Umbilical cord characteristics and their association with adverse pregnancy outcomes: A systematic review and meta-analysis

[Fetal death: Expert consensus from the College of French Gynecologists and Obstetricians]

Fetal death is defined as the spontaneous cessation of cardiac activity after fourteen weeks of amenorrhea. In France, the prevalence of fetal death after 22 weeks is between 3.2 and 4.4/1000 births. Regarding the prevention of fetal death in the general population, it is not recommended to counsel for rest and not to prescribe vitamin A, vitamin D nor micronutrient supplementation for the sole purpose of reducing the risk of fetal death (Weak recommendations; Low quality of evidence). It is not recommended to prescribe aspirin (Weak recommendation; Very low quality of evidence). It is recommended to offer vaccination against influenza in epidemic periods and against SARS-CoV-2 (Strong recommendations; Low quality of evidence). It is not recommended to systematically look for nuchal cord encirclements during prenatal screening ultrasounds (Strong Recommendation; Low Quality of Evidence) and not to perform systematic antepartum monitoring by cardiotocography (Weak Recommendation; Very Low Quality of Evidence). It is not recommended to ask women to perform an active fetal movement count to reduce the risk of fetal death (Strong Recommendation; High Quality of Evidence). Regarding evaluation in the event of fetal death, it is suggested that an external fetal examination be systematically offered (Expert opinion). It is recommended that a fetopathological and anatomopathological examination of the placenta be carried out to participate in cause identification (Strong Recommendation. Moderate quality of evidence). It is recommended that chromosomal analysis by microarray testing be performed rather than conventional karyotype, in order to be able to identify a potentially causal anomaly more frequently (Strong Recommendation, moderate quality of evidence); to this end, it is suggested that postnatal sampling of the placental fetal surface for genetic purposes be preferred (Expert Opinion). It is suggested to test for antiphospholipid antibodies and systematically perform a Kleihauer test and a test for irregular agglutinins (Expert opinion). It is suggested to offer a summary consultation, with the aim of assessing the physical and psychological status of the parents, reporting the results, discussing the cause and providing information on monitoring for a subsequent pregnancy (Expert opinion). Regarding announcement and support, it is suggested to announce fetal death without ambiguity, using simple words and adapting to each situation, and then to support couples with empathy in the various stages of their care (Expert opinion). Regarding management, it is suggested that, in the absence of a situation at risk of disseminated intravascular coagulation or maternal vitality, the patient's wishes should be taken into account when determining the time between the diagnosis of fetal death and induction of birth. Returning home is possible if it's the patient wish (Expert opinion). In all situations excluding maternal life-threatening emergencies, the preferred mode of delivery is vaginal delivery, regardless the history of cesarean section(s) history (Expert opinion). In the event of fetal death, it is recommended that mifepristone 200mg be prescribed at least 24hours before induction, to reduce the delay between induction and delivery (Low recommendation. Low quality of evidence). There are insufficient data in the literature to make a recommendation regarding the route of administration (vaginal or oral) of misoprostol, neither the type of prostaglandin to reduce induction-delivery time or maternal morbidity. It is suggested that perimedullary analgesia be introduced at the start of induction if the patient asks, regardless of gestational age. It is suggested to prescribe cabergoline immediately in the postpartum period in order to avoid lactation, whatever the gestational age, after discussing the side effects of the treatment with the patient (Expert opinion). The risk of recurrence of fetal death after unexplained fetal death does not appear to be increased in subsequent pregnancies, and data from the literature are insufficient to make a recommendation on the prescription of aspirin. In the event of a history of fetal death due to vascular issues, low-dose aspirin is recommended to reduce perinatal morbidity, and should not be combined with heparin therapy (Low recommendation, very low quality of evidence). It is suggested not to recommend an optimal delay before initiating another pregnancy just because of the history of fetal death. It is suggested that the woman and co-parent be informed of the possibility of psychological support. Fetal heart rate monitoring is not indicated solely because of a history of fetal death. It is suggested that delivery not be systematically induced. However, induction can be considered depending on the context and parental request. The gestational age will be discussed, taking into account the benefits and risks, especially before 39 weeks. If a cause of fetal death is identified, management will be adapted on a case-by-case basis (expert opinion). In the event of fetal death occurring in a twin pregnancy, it is suggested that the surviving twin be evaluated as soon as the diagnosis of fetal death is made. In the case of dichorionic pregnancy, it is suggested to offer ultrasound monitoring on a monthly basis. It is suggested not to deliver prematurely following fetal death of a twin. If fetal death occurs in a monochorionic twin pregnancy, it is suggested to contact the referral competence center, in order to urgently look for signs of acute fetal anemia on ultrasound in the surviving twin, and to carry out weekly ultrasound monitoring for the first month. It is suggested not to induce birth immediately.

