Clinicopathologic Study of Placentas From Women With a Fontan Circulation.

BACKGROUND: Pregnant women with a Fontan circulation have a high risk of obstetric complications, such as preterm delivery and small for gestational age (SGA), which may be affected by low blood flow to the placenta and hypoxia. This study investigated placental pathology in a Fontan circulation.Methods and Results:Eighteen pregnancies in 11 women with a Fontan circulation were reviewed. Pregnancy outcomes showed 9 miscarriages and 9 live births, with 4 preterm deliveries. Five neonates were SGA (<5th percentile). Eight placentas from live births in 7 women were available for the study. Five placentas had low weight placenta for gestational age, and 7 grossly showed a chronic subchorionic hematoma. Histological examination revealed all placentas had some form of histological hypoxic lesions: maternal vascular malperfusion in 7, fetal vascular malperfusion in 1, and other hypoxia-related lesions in 8. Quantitative analyses, including immunohistochemistry (CD31, CD68, and hypoxia inducible factor-1α antibodies) and Masson's trichrome staining, were also performed and compared with 5 control placentas. Capillary density and the area of fibrosis were significantly greater in placentas from women with a Fontan circulation than in control placentas. CONCLUSIONS: Placentas in a Fontan circulation were characterized by a high frequency of low placental weight, chronic subchorionic hematoma, and constant histological hypoxic changes, which could reflect altered maternal cardiac conditions and lead to poor pregnancy outcomes.

Clinical management of coagulation status and placenta previa in a pregnant woman with Marfan's syndrome after mitral and aortic mechanical heart valve replacement.

Pregnancy with a mechanical heart valve (MHV) is high risk for valve thrombosis because pregnancy is a hyper-coagulation state. In addition, warfarin use during pregnancy is restricted due to its fetotoxicity, and postpartum bleeding may be increased with anticoagulation. In particular, placenta previa under anticoagulation may cause massive postpartum bleeding. The optimal anticoagulation for a pregnant woman with mitral and aortic double MHVs is not known. In addition, suitable techniques for control of bleeding in a case of placenta previa under anticoagulation are not known. Thus, a case of a pregnant woman with mitral and aortic double MHVs and placenta previa is presented. The case was managed without valve thrombosis through precise unfractionated heparin dose adjustment and frequent activated partial thromboplastin time monitoring, along with maintenance of antithrombin levels. Compression sutures were found to be effective for controlling bleeding from the attachment site of placenta previa even under anticoagulation.

Pregnancy outcomes in women with dilated cardiomyopathy: Peripartum cardiovascular events predict post delivery prognosis.

BACKGROUND: The number of pregnant women with dilated cardiomyopathy (DCM) is relatively small, and therefore their prognosis after pregnancy is unknown. This study aims to elucidate pregnancy outcomes among women with DCM, as well as the long-term prognosis after pregnancy. METHODS: Thirty-five pregnancies and deliveries in 30 women, diagnosed with DCM before pregnancy, were retrospectively analyzed. RESULTS: All women had a left ventricular ejection fraction (LVEF) over 30% and belonged to the New York Heart Association (NYHA) class I or II before pregnancy. The mean gestational age at delivery was 36 weeks with 15 (43%) preterm deliveries. Eight pregnancies (23%) were complicated by peripartum cardiac events including 1 ventricular arrhythmia, 6 heart failures, and 1 significant deterioration in LVEF requiring termination of pregnancy. NYHA class II, pre-pregnancy use of angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker/diuretics, elevated brain natriuretic peptide (BNP), and advanced diastolic dysfunction assessed by Doppler echocardiography were defined as risk factors for cardiac events. Although the more severe cases took beta-blockers during pregnancy, the rates of cardiac events and decreasing LVEF did not differ significantly between those taking beta-blockers and those who were not. Values of LVEF decreased by almost 10% after the average 4-year post-delivery follow-up period. The long-term event-free survival was considerably worse among women with peripartum cardiac events than in those without (p<0.0001). CONCLUSIONS: DCM women with pre-pregnancy LVEF over 30% tolerated pregnancy, but the rate of preterm delivery was high. Peripartum cardiovascular events occurred more often in women with NYHA class II, as well as those who received medications before and during pregnancy and showed more elevated BNP and advanced diastolic dysfunction before pregnancy. Beta-blockers likely allowed similar outcomes for DCM patients with lower initial LVEFs. Close monitoring later in life is required, particularly among the women with peripartum cardiac events.

