Prevalence, Risk Factors, and Perinatal Outcomes of Velamentous Umbilical Cord Insertion in Twin Pregnancies: A Single-Center Retrospective Study

BACKGROUND

The effect of velamentous cord insertion (VCI) on perinatal outcomes in twin pregnancies is unclear due to conflicting findings. This retrospective study aimed to examine VCI prevalence and related risk factors in twin pregnancies and its association with adverse perinatal outcomes.

METHODS

Women with twin pregnancies who delivered between January 2012 and December 2021 in a single tertiary hospital were included. The participants were divided into dichorionic (DC) and monochorionic diamniotic (MCDA) groups, and their maternal and fetal characteristics and VCI rates were compared. Logistic regression models were used to identify risk factors for VCI and VCI-related perinatal outcomes.

RESULTS

Among the 694 twin pregnancies included in this study, the VCI rate was significantly higher in MCDA than in DC twins. Body mass index and MCDA twins were significant risk factors for VCI, whereas assisted reproductive technology pregnancy was a significant protective factor against VCI. In DC twins, VCI did not affect perinatal outcomes. In MCDA twins, VCI was a significant risk factor for fetal growth restriction, twin-to-twin transfusion syndrome, and preterm birth at <36 weeks.

CONCLUSIONS

VCI was a prominent risk factor for adverse perinatal outcomes only in MCDA twins. Antenatal sonographic assessment of the umbilical cord insertion site would be beneficial.

Impact of the interpregnancy interval after cesarean delivery on subsequent perinatal risks: a retrospective study

PURPOSE

To assess the impact of the interpregnancy interval (IPI) after cesarean delivery on the risks of adverse perinatal events during subsequent pregnancies.

METHODS

We retrospectively examined perinatal outcomes of subsequent pregnancies of women whose most recent birth experience involved cesarean delivery at our hospital between January 2014 and December 2019. IPI was defined as the time between live birth and subsequent conception. Three IPI groups: < 18 months, 18-60 months, and > 60 months, were assessed. The risks of preterm birth, preeclampsia, placenta previa, placental abruption, fetal growth restriction, and successful vaginal birth were compared among the three IPI groups using uni- and multivariate analyses.

RESULTS

We registered 592 births after cesarean delivery: 178, 288, and 126 in the IPI < 18 months, 18-60 months, and > 60 months groups, respectively. The groups did not differ significantly regarding perinatal outcomes. The multivariate analysis revealed no significant differences in the risks of adverse perinatal outcomes among all groups. The odds ratios (ORs) for preterm birth at < 37 weeks of gestation were 1.24 and 1.64 for those in the < 18 months and > 60 months groups, respectively (P = 0.362 and P = 0.055, respectively). The groups did not differ significantly regarding vaginal birth success rate (ORs 1.72 for the < 18 months group, 0.49 for the > 60 months group; P = 0.486 and P = 0.446, respectively).

CONCLUSION

After cesarean delivery, IPIs shorter than 18 months and longer than 60 months do not significantly impact the risks of adverse perinatal outcomes or successful vaginal birth compared with IPIs of 18-60 months.

Maternal Renal Dysfunction in Late Pregnancy in Twin and Singleton Pregnancies: Retrospective Study

This study aimed to evaluate the differences in the impact on maternal renal function between singleton and twin pregnancies in the second half of pregnancy. It retrospectively enrolled 1711 pregnant women consisting of 1547 singleton pregnancies and 164 twin pregnancies from Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital from January 2019 to June 2021. Patients underwent renal function tests (serum blood urea nitrogen, creatinine, and estimated glomerular filtration rate (eGFR)) at least one month before delivery. The main outcome measure was maternal renal dysfunction, defined as a serum creatinine level above 0.8 mg/dL. The serum creatinine level was significantly higher and the eGFR was significantly lower in twin than in singleton pregnancies (p < 0.001). In addition, the rate of renal dysfunction was significantly higher in twin than in singleton pregnancies (7.9% vs. 2.6%; p < 0.01). Multivariate analysis revealed that twin pregnancy (odds ratio (OR) 3.38), nulliparity (OR 2.31), and preeclampsia (OR 3.64) were significant risk factors for maternal renal dysfunction. Maternal renal dysfunction was observed in 13 twin pregnancies, all of which recovered to within normal limits during the early months of the postpartum period. Twin pregnancy is a significant risk factor for maternal renal dysfunction; renal function should be carefully monitored in twin pregnancies.