Placental and umbilical cord anomalies detected by ultrasound as clinical risk factors of adverse perinatal outcome: Case series review of selected conditions. Part 1: Placental abnormalities

BACKGROUND

The aim of this extended review of multicenter case series is to describe the prenatal ultrasound features and pathogenetic mechanisms underlying placental and umbilical cord anomalies and their relationship with adverse perinatal outcome. From an educational point of view, the case series has been divided in three parts; Part 1 is dedicated to placental abnormalities.

METHODS

Multicenter case series of women undergoing routine and extended prenatal ultrasound and perinatal obstetric care.

RESULTS

Prenatal ultrasound findings, perinatal care, and pathology documentation in cases of placental pathology are presented.

CONCLUSIONS

Our case series review and that of the medical literature confirms the ethiopathogenetic role and involvement of placenta abnormalities in a wide variety of obstetrics diseases that may jeopardize the fetal well-being. Some of these specific pathologies are strongly associated with a high risk of poor perinatal outcome.

Twisting the theory on the origin of human umbilical cord coiling featuring monozygotic twins

The human umbilical cord (hUC) is the lifeline that connects the fetus to the mother. Hypercoiling of the hUC is associated with pre- and perinatal morbidity and mortality. We investigated the origin of hUC hypercoiling using state-of-the-art imaging and omics approaches. Macroscopic inspection of the hUC revealed the helices to originate from the arteries rather than other components of the hUC. Digital reconstruction of the hUC arteries showed the dynamic alignment of two layers of muscle fibers in the tunica media aligning in opposing directions. We observed that genetically identical twins can be discordant for hUC coiling, excluding genetic, many environmental, and parental origins of hUC coiling. Comparing the transcriptomic and DNA methylation profile of the hUC arteries of four twin pairs with discordant cord coiling, we detected 28 differentially expressed genes, but no differentially methylated CpGs. These genes play a role in vascular development, cell-cell interaction, and axis formation and may account for the increased number of hUC helices. When combined, our results provide a novel framework to understand the origin of hUC helices in fetal development.

The benefit of active management in true knot of the umbilical cord: a retrospective study

PURPOSE

To compare perinatal outcomes between active and routine management in true knot of the umbilical cord (TKUC).

METHODS

A retrospective study of singletons born beyond 22 6/7 weeks with TKUC. Active management included weekly fetal heart rate monitoring(FHRM) ≥ 30 weeks and labor induction at 36-37 weeks. Outcomes in active and routine management were compared, including composite asphyxia-related adverse outcome, fetal death, labor induction, Cesarean section (CS) or Instrumental delivery due to non-reassuring fetal heart rate (NRFHR), Apgar5 score < 7, cord Ph < 7, neonatal intensive care unit (NICU) admission and more.

RESULTS

The Active (n = 59) and Routine (n = 1091) Management groups demonstrated similar rates of composite asphyxia-related adverse outcome (16.9% vs 16.8%, p = 0.97). Active Management resulted in higher rates of labor induction < 37 weeks (22% vs 1.7%, p < 0.001), CS (37.3% vs 19.2%, p = 0.003) and NICU admissions (13.6% vs 3%, p < 0.001). Fetal death occurred exclusively in the Routine Management group (1.8% vs 0%, p = 0.6).

CONCLUSION

Compared with routine management, weekly FHRM and labor induction between 36 and 37 weeks in TKUC do not appear to reduce neonatal asphyxia. In its current form, active management is associated with higher rates of CS, induced prematurity and NICU admissions. Labor induction before 37 weeks should be avoided.

Relationship between ultrasound parameters of the umbilical and middle cerebral arteries and intrauterine fetal distress

BACKGROUND

By comprehensively analyzing the blood flow parameters of the umbilical and middle cerebral arteries, doctors can more accurately identify fetal intrauterine distress, as well as assess its severity, so that timely interventions can be implemented to safeguard the health and safety of the fetus.

