Spontaneous Renal Rupture During Pregnancy: A Contemporary Literature Review and Guide to Management.

IMPORTANCE: Spontaneous renal rupture is a rare pregnancy complication, which requires a high index of suspicion for a timely diagnosis to prevent a poor maternal or fetal outcome. OBJECTIVE: This review highlights risk factors, pathophysiology, symptoms, diagnosis, management, and complications of spontaneous renal rupture in pregnancy. EVIDENCE ACQUISITION: A literature search was carried out by research librarians using the PubMed and Web of Science search engines at 2 universities. Fifty cases of spontaneous renal rupture in pregnancy were identified and are the basis of this review. RESULTS: The first case of spontaneous renal rupture in pregnancy was reported in 1947. Rupture occurs more commonly on the right side and during the third trimester. Pain was a reported symptom in every case reviewed. Treatment usually consists of stent or nephrostomy tube placement. Conservative management has been reported. CONCLUSIONS: When diagnosed early and managed appropriately, maternal and fetal outcomes are favorable. Preterm delivery is the most common complication. RELEVANCE: Our aim is to increase the awareness of spontaneous renal rupture in pregnancy and its associated complications in order to improve an accurate diagnosis and maternal and fetal outcomes.

Preconception, Antepartum, and Peripartum Care for the Woman With a Spinal Cord Injury: A Review of the Literature.

IMPORTANCE: Spinal cord injury (SCI) may result in temporary or permanent loss of sensory, motor, and autonomic function, presenting unique medical and psychosocial challenges in women during their childbearing years. OBJECTIVE: The aim of this study was to review the literature and describe the spectrum of pregnancy considerations, complications, and evidence-based obstetric practices in women with SCI. EVIDENCE ACQUISITION: A literature search was undertaken using the search engines of PubMed and Web of Science using the terms "spinal cord injury" or "spinal cord complications" and "pregnancy outcomes" or "pregnancy complications." The search was limited to the English language, and there was no restriction on the years searched. RESULTS: The search identified 174 abstracts, 50 of which are the basis for this review. Pregnancy in women who have experienced an SCI requires a multidisciplinary approach. Common complications during pregnancy include recurrent urinary tract infection, upper respiratory tract infection, hypertension, venous thromboembolism, and autonomic dysreflexia (AD), which is a potentially life-threatening complication. Obstetricians should avoid potential triggers and be familiar with acute management of AD. Postpartum complications include difficulty initiating and maintaining breastfeeding and increased risk of postpartum depression and other mental health issues. CONCLUSIONS AND RELEVANCE: Obstetricians caring for women with an SCI must be familiar with the unique challenges and complications that may occur during pregnancy and puerperium. RELEVANCE STATEMENT: An evidence-based literature review of the care of pregnant women with spinal cord injury.

Can maternal characteristics on admission for preterm prelabor rupture of membranes predict pregnancy latency?

BACKGROUND: Latency duration after preterm prelabor rupture of membranes has been an area of investigation for many years. Previously described factors associated with latency include gestational age at the time of rupture, cervical dilation of >1 cm, vaginal bleeding at the time of presentation, and oligohydramnios. However, little is known about the impact of composite maternal factors and presenting symptoms on the duration or prediction of the latency period. OBJECTIVE: This study aimed to determine whether maternal factors and subjective presenting symptoms can predict pregnancy latency after preterm prelabor rupture of membranes. STUDY DESIGN: This is a retrospective observational study of singleton pregnancies complicated by preterm prelabor rupture of membranes for over 3 years at a single institution utilizing a uniform management protocol. Maternal demographics, obstetrical data, maternal subjective symptoms and physical examination findings on admission, amniotic fluid volume assessment, presence of contractions, and maternal perception of feeling unwell were collected and analyzed. Clinical characteristics were summarized with mean and standard deviation for continuous measures and frequency and percentages for categorical variables. For skewed variables, medians with 25th and 75th percentiles were reported. Cumulative latency duration (ie, survival time) was estimated with a Kaplan-Meier model. Multivariable Cox proportional hazards regression model with backward variable selection was used to determine the effects of maternal factors on latency duration. RESULTS: Of the 212 patients available for analysis, there was a considerable variability in the latency duration with values ranging between 0 and 119 days. Factors related to latency duration included maternal age, parity, gestational age at rupture, cervical dilation, amniotic fluid volume, and contractions. Advancing maternal age (P=.012), increased gestational age at rupture (P<.0001), cervical dilation of ≥3 (vs 0; P<.0001), anhydramnios or oligohydramnios (vs normal amniotic fluid; P<.0001), cramping (P=.012), and painful contractions (P=.015) were associated with a shorter latency duration. Utilizing these statistically significant factors, we constructed a nomogram to predict latency for 1-day, 1-week, and overall median latency duration. CONCLUSION: Maternal factors and presenting symptoms can predict pregnancy latency after preterm prelabor rupture of membranes. We created a nomogram for clinical use that provides a visual display of the probability of pregnancy latency. This tool may be useful for counseling and providing additional information on expectations for providers and patients with pregnancies complicated by preterm prelabor rupture of membranes.

Elective Induction of Labor Compared With Expectant Management of Nulliparous Women at 39 Weeks of Gestation: A Randomized Controlled Trial.

