Isolated Single Umbilical Artery as a Risk Factor for Urinary Tract Infections in Childhood.

OBJECTIVE: This study aimed to determine whether isolated single umbilical artery (iSUA), even absent identifiable genitourinary (GU) abnormalities, increases the risk of GU infection during childhood. STUDY DESIGN: Retrospective population-based comparison of fetuses with iSUA versus normal three-vessel cords. Fetuses with growth restriction, prematurity, multiple gestations, and anatomical or chromosomal anomalies were excluded. The primary outcome was hospital-associated GU infection during the first 18 years of life. Kaplan-Meier's survival curves were used to assess cumulative risk; Cox's multivariable models were used to adjust for confounders. RESULTS: Among 227,599 term singleton deliveries, children with iSUA (n = 729) had a higher incidence (1.8 vs. 0.6%, p < 0.001) and cumulative incidence (log-rank test, p < 0.001) of hospital-associated GU infection. The Cox's models confirmed these findings (hazard ratio: >2.82, confidence interval: 1.63-4.87 in composite models). CONCLUSION: iSUA represents an independent risk factor for GU infection. Urinary tract imaging may be warranted.

Evaluation of right ventricular function in fetuses with isolated single umbilical artery using spatiotemporal image correlation M-mode.

BACKGROUND: Postnatal outcome of fetuses with isolated single umbilical artery (SUA) is determined mainly by right ventricular function. Our study examined whether there are differences in right ventricular function during the gestation period of fetuses with isolated SUA compared to healthy fetuses. METHODS: A prospective study was conducted on 77 fetuses with isolated SUA and 77 gestational age-matched controls from 22 to 39 weeks. For gestational age grouping, the isolated SUA fetuses and the control fetuses were divided into the second trimester group (22-27 weeks; 43 fetuses) and third trimester group (28-39 weeks; 34 fetuses). The fetal tricuspid annular plane systolic excursion (f-TAPSE) M-mode was applied to the tricuspid annulus, parallel to the ventricular septum, and the amplitude of the resulting wave was assessed using spatiotemporal image correlation (STIC) M-mode. We investigated the possible changes to the STIC M-mode indices during the course of pregnancy in both the isolated SUA and control groups. The relationship between f-TAPSE and gestational age was analyzed. Additionally, the correlations between f-TAPSE and birth weight was analyzed, and the birth weight differences between the isolated SUA and control groups in the third trimester were analyzed according to postpartum results. RESULTS: There was a significant difference in f-TAPSE between isolated SUA and control group in the third trimester (P < 0.05). There were significant correlations between gestational age (GA) and f-TAPSE among control fetuses (R2 = 0.9049; P < 0.01). A significant, positive correlation between GA and f-TAPSE was also found with isolated SUA fetuses (R2 = 0.8108; P < 0.01). The prevalence of small-for-gestational-age (SGA) fetuses and of discordant birth weight fetuses was significantly higher in the isolated SUA group than in the control group. In univariate analysis, the presence of an isolated SUA was associated with lower birth weight (2940 g compared with 3260 g) and with higher prevalence of SGA (13.0% compared with 3.9%; P < 0.01). The correlations between the birth weight and f-TAPSE in the two groups were analyzed in the third trimester, and the correlation in the isolated SUA group was better than that of the control group (R2 was 0.623 and 0.463 in the isolated SUA group and the control group, respectively). CONCLUSIONS: Right ventricular function in isolated SUA is altered as early as in fetal third trimester. STIC M-mode can measure the right heart function of the fetus and may predict isolated SUA with SGA.

Reference charts for umbilical Doppler pulsatility index in fetuses with isolated two-vessel cord.

PURPOSE: To determine reference values for umbilical Doppler pulsatility index in fetuses with isolated two-vessel cord and to compare these values with standard umbilical Doppler pulsatility index curves from 23 to 40 gestational weeks. METHODS: A retrospective longitudinal cohort study was conducted between January 2014 and December 2017 in a tertiary referral hospital and included 62 pregnant women with isolated single umbilical artery (two-vessel cord) and 174 measurements. Only uncomplicated term pregnancies were included. A reference curve for umbilical Doppler pulsatility index was built up and compared with a standard curve commonly used for fetuses with three-vessel cord. RESULTS: Umbilical Doppler pulsatility index values were much lower than expected in cases with two-vessel cord compared to 3-vessel cord: mean of the regression equations was 1.02 ± 0.23 vs. 0.86 ± 0.19, respectively (p value < 0.001). This difference was quite constant across the gestational weeks considered, showing that the slopes of the two regressions were very similar. CONCLUSION: Reference curves for umbilical Doppler pulsatility index in two-vessel cord pregnancies were determined. Pulsatility index values were significantly different compared with those commonly used for three-vessel cord. Using lower reference values for umbilical pulsatility index in cases with two-vessel cord may allow a better identification of fetuses affected with intrauterine growth restriction, thus improving fetal surveillance.