AIM

To identify the relationship between ultrasound parameters of the umbilical and middle cerebral arteries and intrauterine distress.

METHODS

Clinical data of pregnant women admitted between January 2021 and January 2023 were collected and divided into the observation and control groups (n = 50 each), according to the presence or absence of intrauterine distress. The ultrasound hemodynamic parameters of the uterine artery (UtA), fetal middle cerebral artery (MCA), and umbilical artery (UmA) were compared with neonatal outcomes and occurrence of intrauterine distress in the two groups.

RESULTS

Comparison of ultrasonic hemodynamic parameters, resistance index (RI), pulsatility index (PI), and systolic maximal blood flow velocity of UmA compared to diastolic blood flow velocity (S/D), revealed higher values of fetal MCA, PI, and S/D of UmA in pregnant women with UtA compared to controls (P < 0.05), while there was no difference between the two groups in terms of RI (P < 0.05) The incidence of a neonatal Apgar score of 8-10 points was lower in the observation group (66.7%) than in the control group (90.0%), and neonatal weight (2675.5 ± 27.6 g) was lower than in the control group (3117.5 ± 31.2 g). Further, cesarean section rate was higher in the observation group (70.0%) than in the control group (11.7%), and preterm labor rate was higher in the observation group (40.0%) than in the control group (10.0%). The incidence of fetal distress, neonatal growth restriction and neonatal asphyxia were also higher in the observation group (all P < 0.05).

CONCLUSION

Fetal MCA, UmA, and maternal UtA hemodynamic abnormalities all develop in pregnant women with intrauterine distress during late pregnancy, which suggests that clinical attention should be paid to them, and monitoring should be strengthened to provide guidance for clinical intervention.

Double true umbilical cord knots coexisting with a nuchal cord with successful fetal outcome: A case report

Umbilical nodes and cords play a crucial role in fetal development and are essential for the transfer of nutrients and oxygen between the mother and the fetus. Sonographic diagnosis of umbilical nodes and cords has become an integral part of prenatal care, allowing for the early detection of abnormalities and potential complications. The umbilical cord is a vital structure connecting the fetus to the placenta, providing essential nutrients and oxygen for fetal growth and development. Sonographic examination of the umbilical cord and its associated nodes has become an indispensable tool in prenatal care, enabling the early detection of abnormalities and potential complications. This review aims to analyze the current literature on sonographic diagnosis of umbilical nodes and cords, highlighting the key points and advancements in this field. A 37-year-old booked G4P2+1A2 Nigerian woman was registered for prenatal tertiary health care at 12 weeks of gestation. The booking investigations were normal and the booking packed cell volume was 37%. She was compliant with scheduled clinic visits and routine drugs. Pregnancy was carried to term uneventfully. Elective cesarean section was successfully performed at 38 weeks of gestation owing to the patient's prior history of third-degree perineal tear. The intraoperative findings included a loose cord around the neck of the baby and double true knots along the length of the 65 cm umbilical cord. The baby was delivered with appearance, pulse, grimace, activity and respiration (APGAR) scores of 7 in the first minute, 9 in the fifth minute, and the birth weight was 3.0 kg. Mother and baby were discharged 48 h postpartum in stable clinical condition. Although the presence of true double umbilical knots is rare, its coexistence with the nuchal cord is even rarer. There are risk factors associated with true umbilical knots. The possible risk factor implicated in this index case is the gender of the fetus and maternal multiparity. True umbilical knots are usually associated with certain fetal negative outcomes of pregnancy. There are currently no evidence-based treatment options available.

Are reduced fetal movements "merely" a maternal perception or truly a reflection of umbilical cord complications? A clinical trial

OBJECTIVE

To characterize obstetric outcomes and the association with umbilical cord (UC) complications among women complaining of reduced fetal movements (RFMs).

METHODS

This retrospective cohort compared women with a perception of RFMs within 2 weeks prior to delivery with women who reported no changes in fetal movements in terms of maternal characteristics and neonatal outcomes. A primary outcome of UC complications at delivery was defined. Multivariable regression analysis was performed to identify independent associations with RFMs and UC complications.

