The impact of nuchal cord on umbilical cord blood gas analysis and ischaemia-modified albumin levels in elective C-section

Umbilical Artery Cord Gas Abnormalities in the Presence of a Nuchal Cord in Term Singleton Pregnancies: A Cohort Study

OBJECTIVE

The clinical significance of nuchal cord (NC) at the time of delivery is unclear. Studies have found that NC is associated with lower umbilical artery (UA) pH. Since fetal hypercarbia precedes respiratory acidosis, we hypothesize UA pCO2 is elevated in neonates with NC at the time of delivery.

STUDY DESIGN

This is a secondary analysis of a prospective cohort study of women with full-term singleton pregnancies admitted in labor or for induction of labor at an institution with a universal umbilical cord gas policy. We compared patients with NC at the time of delivery to those without NC. Women were excluded if they did not have validated UA gases, had a major fetal anomaly, or had an intrauterine fetal demise. The primary outcome of the study was UA pCO2. Secondary outcomes were other components of UA gas and neonatal morbidity composite. Baseline characteristics were compared utilizing chi-square or Fisher's exact test or the Student's t-test. UA gas parameters were compared using the Kruskal-Wallis test. Multivariable logistic regression was utilized to adjust for confounders.

RESULTS

Of the 8,580 study participants, 7,608 had validated umbilical cord gases. The incidence of NC in the population was 24.15% (n = 1,837). UA pCO2 was higher in those with NC than without (58 mm Hg [53-64] vs. 55 mm Hg [50-60], p < 0.01). There was a greater odds of hypercarbia in the NC group (pCO2 > 65 mmHg; adjusted odds ratio [aOR]: 1.97, 95% confidence interval [CI]: 1.72-2.25, p < 0.01). Additionally, the NC group was more likely to be mildly acidemic (pH < 7.2, aOR: 1.74, 95% CI: 1.51-2.01, p < 0.01). There was no difference in composite neonatal morbidity between the groups.

CONCLUSION

NC is associated with an increased risk of hypercarbia and acidemia. However, this is not associated with increased risk of neonatal morbidity.

KEY POINTS

· Nuchal cord is associated with an increased risk of hypercarbia and mild acidemia.. · Nuchal cord is not likely associated with neonatal morbidity.. · Neonatal management should not be altered due to the presence of a nuchal cord at delivery..

Is There an Added Neonatal Risk in Vacuum-Assisted Deliveries with Nuchal Cord?

This retrospective cohort study assessed the association between nuchal cord and adverse outcomes during vacuum-assisted delivery (VAD). Women with singleton pregnancies, 34−41-weeks gestation, who underwent VAD, from 2014 to 2020 were included. The primary outcome was umbilical cord pH ≤ 7.1. Secondary outcomes were neonatal intensive care unit admission, Apgar scores, pH < 7.15, subgaleal hematoma, shoulder dystocia and third/fourth-degree perineal tear. Outcomes were compared between neonates with (1059/3754, 28.2%) or without (71.8%) nuchal cord after VAD. No difference in cord pH ≤ 7.1 was found between groups. The nuchal cord group had a lower rate of nulliparity (729 (68.8%) vs. 2004 (74.4%), p = 0.001) and higher maternal BMI (23.6 ± 4.3 vs. 23.1 ± 5, p = 0.017). Nuchal cord was associated with higher rates of induction (207 (19.5%) vs. 431 (16%), p = 0.009) and lower birthweights (3185 ± 413 vs. 3223 ± 436 g, p = 0.013). The main indication for VAD in 830 (80.7%) of the nuchal cord group was non-reassuring fetal heart rate (NRFHR) vs. 1989 (75.6%) controls (p = 0.004). The second stage was shorter in the nuchal cord group (128 ± 81 vs. 141 ± 80 min, p < 0.001). Multivariate regression found nulliparity, induction and birthweight as independent risk factors for nuchal cord VAD. Although induction and NRFHR rates were higher in VAD with nuchal cord, the rate of umbilical cord acidemia was not.

The effect of nuchal umbilical cord on fetal cardiac and cerebral circulation-cross-sectional study

OBJECTIVES

The subject of our analysis is the influence of umbilical cord collision around the fetal neck on the fetal heart function and cerebral circulation.

