Prediction of maternal and fetal pharmacokinetics of indomethacin in pregnancy.

AIMS: Indomethacin is used for the treatment of preterm labour, short cervices and idiopathic polyhydramnios during pregnancy. Few studies have described the pharmacokinetics (PK) of indomethacin during pregnancy. This study aimed to determine maternal and fetal PK of indomethacin during different trimesters of pregnancy using physiologically based PK (PBPK) modelling and simulations. METHODS: Full PBPK simulations were performed in nonpregnant subjects and pregnant subjects from each trimester of pregnancy at steady state using Simcyp's healthy volunteers and pregnancy PBPK model, respectively. The fetal exposures were predicted using a fetoplacental pregnancy PBPK model. The models were verified by comparing PBPK-based predictions with observed PK profiles. RESULTS: Predicted exposure (AUC0-6h ) and clearance of indomethacin in nonpregnant women and pregnant women are similar to the clinical observations. AUC0-6h of indomethacin is approximately 14, 24 and 32% lower, consistent with 18, 34 and 52% higher clearance in the first, second and third trimesters of pregnancy, respectively, compared to nonpregnant women. Predicted fetal plasma exposures increased by approximately 30% from the second trimester to the third trimester of pregnancy. CONCLUSION: A mechanistic PBPK model adequately described the maternal and the fetal PK of indomethacin during pregnancy. As the pregnancy progresses, a modest decrease (≤32%) in systemic exposures in pregnant women and a 33% increase in fetal exposures to indomethacin were predicted. Higher fetal exposures in the third trimester of pregnancy may pose safety risks to the fetus. Additional studies are warranted to understand the exposure-response relationship and provide appropriate dosing recommendations during pregnancy that consider both safety and efficacy.

Amniotic fluid embolism: principles of early clinical management.

Amniotic fluid embolism is an uncommon, but potentially lethal, complication of pregnancy. Because amniotic fluid embolism usually is seen with cardiac arrest, the initial immediate response should be to provide high-quality cardiopulmonary resuscitation. We describe key features of initial treatment of patients with amniotic fluid embolism. Where available, we recommend performing transthoracic or transesophageal echocardiography as soon as possible because this is an easy and reliable method of identifying a failing right ventricle. If such failure is identified, treatment that is tailored at improving right ventricular performance should be initiated with the use of inotropic agents and pulmonary vasodilators. Blood pressure support with vasopressors is preferred over fluid infusion in the setting of severe right ventricular compromise. Amniotic fluid embolism-related coagulopathy should be managed with hemostatic resuscitation with the use of a 1:1:1 ratio of packed red cells, fresh frozen plasma, and platelets (with cryoprecipitate as needed to maintain a serum fibrinogen of >150-200 mg/dL). In cases that require prolonged cardiopulmonary resuscitation or, after arrest, severe ventricular dysfunction refractory to medical management, consideration for venoarterial extracorporeal membrane oxygenation should be given.

Acute Management of Ischemic Stroke During Pregnancy.

Acute stroke in pregnancy can be devastating. Although neurologists will at some point be involved in the management, most of these patients are likely to first be evaluated by an obstetric care provider. It is, therefore, important for obstetric care providers to have an understanding of the presentation and management of stroke, particularly in the initial period when the window of opportunity for therapy is critical. Once suspected, a head computed tomography (CT) without contrast media should be performed without delay to rule out a hemorrhagic component. Patients presenting within 4.5 hours of symptom onset and with an initial normal head CT scan are candidates for alteplase (tissue plasminogen activator [tPA]). Blood pressure (BP) control is paramount when administering tPA. During pregnancy, we recommend maintaining a BP between 140-160/90-110 mm Hg during tPA treatment. Pregnancy should not be a contraindication for mechanical thrombectomy in carefully selected patients. The use of therapeutic anticoagulation during the acute management of ischemic stroke is not indicated owing to an increased risk of hemorrhagic transformation. Supportive therapy should include aggressive treatment of fever, avoidance of hypotonic maintenance fluids, and maintenance of normal serum sodium levels. Serum glucose levels should be kept between 140 and 180 mg/dL. Antiplatelet agents are indicated for secondary prevention. The management of cerebral venous sinus thrombosis, carotid and vertebral dissections, and reversible cerebral vasoconstrictive disease should overall follow same guidelines as for nonpregnant individuals.