Discrepancy Between Pre- and Postnatal Diagnoses of Congenital Heart Disease and Impact on Neonatal Clinical Course　- A Retrospective Study at a Japanese Tertiary Institution.

BACKGROUND: Congenital heart disease (CHD) is often diagnosed prenatally using fetal echocardiography, but few studies have evaluated the accuracy of these fetal cardiac diagnoses in detail. We investigated the discrepancy between pre- and postnatal diagnoses of CHD and the impact of discrepant diagnoses.Methods and Results:This retrospective study at a tertiary institution included data from the medical records of 207 neonates with prenatally diagnosed CHD admitted to the cardiac neonatal intensive care unit between January 2011 and December 2016. Pre- and postnatal diagnoses of CHD differed in 12% of neonates. Coarctation of the aorta and ventricular septal defects were the most frequent causes of discrepant diagnosis. Unexpected treatments were added to 38% of discrepant diagnostic cases. However, discrepant diagnoses did not adversely affect the clinical course. The 9% of the 207 neonates who required invasive intervention within 24 h of delivery were accurately diagnosed prenatally. CONCLUSIONS: Pre- and postnatal diagnoses differed in only a few neonates, with differences not adversely affecting the clinical course. Neonates who required invasive intervention immediately after delivery were accurately diagnosed prenatally. Prenatal diagnosis thus seems to contribute to improved prognosis in neonates with CHD.

Appropriate delivery method for cardiac disease pregnancy based on noninvasive cardiac monitoring.

Background There are numerous significant physiological changes occurring in circulation during labor. To detect these rapid hemodynamic changes, invasive and intermittent measurement techniques are not reliable. To suggest a suitable delivery method for pregnancy with cardiac disease, this study analyzed how each delivery method influences cardiac function using a noninvasive and continuous measurement technique. Methods A prospective study was accomplished at the National Cerebral and Cardiovascular Center in Japan from October 1, 2014, to November 30, 2018. The classification of the healthy heart pregnant women was according to the delivery method: vaginal delivery (VD) without epidural anesthesia, VD with epidural anesthesia, and caesarean section (CS). The hemodynamic parameters cardiac index (CI), stroke volume index (SI), and heart rate (HR) were evaluated regularly throughout delivery by noninvasive electrical cardiometry monitor. Results Ten cases were examined for each group. CI and HR were significantly increased before VD, while the increase in CI and HR was mild in the epidural group in comparison to the nonepidural group. SI was increased toward the delivery in the epidural group, and it was constant in the nonepidural group. However, there was no alteration in the level of outcomes of the two groups. In CS, SI increased and HR decreased before delivery. After delivery, SI continued to increase, while HR did not change but CI increased. Conclusion In VD, the increase in venous circulation according to the autotransfusion is managed by increasing HR. By epidural anesthesia, the increase in HR was suppressed and SI was increased. However, as epidural anesthesia increases the vascular capacity, the level of SI outcome was comparable. In CS, the HR was decreased because of the spinal anesthesia and the SI was increased because of many factors like hydration. As there are many factors to control in CS, VD with epidural anesthesia will be the first preference for most cardiac patients.

A less-intensive anticoagulation protocol of therapeutic unfractionated heparin administration for pregnant patients.

Heparin anticoagulant therapy for thromboembolic disorders during pregnancy is problematic due to unexpected adverse bleeding. To avoid bleeding, we have used a less-intensive anticoagulation protocol of unfractionated heparin (UFH). The protocol had a therapeutic activated partial thromboplastin time (APTT) ratio of 1.5-2.0 with the control value, a UFH dose of ≤ 30,000 U/day, and an antithrombin (AT) activity target of ≥ 70%. In the present study, we evaluated this protocol using an anti-Xa assay. We collected UFH-treated plasma samples from ten consecutive pregnant Japanese patients with current or previous thromboembolic disorders. Seven patients remained in the therapeutic APTT ratio range (heparin-sensitive [HS] group). The other three patients had difficulty remaining within the therapeutic range (heparin-resistant [HR] group). In the HR group, two had AT deficiency and one had congenital absence of the inferior vena cava. Of the HS and HR samples, 73% and 31%, respectively, were within the therapeutic anti-Xa activity range 0.3-0.7 U/mL, indicating difficulty for the HR group to remain within the therapeutic range. Neither major bleeding nor symptomatic thromboembolic episodes occurred in either group. These findings suggest that the less-intensive anticoagulation protocol is permissive and may be beneficial in the HS group.

