Umbilical Artery Blood pH Values Research Articles

The implications for advanced maternal age on pregnancy complications and adverse neonatal outcomes

Objective This study aimed to determine the effect of advanced maternal age (AMA) on maternal and neonatal outcomes in pregnant women aged ≥35 years compared with patients aged 30–34 years. Also, we aimed to analyze the risk estimates of potential confounders to identify whether these variables contributed to the development of adverse pregnancy outcomes or not. Methods This retrospective cohort study included 2284 pregnant women aged ≥35 years at the time of delivery who was delivered in a tertiary referral hospital from January 1, 2016, to December 31, 2020. We further classified these women into two subgroups: 35–39 years as early AMA (EAMA), and ≥40 years as very AMA (VAMA). Pregnancy complications and adverse neonatal outcomes were recorded. Results Compared to younger women, pregnant AMA women had significantly higher risks of complicated pregnancies, including a higher risk of gestational diabetes mellitus (GDM, p<0.001), polyhydramnios (p<0.001), cesarean section (p<0.001), stillbirths (p<0.001), major fetal abnormality (p<0.001), preterm delivery (p<0.001), lower birth weight (p<0.001), lower 5-minute Apgar scores (p<0.001), lower umbilical artery blood pH values (p<0.001), neonatal intensive care unit (NICU) admission (p<0.001), and length of NICU stay (p<0.001). Conclusion We found a strong and significant association between VAMA and adverse pregnancy outcomes, including an increased risk of GDM, polyhydramnios, cesarean section, and adverse neonatal outcomes, including a higher risk of stillbirths, preterm delivery, lower birth weight, lower 5-minute Apgar scores, and NICU admission.

The relationship between first-trimester pregnancy-associated plasma protein-A levels and intrapartum fetal distress development.

To investigate the relationship between the development of intrapartum fetal distress and serum pregnancy-associated plasma protein-A (PAPP-A) levels measured during first-trimester aneuploidy screening tests. This retrospective study included 283 uncomplicated pregnancies that resulted in full-term live births via spontaneous labor or with the induction by oxytocin. Cases were divided into two groups based on whether their first-trimester PAPP-A multiple of the median (MoM) levels were ≤0.5 (Group 1, n=75) or >0.5 (Group 2, n=208). As primary end points, the rate of cesarean section (C/S), the rate of C/S due to fetal distress, and the umbilical artery blood pH values in cases of C/S for fetal distress were compared between the two groups. Statistical analyses were performed using the Chi-square test and independent samples t-test. P≤0.05 were considered statistically significant. The mean gestational age at birth and the birth weights were significantly lower in Group 1 than in Group 2 (p=0.002 and p=0.007, respectively). Although the rate of C/S was similar between the groups (p=0.823), the rate of C/S due to fetal distress was significantly higher in Group 1 than in Group 2 (68.4% vs. 42%, respectively; p=0.050) and the mean umbilical artery blood pH value for C/S deliveries indicated by fetal distress was lower (p=0.048) in Group 1 than in Group 2. When the mode of delivery was analyzed according to the application of labor induction, both the C/S delivery rates (31.6% in Group 1 and 31.7% in Group 2; p=0.992) and C/S delivery rates due to fetal distress (66.7% in Group 1 and 46.2% in Group 2; p=0.405) were similar in both groups. Low PAPP-A levels (≤0.5 MoM) in the first trimester are associated with the risk of intrapartum fetal distress development and the likelihood of C/S for fetal distress. Nonetheless, this risk is not affected by labor induction.

The effects of a history of seizures during pregnancy on umbilical arterial blood gas values in pregnant women with epilepsy.

The objective of this study is to investigate if the number of seizures that occur during pregnancy has any effect on umbilical arterial blood gas values at delivery. In total, 55 women who were 37 to 41 weeks pregnant and diagnosed with generalized tonic-clonic epilepsy and 50 pregnant women with similar characteristics but not diagnosed as epileptic were included in this study. The patients diagnosed with epilepsy were divided into two groups: 27 patients with a history of at least 5 epileptic seizures during pregnancy and 28 who had no seizures during pregnancy. All patients diagnosed with epilepsy had a history of caesarean delivery or a caesarean section under general anesthesia on the advice of neurology. Pregnant women in the control group were also chosen from among patients who had a caesarean on account of a previous caesarean delivery. In the cases included in the study, umbilical arterial blood gas sampling was performed immediately after delivery. When the control group without epilepsy was compared with pregnant women who had no history of epileptic seizures during pregnancy, no difference was found in umbilical arterial blood gas values (p>0.05). When patients with a history of 5 or more epileptic seizures during pregnancy were compared with the control group without epilepsy and the patients with epilepsy who had no history of seizures during pregnancy, there was no statistically significant difference (p>0.05), although their umbilical arterial blood pH values were found to be lower, while partial carbon dioxide pressure (pCO2), values were higher and partial oxygen pressure (pO2) values were lower. Taking potential fetal risks into consideration, maternal generalized tonic-clonic epileptic seizures might be worrying. Tonic-clonic seizures that occur during pregnancy appear to be associated with temporary hypoxia. Therefore, monotherapy for seizures and treatment at the lowest effective dose should be administered to women with epilepsy in the preconception and prenatal term.

