First-trimester placenta accreta (PA) is a rare event, but it can be life-threatening for the mother and mostly ends with hysterectomy. There are few reported cases worldwide. In this article the authors report a case of miscarriage hysterectomy at 11 weeks’ gestation due to undiagnosed first-trimester PA. 

Also, the authors reviewed the medical literature, over the past 20 years, of first-trimester PA diagnosed after occurrence of severe bleeding during the evacuation of the retained products of conception (ERPC) or in the post-miscarriage period.

Introduction

At such an early stage of pregnancy, abnormal placentation is mostly diagnosed because of massive haemorrhage during subsequent uterine evacuation.1 Clinically, however, it is of extreme importance to diagnose placenta accreta/percreta prior to delivery or uterine evacuation to allow prevention of expected maternal morbidity or even mortality.2 

This study reports a case of a pregnant woman at 11 gestational weeks presenting with heavy vaginal bleeding due to early foetal demise. Urgent ERPC was performed and complicated by severe bleeding. With all efforts to control the uterine bleeding, the case ended with an emergency hysterectomy.

Case report

A 37-year old woman, G3 P2, with a history of two previous Caesarean deliveries, was admitted to the emergency unit at Abha Maternity Hospital (Saudi Arabia) due to vaginal bleeding and lower abdominal pain at 11 weeks’ gestation, by the last menstrual period. On admission, ultrasound (US) examination showed an early foetal demise at eight weeks + 4 days. An anterior lower placenta was noticed, reaching the internal cervical OS, but not covering it. 

Anteriorly, in the isthmo-corporal region, the placenta showed many irregular-shaped hypoechoic and anechoic spaces that infiltrated the adjacent myometrium. These findings were suggestive of an underlying placental pathology. Early partial molar changes were suspected as well. Laboratory findings were considered normal, including beta-HCG level, which was in the normal range for the gestational age. During the ERPC, the patient developed severe vaginal bleeding which we could not manage conservatively. At the emergency laparotomy a haemorrhagic mass was seen in the region of the old Caesarean section scars (± 2-3cm) and extending behind the urinary bladder. 

During exposure of the isthmo-corporal region, a bladder injury occurred due to dense adhesions. The haemorrhagic mass was opened and showed placental villi invading the anterior uterine wall; this was highly suggestion of penetration by PA. The uterus was opened and adherent placental tissues were removed by piece-meal technique with uterine curettage and packing, but heavy bleeding continued. 

Conservative measures including uterine compression, packing and bilateral ligation of the uterine arteries failed to control the bleeding. Emergency subtotal hysterectomy was performed but bleeding continued from the isthmus; hence, total hysterectomy had to be completed. Intra-operatively, the total blood loss was estimated at ~3,500-4,000ml. Nine units of packed RBCs and four units of fresh frozen plasma were transfused. 

The histopathology results confirmed the diagnosis of PA. There was no evidence of molar changes in the placental villi. Retrospective analysis of the ultrasound finding that was interpreted as a feature of possible molar changes could be evidence of placental invasion. 

Early pregnancy US does not usually include detailed examination of both localisation and implantation of the placenta, because it is not important at this stage and technically not obvious. Theoretically, it can be assumed that, even at this early stage, a detailed ultrasound examination of the uterine wall, in patients with risk factor for placenta accreta, could reveal abnormal placentation.

Discussion and review of literatures

Over the past decade literature reports showed an increased incidence of abnormal placentation including PA and low implantation. Placenta accreta is a major obstetric problem associated with serious surgical morbidities, particularly massive haemorrhage (> 3l). PA was found to be the cause of peripartum hysterectomy in > 9% of cases.3 Although the aetiology of PA is unknown, a number of risk factors have been identified on the basis of previous case reports. 

These risk factors include a history of previous Caesarean section. The repeated lower segment or classical Caesarean sections are often reported in association with the development of PA. Nevertheless, few reported cases of PA involved healthy patients without any uterine scar. Other risk factors are parity and previous history of dilation and curettage (D&C). Whenever placenta praevia is present, the probability of PA increases from 5% without previous Caesarean section to > 24% with one, and up to 67% with four or more Caesarean sections.4, 5, 6 

On reviewing medical literatures over the past 20 years, the 23 reported cases of PA during the first trimester of pregnancy (≤ 12 weeks) were mostly discovered after severe bleeding, either during the ERPC1,5,6,7,8 or in the post-abortive weeks.9,10 This is mainly due to the difficulty of the diagnosis of PA during the first trimester compare to the second and third trimesters. 

The currently known prenatal sonographic characteristic features of PA in the first trimester are: low-lying gestational sac and diffuse dilatation of the intra-placental vessels called ‘lacunae’.1,11 Also, PA could be suspected if a part of the lining of the gestational sac was embedded in the previous Caesarean section scar with irregular decidual layer and thinning of the underlying uterine wall.12 However, in the very early pregnancy – around five to six gestational weeks – the possibility of cervical ectopic pregnancy should be highlighted.   

Ultrasound presentation of multiple hypoechoic or anechoic areas within the placenta is a characteristic feature of PA. This finding in the second and third trimesters was found to have an excellent sensitivity and specificity (~ 80% and 95%, respectively).13 Using this characteristic US feature Buetow, Shih et al and Chen et al reported transvaginal US diagnosis of PA as early as eight and nine weeks gestation. These cases ended by hysterectomy due to heavy vaginal bleeding, either immediately or a few weeks later, with histopathological confirmation of PA.5, 11,12  

Recently, Stirnemann et al14 implemented a first-trimester prospective screening trial for PA. They suggested that the rationale for 11-14 weeks’ screening in the high-risk group allowed early diagnosis and planning for optimal management.

With colour Doppler US and power Doppler imaging, evidence of first-trimester PA is similar to that seen in the second and third trimesters, including: diffuse turbulent flow in the placental lacunae and increased peripheral vascularity. These findings could be seen as early as eight and nine weeks’ gestation. Furthermore, magnetic resonance imaging (MRI) with or without gadolinium can be used as a supplementary diagnostic modality for further improving the prenatal diagnosis.1,11

The review shows that hysterectomy has been the traditional treatment for PA and conservative treatment caused a four-times-higher mortality rate than treatment with an immediate hysterectomy. However, there is only a little experience in treatment of the disease during the first trimester. Therefore, the choice between hysterectomy and conservative management is dependent on the severity of the bleeding.2 

In this survey the authors found that hysterectomy was the standard procedure for the management of first-trimester PA. Out of the 23 reported cases, 17 cases had hysterectomy, four cases had uterine artery embolisation, one case had laparoscopic resection of the affected area of the uterus and the last case was treated by methotrexate. These conservative minimally invasive procedures had been used in order to preserve fertility. 

Yang et al6 performed a prophylactic first-trimester hysterectomy (at 12 weeks’ gestation) after diagnosis of low implanted PA in a 33-year-old woman, with a history of two previous Caesarean deliveries. Bilateral uterine artery embolisation was performed preoperatively to reduce expected bleeding during hysterectomy. Adjuvant therapy with methotrexate had been used to expedite resorption of the placenta. It was found that there was reduction in the hysterectomy rate from 85% to 15% when placental retention was allowed. Morbidities associated leaving the placenta in situ mainly included infection and coagulation disorder, which may necessitate subsequent hysterectomy.3,15

In conclusion, women at high risk of PA could be considered for detailed US examination during the first trimester. Early diagnosis may allow earlier elective intervention that prevents maternal morbidity and mortality. Clear evidence guiding screening, diagnosis and management is needed. Considering the rising rate of Caesarean deliveries, the incidence of PA in early gestation will increase. 

References

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