Impact of Pregnancy on Aortic Root in Women with Repaired Conotruncal Anomalies.

The effect of pregnancy on aortic root in women with repaired conotruncal anomalies (CTA) has not been clarified. This study examined aortic diameters during and after pregnancy in women with repaired CTA. A retrospective review of consecutive pregnant women with repaired CTA was performed for results of echocardiography from 1 year before pregnancy to 3 years after delivery and compared with findings from healthy pregnant volunteers. Participants comprised 42 subjects and 49 deliveries with repaired CTA (CTA group), and 47 healthy pregnant women (control group). Although no maternal aortic events were encountered, aortic diameters during pregnancy increased by 1.0 ± 2.2 mm (maximum, 7.0 mm) in the CTA group and 0.6 ± 1.3 mm (maximum, 3.4 mm) in the control group (p = 0.13). The CTA subgroup with increase in aortic diameter ≥ 3.5 mm during pregnancy showed no reversion to baseline diameter at follow-up > 6 months after delivery. Significant risk factors for increased aortic diameter and no reversal included pulmonary atresia, history of aortopulmonary shunt, older age at repair, and smaller left ventricular end-diastolic diameter pre-pregnancy. Women with repaired CTA tolerated pregnancy and delivery well. However, the aortic root progressively dilated during pregnancy and 1/4 of them, especially those with longstanding high aortic blood flow before repair, showed an increase of aortic root size of ≥ 3.5 mm during the peripartum period; this dilatation tended not to revert to the pre-pregnancy diameter. Therefore, serial measurement of the aortic root during pregnancy and after delivery is recommended in these women.

Predicting postpartum cardiac events in pregnant women with complete atrioventricular block.

BACKGROUND: Women with complete atrioventricular block (CAVB) can tolerate hemodynamic changes during pregnancy; however, the incidence of cardiac events in women with CAVB may increase after delivery. The aim of this study was to investigate predictive factors for postpartum cardiac events in pregnant women with CAVB. METHODS AND RESULTS: Pregnant women with CAVB who received perinatal management at a tertiary cardiac center from 1981 to 2015 were retrospectively reviewed. Univariate and multivariate logistic analyses of postpartum cardiac events were performed. Postpartum cardiac event was defined as cardiopulmonary arrest, cardiac failure, or the need for permanent pacemaker implantation (p-PMI) within 3 months after delivery. A total of 63 pregnancies in 36 women with CAVB were included in this study; 25 had undergone p-PMI before pregnancy. Regardless of p-PMI status, women with CAVB had no further increases in heart rate during the second and third trimesters. No heart failure was found during pregnancy and delivery. Postpartum cardiac events occurred in 9 pregnancies (14.3%) in 8 women with CAVB; 3 had cardiac failure and p-PMI, 3 had cardiac failure, 2 required p-PMI, and 1 had cardiopulmonary arrest. Multivariate analysis showed that perinatal ventricular pause (odds ratio 11.60, 95% confidence interval 1.90-82.18, p<0.01) and family history of CAVB (odds ratio 10.59, 95% confidence interval 1.36-90.56, p=0.03) were associated with postpartum cardiac events. CONCLUSIONS: All cardiac events occurred during the postpartum period among women with CAVB, and ventricular pause during the perinatal period and a family history of CAVB were predictors of postpartum cardiac events. Close follow-up should be considered during the postpartum period for women with high-risk CAVB.

Recurrent Congenital Heart Diseases Among Neonates Born to Mothers with Congenital Heart Diseases.