Transabdominal recordings of fetal heart rate in extremely small fetuses.

INTRODUCTION: As part of the fetal assessment for the Safe Passage Study, we recorded raw data of the fetal ECG via five maternal abdominal wall electrodes from 20 weeks to 23 weeks 6 days' gestation. MATERIALS: For this study were extracted and analyzed the FHR patterns from the stored raw data in 16 stillbirths where the fetus weighed less than 1000 g and where autopsy was performed. RESULTS: Birth weights ranged from 190 to 970 g. The proportion FHR signal loss ranged from 0.3% to 21.1%. In the smallest fetus the heart weighed 1.3 g, yet the FHR signal loss was only 0.9%.

Effect of CYP2C9 Polymorphisms on the Pharmacokinetics of Indomethacin During Pregnancy.

BACKGROUND AND OBJECTIVE: Cytochrome P450 (CYP) 2C9 catalyzes the biotransformation of indomethacin to its inactive metabolite O-desmethylindomethacin (DMI). The aim of this work was to determine the effect of CYP2C9 polymorphisms on indomethacin metabolism in pregnant women. METHODS: Plasma concentrations of indomethacin and DMI at steady state were analyzed with a validated LC-MS/MS method. DNA was isolated from subject blood and buccal smear samples. Subjects were grouped by genotype for comparisons of pharmacokinetic parameters. RESULTS: For subjects with the *1/*2 genotype, the mean steady-state apparent oral clearance (CL/Fss) of indomethacin was 13.5 ± 7.7 L/h (n = 4) and the mean metabolic ratio (AUCDMI/AUCindomethacin) was 0.291 ± 0.133. For subjects with the *1/*1 genotype, these values were 12.4 ± 2.7 L/h and 0.221 ± 0.078, respectively (n = 14). Of note, we identified one subject who was a carrier of both the *3 and *4 alleles, resulting in an amino acid change (I359P) which has not been reported previously. This subject had a metabolic ratio of 0.390 and a CL/Fss of indomethacin (24.3 L/h) that was nearly double the wild-type clearance. CONCLUSION: Although our results are limited by sample size and are not statistically significant, these data suggest that certain genetic polymorphisms of CYP2C9 may lead to an increased metabolic ratio and an increase in the clearance of indomethacin. More data are needed to assess the impact of CYP2C9 genotype on the effectiveness of indomethacin as a tocolytic agent.

Medical management of postpartum hemorrhage: An update.

Obstetrical hemorrhage is the most common cause of maternal mortality worldwide. Together with adequate surgical control and judicious transfusion of blood products, the use of pharmacological agents (e.g., tranexamic acid) and clotting factor concentrates (e.g., fibrinogen concentrates and prothrombin complex concentrates) results in improved hemostasis and decreased bleeding-associated mortality. Guidance in the administration of these agents with the use of viscoelastic testing will likely become standard of care in the near future.

Progressive Devascularization: A Novel Surgical Approach for Placenta Previa.

Background The gold standard for antenatal diagnosis of placenta previa is the transvaginal ultrasonography. In placenta previa cases, separation of placental and uterine tissues is challenging even for the most experienced surgeons. Life-threatening obstetrical complications from cesarean deliveries with placenta previa include peripartum hemorrhage, coagulopathy, blood transfusion, peripartum hysterectomy, and multiple organ failure. Cases We detailed the 3 cases of placenta previa that underwent bilateral uterine artery ligation; if hemostasis was not achieved, horizontal mattress sutures were placed in the lower uterine segment. All patients were discharged with minimal morbidity. Conclusion For patients with placenta previa and low risk for placenta creta, counseling should include the risk for maternal morbidity and criteria for pursuing peripartum hysterectomy. Our devascularization, a stepwise surgical approach, shows promising outcomes in placenta previa cases. Précis We propose a novel surgical approach, using a progressive devascularization surgical technique, for management of women with placenta previa, undergoing cesarean delivery.

Damage-Control Surgery for Obstetric Hemorrhage.