Evaluation of the risk factors for antepartum hemorrhage in cases of placenta previa: a retrospective cohort study

Objective

The aim of this study was to examine the risk factors for antepartum hemorrhage (APH) in women with placenta previa.

Methods

In this retrospective cohort study, we analyzed the medical records of 233 women with singleton pregnancies presenting with placenta previa whose deliveries were performed at our hospital between January 2009 and July 2018.

Results

Of the 233 women included in this study, 130 (55.8%) had APH. In the APH group, the gestational age and neonatal birth weight were significantly lower compared with the no hemorrhage group. Maternal age <30 years and multiparity were identified as significant risk factors for APH in both the univariate and multivariate analyses. Focusing on the previous route of delivery in multiparous women, the risk of APH was significantly higher in multiparous women who had experienced at least one vaginal delivery compared with nulliparous women (adjusted odds ratio (OR): 3.42 [95% confidence interval: 1.83–6.38]).

Conclusion

We showed that women with placenta previa who were under 30 years old and who had a history of vaginal delivery may be at significant risk of experiencing APH.

Evaluation of the risk of umbilical cord prolapse in the second twin during vaginal delivery: a retrospective cohort study

OBJECTIVE

This study aimed to evaluate the success rate of vaginal delivery, the reasons for unplanned caesarean delivery, the rate of umbilical cord prolapse and the risk of umbilical cord prolapse in twin deliveries.

DESIGN

Retrospective cohort study.

SETTING

Single institution.

PARTICIPANTS

This study included 455 women pregnant with twins (307 dichorionic and 148 monochorionic) who attempted vaginal delivery from January 2009 to August 2018. The following criteria were considered for vaginal delivery: diamniotic twins, cephalic presentation of the first twin, no history of uterine scar, no other indications for caesarean delivery, no major structural abnormality in either twin and no fetal aneuploidy.

RESULTS

The rate of vaginal delivery of both twins was 89.5% (407 of 455), caesarean delivery of both twins was 7.7% (35 of 455) and caesarean delivery of only the second twin was 2.9% (13 of 455). The major reasons for unplanned caesarean delivery were arrest of labour and non-reassuring fetal heart rate pattern. The rate of umbilical cord prolapse in the second twin was 1.8% (8 of 455). Multivariate analysis revealed that abnormal umbilical cord insertion in the second twin (velamentous or marginal) was the only significant factor for umbilical cord prolapse in the second twin (OR, 5.05, 95% CI 1.139 to 22.472, p=0.033).

CONCLUSIONS

Abnormal umbilical cord insertion in the second twin (velamentous or marginal) was a significant factor for umbilical cord prolapse during delivery. Antenatal assessment of the second twin's umbilical cord insertion using ultrasonography would be beneficial.

The efficacy of therapeutic cervical cerclage in singleton pregnancies: a retrospective study

OBJECTIVES

We compared the pregnancy prolongation effect attributable to cervical cerclage to that achieved by conservative management, and determined the cervical length for which cervical cerclage is effective.

METHODS

We retrospectively examined medical records of 281 women admitted to our hospital between January 2013 and December 2017 for management of threatened preterm birth at 22-28 weeks of gestation. Obstetricians determined suitability for cervical cerclage, which was performed using the McDonald procedure in all cases. Of the 281 subjects, 71 underwent cervical cerclage (cerclage group); the other 210 received conservative therapy (non-cerclage group). We recorded maternal and neonatal characteristics of all patients. The two groups were compared in terms of length of extension of pregnancy and weeks of gestation at delivery. Multivariate analysis was performed to identify factors associated with extension of time to delivery.

RESULTS

Our analyses revealed that the cerclage group was hospitalized earlier in pregnancy than the non-cerclage group (23.7 ± 1.5 weeks vs. 26.4 ± 1.9 weeks, p < .001) and had shorter cervixes (6.0 ± 9.4 mm vs. 16.9 ± 13.0 mm, p < .001). The two groups did not differ significantly in terms of gestational weeks at delivery. Multivariate analysis regarding extension of pregnancy revealed significant differences in extension of pregnancy related with cervical cerclage (26.65 days, 95% CI 17.0 - 36.3, p < .001) and cervical length <10 mm (-27.4 days, 95% CI -36.0--18.8, p < .001). While the time to delivery was extended by cervical cerclage in women with short cervixes (<25 mm), the two groups did not differ when cervical length was ≥15 mm.