The frequency of newborns with congenital heart disease (CHD) is approximately 1% in the general population; however, the recurrence rate of CHD in mothers with CHD differs in ethnicity and reports. We therefore aimed to determine the prevalence of CHD among neonates born to mothers with CHD in our institute in Japan. We reviewed the medical charts of 803 neonates delivered by 529 women with CHD at the National Cerebral and Cardiovascular Center from 1982 to 2016. They included isolated ventricular septal defect (VSD,31.4%), isolated atrial septal defect (ASD, 23.3%), tetralogy of Fallot (TOF,10.6%). We defined CHD in neonates as being diagnosed within 1 month of birth. We estimated that the average rate of the CHD recurrence was 3.1%. The recurrence ratios in each maternal CHD were 8.6%, 7.1%, 6.2%, 4.8%, 3.6%, and 1.5% for PS, CoA, TOF, atrioventricular septal defect, VSD, and ASD, respectively. The rate of CHD in offsprings whose mothers have CHD was 3 times greater than that of mothers with healthy hearts. Almost half of neonates with CHD had the same phenotype as their mother in our series. Especially, PS and CoA were closely related to the type of maternal CHD.

Maternal and fetal outcomes in pregnancy complicated with Eisenmenger syndrome.

OBJECTIVE: The goal of the study was to clarify the risk factors for pregnancy complicated with Eisenmenger syndrome (ES). MATERIALS AND METHODS: A retrospective study was performed in 15 patients with ES who were managed throughout pregnancy at one institution from 1982 to 2013. Cases associated with congenital heart diseases other than atrial septal defect (ASD), ventricular septal defect (VSD), and patent ductus arteriosus (PDA) were excluded. RESULTS: The congenital heart diseases in ES included ASD (n = 3), VSD (n = 9), and PDA (n = 3). Ten women chose termination and 5 continued with their pregnancies. In the 5 continuation cases (PDA 1, VSD 4), worsening of cyanosis, exertional fatigue and dyspnea appeared between 25 and 30 weeks gestation and cesarean section was performed at 30 (28-33) weeks. LVEF, PaO2, and SpO2 decreased and heart rate increased significantly from before pregnancy to 25-30 weeks gestation. From before to during the pregnancy, there were no significant changes in mean PABP or pulmonary vascular resistance (PVR) in four cases with data (582-592, 885 to 868, 1280 to 1291, 1476-1522 dyn × s/cm2). PVR at conception had a negative relationship with delivery weeks. NYHA classes before, during and 1 year after pregnancy were II, III and II. In one recent case, epoprostenol and tadalafil were administered during pregnancy. CONCLUSIONS: Pregnancy with ES has a high risk due to hypooxygenation, cyanosis, and cardiac failure, which can appear as common complications as early as the 2nd trimester. Early interventions with meticulous care are required for these complications during pregnancy and delivery.

Safety and efficacy of a 52-mg levonorgestrel-releasing intrauterine system in women with cardiovascular disease.

AIM: We sought to examine the safety and efficacy of a 52-mg levonorgestrel-releasing intrauterine system (LNG-IUS), and to evaluate the changes in biomarkers of infection, anemia and cardiovascular conditions after LNG-IUS insertion in women with cardiovascular disease. METHODS: We prospectively followed women with a cardiovascular disease in whom a 52-mg LNG-IUS was inserted between 2009 and 2015. The primary outcome was the frequency of cardiovascular and gynecologic side effects due to the LNG-IUS over the year after LNG-IUS insertion. The secondary outcomes were the changes in menstrual blood loss and biomarkers, e.g., white blood cell count and the levels of C-reactive protein, hemoglobin and brain natriuretic peptide. We also evaluated the 24-month continuation rate of LNG-IUS. RESULTS: A total of 34 women were prospectively followed-up, including two women with pulmonary hypertension. No cardiovascular side effects were identified during the 1 year after LNG-IUS insertion, other than one case of mild vasovagal reaction at insertion. Neither the white blood cell count nor the C-reactive protein value increased after LNG-IUS insertion. The menstrual blood loss was decreased in most subjects and the median hemoglobin levels increased significantly within 1 year after insertion (P < 0.001 and P = 0.002). Moreover, brain natriuretic peptide levels tended to decrease in correspondence with the hemoglobin elevation (P = 0.074). The 24-month LNG-IUS continuation rate was 97% (95% confidence interval 85-100). CONCLUSION: No clinically significant cardiovascular event was identified during the 1 year after 52-mg LNG-IUS insertion among women with cardiovascular disease. The 52-mg LNG-IUS may have specific favorable effects by decreasing the risk of iron deficiency anemia in these women.

Pregnancy outcomes and mid-term prognosis in women after arterial switch operation for dextro-transposition of the great arteries - Tertiary hospital experiences and review of literature.