RESULTS

In all, 46 103 women were included, 2591 (5.6%) of whom reported RFMs and 43 512 (94.4%) in the control group. Compared with controls, the RFM group was more likely to be nulliparous (42.6% vs 32.2%, P < 0.001), smokers (6.4% vs 5.4%, P = 0.029), or obese (body mass index >30) (16.4% vs 11.6%, P < 0.001). They were also more likely to have an anterior placenta (56.2% vs 51.8%, P < 0.001) and poly/oligohydramnios (0.7% vs 0.4%, P = 0.015 and 3.6% vs 2.1%, P < 0.001, respectively). Induction of labor was more common in the RFM group (33.9% vs 19.7%, P < 0.001), as well as meconium (16.8% vs 15.0%, P = 0.026) and vacuum extractions (10.1% vs 8.0%, P < 0.001). Higher rates of stillbirth and the severe composite neonatal outcome were observed in the RFM group (1.5% vs 0.2%, P < 0.001 and 0.6% vs 0.3%, P = 0.010, respectively). The RFM group was characterized by higher rates of triple nuchal cord (P = 0.015), UC around body or neck (32.2% vs 29.6%, P = 0.010), and true knot (2.3% vs 1.4%, P = 0.002). Multivariable logistic regression found RFMs to be independently associated with triple nuchal cord and with a true cord knot. A sub-analysis including only cases of stillbirth (n = 127) revealed even higher rates of UC complications: 7% of all stillbirths presented with a true cord knot (20% true knots were found in stillbirths preceded by RFMs vs 6.1% in stillbirth cases without RFMs). Additionally, 33.8% of all stillbirths presented with nuchal cord (40% preceded by RFMs vs 33.3% without RFMs).

CONCLUSIONS

RFMs are associated with increased risk of UC complications observed at delivery, as well as increased risk of stillbirth and neonatal adverse outcomes.

Adverse pregnancy outcomes and the abnormal umbilical cord coiling index

BACKGROUNDS

The abnormal umbilical cord coiling index (UCI) may be one of the ways to predict adverse pregnancy outcomes. This study attempted to determine the association between abnormal UCI and maternal, fetal, and neonatal outcomes.

METHODS

This longitudinal study was conducted on 400 women referred for delivery from April to August 2021. UCI was calculated by dividing the total number of coils by the total length of the umbilical cord in centimeters. In eligible cases, the length of the umbilical cord and the number of vascular coils along the total umbilical cord were measured after birth. UCI less than the 10th percentile and more than the 90th percentile was considered abnormal, and between the 10th and 90th percentiles was considered normal. Data were analyzed using SPSS version 20. P < 0.05 were considered statistically significant.

RESULTS

The mean length of the umbilical cord was 56.12±8.38 cm, the number of umbilical cord rings was 13.70±3.51, and the UCI was 0.24±0.07. In the regression analysis, women with gestational diabetes had a significant association with abnormal UCI (P = 0.044). Thus, the probability of abnormal UCI was about 3.5 times higher in women with gestational diabetes than in normal pregnancies. Also, the history of stillbirth had a significant association with abnormal UCI (P < 0.05).

CONCLUSION

It is recommended to perform a UCI examination after delivery as part of a neonatal examination to find an explanation for maternal, fetal, and neonatal outcomes.

Adverse outcomes of nonnuchal umbilical cord entanglement

OBJECTIVE

To evaluate perinatal effects of umbilical cord entanglement (UCE) of different body parts.

METHODS

The database of a tertiary medical center was retrospectively searched for women who gave birth to a liveborn singleton newborn in 2014-2018. Those diagnosed postpartum with UCE were matched 1:10 with women who were not and compared for adverse obstetric and neonatal outcomes, overall and by site of entanglement.

RESULTS

A total of 14 299 women were evaluated, of whom 1243 were diagnosed with UCE: 78.7% neck, 26% trunk, 6.7% limb. UCE was associated with lower birth weight percentile and higher rate of small for gestational age, but findings were significant only for neck and trunk UCE. On multivariate regression analysis adjusted for maternal age, parity, gestational age at birth, and history of cesarean delivery, UCE was an independent risk factor for nonreassuring fetal heart rate, labor induction, operative vaginal delivery, cesarean delivery, and meconium-stained amniotic fluid, but not for lower absolute birth weight/birth weight percentile, small for gestational age, low 1-min Apgar score, or neonatal asphyxia.