CONCLUSIONS

Cervical cerclage was a significant positive factor and short cervix was a significant negative factor for elongating pregnancy. In primigravida and multigravida women with no history of preterm birth, when the cervix is short (<10 mm), cervical cerclage should be recommended.

Factors associated with intrapartum cesarean section in women aged 40 years or older: a single-center experience in Japan

Objective: To elucidate the efficacy and safety of attempting a vaginal birth and to understand the factors that contribute to the increased risk of operative delivery in women aged 40 years or older.Methods: A database of the Japanese Red Cross Nagoya Daiichi Hospital was reviewed to identify women aged 40 years or older with singleton, vertex, and vital pregnancies who attempted vaginal delivery at and after 37 + 0 gestational weeks between January 2011 and December 2016.Results: A total of 415 women met the criteria for inclusion in this study, including 372 and 43 women who gave birth by vaginal delivery and by intrapartum cesarean section (CS), respectively. Vaginal delivery was observed in 84.1% (201/239) and 97.2% (171/176) of nulliparous and multiparous women, respectively. In a logistic regression model, nulliparity [odds ratio (OR), 5.18; 95% confidence interval (CI), 1.91-14.00], assisted reproductive technology (OR, 2.83; 95% CI, 1.42-5.62), and admission for induction of childbirth (OR, 2.68; 95% CI, 1.08-6.67) were associated with a higher likelihood of intrapartum CS. Of 372 women who delivered vaginally, 62 women needed operative delivery. Operative delivery was necessary for 25.4% (51/201) and 6.4% (11/171) of nulliparous and multiparous women, respectively. A logistic regression model identified nulliparity (OR, 3.91; 95% CI, 1.89-8.08) and administration of ecbolic (OR, 2.49; 95% CI, 1.21-5.10) as being independent factors associated with vacuum extraction.Conclusions: Maternal age 40 years or older should not be a barrier for attempting a vaginal delivery, and those women should be encouraged to attempt a vaginal delivery.

The impact of the abruption severity and the onset-to-delivery time on the maternal and neonatal outcomes of placental abruption

Objective: We examined the impact of the abruption severity and the onset-to-delivery time on the maternal and neonatal outcomes of cases of clinically diagnosed placental abruption (PA).Material and methods: We investigated 84 patients who were diagnosed with PA at our hospital from January 2009 to September 2017. We classified the patients with PA into three groups based on the extent of the abruption: (1) mild abruption, <20%; (2) moderate abruption, 20-49%; (3) severe abruption, ≥50%, which was defined by the attending obstetricians at the time of delivery. The neonatal outcome was measured by the umbilical artery pH and the maternal outcome was measured by the obstetric disseminated intravascular coagulation score (DIC score).Results: The rate of hypertensive disorders of pregnancy in the moderate abruption group was significantly lower than that in other groups (p = .010). The umbilical artery pH was below 7.00 in 29 cases. The umbilical artery pH of the severe abruption group (6.92) was the lowest and was significantly lower in comparison to other groups (mild group [7.24], p < .001; moderate group [7.11], p < .05). There was a significant correlation between the onset-to-delivery time and the umbilical artery pH in the moderate group (R = -0.43). The maternal DIC scores in the three groups did not differ to a statistically significant extent.Conclusions: The severity of placental separation is significantly correlated with poor neonatal outcomes and there was a significant negative correlation between the onset-to-delivery time and the umbilical artery pH in moderate abruption.

Continuous amnioinfusion in women with PPROM at periviable gestational ages

Objective: To elucidate the efficacy of continuous amnioinfusion on perinatal outcome in women with preterm premature rupture of membranes (PPROM) at periviable gestational ages.Methods: A database was reviewed to identify women with singleton pregnancies who were admitted to the Japanese Red Cross Nagoya Daiichi Hospital due to PPROM before 26 + 0-week gestation between July 2009 and July 2017.Results: A total of 81 women met the criteria for inclusion in this study including 70 and 11 women with and without amnioinfusion, respectively. The latency period between PPROM and delivery was significantly longer in women who underwent amnioinfusion compared with women without amnioinfusion (median: 13 versus 4 days, p < .001). In the survival analysis, the number of women who remained undelivered was significantly higher in the amnioinfusion group than in the non-amnioinfusion group for each gestational age after PPROM (p < .001). Cox's proportional hazards analysis with stepwise backward selection showed that both white blood cell counts on admission and amnioinfusion finally remained as variables that affected the time interval between PPROM and delivery [hazard ratio (95% confidence interval): 1.12 (1.06-1.18) and 0.34 (0.12-0.98), respectively].Conclusions: Continuous amnioinfusion in women with PPROM at periviable gestational ages resulted in significant prolongation of pregnancy and may help improve neonatal outcomes.