Damage-control surgery (abdominopelvic packing followed by a period of medical stabilization in the intensive care unit) is a life-saving intervention usually reserved for critically injured patients who may not survive an attempt to achieve hemostasis and complete repair of the damage in the operating room. Most obstetricians have little or no experience in this area, although the use of damage-control surgery in selected cases may be life-saving. This approach should be considered when arterial bleeding has been controlled and persistent bleeding is deemed to be secondary to coagulopathy that is refractory to blood product replacement, particularly in the presence of hypothermia, acidosis, and vasopressor requirement. A prototypical (albeit hypothetical) case is described here in which damage-control surgery is indicated.

Genetic Variation, Magnesium Sulfate Exposure, and Adverse Neurodevelopmental Outcomes Following Preterm Birth.

OBJECTIVE: To evaluate the association of magnesium sulfate (MgSO4) exposure and candidate gene polymorphisms with adverse neurodevelopmental outcomes following preterm birth. STUDY DESIGN: We performed a nested case-control analysis of a randomized trial of maternal MgSO4 before anticipated preterm birth for the prevention of cerebral palsy (CP). Cases were children who died within 1 year of life or were survivors with abnormal neurodevelopment at age 2 years. Controls were race- and sex-matched survivors with normal neurodevelopment. We analyzed 45 candidate gene polymorphisms in inflammation, coagulation, and vascular regulation pathways and their association with (1) psychomotor delay, (2) mental delay, (3) CP, and (4) combined outcome of death/CP. Logistic regression analyses, conditional on maternal race and child sex, and adjusted for treatment group, gestational age at birth and maternal education, were performed. RESULTS: Four hundred and six subjects, 211 cases and 195 controls, were analyzed. The strongest association was for IL6R (rs 4601580) in which each additional copy of the minor allele was associated with an increased risk of psychomotor delay (adjusted odds ratio 3.3; 95% confidence interval, 1.7-6.5; p < 0.001). CONCLUSION: Candidate gene polymorphisms are associated with death and adverse neurodevelopmental outcomes following preterm birth. MgSO4 may abrogate this genotype association for some loci.

Stroke Volume Recruitability during the Third Trimester of Pregnancy.

OBJECTIVE: It is unknown whether the heart operates in the ascending or flat portion of the Starling curve during normal pregnancy. Pregnant women do not respond to the passive leg-raising maneuver secondary to mechanical obstruction of the inferior vena cava by the gravid uterus. Our objective was to evaluate if administration of a fluid bolus increases baseline stroke volume (SV) among healthy pregnant patients during the third trimester. STUDY DESIGN: Healthy pregnant women who underwent elective term cesarean sections were included. A noninvasive cardiac output monitor was used to measure hemodynamic variables at baseline and after administration of a 500-mL crystalloid bolus. RESULTS: Forty-five women were included in the study. Fluid administration was associated with a statistically significant increase in SV from a baseline value of 71 ± 11 to 90 ± 19 mL (95% confidence interval [CI]: 13.67-21.49; p < 0.01) and a significant decrease in maternal heart rate from a baseline of 87 ± 9 beats per minute to 83 ± 8 after the fluid bolus (95% CI: -6.81 to -2.78; p = 0.03). No changes in peripheral vascular resistances or any other measured hemodynamic parameters were noted with volume expansion. CONCLUSION: In healthy term pregnancy, the heart operates in the ascending portion of the Starling's curve, rendering it fluid responsive.

Extracorporeal membrane oxygenation (ECMO) during pregnancy and postpartum.

Extracorporeal membrane oxygenation (ECMO) can provide respiratory support (VV-ECMO) or both respiratory and circulatory support (VA-ECMO). The use of ECMO has increased dramatically as a result of simpler technology. No level I evidence is yet available reflecting improved outcomes with ECMO. The use of this technology during pregnancy may be indicated in very select cases and should be delivered in centers with dedicated ECMO specialized units.

Tranexamic Acid for the Management of Obstetric Hemorrhage.

