Clinicopathologic Study of Placentas From Women With a Fontan Circulation.
Yokouchi-Konishi T, Ohta-Ogo K, Kamiya CA, Shionoiri T, Nakanishi A, Iwanaga N, Ohuchi H, Kurosaki K, Ichikawa H, Noguchi T, Ishibashi-Ueda H, Yoshimatsu J. Circ J. 2021 Dec 24;86(1):138-146. doi: 10.1253/circj.CJ-21-01a33. PMID: 34497162
Take Home Points:
- Pregnant women with a Fontan circulation have a high incidence of low placental weight, and chronic subchorionic hematoma.
- Hypoxic lesions are seen consistently on histologic examination in all the placentas.
- Capillary density and the area of fibrosis were significantly greater in placentas from women with a Fontan circulation than in control placentas.
Commentary from Dr. Manoj Gupta (New York City, NY, USA), chief section editor of Pediatric & Fetal Cardiology Journal Watch.
What is known about pregnancy in patients with Fontan physiology:-
(Circulation: Cardiovascular Quality and Outcomes. 2018;11:e004575)
- Fontan palliation is a life-saving surgical procedure for patients with complex congenital heart disease.
- Fontan palliation results in derangement of the normal cardiovascular hemodynamics that might adversely affect pregnancy.
- Arrhythmias and heart failure are the most frequent cardiac complications among women after Fontan palliation during pregnancy.
- Miscarriages are common in these patients, and successful pregnancies can be frequently complicated with premature deliveries and intrauterine growth retardation.
- Postpartum hemorrhage is common among these patients
Introduction:
High rates of miscarriage (45.0–54.8%), preterm delivery (59.0–70.4%), and SGA babies (20.0–55.6%) have been reported among pregnant women who have a Fontan circulation.
Results
Of 18 pregnancies in 11 women in this study, 9 pregnancies in 6 women ended before 22 weeks of gestation. From the 9 continuing pregnancies, 8 placentas were available for detailed clinical and histopathological description, and 7 placentas were available for quantification analysis.
Cardiovascular Complications of the 8 Pregnancies with Placental Histology:
Two women had cardiovascular events during pregnancy. One (Delivery case 2-1) experienced atrial tachycardia, which required defibrillation and medication at 14 weeks of gestation. Because this woman also had sick sinus syndrome, she experienced extreme bradycardia with antiarrhythmic medications and proceeded to pacemaker insertion at 20 weeks of gestation.
Another woman (Delivery case 3) suffered worsening AVVR at 36 weeks of gestation and underwent an emergency cesarean section.
Cardiovascular events occurred after delivery in 4 women: atrial tachycardia 2 days after delivery (n=1; Delivery case 1); intraventricular thrombosis 8 days after delivery (n=1; Delivery case 2-2); and heart failure 4 weeks (n=1; Delivery case 5) and 6 weeks (n=1; Delivery case 7) after delivery.
Obstetrics and Neonatal Outcomes of the 8 Pregnancies with Placental Histology:
In the 8 pregnancies with placental histology, the median gestational age at delivery was 36 weeks. There were 4 preterm deliveries, and 4 women delivered at 37 weeks. Two (25.0%) women had chronic subchorionic hematoma (SCH) (Delivery cases 1 and 2-1) and gestational diabetes (Delivery cases 2-1, 2-2), and 1 (12.5%) woman had hypertensive disorders of pregnancy (Delivery case 2-2). All neonates, including the 5 who were SGA (62.5%), survived to hospital discharge without complications. None of them had CHD. The peak VO2 in the mothers of SGA infants was lower than that in mothers of appropriate for gestational age infants (19.35±2.69 vs. 26.6±1.27mL/kg/min; P=0.026)
Gross and Histological Findings of the 8 Placentas:
Five placentas had low placental weight for gestational age and had a low fetal/placental ratio. The presence of a low-weight placenta and SGA status was concordant in 6 of 8 neonates. Of the remaining 2 neonates, 1 baby with SGA had a normal-weight placenta and the other had a low-weight placenta but a normal birth weight. Of the 8 placentas, all but 1 showed chronic SCH (massive, n=1; multifocal, n=6); 4 were circummarginate and 1 was circumvallate. Histologically, all specimens showed evidence of placental hypoxia (MVM, n=7; FVM, n=1). None showed decidual vasculopathy. All 8 placentas showed hypervascularity, and 7 had chorangiosis and villous stromal fibrosis. Placentas of the study group had significantly greater capillary density (537 [471–639] vs. 424 [292–543] number/mm2; P=0.03) and area of fibrosis (44.3 [39.2–50.8] vs. 32.4 [29.1– 43.8] %; P=0.01) than control placentas, and there was a significant correlation between capillary density and area of fibrosis (P=0.0007.
Placental findings of 8 deliveries in 7 women with Fontan – TABLE
Discussion:
Placentas of women with a Fontan circulation are considered highly exposed to hypoxia and low perfusion, which could influence placental growth and function. Because uteroplacental blood flow is perfusion dependent, improving cardiac output to the level required by pregnancy is important to improve pregnancy outcomes. However, there is no way to directly increase cardiac output. Bed rest may improve pregnancy prognosis by increasing the blood supply to the uterus. With regard to hypoxia, oxygen supply and correcting any iron deficiency anemia may improve obstetric outcomes.
Although women with Fontan circulation are at significantly increased risk of maternal and fetal complications, pregnancy is not contraindicated, and many of these women can have a successful pregnancy with close management by a multidisciplinary team composed of team members from cardiology, MFM, anesthesiology, and neonatology. American Journal of Obstetrics & Gynecology MFM, Volume 3, Issue 1, January 2021, 100257
Conclusions:
The placentas in women with a Fontan circulation were characterized by hypoxic changes, growth impairment, and chronic SCH, which could play important roles in poor pregnancy outcomes.