CONCLUSION

While fetuses with UCE might be more compromised during labor, they apparently recover shortly after birth. The impact on perinatal outcomes was similar for UCE of the neck and trunk and lower for UCE of the limb.

Cardiac Adaptation and Preferential Streaming in Fetuses with Multiple Nuchal Cords

The echocardiographic monitoring of a fetus with multiple nuchal cords around the fetal neck is important as it may result in cardiac remodeling and preferential streaming, thus affecting the condition of the fetus. The main aim of our study was to assess whether the collision of the umbilical cord around the fetal neck can lead to discrepancies in the size of the pulmonary artery and the aorta in the three-vessel view and to an increase in the size of the heart, which may result from the compression of the carotid arteries caused by the umbilical cord wrapping around the fetal neck. A total number of 854 patients were included in this study and divided into three groups. Group A (control group) included 716 fetuses (84%) without the umbilical cord around the fetal neck. Group B (study group B) included 102 fetuses (12%) with one coil of the umbilical cord around the fetal neck. Group C (study group C) included 32 fetuses (4%) with two coils of the umbilical cord around the fetal neck. The range of the gestational age of the patients considered for this study was 27-40.2 weeks based on the ultrasound biometry and was not statistically different between the analyzed groups A, B and C (p > 0.05). The Pa/Ao index was calculated by dividing the value of the width of the pulmonary artery (in mm) to the width of the aorta (in mm) measured in the ultrasound three-vessel view. We found that fetuses that the fetuses with one and two coils of the umbilical cord around the neck showed significantly higher values of the width of the pulmonary trunk with the unchanged value of the aorta width. Therefore, we also observed significantly higher values of the ratio of the pulmonary trunk to the aorta for the fetuses wrapped with the umbilical cord around the neck compared with the control group without the umbilical cord around the neck (. Moreover, in the fetuses with one and two coils of the umbilical cord around the fetal neck, an increased amount of amniotic fluid was observed, whereas larger dimensions of CTAR in the fetuses with two coils of the umbilical cord around the neck were present (p < 0.05). The wrapping of the fetus with the umbilical cord around the fetal neck may induce the redistribution of blood flow, leading to fetal heart enlargement and disproportion and may be the cause of polyhydramnios.

Prediction of postnatal abnormal umbilical cord coiling by antenatal evaluation in pregnant women: Diagnostic accuracy study; a systematic review

STUDY OBJECTIVE

Umbilical cord abnormalities increase neonatal morbidity and mortality. Considering uncertainties about the best time of an antenatal ultrasonography scan to evaluate the umbilical coiling index (UCI), this systematic review was designed to assess the diagnostic accuracy value of antenatal ultrasound assessments to predict abnormal postpartum UCI.

METHODS

All observational, cross-sectional, case-control, cohort, and diagnostic accuracy studies up to March 26, 2022, were searched and assessed according to PRISMA guidelines in Ovid, Cochrane, Scopus, PubMed, Web of Science, Embase, Proquest, Science Direct, and Clinical Key databases, and Google Scholar search engine.

RESULTS

The total number of 63 190 documents were retrieved from databases. The duplicates (19 272) were removed, 43 918 articles were screened for relevance, and 56 papers were selected for full-text evaluation, resulting in 14 qualified pieces subjected to the quality CASP tools for each type of study. Finally, six articles were evaluated, extracted, and confirmed. Overall, we had 16 evaluations (11 normal pregnancies, 4 gestational diabetes mellitus, and 1 group at risk for small gestational age), from which 9 and 7 were respectively performed in the second and third trimesters. Most of the evaluations considered both hypocoiling and hypercoiling. The sensitivity, specificity, and area under curves (AUCs) change range between the evaluations were 0.09-0.97, 0.59-0.96, and 0.262-0.84, respectively.

CONCLUSION

Observing any coiling abnormalities in every trimester, both the second and third, is highly sensitive to predicting abnormal postnatal UCI (pUCI). Conclusively, any detected antenatal abnormality is worth attention. Both trimesters' evaluations are essential, and no superiority is seen for any of them. The systematic review revealed statistical and clinical heterogeneity; a meta-analysis was impossible.