Factors associated with delivery at or after 28 weeks gestation in women with bulging fetal membranes before 26 weeks gestation

OBJECTIVE

To elucidate the factors that contribute to prolonged pregnancy and promote neonate survival in women with bulging fetal membranes.

METHODS

A database was reviewed to identify women with singleton pregnancies who underwent amniocentesis on admission to determine amniotic fluid neutrophil elastase levels before 26 + 0 weeks gestation between July 2001 and January 2015. Following delivery, the placentas of these patients were examined for histologic chorioamnionitis.

RESULTS

Ninety-seven women delivered before 28 weeks gestation, and 117 women delivered at or after 28 weeks gestation. Rescue cerclage performed via the McDonald procedure (adjusted odds ratio [aOR]: 3.78; 95% confidence interval [CI]: 1.35-11.80) was associated with a higher likelihood of reaching at least 28 weeks gestation before delivery, whereas protruding membranes (aOR: 0.38; 95% CI: 0.18-0.78), elevated amniotic neutrophil elastase levels (≥0.15 μg/ml) (aOR, 0.41; 95% CI: 0.20-0.82) and elevated peripheral C-reactive protein levels (≥0.4 mg/dl) (aOR: 0.34; 95% CI: 0.180.65) were associated with a significantly reduced likelihood of reaching this gestational age before delivery. Among women who underwent rescue cerclage, amniorrhexis was associated with a negative prognosis (aOR: 0.18; 95% CI: 0.05-0.51).

CONCLUSIONS

Intra-amniotic inflammation, protrusion of fetal membranes and amniorrhexis are factors that may prevent pregnancy prolongation. Rescue cerclage improves pregnancy outcomes.

Effects of seasonal changes in dietary energy on body weight of captive Japanese macaques (Macaca fuscata)

Food availability varies seasonally for wild animals, and body weight fluctuates accordingly in the wild. In contrast, controlling availability of diet under captive condition is difficult from keepers' standpoint, and monotonous diet often causes health problems in captive animals. We evaluated the effects of a seasonally controlled diet on body weight of captive Japanese macaques (Macaca fuscata) in an outside enclosure at Ueno Zoo, Tokyo, Japan. We fed a high-energy diet in spring and fall, and a more restricted diet in summer and winter for 3 years (2011-2013). Seasonal changes in body weight were similar to those that occur in wild macaques: for both sexes, body weight was higher in spring and fall and lower in winter. A decrease in body weight between fall and winter occurred only in adults, which implied that reducing dietary intake in winter had a more severe effect on adults than on juveniles. Different from wild populations, the body weight of captive macaques did not decrease between spring and summer, which we attributed to a lack of movement within the enclosure and to excess energy intake in summer. In addition to controlling dietary composition, providing large enclosure with complex structure and making efforts of giving unpredictability in feeding are necessary to motivate the captive animals to be more active, which would cause the macaques to show seasonal change in body weight, which is found in wild.

Divergent selection for opsin gene variation in guppy (Poecilia reticulata) populations of Trinidad and Tobago

The guppy is known to exhibit remarkable interindividual variations in spectral sensitivity of middle to long wavelength-sensitive (M/LWS) cone photoreceptor cells. The guppy has four M/LWS-type opsin genes (LWS-1, LWS-2, LWS-3 and LWS-4) that are considered to be responsible for this sensory variation. However, the allelic variation of the opsin genes, particularly in terms of their absorption spectrum, has not been explored in wild populations. Thus, we examined nucleotide variations in the four M/LWS opsin genes as well as blue-sensitive SWS2-B and ultraviolet-sensitive SWS1 opsin genes for comparison and seven non-opsin nuclear loci as reference genes in 10 guppy populations from various light environments in Trinidad and Tobago. For the first time, we discovered a potential spectral variation (180 Ser/Ala) in LWS-1 that differed at an amino acid site known to affect the absorption spectra of opsins. Based on a coalescent simulation of the nucleotide variation of the reference genes, we showed that the interpopulation genetic differentiation of two opsin genes was significantly larger than the neutral expectation. Furthermore, this genetic differentiation was significantly related to differences in dissolved oxygen (DO) level, and it was not explained by the spatial distance between populations. The DO levels are correlated with eutrophication that possibly affects the color of aquatic environments. These results suggest that the population diversity of opsin genes is significantly driven by natural selection and that the guppy could adapt to various light environments through color vision changes.