OBJECTIVE: Arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA) has gradually replaced the atrial switch operation and has become the standard operation. To date, the outcomes of pregnant women with d-TGA after this new operation have not been investigated. In this study, we investigated the impact of ASO on pregnant outcomes and mid-term prognosis in women with d-TGA and compared with the atrial switch operation through the literature review. METHODS AND RESULTS: There were 20 pregnancies in 10 women with d-TGA after ASO and 6 resulted in abortion. Among 14 successful pregnancies in 10 women, 11 pregnancies achieved the term delivery and 3 pregnancies, including 1 twin pregnancy, resulted in preterm labor. Maternal cardiovascular events occurred in 4 (heart failure and arrhythmias in 3 and arrhythmia in 1), and all were controllable with medications. Risk factors for the peripartum cardiac events were older age at ASO and delivery, and higher concentration of brain natriuretic peptide (BNP) at first trimester (p<0.05). In 7-60 month-follow-up after delivery, no case showed deterioration of functional class and systemic ventricular function. According to the literature review, women after ASO demonstrated a better prognosis than those after the atrial switch operation. CONCLUSIONS: The majority of women with d-TGA after ASO tolerated pregnancy and delivery well. The older age at ASO, an elderly pregnancy, and higher BNP levels at the first trimester were possibly risk factors of peripartum cardiovascular events among the group. The literature reviews and this study may indicate the advantage of systemic left ventricle compared with systemic right ventricle in long-term outcomes after delivery.

Cardiomyopathy Phenotypes and Pregnancy Outcomes with Left Ventricular Noncompaction Cardiomyopathy.

Little is known about pregnancies of left ventricular noncompaction cardiomyopathy (LVNC), much less cases in which LVNC was definitively diagnosed prepregnancy. We report the cases of three pregnant Japanese women definitively diagnosed with LVNC prepregnancy. Case 1 presented LVNC with restrictive phenotype. Her pregnancy was terminated due to exacerbated pulmonary hypertension and low output status at 30 weeks' gestation. Case 2 presented isolated LVNC with nonsustained ventricle tachycardia. A cesarean section was performed at 36 weeks' gestation because of placenta previa. Case 3 presented dilated LVNC. Labor induction was performed because of decreased left ventricular ejection fraction, leading to a vaginal delivery at 37 weeks' gestation. In all cases, no thromboembolic event was identified during pregnancy; two patients received anticoagulants. We reviewed all English-literature cases of pregnant women definitively diagnosed with LVNC prepregnancy to analyze causes of adverse pregnancy outcomes and the necessity of anticoagulation. Four of the six pregnancies identified were terminated due to exacerbated cardiomyopathy phenotypes and not complications due to noncompaction itself, resulting in three cases' preterm deliveries. No thromboembolic event was identified by maintenance of the anticoagulation strategy determined prepregnancy. In pregnancies with LVNC, the possibility of a severe cardiac event and the indications for termination of the pregnancy can depend on the cardiomyopathy phenotypes, not noncompaction itself. Anticoagulation only because of the pregnancy itself may be redundant. In the management of LVNC during pregnancy, close monitoring of the condition of different phenotypes and reassessment of the necessity of anticoagulation can contribute to the pregnancy outcome.

Utility of Fluid Assessment Based on the Intrathoracic Impedance Monitoring in a Peripartum Woman with Heart Disease.

Recently, implantable cardioverter-defibrillators (ICD) have become capable of monitoring intrathoracic impedance to detect an increased fluid volume and heart failure. Pregnancy is a well-known cause of an increased body fluid volume; however, it is not clear whether the measurement of intrathoracic impedance by ICD is clinically useful for precisely detecting heart failure in pregnant women. We herein report the case of a 39-year-old woman with an ICD that had been implanted after an event of ventricular fibrillation due to severe aortic regurgitation with a bicuspid aortic valve. Elevated right ventricular pressure and brain natriuretic peptide levels were detected at 37 weeks of gestation and postpartum. At the same time, the ICD's stored fluid index gradually increased and exceeded the threshold on the 10th day after delivery. She was treated with diuretics and recovered from postpartum heart failure. The physiological volume changed in the perinatal period, but we were still able to detect heart failure by ICD. Intrathoracic impedance monitoring is effective in the perinatal field.

Changes in echocardiographic parameters and hypertensive disorders in pregnancies of women with aortic coarctation.