Umbilical Cord Diseases Affecting Obstetric and Perinatal Outcomes

BACKGROUND

(1) The aim of this article is to describe the physiopathology underlying umbilical cord diseases and their relationship with obstetric and perinatal outcomes. (2) Methods: Multicenter case series of umbilical cord diseases with illustrations from contributing institutions are presented. (3) Results: Clinical presentations of prenatal ultrasound findings, clinical prenatal features and postnatal outcomes are described. (4) Conclusions: Analysis of our series presents and discusses how umbilical cord diseases are associated with a wide variety of obstetric complications leading to a higher risk of poor perinatal outcomes in pregnancies. Knowing the physiopathology, prenatal clinical presentations and outcomes related to umbilical diseases allow for better prenatal counseling and management to potentially avoid severe obstetric and perinatal complications.

Effect of Extra-abdominal Vein Varix on the Stress Distribution in Umbilical Cord: A Simulation Study

The umbilical cord is a critical structure linking the fetus to the placenta and is surrounded by the amniotic fluid. It is composed of a vein, two arteries coiled around the vein, and Wharton's jelly surrounding the blood vessels. In this study, the stress distribution of the arteries, vein, and Wharton's jelly of an umbilical cord with extra-abdominal umbilical vein varix is analyzed for varying amniotic pressure using finite element analysis. Four diameters are considered for the umbilical vein, 6.5 mm, 11 mm, 15.5 mm, and 20 mm, with 6.5 mm corresponding to the normal vein diameter. The amniotic pressure is varied from 15-105 mmHg in steps of 15 mmHg, to simulate contractions during labour. Stress distribution is obtained and the peak stresses are analyzed. According to the results, the peak stress in the Wharton's jelly and the umbilical vein increases nonlinearly with increasing amniotic pressure. The peak stress in umbilical arteries initially decreases till the amniotic pressure reaches 45 mmHg and thereafter increases. This might be due to asymmetric deformation of the Wharton's jelly at the pressure range below arterial pressure.Clinical Relevance- This study could be useful in understanding the fundamental mechanics of extra-abdominal umbilical vein varix and help in development of better treatment protocols.

Effect of the Presence of Nuchal Cords on Vaginal Breech Labor

OBJECTIVE

Breech delivery has been reported to be associated with a high incidence of abnormal fetal heart rate pattern leading to neonatal asphyxia. In this study, we examined the effect of the presence of nuchal cords on perinatal outcomes of vaginal breech labor.

METHODS

We reviewed the obstetric records of all singleton breech labor cases at the Japanese Red Cross Katsushika Maternity Hospital between 1999 and 2011. Of the 266 breech labor cases in singleton pregnancies, the presence of nuchal cords was recognized in 50 cases (18.8%) on neonatal findings at birth. We compared the clinical characteristics and perinatal outcomes between the breech labor cases with and without nuchal cords. A chi-square test was used for categorical data, and a p-value <0.05 was considered significant.

RESULTS

It was found that the incidence of fetal heart rate abnormality during breech labor or neonatal asphyxia in the deliveries with nuchal cords was not significantly different from that in those without nuchal cords. Also, there was no significant difference in the rate of emergent caesarean delivery between the two labors with and without nuchal cords.

CONCLUSION

The current results suggest that the presence of nuchal cords may not be associated with perinatal outcomes. Our results may become one of several pieces of evidence leading to the alleviation of anxiety in pregnant women with breech presentation and fetal nuchal cords.

True Knot of the Umbilical Cord and Associated Adverse Perinatal Outcomes: A Case Series

An actual knot that forms during pregnancy is known as a true knot of the umbilical cord (TKUC) which is seen in 0.3% to 1.2% of pregnancies. TKUC is noteworthy because it can lead to a variety of adverse perinatal outcomes, including infants with low Apgar scores, small for gestational age (SGA) fetuses, fetal hypoxia, and also in some cases fetal death. Here, we present instances of TKUC of three patients and the various associated perinatal outcomes.

How to Reach the Best Ultrasound Performance in the Delivery Room

Ultrasonography is an instrument that is present in the maternal-fetal assessment throughout pregnancy and with widely documented benefits, but its use in intrapartum is becoming increasingly relevant. From the assessment of labor progression to the assessment of placental disorders, ultrasound can be used to correlate with physiological findings and physical examination, as its benefit in the delivery room cannot yet be proven. There are still few professionals with adequate training for its use in the delivery room and for the correct interpretation of data. Thus, this article aims to present a review of the entire applicability of ultrasound in the delivery room, considering the main stages of labor. There is still limited research in evidence-based medicine of its various possible uses in intrapartum, but it is expected that further studies can bring improvements in the quality of maternal and neonatal health during labor.