Ultrasonic-induced nucleation of ice in water containing air bubbles

Cavitation induced by ultrasonic vibrations can cause nucleation of ice in supercooled water. In this study, the time required for ultrasonic-induced nucleation of ice was measured for water containing two different size distributions of air bubbles. When the water was supersaturated with air bubbles, there was a time lag of about 0.5 s between the onset of ultrasonic irradiation and the onset of ice nucleation, and the probability of ice nucleation was unusually high within 0.5-1.1 s after the onset of ultrasonic irradiation. These results cannot be explained by conventional models alone, in which the collapse of a cavitation bubble triggers the nucleation of ice. Secondary effects appear to also influence ice nucleation.

Mitosis-specific phosphorylation of smooth muscle regulatory light chain of myosin II at Ser-1 and/or -2 and Thr-9 in sea urchin egg extract

We analyzed the kinase activities capable of phosphorylating the regulatory light chain of myosin-II (MRLC) from chicken gizzard in unfertilized and fertilized sea urchin egg extracts. Total kinase activity phosphorylating MRLC in vitro did not fluctuate throughout the first cell cycle. Phosphopeptide mapping analysis showed that MRLC was phosphorylated at two different sites corresponding to myosin light chain purified from chicken gizzard (MLCK) and protein kinase C (PKC) phosphorylation sites, namely MLCK and PKC sites, respectively. The activity of the kinase(s) responsible for phosphorylation of MRLC at PKC sites showed a significant increase at metaphase. Phosphoamino acid analysis revealed that this increase in MRLC phosphorylation was due to phosphorylation at serine residue (Ser-1 and/or Ser-2) and a threonine residue (Thr-9). This increase in phosphorylation at PKC sites is occurred concomitantly with an increase in histone H1 kinase activity. In contrast, MRLC phosphorylation at MLCK sites showed no significant changes during the first cell cycle. Butyrolactone I, a selective inhibitor of p34cdc2 kinase, inhibited the activity of the kinase(s) responsible for phosphorylation of MRLC at PKC sites at metaphase. These results suggest that the increase in MRLC phosphorylation at PKC sites (Ser-1 and/or -2, and Thr-9) at metaphase may be induced by p34cdc2 kinase. Thus, p34cdc2 kinase may be involved in the regulation of MRLC phosphorylation during cell division.

Detection of beta-1,2-mannosyltransferase in Candida albicans cells

A particulate insoluble fraction from Candida albicans J-1012 (serotype A) strain cells was obtained as the residue after extracting a 105,000 x g pellet of cell homogenate with 1% Triton X-100. Incubation of this fraction with a mannopentaose, Man beta 1-->2Man alpha 1-->(2Man alpha 1-->)(2)2Man (alpha beta Man5), in the presence of GDP-mannose followed by high performance liquid chromatography showed the formation of a mannohexaose. Analysis of the product by 1H NMR indicates that alpha beta Man5 was changed to Man beta 1-->2Man beta 1-->2Man alpha 1-->(2Man alpha 1-->)2 2Man (alpha beta Man6). This beta-1,2-mannosyltransferase (ManTase) II activity was completely inhibited by Zn2+ and was not restored by the addition of EDTA. The corresponding enzyme fraction from C. albicans NIH B-792 (serotype B) strain cells, the mannan of which does not possess both the alpha beta Man5 and alpha beta Man6 side chains, also exhibited the same beta-1,2-ManTase II activity.

Etiology of idiopathic scoliosis

The following investigations concerning scoliosis are in progress at Tokushima University: (1) a study of the incidence of equilibrial dysfunction; (2) a study of the nature of dysequilibrium, with special reference to the origin (functional or organic); (3) a field survey of scoliosis associated with equilibrial dysfunction in school children; (4) a study of experimental and clinical metabolic disturbances in scoliosis; (5) a study of postural reflex in experimental animals; (6) a study of scoliosis in animals with experimentally produced brain stem lesions; and (7) a study of scoliosis in animals with experimentally produced lesions in the posterior part of the hypothalamus. The hypothetic assumption is that dysfunction of the postural reflex regulation induced by functional or organic disorders at the brain stem center may play an important part in the development of idiopathic scoliosis during the period of rapid growth in children.