The Placenta: Anatomy, Physiology, and Transfer of Drugs

Zakowski, Mark; Herman, N.

doi:10.1016/b978-0-323-05541-3.00004-1

Cited by 10 publications

(6 citation statements)

References 160 publications

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“…Although among anticholinergics, atropine is more effective than glycopyrrolate for HR increase, the placental transfer rate of atropine (F/M ratio; 0.93) is more than glycopyrrolate (F/M ratio; 0.22). Therefore, glycopyrrolate was predicted to be a safe drug to pregnant women because of significantly reduced effects on the fetus [ 15 ]. Glycopyrrolate has a longer duration of action than atropine [ 16 ], and the reduction of gastric juice volume and acidity is more beneficial to pregnant women [ 17 ].…”

Section: Discussionmentioning

confidence: 99%

Comparison of hemodynamic changes between phenylephrine and combined phenylephrine and glycopyrrolate groups after spinal anesthesia for cesarean delivery

Yoon

Cho

Jee

et al. 2012

Korean J Anesthesiol

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BackgroundHypotension remains a common clinical problem of spinal anesthesia for cesarean delivery and phenylephrine is used as a vasopressor to address this. However, phenylephrine reduces maternal cardiac output (CO) due to reflex bradycardia. Glycopyrrolate is safe for the fetus, and increases heart rate (HR). Using a noninvasive measure of CO, we compared maternal hemodynamic changes between the phenylephrine only group (group P) and the phenylephrine plus glycopyrrolate group (group PG).MethodsIn this randomized study, 60 women scheduled for elective cesarean delivery were allocated to group P (n = 30) or group PG (n = 30). In both groups, phenylephrine was infused at 50 µg/min. This infusions stopped if systolic blood pressure (SBP) was higher than the baseline value, and phenylephrine 100 µg was injected if SBP was lower than 80% of the baseline value from spinal anesthesia to delivery. In group PG, glycopyrrolate 0.2 mg was injected intravenously after spinal anesthesia. Hemodynamic parameters, such as SBP, heart rate (HR), stroke volume index (SVI), cardiac index (CI) were measured before and until 15 min after spinal anesthesia.ResultsThere were no significant differences in SBP and SVI compared to the baseline value in each group and between the two groups. HR and CI reduced significantly from 8 min to 15 min in group P compared to the baseline value as well as group PG for each time-point. However, HR and CI were maintained in group PG.ConclusionsThe use of glycopyrrolate added to phenylephrine infusion to prevent hypotension by spinal anesthesia for cesarean delivery was effective in maintaining HR and CI.

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Section: Discussionmentioning

confidence: 99%

Comparison of hemodynamic changes between phenylephrine and combined phenylephrine and glycopyrrolate groups after spinal anesthesia for cesarean delivery

Yoon

Cho

Jee

et al. 2012

Korean J Anesthesiol

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“…It is well known that the normal function of the placenta is the key to optimal fetal growth and development (Longtine & Nelson, 2011). The terminal villi in placenta represent the areas where placental exchange predominates (Zakowski & Herman, 2004), and any modification of their structures could affect placental functions and fetal growth (Zhang et al, 2011). Entire villous surface of the placenta is covered by a continuous layer of multinucleated syncytiotrophoblast, the major fetal surface in contact with maternal blood (Robbins, Skrzypczynska, Zeldovich, Kapidzic, & Bakardjiev, 2010).…”

Section: Discussionmentioning

confidence: 99%

Structural changes, increased hypoxia, and oxidative DNA damage in placenta due to maternal smokeless tobacco use