Obstetric hemorrhage remains the most common cause of maternal mortality worldwide. It is believed that increased fibrinolytic activity, secondary to release and activation of endothelial tissue plasminogen activator, is involved in its pathogenesis. Tranexamic acid (TXA), an antifibrinolytic agent, has been shown to be beneficial in trauma patients if used within 3 hours of injury. A recent large randomized controlled trial showed that TXA given to hemorrhaging women within 3 hours after delivery was associated with decreased risk of death resulting from bleeding with no increase in thromboembolic complications. Limited evidence suggests that prophylactic TXA reduces blood loss at the time of delivery and decreases transfusion rates in the obstetric population. Tranexamic acid appears to be a safe and effective option in the treatment of obstetric hemorrhage. In addition, the limited available evidence supports the need for a well-designed adequately powered clinical trial to test its benefit as a prophylactic agent.

The Role of Placental Carbonyl Reducing Enzymes in Biotransformation of Bupropion and 4-methylnitrosamino-1-(3-pyridyl)-1-butanone.

BACKGROUND: Bupropion (BUP) has a potential to be an effective pharmacotherapy for smoking cessation during pregnancy. Smoking during pregnancy stimulates placental carbonyl reductases that catalyze the biotransformation of BUP. 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) is a potent carcinogen of cigarette smoke. Carbonyl reduction of NNK into 4- methylnitrosamino-1-(3-pyridyl)-1-butanol (NNAL) constitutes a major step in NNK detoxification. Thus, placentas of pregnant smokers on BUP therapy can become a site of drug-drug interaction. Therefore, we investigated the effect of continuous exposure to BUP and cigarette smoke on the activity of placental carbonyl reductases in the formation of NNAL from NNK. METHODS: The reductive metabolism of NNK was determined using microsomal and cytosolic subcellular fractions of placentas obtained from non-smoking women treated with BUP for depression, and women not exposed to BUP: non-smokers (control) and smokers. The effect of BUP and its metabolites on the reductive metabolism of NNK was investigated using subcellular fractions of control placentas. RESULTS: The formation of NNAL from NNK by placental cytosolic fractions of heavy smokers (≥20 cigarettes per day) was lower than that of control (12.1±3.5 nmol.mgP-1 vs 16.5±6.0 nmol.mgP-1, P<0.05). While being exposed to BUP, the activity of placental carbonyl reductases remained unaffected, the formation of NNAL in the placental cytosolic fraction decreased only in the presence of high concentrations of BUP metabolites. CONCLUSION: Smoking during pregnancy decreases the detoxifying capacity of soluble carbonyl reductases towards NNK. Given the experimental conditions, exposure to BUP and its metabolites should not impede the reductive metabolism of NNK by placenta in vivo.

Hyperandrogenemia reduces endothelium-derived hyperpolarizing factor-mediated relaxation in mesenteric artery of female rats.

Women with polycystic ovary syndrome (PCOS) are often presented with hyperandrogenemia along with vascular dysfunction and elevated blood pressure. In animal models of PCOS, anti-androgen treatment decreased blood pressure, indicating a key role for androgens in the development of hypertension. However, the underlying androgen-mediated mechanism that contributes to increased blood pressure is not known. This study determined whether elevated androgens affect endothelium-derived hyperpolarizing factor (EDHF)-mediated vascular relaxation responses through alteration in function of gap junctional proteins. Female rats were implanted with placebo or dihydrotestosterone (DHT) pellets (7.5 mg, 90-day release). After 12 weeks of DHT exposure, blood pressure was assessed through carotid arterial catheter and endothelium-dependent mesenteric arterial EDHF relaxation using wire myograph. Connexin expression in mesenteric arteries was also examined. Elevated DHT significantly increased mean arterial pressure and decreased endothelium-dependent EDHF-mediated acetylcholine relaxation. Inhibition of Cx40 did not have any effect, while inhibition of Cx37 decreased EDHF relaxation to a similar magnitude in both controls and DHT females. On the other hand, inhibition of Cx43 significantly attenuated EDHF relaxation in mesenteric arteries of controls but not DHT females. Elevated DHT did not alter Cx37 or Cx40, but decreased Cx43 mRNA and protein levels in mesenteric arteries. In vitro exposure of DHT to cultured mesenteric artery smooth muscle cells dose-dependently downregulated Cx43 expression. In conclusion, increased blood pressure in hyperandrogenic females is due, at least in part, to decreased EDHF-mediated vascular relaxation responses. Decreased Cx43 expression and activity may play a role in contributing to androgen-induced decrease in EDHF function.

