies ent compared with the invasive previa–PAS subgroup complicated by placenta previa with or without placenta (P = 0.047). Actual birth weight percentile at delivery did accreta spectrum (PAS) disorder, compared with in not differ significantly between the subgroups (P = 0.804). pregnancies with a low-lying placenta. Conclusions No difference was seen in fetal growth in Methods This was a multicenter retrospective cohort pregnancies complicated by placenta previa with PAS study of singleton pregnancies complicated by placenta disorder compared with those without and compared previa with or without PAS disorder, for which maternal with those with a low-lying placenta. There was characteristics, ultrasound-estimated fetal weight and also no increased incidence of either SGA or LGA birth weight were available. Four maternal–fetal medicine neonates in pregnancies with placenta previa and PAS units participated in data collection of diagnosis, disorder compared with those with placenta previa with treatment and outcome. The control group comprised spontaneous separation of the placenta at birth. Adverse singleton pregnancies with a low-lying placenta (0.5–2 cm neonatal outcome in pregnancies complicated by placenta from the internal os). The diagnosis of PAS and depth previa and PAS disorder is linked to premature delivery of invasion were confirmed at delivery using both a and not to impaired fetal growth. Copyright © 2019 predefined clinical grading score and histopathological ISUOG. Published by John Wiley & Sons Ltd. examination. For comparison of pregnancy characteristics and fetal growth parameters, the study groups were matched for smoking status, ethnic origin, fetal sex and INTRODUCTION gestational age at delivery. The risk of placenta previa increases after a single Results The study included 82 women with placenta pre- Cesarean delivery and rises further with increasing via with PAS disorder, subdivided into adherent (n = 35) number of Cesarean deliveries1,2. The main factor Correspondence to: Dr E. Jauniaux, Institute for Women’s Health, University College London, 86–96 Chenies Mews, London WC1E 6HX, UK (e-mail: [email protected]) Accepted: 14 February 2019 Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd. ORIGINAL PAPER 644 Jauniaux et al. associated with placenta accreta spectrum (PAS) disorder for which ultrasound and clinical outcome data were is prior Cesarean delivery and, similar to placenta available. The maternal–fetal medicine units of four previa, the risk of developing PAS in subsequent hospitals (University College Hospitals London, King’s pregnancies increases with the number of previous College Hospital, University of Oxford and Saint Luc Cesarean deliveries3. Epidemiological data suggest that University Hospital) participated in data collection. All the scar left following a Cesarean delivery in the four units are part of regional referral centers and only myometrium of the lower uterine segment encourages patients who were referred prenatally were included in both implantation of the blastocyst in the area of the the study. Multiple pregnancies and those complicated by scar and abnormal adherence or invasion of placental villi diabetes were excluded from the study. Local institutional within the scar tissue. Placenta previa and PAS disorder ethics committee approval was obtained by the principal often occur together, and women with a history of investigator in each of the centers. Retrospective patient Cesarean section and presenting with a low-lying placenta consent was not required for this study as all ultrasound or placenta previa represent the group with the highest records were examined within the center at which the risk of PAS disorder4. examination was performed, basic clinical data were col- Poor vascularization and tissue oxygenation in the lected using a standard clinical audit protocol and all data area of a Cesarean scar is associated with local failure were fully anonymized before being submitted for central of re-epithelialization and decidualization, which has an analysis. impact on both implantation and placentation5–7,aswell In all cases, fetal ultrasound measurements and diag- as a possible effect on placental development and, subse- nosis of abnormal placentation were obtained prenatally quently, fetal growth. Women with a previous Cesarean by expert maternal–fetal medicine physicians using both delivery have been shown to have increased uterine artery transabdominal and transvaginal ultrasound. All preg- resistance in a subsequent pregnancy compared with those nancies were dated using the last menstrual period with with previous vaginal delivery only8. The main compli- confirmation by crown–rump length before 14 weeks of cation of placenta previa during pregnancy is antepartum gestation or biparietal diameter from 14 weeks. Estimated hemorrhage, which affects around 50% of cases9. Further- fetal weight (EFW) and corresponding percentiles were more, recent studies have suggested that pregnancies com- calculated at the time of referral to the specialist unit using plicated by placenta previa are at higher risk of delivering the Hadlock regression formula incorporating abdom- a small-for-gestational-age (SGA) neonate and are associ- inal circumference, femur length, head circumference ated with a higher incidence of placental vascular supply and biparietal diameter17. Using transvaginal ultrasound lesions10,11. Placenta previa with PAS disorder is also asso- examination, a placenta was recorded as ‘low lying’ when ciated with a higher risk of antepartum bleeding due to the the edge was 0.5–2 cm from the internal os of the uterine placental position inside the uterine cavity, but the main cervix. When the placenta was < 0.5cmfromtheinternal risk of major hemorrhage is during delivery, particularly os or completely covering it, it was defined as placenta in cases that remain undiagnosed during pregnancy12. previa (marginal or complete)18. The diagnosis of PAS One of the primary characteristics of PAS disorder disorder was made by maternal–fetal medicine physicians placentation is the absence of decidua in the placenta- experienced with the condition, using the standardized 6,7 tion area . Several authors have found that spiral artery reporting pro-forma proposed by the abnormally invasive 13–15 remodeling is reduced in PAS . Incomplete transfor- placenta (AIP) international expert group19. mation of the spiral arteries and lesions associated with The women were managed according to their local unit maternal vascular malperfusion are commonly found in protocol. Pregnancy and delivery data were collected from placenta-related disorders of pregnancy, such as fetal hospital records. The primary outcome was birth weight 16 growth restriction (FGR) and pre-eclampsia , suggest- and the secondary outcome was the impact of the grade ing that PAS placentation in a pregnancy complicated of PAS disorder. Birth weight percentiles were calculated by placenta previa may have an even greater impact on using the new intrauterine growth curves of the Fetal placental development and function. Placenta previa and Medicine Foundation20. SGA and LGA were defined as PAS disorder are both associated with high risks of pre- birth weight ≤ 10th and ≥ 90th percentiles, respectively. natal and perinatal maternal complications but there are The presence and severity of a PAS disorder was assessed limited data available on their possible impact on fetal