Kumar

Bastia

Borgohain

et al. 2021

Birth Defects Research

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Background Smokeless tobacco (SLT) consumption during pregnancy is a well‐recognized health risk that causes placental damage including hypoxia and oxidative damage. Although consumption of SLT by women varies from region to region, majority of tea leave pluckers consume SLT for relieving stress and pain. Still, the effects of SLT consumption have not been evaluated in tea garden workers (TGW). While previous studies have attempted to report effects of cigarette smoke using in vitro model, hypoxia‐inducible factor (HIF)‐1α expression in human placentae from pregnant women exposed to SLT has not been previously studied. This study was aimed to explore the effects of SLT consumption on placental structure, expression of HIF‐1α and oxidative DNA damage in sample population of TGW. Methods A total of 51 placentae were collected from SLT users and nonusers (n = 30 and 21, respectively) with full‐term normal delivery, who were involved in the plucking of tea leaves during pregnancy in tea plantation. Low birth weight (LBW, i.e., weight <2,500 g) and normal birth weight (NBW) groups among both SLT user and nonuser were compared for the stated parameters. Placental tissues were processed for transmission electron microscopy (TEM) study and immunohistochemical analysis for the expression of HIF‐1α and 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG). Results Altered ultrastructural characteristics were observed in the tertiary villi of LBW group among SLT users which included endothelial cells protrusion into capillary lumen, degenerated nuclei, significant thickening of trophoblast basement membrane and vasculo‐syncytial membrane, abnormalities of the microvilli, swollen or damaged mitochondria, and dilatation in endoplasmic reticulum cisternae. Furthermore, significant reduction in the perimeter, area, and number of the stromal capillary of the tertiary villi of placenta were found in LBW group as compared with NBW group from the SLT users. Enhanced expression for HIF‐1α and oxidative DNA damage (8‐OHdG) biomarker was observed in SLT users as compared with nonusers. Conclusions Maternal SLT exposure during pregnancy may be associated with villus hypoxia and consequently oxidative DNA damage. It is presumed that deleterious effect of SLT exposure on placenta could result in impairment of placental barrier, and restrict nutrient and oxygen supply from mother to fetus, and thus could be a cause of fetal growth restriction.

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“…However, the anaesthesiologists invariably will try to maintain adequate anaesthetic depth in the mother which may lead to the placental transfer of anaesthetic drugs (opioids, induction agents and inhalational agents), thereby influencing the neonatal outcome. [ 20 ] The foetomaternal ratios of anaesthetic agents suggest minimal transfer across the placenta; however, in category 1 CS when the foetus is already compromised, it may be enough to cause neonatal depression. [ 10 ] Further clinical trials are required to investigate the effect of anaesthetic agents on compromised foetal state.…”

Section: Discussionmentioning

confidence: 99%

Influence of anaesthetic technique on maternal and foetal outcome in category 1 caesarean sections – A prospective single-centre observational study

et al. 2018

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Background and Aims:In category 1 caesarean section (CS), there is limited evidence regarding superior anaesthetic technique. Hence, this study was designed to study the influence of anaesthetic technique on the maternal and foetal outcome.Methods:Patient characteristics, indication for CS, decision-to-delivery interval (DDI), uterine incision-to-delivery time (UIDT), cord blood pH, Apgar scores and neonatal and maternal outcome were noted. Composite endpoint (Apgar score <7, umbilical cord blood pH <7.2, neonatal intensive care unit admission or death) was created for adverse neonatal outcome. Logistic regression was done to assess the influence of confounding factors on the occurrence of adverse neonatal outcome.Results:Of 123 patients who underwent category 1 cesarean section, 114 patients were included for analysis. The DDI and UIDT were comparable. One and 5-min Apgar scores were significantly lower in the group general anaesthesia (GA) than in the group spinal anaesthesia (SA). The umbilical cord blood pH was comparable (7.21 ± 0.15 vs 7.25 ± 0.11 in groups GA and SA, respectively). Neonatal intensive care admission and maternal outcome were comparable in both the groups. Subgroup analysis of patients with foetal heart rate of less than 100 showed that group GA had significantly lower 1-min Apgar scores and umbilical cord blood pH and significantly more neonatal admission and mortality. Binominal logistic regression showed that group GA (odds ratio 2.9, 95% confidence intervals 1.27-6.41) and gestational age were independently associated with adverse neonatal outcome.Conclusion:GA for category 1 CS was associated with increased incidence of adverse neonatal outcome.

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The Placenta: Anatomy, Physiology, and Transfer of Drugs

Cited by 10 publications

References 160 publications

Comparison of hemodynamic changes between phenylephrine and combined phenylephrine and glycopyrrolate groups after spinal anesthesia for cesarean delivery

Comparison of hemodynamic changes between phenylephrine and combined phenylephrine and glycopyrrolate groups after spinal anesthesia for cesarean delivery

Structural changes, increased hypoxia, and oxidative DNA damage in placenta due to maternal smokeless tobacco use

Influence of anaesthetic technique on maternal and foetal outcome in category 1 caesarean sections – A prospective single-centre observational study

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