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.

Placental and Umbilical Cord Anomalies Diagnosed by Two- and Three-Dimensional Ultrasound

The aim of this review is to present a wide spectrum of placental and umbilical cord pathologies affecting the pregnancy. Placental and umbilical cord anomalies are highly associated with high-risk pregnancies and may jeopardize fetal well-being in utero as well as causing a predisposition towards poor perinatal outcome with increased fetal and neonatal mortality and morbidity. The permanent, computerized perinatology databases of different international centers have been searched and investigated to fulfil the aim of this manuscript. An extended gallery of prenatal imaging with autopsy correlation in specific cases will help to provide readers with a useful iconographic tool and will assist with the understanding and definition of this critical obstetrical and perinatological issue.

Adverse Perinatal Outcomes of True Knot of the Umbilical Cord: A Case Series and Review of Literature

A true knot of the umbilical cord (TKUC) is an actual knot formed in pregnancy. It is seen in approximately 0.3%-1.2% of all pregnancies. True knots are of significance as they can cause a wide spectrum of adverse perinatal outcomes like small for gestational age (SGA) fetus, low appearance, pulse, grimace, activity, and respiration (Apgar) score at birth, fetal hypoxia, and even fetal demise.

Here, we report a case series of three patients with TKUC and the varied adverse perinatal outcomes associated with them. A low-risk primigravida at term gestation had a suspicious non-stress test (NST). Repeat NST after maternal resuscitation became pathological. Emergency cesarean delivery was performed in view of pathological NST persisting despite intrauterine resuscitation. A healthy male baby weighing 2920 g was delivered, and the umbilical cord had a true knot.

A multigravida at 33 + 3 weeks of gestation was referred with fetal growth restriction (FGR). Color Doppler examination showed absent end-diastolic flow (AEDF) in the umbilical artery (UA). Cesarean delivery was performed in view of FGR stage two with AEDF in the UA at 34 weeks of gestation as per the Barcelona criteria. A male baby weighing 1505 g was delivered. The umbilical cord had a true tight knot. The baby had an Apgar score of 7 at one minute after birth but was shifted to the neonatal intensive care unit (NICU) in view of low birth weight and prematurity. The baby slowly gained weight and was discharged from NICU after 15 days in stable condition.

A multigravida at 32 weeks of gestation was referred with intrauterine fetal demise. Ultrasonography confirmed the presence of a single intrauterine dead fetus corresponding to 30 + 4 weeks of gestation with an estimated fetal weight (EFW) of 1633 g, amniotic fluid index (AFI) equal to nine, and presence of Spalding’s sign. Induction of labor was done, and she expelled a dead macerated male fetus weighing 1825 g. The infantogram was normal. A true umbilical cord knot was found.

The umbilical cord is the source of fetal blood supply; therefore, any cord abnormality can have a significant impact on the fetal outcome. There are various factors that can predispose to TKUC, such as polyhydramnios, increased cord length, monoamniotic twins, male baby, grand multiparity, small fetus, and amniocentesis. TKUC can lead to various adverse outcomes in pregnancy and labor like SGA fetus, low Apgar score at birth, fetal hypoxia, and fetal demise. TKUC increases the risk of fetal demise by as much as four times.

With the development of advanced techniques such as three-dimensional/four-dimensional color Doppler ultrasounds, TKUC can be diagnosed antenatally in the form of a four-leaf-clover, a “hanging-noose sign,” or by an unusual multicolor pattern in the cord. The prenatal detection rate of TKUC is only 12%. It mostly remains undetected unless visualized incidentally. Although TKUC is not rare and can have serious outcomes, the importance of its antenatal diagnosis has not been determined. It should be suspected in patients with risk factors, and emphasis should be placed on its antenatal diagnosis on ultrasonography to avoid obstetric disasters in otherwise low-risk females. Though there is no specific management of these cases, a good clinical outcome can be achieved if TKUC is diagnosed antenatally and monitored closely until fetal maturity is attained.

Umbilical Cord Knots: Is the Number Related to Fetal Risk?