METHODS

Our study was carried out on a group of 115 fetuses from single pregnancies with physiological course, during the 15th to 40th week of pregnancy. In our analysis, we examined the following parameters: Tei index for right ventricle, Tei index for left ventricle with Tei index components: isovolumetric contraction time, isovolumetric relaxation time, ejection time and cardiothoracic area ratio, middle cerebral artery peak systolic velocity (PS MCA), middle cerebral artery pulsatility index (PI MCA). Gestational age in our study was: 28+2±34. The study group of patients with fetal umbilical cord around neck group (fUCAN) included 38 fetuses (20 males, 18 females). The control group of patients with no fetal umbilical cord around neck group (NfUCAN) included 77 fetuses (43 males, 34 females).

RESULTS

In our study, we found no significant differences in the values obtained: Tei LV in fUCAN: 0.5±0.1 vs. in NfUCAN: 0.5±0.1; p=0.42), Tei RV in fUCAN: 0.5±0.2 vs. in NfUCAN: 0.4±0.1; (p=0.2). Tricuspid valve regurgitation-TR was observed with the following frequency: fUCAN: 7/38, 18% vs. NfUCAN: 13/77, 17%; p=0.8. MCA PS in study fUCAN group was significantly higher than in NfUCAN (40.2±11.5 vs. 32.5±9.5; p=0.003), although other hemodynamic and clinical variables did not differ between the study and control groups.

CONCLUSIONS

The fetal nuchal umbilical cord collision did not affect the fetal heart function expressed as Tei index, at the time of fetal heart examination (at mean gestational age 29+4 weeks). The fUCAN group presented elevated PS MCA, which was not related to other hemodynamic and clinical variables between the study and control groups.

Evaluation of umbilical cord entanglement as a predictive factor of adverse pregnancy outcomes: A meta-analysis

The purpose of the present systematic review is to summarize current data concerning the impact of umbilical cord entanglement on adverse pregnancy outcomes. We used the Medline, Scopus, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar databases. We selected all observational (both prospective and retrospective) studies for inclusion. Meta-analysis of the risk ratios (RR) was performed with RevMan 5.3 software. Univariate meta-regression and leave-one-out meta-analysis was performed with Open Meta-Analyst statistical software. Trial sequential analysis was performed with the TSA software. Overall, twenty studies were included in the present study with 267,233 pregnant women (50.103 with cord entanglement and 217,130 controls). An increased risk of neonatal Apgar score <7 at the first minute of life was observed among cases with cord entanglement (RR = 1.75, 95% CI 1.46, 2.11). Fetal distress was significantly higher in the entanglement group (RR 1.50, 95% CI 1.33, 1.69). The incidence of fetal pH < 7.1 was also significantly higher in the entanglement group (RR 1.73, 95% CI 1.48, 2.03). Adequate power was observed in all investigated outcomes of our primary analysis after evaluating the results of the TSA analysis. Prediction intervals designated that future studies were likely to report increased risk of low Apgar score at the first minute of life, increased risk of fetal distress as well as of observing a fetal pH < 7.1. Concluding, the findings of this systematic review suggest that there is sufficient evidence to support the involvement of cord entanglement to adverse neonatal perinatal outcomes.

Adverse pregnancy outcomes and multiple nuchal cord loops

PURPOSE

To evaluate the effects of nuchal cord and the number of loops during labor and delivery on delivery outcomes among women with singleton pregnancy who delivered vaginally.

METHODS

This retrospective cohort study included 42,798 women with singleton, vertex, and vaginal deliveries at 24-43 weeks of gestation. We analyzed delivery outcomes based on the number of nuchal cord loops.

RESULTS

A total of 42,798 deliveries met the inclusion criteria, of which, 3809 (8.9%) had nuchal cord with 1 loop at delivery, 1035 (2.42%) had 2 loops, and 258 (0.6%) had 3 loops. Nuchal cord with 3 loops compared to no nuchal cord has been associated with higher incidence of intrauterine fetal death (1.9%), Apgar scores less than 7 at 1 and 5 min (7.4%, 2.3%), and higher rate of operative vaginal deliveries (17.5%). Nuchal cord with 2 or 3 loops was associated with higher incidence of intrauterine growth restriction (10.2%, 11.6%).  In a multiple logistic regression model, nuchal cord with 3 loops was an independent risk factor for operative vaginal delivery and Apgar score less than 7 in 1 min.

CONCLUSIONS

In the case of vaginal delivery in the presence of nuchal cord, as the number of nuchal cord loops increased, so did the number of adverse delivery outcomes. While 3 loops were associated with higher incidence of intrauterine fetal death, intrauterine growth restriction, increased operative vaginal deliveries, and low Apgar scores, 1 loop was not associated with adverse perinatal outcomes.