Hemostatic Resuscitation in Peripartum Hysterectomy Pre- and Postmassive Transfusion Protocol Initiation.

Background Massive transfusion protocols (MTPs) have been examined in trauma. The exact ratio of packed red blood cells (PRBC) to other blood replacement components in hemostatic resuscitation in obstetrics has not been well defined. Objective The objective of this study was to evaluate hemostatic resuscitation in peripartum hysterectomy comparing pre- and postinstitution of a MTP. Study Design We conducted a retrospective, descriptive study of women undergoing peripartum hysterectomies from January 2002 to January 2015 who received ≥ 4 units of PRBC. Individuals were grouped into either a pre-MTP institution group or a post-MTP institution group. The post-MTP group was subdivided into those who had the protocol activated (MTP) versus not activated (no MTP). Primary outcomes were estimated blood loss (EBL) and need for blood product replacement. The secondary outcome was a composite of maternal morbidity, including need for mechanical ventilation, venous thromboembolism, pulmonary edema, acute kidney injury, and postpartum infection. A Mann-Whitney U test was used to compare continuous variables, and a chi-squared test was used for categorical variables with significance of p < 0.05. Results Of the 165 women who had a peripartum hysterectomy during the study period, 62 received four units or more of PRBC. No significant differences were noted in EBL or blood product replacement between the pre-MTP (n = 39) and post-MTP (n = 23) groups. Similarly, the MTP (n = 6) and no MTP (n = 17) subgroups showed no significant difference between EBL and overall blood product replacement. Significant differences were seen in transfusion of individual blood products, such as fresh frozen plasma (FFP) (MTP = 4, no MTP = 2; p = 0.02) and platelets (plts) (MTP = 6, no MTP = 0; p = 0.03). The use of high ratio replacement therapy for both plasma and plts was more common in the MTP group (FFP/PRBC ratio [MTP = 0.5, no MTP = 0.3; p = 0.02]; plts/PRBC ratio [MTP = 0.7, no MTP = 0; p = 0.03]). There were no differences in the secondary outcome between pre- and post-MTP or MTP and no MTP. Conclusion Initiation of the MTP did result in an increase in transfusion of FFP and plts intraoperatively. At our institution, the MTP is underutilized, but it appears that providers are more cognizant of the use of high transfusion ratios.

Bupropion sustained release for pregnant smokers: a randomized, placebo-controlled trial.

BACKGROUND: Bupropion is used to treat depression during pregnancy. However, its usefulness as a smoking cessation aid for pregnant women is not fully known. OBJECTIVE: The objective of the study was to evaluate the preliminary efficacy of bupropion sustained release for smoking cessation during pregnancy. STUDY DESIGN: We conducted a randomized, prospective, double-blind, placebo-controlled, pilot trial. Pregnant women who smoked daily received individualized behavior counseling and were randomly assigned to a 12 week, twice-a-day treatment with 150 mg bupropion sustained release or placebo. The primary study objectives were to determine whether bupropion sustained release reduces nicotine withdrawal symptoms on the quit date and during the treatment period compared with placebo and whether it increases 7 day point prevalence abstinence at the end of the treatment period and at the end of pregnancy. RESULTS: Subjects in the bupropion (n = 30) and placebo (n = 35) groups were comparable in age, smoking history, number of daily smoked cigarettes, and nicotine dependence. After controlling for maternal age and race, bupropion sustained release reduced cigarette cravings (1.5 ± 1.1 vs 2.1 ± 1.2, P = .02) and total nicotine withdrawal symptoms (3.8 ± 4.3 vs 5.4 ± 5.1, P = .028) during the treatment period. Administration of bupropion sustained release reduced tobacco exposure, as determined by levels of carbon monoxide in exhaled air (7.4 ± 6.4 vs 9.1 ± 5.8, P = .053) and concentrations of cotinine in urine (348 ± 384 ng/mL vs 831 ± 727 ng/mL, P = .007) and increased overall abstinence rates during treatment (19% vs 2%, P = .003). However, there was no significant difference in 7 day point prevalence abstinence rates between the 2 groups at the end of medication treatment (17% vs 3%, P = .087) and at the end of pregnancy (10% vs 3%, P = .328). CONCLUSION: Individual smoking cessation counseling along with the twice-daily use of 150 mg bupropion sustained release increased smoking cessation rates and reduced cravings and total nicotine withdrawal symptoms during the treatment period. However, there was no significant difference in abstinence rates between groups at the end of medication treatment and at the end of pregnancy, likely because of the small sample size. A larger study is needed to confirm these findings and to examine the potential benefit/ risk ratio of bupropion sustained release for smoking cessation during pregnancy.