Relationship Between Oxygen Saturation and Umbilical Cord pH Immediately After Birth

The aim of this study is to determine the relationship between oxygen saturation (SpO(2)) by pulse oximetry levels and umbilical cord arterial pH values in healthy newborns during the first 15 minutes of life. The study was performed with healthy term, appropriate-for-gestational-age newborn infants. The infants were divided in two groups: umbilical cord arterial blood pH value ≤7.19 (group 1) and >7.19 (group 2); SpO(2) levels during the first 15 minutes of life were compared between groups. The study was completed with 129 infants (33 in group 1 and 96 in group 2). A significant correlation was found between first-measured preductal and postductal SpO(2) levels by pulse oximetry and umbilical cord arterial pH values ([r²:0.72(0.62 -0.79); p < 0.001] and [r²:0.32(0.25 - 0.54); p < 0.001], respectively). In group 1, infants had lower SpO(2) levels at both preductal and postductal measurements during the first 11 minutes of life and time to reach ≥90% SpO(2) level was longer compared with infants in group 2. Determination of umbilical arterial blood pH values, in addition to clinical findings and oxygen saturation measurements, might be helpful in deciding the concentration of oxygen and whether or not to continue oxygen supplementation in the delivery room.

The Continuing Value of the Apgar Score for the Assessment of Newborn Infants

Background The 10-point Apgar score has been used to assess the condition and prognosis of newborn infants throughout the world for almost 50 years. Some investigators have proposed that measurement of pH in umbilical-artery blood is a more objective method of assessing newborn infants. Methods We carried out a retrospective cohort analysis of 151,891 live-born singleton infants without malformations who were delivered at 26 weeks of gestation or later at an inner-city public hospital between January 1988 and December 1998. Paired Apgar scores and umbilical-artery blood pH values were determined for 145,627 infants to assess which test best predicted neonatal death during the first 28 days after birth. Results For 13,399 infants born before term (at 26 to 36 weeks of gestation), the neonatal mortality rate was 315 per 1000 for infants with five-minute Apgar scores of 0 to 3, as compared with 5 per 1000 for infants with five-minute Apgar scores of 7 to 10. For 132,228 infants born at term (37 weeks of gest...

Fetal effects of prophylactic ephedrine and maternal hypotension during regional anesthesia for cesarean section

The purpose of this study was to evaluate the effects of a prophylactic intravenous bolus of ephedrine on the incidence and severity of maternal hypotension and on neonatal outcome. Term healthy parturients (n = 122) scheduled for elective repeat cesarean section under regional anesthesia were studied. Ninety-two women received 10 mg ephedrine as a prophylactic intravenous bolus prior to intrathecal epidural local anesthesia. Thirty parturients who served as controls did not receive prophylactic ephedrine. Maternal blood pressures, Apgar scores, and umbilical cord blood acid-base status were evaluated. Sixty-three of 92 women (69%) who received intravenous prophylactic ephedrine prior to regional anesthesia developed hypotension compared to 21 (70%) controls. The mean (+/- SD) lowest systolic blood pressure was similar in both groups (95.6 +/- 12.9 vs. 96 +/- 8.9 mmHg; P = 0.86). The mean (+/-SD) fetal pH was significantly lower with prophylactic ephedrine than controls (7.24 +/- 0.07 vs. 7.28 +/- 0.05; P = 0.001). The frequency of umbilical artery blood pH < 7.20 was 10.6% for the ephedrine group vs. 3.2% for controls (P = 0.024). Among newborns of hypotensive mothers, the frequency of umbilical artery blood pH < 7.20 was 30.2% and 4.6% for the ephedrine and control groups, respectively (P = 0.018). Intravenous prophylaxis with ephedrine did not significantly decrease the frequency of hypotension in women receiving regional anesthesia and resulted in a greater proportion of umbilical artery blood pH values < 7.20.

