Unexpected placenta accreta spectrum after the use of assisted reproductive technology in women with adenomyomectomy

A 37-year-old Japanese primipara woman presented to our hospital at 11 weeks gestation, returning to her parents’ house to give birth. The woman had adenomyosis resulting in sterility and hoped to become pregnant. She had previously undergone adenomyomectomy and right chocolate cystectomy to improve her fertility at her previous medical institution. At that time, her surgeons had opened the uterine cavity from the anterior surface of the uterus and had excised the lesion, including the serosa existing on the posterior wall of the uterus, using an electric knife. Subsequently, pregnancy was established using ART (intracytoplasmic sperm injection and frozen embryo transfers). At 29 weeks, although she had no symptoms, she was admitted to our hospital due to the risk of preterm birth owing to a shortened cervical length. Magnetic resonance imaging (MRI) at 30 weeks showed no evidence of placenta previa, and the placenta was mainly located on the left fallopian tube angle and partially on the posterior wall ( Figure 1 ). Because of the location of placentation, the uterine wall was extruded toward the left fallopian tube ( Figure 2 ). MRI also showed loss of continuity of the uterine wall, suggesting the presence of unexpected PAS ( Figure 2 ). Sagittal T2-weighted MRI at 30 weeks showed no evidence of placenta previa, and the placenta was mainly located on the posterior wall (T2). Coronal T2-weighted MRI at 30 weeks showed that the placenta was mainly located on the left fallopian tube angle. Because of the location of placentation with Figure 1 , the uterine wall was extruded toward the left fallopian tube (circle). The MRI also showed a loss of continuity of the uterine wall (arrow), suggesting the presence of unexpected PAS. Emergency cesarean section was performed at 34 weeks because of PROM. During laparotomy, we found that the Douglas fossa was completely closed via a strict adhesion between the uterine surface, both right and left ovaries, sigmoid intestine, and small intestine ( Figure 3 ). This strict adhesion would complicate the performance of a cesarean hysterectomy in case of emergency. Intraoperative image. The Douglas fossa was completely closed because of strict adhesion between the uterine surface, bile ovary, sigmoid intestine, and small intestine. A baby weighing 2,321 g (Apgar score 7 at 1 min, 7 at 5 min) was delivered through a lower uterine transverse incision. As there was no sign of placental separation, manual removal of the placenta was conducted, resulting in a blood loss of 2,000 mL, mainly at the site of placentation. Eventually, two units of red blood cells were transfused, and the uterus was successfully preserved without any further intervention. The patient was discharged without any complications at 5 days postpartum. Histopathological examination showed stage 3 chorioamnionitis and no evidence of funisitis.

This work did not receive any specific grant from funding agencies.

Informed consent was obtained from the patients for publication of this work.

Adenomyosis is associated with reproductive problems. Uterine surgery is one of the strategies applied in women with adenomyosis who hope to become pregnant. However, surgery carries the risk of obstetric outcomes. Sugiyama et al. reviewed 10 cases of obstetric outcomes in women who underwent adenomyomectomy before pregnancy 6) and reported three patients who showed preterm delivery; all three of them had a very thin uterus to the extent that the fetus could be observed through the uterine wall, suggesting abnormal placental adhesion. Uterine rupture during pregnancy is another potential risk factor for women who have undergone adenomyomectomy. A recent review by Morimatsu et al. showed that the rate of uterine rupture after adenomyomectomy during pregnancy is 6.0% 7) . ART is another established strategy to overcome sterility. In addition to these reports, the present case showed unexpected PAS, which was clinically diagnosed at delivery. Using the largest Japanese birth cohort study, Kyozuka et al. previously reported that ART is an independent risk factor for unexpected PAS 8) . The reason ART increases the risk of PAS is not entirely clear. Esh et al. proposed two possible pathogeneses: 1) mechanical factors, including primary deficiency in the decidua due to local trauma at the uterine wall, and 2) biological factors, including abnormal maternal response to trophoblast invasion 9) . Our case showed unexpected PAS due to adenomyosis treated via pre-conceptional uterine surgery followed by ART. The MRI findings in these cases suggest that the placenta was attached around the fallopian tube where the decidua is more likely to be deficient. Although cases with morbid adherent placentation (MAP) following laparoscopic adenomyomectomy have been reported 10) , the causal relationship between adenomyomectomy itself and MAP is unknown. So far, we attributed the unexpected PAS to ART, in which the frozen embryo easily transfers to the fallopian tube where the decidua is more likely to be thin. Because adenomyosis in pregnancy is rare, its obstetric outcomes, including maternal morbidity, are unknown. With advances in ART, the number of pregnancies with adenomyosis is increasing. Recently, using a Japanese birth cohort study, Yamaguchi et al. reported that adenomyosis increases the risk of preterm birth <37 weeks (aOR [adjusted odds ratio]: 2.5, 95%CI [confidence interval] 1.8-3.4), and <34 weeks (aOR: 1.9, 95%CI: 1.0-3.6) 3) , as was shown in our case. In these cases, two clinical implications were identified for pregnant women undergoing adenomyomectomy: first, pregnant women who conceived after adenomyomectomy had increased risk of unexpected PAS, which could require unexpected medical intervention, including manual removal of the adherent placenta, which could cause life-threatening postpartum hemorrhage 11) and/or increased morbidity 12) because they usually conceived via ART. Second, these unexpected medical interventions could occur suddenly because adenomyosis itself carries a risk of preterm birth. Therefore, specialists in endocrinology and infertility should provide medical care in addition to achieving short-term outcomes, such as a positive pregnancy test, and provide information about adverse outcomes. In conclusion, obstetric care providers need to pay attention to cases where patients with adenomyosis have conceived by ART after adenomyomectomy, and these women need multidisciplinary management strategies soon after achieving pregnancy.

This case report was peer reviewed.

All authors were involved in the clinical care of the patient and contributed to the conception, drafting, review, and revision of the manuscript. All authors saw and approved the final version of the paper and take full responsibility for the work.

Adenomyosis is defined as the ectopic proliferation of endometrial glands and stroma within the myometrium of the uterus, which causes the uterus to become edematous and enlarged 1 , 2) . Adenomyosis affects up to 10-20% of women of reproductive age 3) and often results in severe dysmenorrhea and/or hypermenorrhea. The disease occurs more often in women between the ages of 30 and 40 years, and it is widely accepted that adenomyosis is related to reproductive disorders. Several studies have reported that adenomyosis affects fertility, resulting in women requiring assisted reproductive technology (ART) 3) . Placenta accreta spectrum (PAS) is a significant obstetric complication that can cause life-threatening bleeding. Conventionally, PAS is strongly associated with placenta previa 4) . However, PAS may occur unexpectedly, in the absence of placenta previa; therefore, it cannot be diagnosed until delivery, necessitating intensive emergency care 5) . Here, we present the case of a woman with unexpected PAS who conceived after adenomyomectomy following ART. In this case, we performed an emergency cesarean section due to preterm rupture of the membrane (PROM), and the patient was clinically diagnosed with unexpected PAS at the time of delivery, and manual placenta removal was required.

Adjusted odds ratio: aOR Assisted reproductive technology: ART Confidence interval: CI Magnetic resonance imaging: MRI Placenta accreta spectrum: PAS Preterm rupture of membrane: PROM

The authors have no potential conflicts of interest to declare.