Demonstration of early efficacy results of the delayed-release combination of doxylamine-pyridoxine for the treatment of nausea and vomiting of pregnancy.

BACKGROUND: Nausea and vomiting of pregnancy (NVP) affects up to 80% of expecting mothers. In April 2013 the FDA approved the delayed-release combination of doxylamine succinate and pyridoxine hydrochloride (Diclegis®) for NVP, based in part, on the results of a phase III randomized trial demonstrating the efficacy of this drug combination [study drug marketed under the trade name Diclectin® in Canada and Diclegis® in the United States] compared to placebo in pregnant women. Study drug dosing occurred for 14 days, which is substantially longer than what has been performed in similar studies. The objective of this study was to evaluate, through secondary analysis, whether the primary measure of efficacy can be demonstrated after five days of treatment. METHODS: Women suffering from NVP were randomized to receive Diclegis® (n = 131) or placebo (n = 125) for 14 days at doses ranging from two to four tablets a day, based on a pre-specified titration protocol. The primary efficacy endpoint was the change in the validated Pregnancy-Unique Quantification of Emesis (PUQE) score at baseline versus Day 15 between Diclegis®-treated and placebo-treated women. For the present study, the change in PUQE score between baseline and Day 15 (end of the study) was compared to the changes observed for Days 3, 4, and 5. RESULTS: The use of delayed-release doxylamine succinate and pyridoxine hydrochloride tablets show improved NVP symptom control as compared to placebo on Days 3,4 and 5, with sustained efficacy until the end of the trial. CONCLUSION: A four day study drug dosing trial with Diclegis® is sufficient to document efficacy, as the results are similar to those achieved after 14 study drug dosing days. The benefit seen at the earlier time validates drug efficacy and minimizes the natural course of improvement. TRIAL REGISTRATION: CTR No. NCT006 14445 2007.

Guillain-Barré Syndrome in Pregnancy.

Guillain-Barré syndrome has been reported in pregnancy and is a potentially lethal condition. It affects the nervous system with acute onset of symmetric ascending weakness and may result in frank respiratory failure and autonomic dysfunction. Most patients recall symptoms of a respiratory or gastrointestinal illness in the weeks preceding the onset of weakness. Recent evidence suggests a potential role of the Zika virus as a trigger for the syndrome. The diagnosis of Guillain-Barré is clinical. Supportive measures include venous thromboembolism prophylaxis, aggressive physical therapy, pressure ulcer prevention, enteral nutrition, and respiratory support. The mainstay of management comprises plasmapheresis or administration of intravenous immunoglobulins. Affected patients must be closely monitored for development of respiratory failure and autonomic dysfunction. Treatment during pregnancy should follow the same principles as for nonpregnant individuals.

Conservative Management and Planned Surgery for Periviable Advanced Extrauterine Abdominal Pregnancy with Favorable Outcome: Report of Two Cases.

Advanced abdominal pregnancy is an extremely rare condition that poses diagnostic and management challenges. A high index of suspicion and careful assessment of the patient's symptoms, supplemented with obstetric ultrasound, and magnetic resonance imaging, are crucial for timely diagnosis and management to prevent life-threatening complications. The presence of periviable fetuses in advanced abdominal pregnancies increases the challenge to achieve a balance between maternal and fetal benefits and risks. Early diagnosis and management decisions via a multidisciplinary approach and planned delivery are of paramount importance to minimize complications and achieve favorable maternal and fetal outcomes. Even in the setting of oligohydramnios and suspected preterm premature rupture of membranes, in-patient conservative management and an individualized planned surgical approach that includes removing or leaving the placenta in place are appropriate for managing the periviable abdominal pregnancy.