Fetal Effects of Prophylactic Ephedrine and Maternal Hypotension During Regional Anesthesia for Cesarean Section

The purpose of this study was to evaluate the effects of a prophylactic intravenous bolus of ephedrine on the incidence and severity of maternal hypotension and on neonatal outcome. Term healthy parturients (n = 122) scheduled for elective repeat cesarean section under regional anesthesia were studied. Ninety-two women received 10 mg ephedrine as a prophylactic intravenous bolus prior to intrathecal epidural local anesthesia. Thirty parturients who served as controls did not receive prophylactic ephedrine. Maternal blood pressures, Apgar scores, and umbilical cord blood acid-base status were evaluated. Sixty-three of 92 women (69%) who received intravenous prophylactic ephedrine prior to regional anesthesia developed hypotension compared to 21 (70%) controls. The mean (±SD) lowest systolic blood pressure was similar in both groups (95.6 ± 12.9 vs. 96 ± 8.9 mmHg; P = 0.86). The mean (±SD) fetal pH was significantly lower with prophylactic ephedrine than controls (7.24 ± 0.07 vs. 7.28 ± 0.05; P = 0.001). The frequency of umbilical artery blood pH < 7.20 was 10.6% for the ephedrine group vs. 3.2% for controls (P = 0.024). Among newborns of hypotensive mothers, the frequency of umbilical artery blood pH < 7.20 was 30.2% and 4.6% for the ephedrine and control groups, respectively (P = 0.018). Intravenous prophylaxis with ephedrine did not significantly decrease the frequency of hypotension in women receiving regional anesthesia and resulted in a greater proportion of umbilical artery blood pH values < 7.20.

Fetal acidemia associated with regional anesthesia for elective cesarean delivery

To determine the prevalence, magnitude, and type of fetal acidemia associated with contemporary obstetric anesthetic techniques. Umbilical artery blood gases were obtained in 1601 singleton pregnancies delivered by elective cesarean. General anesthesia was used in 371 (23%) women, epidural in 286 (18%), combined spinal-epidural in 659 (41%), and spinal in 231 (14%). Approximately 18% of infants exposed to regional anesthetics had umbilical artery blood pH values 7.19 or less, 42 (3%) infants had pH values less than 7.10, and nine (1%) had values 6.99 or less. The incidence of fetal acidemia was greater in spinal and combined spinal-epidural procedures compared to epidural anesthetics. Fetal acidemia was predominantly respiratory in type because carbon dioxide pressure was abnormally increased when fetal acidemia was diagnosed. Regional anesthesia is associated with fetal acidemia, occasionally severe, and has features of an acute respiratory type of acidemia. Fetal acidemia is less frequent with epidural anesthesia compared to subarachnoid techniques.

Prophylactic intrapartum amnioinfusion: A randomized clinical trial

Amnioinfusion was performed in a prospective, randomized trial of 60 women in the latent phase of labor with oligohydramnios, as defined by an amniotic fluid index ≤5.0 cm. All fetuses were at least 37 weeks' gestational age, had normal baseline fetal heart rate variability, and no clinically significant fetal heart rate decelerations at the outset. Subjects in the amnioinfusion group ( n = 30) were titrated to and maintained at an amniotic fluid index level ≥8.0 cm throughout labor. In the group receiving amnioinfusion, significantly lower rates of meconium passage ( p = 0.04), severe variable decelerations ( p = 0.04), end-stage bradycardia ( p = 0.05), and operative delivery for fetal distress ( p = 0.002) occurred. Significantly higher umbilical arterial blood pH values were also noted in the infusion group ( p = 0.02). We conclude that prophylactic intrapartum amnioinfusion is an important technique for the reduction of intrapartum morbidity.

Induction of labour: The effect of vaginal prostaglandin or i.v. oxytocin — a matter of time only?

Ninety-one pregnant women with unfavourable cervix (Bishop score no higher than 6) were randomly allocated to induction of labour with either prostaglandin E 2 suppositories 2.5 mg 1–2 a day or i.v. oxytocin 4–32 mU/min. The induction procedure was carried on for 2 days. For statistical comparison of efficacy, life table analysis and the logrank test were used with vaginal delivery as the aimed ‘event’. Prostaglandin suppositories were more efficient after 12 h (p < 0.025) and 24 h (p < 0.005), whereas no difference in efficacy was observed after 48 h. Vaginal delivery was obtained within 48 h in 74% of the women in the prostaglandin group and in 70% in the oxytocin group. No difference was observed in methods of delivery or neonatal Apgar scores, though, in neonates delivered vaginally within 2 days, lowered umbilical artery blood pH values were found after prostaglandin E 2 suppositories (p < 0.05). The patients attitude toward the method of induction was highly in favour of the prostaglandin suppositories. Prostaglandin E 2 suppositories are considered excellent for induction of labour if delivery has to be within 24 h, whereas the two methods are equally effective after 48 h.