True knots of the umbilical cord (UC) are a rare occurrence and are reported in 0.4–1.2% of deliveries. The compression of true knot of the UC can cause obstruction of the fetal circulation, leading to intra-uterine growth retardation or fetal death. Predisposing factors for the genesis of the true UC knot are numerous and include all the conditions, which lead to a relatively large uterine volume. This situation may predispose to free and excessive fetal movements. Although not all true knots lead to perinatal complications, they have been associated with adverse pregnancy outcomes, including fetal distress, fetal hypoxia, intra-uterine growth restriction (IUGR), long-term neurological damage, caesarean delivery and stillbirth. We present a rare case of operative delivery with vacuum in a multiparous woman at term of pregnancy with a double true knot of the UC. As in most cases, the diagnosis was made after delivery, as there were no fetal symptoms during pregnancy. Some authors assume that 3D power sonography may be useful in the diagnosis of true UC knots. However, 3D power Doppler cannot be considered as a definitive method. There are no specific prenatal indications to induce the physician to look for ultrasound signs suggestive of umbilical true knot. Some studies argue that cases of fetal death and fetal risk are directly related to the number of knots. We also support this thesis, even if further observational and retrospective studies are needed to demonstrate it.

The Relationship between Nuchal Cord and Adverse Obstetric and Neonatal Outcomes: Retrospective Cohort Study

Objective: The twisting of the umbilical cord around the fetal neck is a common phenomenon in the delivery room, and despite the lack of univocal evidence of its negative impact on perinatal events, it causes anxiety and stress in patients. The aim of the study was to assess the prevalence of nuchal cord and its impact on adverse obstetric and neonatal outcomes. Methods: We conducted a retrospective cohort study. All patients who gave birth in the clinic within one year (n = 1467) were included in the study group. We compared the prevalence of nuchal cord in distinct subgroups of patients. In the next stage, we estimated the chance of specific perinatal outcomes and compared the neonatal outcomes between groups with and without nuchal cord. Results: Nuchal cord was present in 24% of labors. It was twice as common among patients giving birth vaginally (32.14%) than among patients giving birth by a caesarean section (16.78%, p < 0.001). Nuchal cord was also more frequent in births with meconium-stained amniotic fluid (33.88% vs. 23.34%, p = 0.009). In the group of patients with nuchal cord, we observed a slight increase in the risk of a non-reassuring fetal heart rate trace (OR = 1.55, CI 95% 1.02−2.36) as an indication of the completion of labor by caesarean delivery. We did not note an increase in the risk of completing natural childbirth by vacuum extraction. In the group of nuchal cord patients, there was a higher chance of a serious or moderate neonatal condition in the first minute of life (Apgar 0−7 points) (OR = 2.00, 95% CI = 1.14−3.49). Conclusions: Nuchal cord increases the risk of a caesarean delivery due to a non-reassuring fetal heart rate trace. Nuchal cord increases the chance of a reduced Apgar score (0−7 points) in the first minute of life. The observed relationships do not translate to neonatal arterial blood gas testing.

Clinically Relevant Prenatal Ultrasound Diagnosis of Umbilical Cord Pathology

Umbilical cord abnormalities are not rare, and are often associated with structural or chromosomal abnormalities, fetal intrauterine growth restriction, and poor pregnancy outcomes; the latter can be a result of prematurity, placentation deficiency or, implicitly, an increased index of cesarean delivery due to the presence of fetal distress, higher admission to neonatal intensive care, and increased prenatal mortality rates. Even if the incidence of velamentous insertion, vasa praevia and umbilical knots is low, these pathologies increase the fetal morbidity and mortality prenatally and intrapartum. There is a vast heterogeneity among societies’ guidelines regarding the umbilical cord examination. We consider the mandatory introduction of placental cord insertion examination in the first and second trimester to practice guidelines for fetal ultrasound scans. Moreover, during the mid-trimester scan, we recommend a transvaginal ultrasound and color Doppler assessment of the internal cervical os for low-lying placentas, marginal or velamentous cord insertion, and the evaluation of umbilical cord entanglement between the insertion sites whenever it is incidentally found. Based on the pathological description and the neonatal outcome reported for each entity, we conclude our descriptive review by establishing a new, clinically relevant classification of these umbilical cord anomalies.

Current Resources for Evidence-Based Practice, March 2021

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes a discussion of men's experiences of pregnancy loss and commentaries on reviews focused on the effects of perineal massage on perineal trauma and air pollution and heat exposure on birth outcomes.