Impact of isolated single umbilical artery on pregnancy outcome and delivery in full-term births.

AIM: To identify whether an isolated single umbilical artery (ISUA) impacts pregnancy outcome and delivery mode in single and full-term births. METHODS: A retrospective study was carried out on 93,592 pregnant women (singleton pregnancy; full-term birth; no known fetal chromosomal and structural anomalies) who gave birth between January 2011 and January 2012 in 39 hospitals within China. Pregnancy outcomes and modes of delivery were compared between research (313 cases with ISUAs) and comparison groups (1,252 cases with three-vessel cords in a 1:4 ratio randomly matched by parity). RESULTS: The birth weights (3264.71 ± 469.95 g vs 3340.76 ± 434.25 g, P = 0.001), birth lengths (48.51 ± 2.84 cm vs 49.99 ± 1.65 cm, P = 0.000), placental weights (511.31 ± 76.43 g vs 545.31 ± 85.06 g, P = 0.002), umbilical cord lengths (52.64 ± 8.82 cm vs 54.08 ± 7.81 cm, P = 0.002) and Apgar scores within one min of birth (8.83 ± 0.96 vs 9.57 ± 0.75, P = 0.000) of newborn infants were significantly lower in the research than the comparison group; the incidence of small for gestational age (10.94% vs 5.39%, P = 0.000) and low birth weight infants (6.69% vs 1.98%, P = 0.000) were significantly higher in the research group. There was no significant difference in fetal/placental weight, incidence of velamentous cord insertions, 1 min Apgar score < 7, 5 min Apgar score < 7 or vaginal or emergency cesarean delivery rates as a result of fetal factors between the two groups. CONCLUSION: An ISUA is associated with an adverse pregnancy outcome; however does not decrease the rate of vaginal delivery in full-term births.

Maternal Floor Infarction/Massive Perivillous Fibrin Deposition Associated with Hypercoiling of a Single-Artery Umbilical Cord: A Case Report.

Maternal floor infarction is a rare and idiopathic placental disorder associated with adverse obstetric outcomes and a high rate of recurrence in subsequent pregnancies. The pathogenesis of maternal floor infarction is unclear but has been linked to diverse underlying maternal conditions, including gestational hypertension/preeclampsia, immune-mediated diseases, and thrombophilia. Few reports link maternal floor infarction to fetoplacental conditions. We report a 34-week, macerated, growth-restricted male fetus for which the placenta showed maternal floor infarction. The umbilical cord showed excessive coiling and a single umbilical artery. These cord changes are postulated to have resulted in increased placental villous resistance and decreased fetal blood flow, creating a hydrostatic pressure gradient between the villous stroma and the intervillous space. The pressure changes could then lead to trophoblast damage and fibrinoid deposition, contributing to the maternal floor infarction in this case.

Umbilical artery blood flows among pregnancies with single umbilical artery: a prospective case-control study.

OBJECTIVES: To evaluate peak systolic velocity (PSV) in the umbilical artery (UA) among patients with single umbilical artery (SUA) as compared with patients with three vessel cords. METHODS: A prospective case-control study was performed. UA blood flow velocimetry was obtained from fetuses with SUA and from a control group with three vessel cord. PSV and pulsatility index (PI) were measured. Patients' characteristics were compared for statistical differences and a linear regression model was constructed for the different groups. RESULTS: UA Doppler velocimetry measurements were obtained from 29 patients with SUA and from 29 controls matched for gestational age. The differences between UA PI with and without SUA were significant (F = 3.471; p = 0.0379) showing a lower PI in the SUA group. However, no significant statistical difference was found in PSV between these two groups (F = 0.149; p = 0.86). CONCLUSIONS: While the impedance in the UA of patients with a SUA was lower compared with patients with a normal umbilical cord, the PSV did not differ.

Single umbilical artery: Does side matter?

INTRODUCTION: The aim of this study was to determine if laterality of an absent umbilical artery (AUA) is associated with specific sonographic findings, chromosomal defects or postpartum birth defects. MATERIALS AND METHODS: In this retrospective cohort study, ultrasound reports and medical records of patients who received an obstetric ultrasound at the University of Iowa Hospitals and Clinics with an identified laterality of the AUA from 1989 to 2007 (n = 405) were reviewed. Rates of sonographic abnormalities between fetuses with a right versus left AUA were compared using Fisher's exact test. Adjustments for confounding were made using logistic regression modeling. The significance level was set at 0.05. RESULTS: Right AUAs on ultrasound demonstrate higher unadjusted rates of ultrasound abnormalities with a higher percentage of fetuses with >1 additional abnormality (51.1 vs. 37.0%; p = 0.0043). The left AUA group had a significantly higher percentage of isolated AUA (63.0 vs. 48.8%; p = 0.004). In a multivariate analysis, a sonographic right AUA was significantly associated with gastrointestinal (GI) and genitourinary (GU) abnormalities. No other ultrasonographic and umbilical artery Doppler abnormalities, chromosomal defects or postpartum birth defects were significantly associated with a specific laterality of the AUA. DISCUSSION: Our study identified a significant association between a right AUA and concomitant fetal GI and GU abnormalities. Contrary to previous reports, we conclude that laterality of the AUA may prove to be an easily identified early marker of fetal abnormalities.