Prophylactic intrapartum amnioinfusion: A randomized clinical trial

Amnioinfusion was performed in a prospective, randomized trial of 60 women in the latent phase of labor with oligohydramnios, as defined by an amniotic fluid index less than or equal to 5.0 cm. All fetuses were at least 37 weeks' gestational age, had normal baseline fetal heart rate variability, and no clinically significant fetal heart rate decelerations at the outset. Subjects in the amnioinfusion group (n = 30) were titrated to and maintained at an amniotic fluid index level greater than or equal to 8.0 cm throughout labor. In the group receiving amnioinfusion, significantly lower rates of meconium passage (p = 0.04), severe variable decelerations (p = 0.04), end-stage bradycardia (p = 0.05), and operative delivery for fetal distress (p = 0.002) occurred. Significantly higher umbilical arterial blood pH values were also noted in the infusion group (p = 0.02). We conclude that prophylactic intrapartum amnioinfusion is an important technique for the reduction of intrapartum morbidity.

Diagnosis of birth asphyxia on the basis of fetal pH, Apgar score, and newborn cerebral dysfunction

Imprecise diagnosis of birth asphyxia coupled with uncertainties about causal factors for neurologic abnormalities in the newborn have greatly fueled the current litigation crisis in obstetrics. Our goal was to more precisely define birth asphyxia based on fetal condition as measured by umbilical artery blood pH, Apgar scores, and neurologic condition of newborns. We selected for study 2738 patients with singleton pregnancies with cephalic presentations who were delivered of infants at term to avoid complications such as prematurity, which may affect infant outcome independent of birth condition. The basis for study of these particular patients were defined criteria for high risk and an indicated arterial cord pH value. A total of five infants demonstrated cerebral dysfunction as evidenced by seizures during the neonatal period. Infection was linked to seizures in three of these infants; one infant had neonatal asphyxia and only one infant's clinical course could be attributed solely to birth events (uterine rupture). Stratification of umbilical artery blood pH values, Apgar scores, and combinations of these dependent variables in relation to newborn clinical outcomes revealed that infants must be severely depressed at delivery before birth asphyxia can be reliably diagnosed. Such depression includes Apgar scores <_3 at 1 and 5 minutes plus umbilical artery pH values <7.00.

Blood pressure values in the arm and calf of normal newborns and those with coarctation of the aorta : Myung K. Park M.D. and Da-Hae Lee M.D., Department of Pediatrics, University of Texas Medical School, San Antonio, Tx. U.S.A.

The aim of this study is to determine the relationship between oxygen saturation (SpO2) by pulse oximetry levels and umbilical cord arterial pH values in healthy newborns during the first 15 minutes of life.The study was performed with healthy term, appropriate-for-gestational-age newborn infants. The infants were divided in two groups: umbilical cord arterial blood pH value ≤7.19 (group 1) and >7.19 (group 2); SpO2 levels during the first 15 minutes of life were compared between groups.The study was completed with 129 infants (33 in group 1 and 96 in group 2). A significant correlation was found between first-measured preductal and postductal SpO2 levels by pulse oximetry and umbilical cord arterial pH values ([r²:0.72(0.62 -0.79); p < 0.001] and [r²:0.32(0.25 – 0.54); p < 0.001], respectively). In group 1, infants had lower SpO2 levels at both preductal and postductal measurements during the first 11 minutes of life and time to reach ≥90% SpO2 level was longer compared with infants in group 2.Determination of umbilical arterial blood pH values, in addition to clinical findings and oxygen saturation measurements, might be helpful in deciding the concentration of oxygen and whether or not to continue oxygen supplementation in the delivery room.

FETAL-NEONATAL STATUS FOLLOWING CAESAREAN SECTION FOR FETAL DISTRESS

Fetal biochemical and neonatal clinical data were compiled in 126 emergency Caesarean sections performed for fetal distress. The choice of anaesthetic technique was determined by the wishes of the mother. General anaesthesia was administered to 71 parturients and regional analgesia to 55 (subarachnoid block 33, extension of extradural block 22). The aetiologies of fetal distress and the skin incision-delivery and uterine incision-delivery intervals were not significantly different between the two anaesthesia groups. Umbilical artery blood pH values were higher than the last scalp capillary blood pH values in 63% of the general anaesthesia and in 80% of the regional analgesia cases. Umbilical vein and artery blood-gas and pH data were similar in the two anaesthesia groups, but 1-min Apgar scores were significantly better following regional analgesia. Despite the presence of fetal distress, subarachnoid blockade was a most suitable method of anaesthesia in experienced hands.