OBJECTIVES: Pregnancy can be well tolerated after the repair of aortic coarctation. However, a higher incidence of hypertensive disorders during these pregnancies was reported. We analyzed the perinatal changes in echocardiographic parameters in women with aortic coarctation and investigated the risk factors of gestational hypertension (GH). METHODS: We retrospectively identified 15 pregnancies in nine Japanese women with aortic coarctation between 1982 and 2015. We categorized the patients according to the presence/absence of GH as the group with GH(n=3) and that without GH(n=12). The echocardiographic parameters were compared between groups. RESULTS: Our analysis revealed that a pre-pregnancy Doppler-measured pressure gradient≥20mmHg and a left ventricular mass index≥95g/m2 were significant risk factors for GH. The left ventricular end-diastolic diameters at the first and the third trimesters, the left ventricular end-systolic diameters at the first trimester, and the left ventricular ejection fraction at the third trimester were also significantly higher in the pregnancies with GH. All of these findings had been obtained before the patients' GH occurred. CONCLUSIONS: Hypertrophy of the left ventricle with a lower ejection fraction and a high pressure gradient across the coarctation were risk factors for GH in the patients with aortic coarctation. Thus, serial measurements using echocardiography are important for predicting GH in women with aortic coarctation. However, further research investigating this finding with a larger sample size is needed.

Intra- and post-partum acute aortic dissection (Stanford type B): Report of two cases.

Pregnancy with Marfan syndrome (MFS) presents challenges to the clinician because of the increased incidence of maternal cardiovascular complications, including acute aortic dissection (ADD) and the involvement of the fetus owing to the urgency of the need for surgery and the low likelihood of survival with premature delivery. Patient 1 was a 36-year-old pregnant Japanese woman with MFS who was referred at 16 gestational weeks with aortic root diameter 35.1 mm. Stanford type B AAD occurred on delivery without evident blood pressure changes. Patient 2 was a 31-year-old pregnant Japanese woman with MFS with aortic root diameter 28.3 mm at 20 gestational weeks after David procedure. Ultimately fatal Stanford type B AAD occurred on post-partum day 15. Both patients were treated with beta-blockers when AAD occurred. Although these two patients were initially considered to have relatively low risk according to previous reports and guidelines, AAD occurred. It is very important to provide information about these high pregnancy risks to women with MFS before conception, and to follow MFS pregnancies with great caution.

Management of pulmonary vasodilator therapy in three pregnancies with pulmonary arterial hypertension.

Pregnancy with pulmonary arterial hypertension (PAH) has a significantly high risk of maternal death and women with PAH are basically advised to avoid pregnancy. Recently, several reports have described pregnant women with PAH who were treated with pulmonary vasodilators during pregnancy and delivered safely. However, the efficacy of this treatment during pregnancy is still not clear. Here we report on the short-term outcomes of three primiparous women with PAH who were prescribed pulmonary vasodilator therapy during their pregnancies. All women delivered preterm due to cardiac and/or obstetric reasons and were discharged without any complication. Pulmonary vasodilator therapy can be used safely during the pregnancies of PAH patients and may contribute to improved maternal and fetal prognoses.

Impact of pregnancy on the size of small cerebral aneurysm.

OBJECTIVE: Because the management of cerebral aneurysms during pregnancy remains controversial, the objective of this study was to perform a retrospective review of pregnant women with cerebral aneurysms to determine whether pregnancy is a risk factor for aneurysm rupture. METHODS: The change in size of aneurysms during pregnancy was examined by performing repeat magnetic resonance angiography in five pregnant women with cerebral aneurysms between 2005 and 2013. The outcome examined was development of subarachnoid hemorrhage. RESULTS: Among the five pregnancies, there were eight cerebral aneurysms. Subarachnoid hemorrhage did not developed during any pregnancy. In four of the pregnancies, the cerebral aneurysms did not change in size during pregnancy, remaining 2-5 mm. Although in one pregnancy, the aneurysm increased from 6 to 7 mm during the third trimester, it returned to its original size in the postpartum period. CONCLUSIONS: We suggest that if the cerebral aneurysm is small (≤ 5 mm), it is likely to remain unchanged despite the increase in circulating blood volume during pregnancy. Cerebral aneurysms greater than 5 mm but without blebs, irregular shape, high-risk location, or increased aspect ratio are also at low risk of rupture and are not likely to change during pregnancy.