Single umbilical artery in twin pregnancies.

OBJECTIVE: Our purpose was to evaluate the antenatal incidence of single umbilical artery (SUA) in twin pregnancies according to chorionicity and to assess its relationship with outcome. METHODS: Consecutive twin pregnancies undergoing ultrasound evaluation at our institutions were included. A targeted sonographic evaluation of the umbilical cord and vessels was performed in all cases. Chorionicity was determined according to standard ultrasound criteria. RESULTS: A total of 174 twin pregnancies, 100 dichorionic (DC) and 74 monochorionic (MC), were included in the study. An SUA was identified in 17 (9.8%) pregnancies, and in 18 (5.2%) fetuses. No difference was found in the incidence of SUA in DC and MC twins. Among affected pregnancies, all but one DC twin pregnancy were discordant for SUA. Structural and/or chromosomal abnormalities were present in 27.8% of fetuses with SUA. The prevalence of small-for-gestational-age fetuses and of discordant birth weight (> 20% discordance) was higher in the SUA group than in the rest of the population, although these differences were not statistically significant. Twin pairs discordant for SUA had significantly higher weight discordance than those with normal umbilical cords. The sonographic cross-sectional area of the SUA did not appear to show the typical adaptive dilatation usually seen in singleton pregnancies with SUA. CONCLUSIONS: The incidence of SUA in twins is higher than in singletons, with no difference between MC and DC twins. Intrapair discordance for SUA in identical twins provides evidence against an exclusively genetic origin of this anomaly. The apparent failure of compensatory dilatation of the umbilical artery in twins with SUA may explain in part the higher risk for fetal growth restriction in these cases.

Case reports of transient single umbilical artery blood flow in monochorionic twins.

We report two cases of transient single umbilical artery (UA) blood flow in growth-discordant monochorionic twins. The interval of single UA was for one week in case 1 and for a few days in case 2. We speculate a cord factor such as length, twisting, and insertion site can be the etiology of this condition.

Ultrasound predictors of birth weight in euploid fetuses with isolated single umbilical artery.

OBJECTIVE: To evaluate ultrasound parameters, including Doppler assessment, that may influence fetal growth and birth weight in cases of isolated single umbilical artery (SUA). METHODS: Sixty pregnant women with isolated SUA were studied. Doppler measurements of umbilical artery (UA), mean uterine artery (UtA) and fetal middle cerebral artery (MCA) pulsatility indices (PI) were recorded and the corresponding Z-scores were calculated according to gestational age at time of measurement. Additionally, the umbilical vein (UV) to UA diameter and perimeter ratios were calculated. The relationships between ultrasound parameters and customized birth-weight centiles according to sex and gestational age were analyzed. RESULTS: There were significant correlations between birth-weight centile and the Z-score of mean UtA-PI (r = - 0.417, P = 0.008) and the UV to UA perimeter ratio (r = 0.567, P = 0.001). A significant positive correlation between Z-scores of UA-PI and mean UtA-PI (r = 0.428, P = 0.007) was also found. When using stepwise linear regression analysis both mean UtA-PI Z-scores and UV to UA perimeter ratio were included in the predictive model of birth-weight centile (R(2) = 0.46, P < 0.001). CONCLUSIONS: Doppler assessment of mean UtA-PI and the UV to UA perimeter ratio may be useful in the clinical management of isolated SUA cases by identifying a subgroup at higher risk for fetal growth restriction.

Isolated single umbilical artery: need for specialist fetal echocardiography?

OBJECTIVE: To examine the association between single umbilical artery (SUA) and cardiac defects and to determine whether patients with SUA require specialist fetal echocardiography. METHODS: Incidence and type of cardiac defects were determined in fetuses with SUA detected at routine second-trimester ultrasound examination. RESULTS: A routine second-trimester scan was performed in 46 272 singleton pregnancies at a median gestation of 22 (range, 18-25) weeks and an SUA was diagnosed in 246 (0.5%). Cardiac defects were diagnosed in 16 (6.5%) of these cases, including 10 (4.3%) in a subgroup of 233 with no other defects and in six (46.2%) of the 13 with multiple defects. In 11 (68.8%) of the 16 cases with cardiac defects the condition was readily diagnosable by evaluating the standard four-chamber view and the views of the great arteries. In the remaining cases there was left persistent superior vena cava or small ventricular septal defect, where prenatal diagnosis may not be important because they are not associated with adverse outcome. CONCLUSION: Although SUA is associated with an increased incidence of cardiac defects it may not be necessary to refer such patients for specialist fetal echocardiography because the defects are detectable by evaluating standard cardiac views that should be part of the routine second-trimester scan.