OBJECTIVE: To evaluate whether the elective induction of labor in nulliparous women with an unfavorable cervix affects the cesarean delivery rate. METHODS: We conducted a randomized controlled trial at a tertiary care medical center. Nulliparous woman between 38 0/7 and 38 6/7 weeks of gestation who were least 18 years of age with a singleton gestation and a Bishop score of 5 or less were randomized to elective induction of labor or expectant management. The induction of labor group was induced within 1 week of enrollment but not before 39 0/7 weeks of gestation. The control group continued routine prenatal care with admission for labor or obstetric indication. The primary outcome was cesarean delivery. Assuming a 20% rate in women in a control group, 80% power, and a goal to detect a twofold increase to 40% in the induction of labor group, 162 patients were needed. RESULTS: From March 2010 to February 2014, 82 patients were randomly allocated to induction of labor and 80 to expectant management. Baseline characteristics were similar between groups. The cesarean delivery rate in the induction of labor group was 30.5% (25/82) compared with 17.7% (14/79) in the expectant management group (relative risk 1.72, 95% confidence interval 0.96-3.06). CONCLUSION: In nulliparous women with a Bishop score of 5 or less, elective induction after 39 0/7 weeks of gestation compared with expectant management of pregnancy did not double the rate of cesarean delivery. CLINICAL TRIAL REGISTRACTION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT01076062. LEVEL OF EVIDENCE: I.

Accuracy of the Adverse Outcome Index: An Obstetrical Quality Measure.

BACKGROUND: In obstetrics, a nationally accepted set of quality indicators for patient safety was not available in the United States until the development of a set of 10 adverse outcome measures-the Adverse Outcome Index (AOI). The National Perinatal Information Center (NPIC) developed hospital discharge data-based algorithms combined with a small set of supplemental patient data for calculation of the AOI. A study was conducted to determine the specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) of the AOI by using the National Perinatal Information Center (NPIC) algorithm. METHODS: A retrospective chart review of 4,252 obstetrical and neonatal charts from 2003 through 2007 was performed. NPIC definitions were compared with the "gold standard"-chart review. RESULTS: A total of 229 deliveries among the 4,000 randomly selected charts had at least one adverse outcome, reflecting an AOI of 5.7%. For detection of the 10 adverse outcomes within the AOI, the overall sensitivity of the AOI was 81.7%, specificity was 98.2%, PPV was 86.3%, and NPV was 97.4%. The Kappa value for agreement between the coded charts and the chart review was 0.82 (standard deviation=0.01, 95% confidence interval [CI]=0.80-0.85), which is considered very good. DISCUSSION: The AOI is highly reliant on accurate coding and provider documentation and requires validation with manual chart review. Concurrent chart review improves the accuracy of the AOI. Caution is advised when using the AOI as an exclusive measure of assessing obstetric quality because it may be heavily influenced by a single outcome measure; perineal laceration rates represented twice the frequency of all other outcomes combined. The AOI should be modified to better measure preventable adverse events and include a means of accounting for preexisting conditions.

Severe thrombocytopenia after contrast infusion in pregnancy.

BACKGROUND: Intravenous contrast-induced thrombocytopenia is a rare but potentially life-threatening complication in pregnancy. CASE: A 22-year-old woman, gravida 2 para 1, at 33 2/7 weeks of gestation presented with chest pain, shortness of breath, and tachycardia. A computed tomography angiogram was pursued to evaluate for pulmonary embolus. During contrast infusion the woman experienced facial flushing, throat tightening, and worsening dyspnea. Her platelet count was noted to decrease precipitously to 4,000/microliter several hours after the imaging study. With medical management and observation, the woman's platelet count steadily recovered without further exacerbation of thrombocytopenia during gestation. CONCLUSION: Prompt recognition and therapy for intravenous contrast-induced thrombocytopenia during pregnancy are essential to optimize maternal-fetal outcome.

Transversus abdominis plane block for postoperative analgesia after cesarean delivery.

OBJECTIVE: The transversus abdominis plane (TAP) block is the ultrasound-guided placement of a peripheral nerve block in the abdominal wall for pain control. Our objective was to compare postoperative adjunctive oral narcotic use in women who underwent cesarean delivery and received the TAP block vs. those who received neuraxial narcotics. We hypothesize a decrease in narcotic use in women who received the TAP block. METHODS: Retrospective cohort study of women who received a TAP block for postoperative analgesia after cesarean compared to women who did not. The primary outcome was the total number of oral narcotic tablets administered between 24 and 48 h after surgery. An independent t-test and an analysis of covariance were employed to determine significant differences (P < 0.05) between the cohorts and to adjust for confounders. RESULTS: The TAP block cohort utilized 30% less oral narcotic analgesia than the control cohort (3.8 ± 0.5 tablets, P < 0.001). After adjusting for confounders and the presence of antecedent labor, there remained a significant reduction in the total oral narcotic doses given to women who underwent a TAP block compared to other forms of analgesia. CONCLUSION: The TAP block is associated with decreased oral narcotic usage 24-48 h following cesarean delivery.

The distribution and predictive value of Bishop scores in nulliparas between 37 and 42 weeks gestation.

OBJECTIVE: The natural distribution and predictive accuracy of Bishop scores was evaluated to predict cesarean delivery (CD) in nulliparas between 37 and 42 weeks gestation. STUDY DESIGN: Subjects underwent serial digital cervical examinations. The Bishop score was evaluated as a binary and continuous factor to predict CD at each gestational week beginning at 37 weeks. Bishop scores were categorized as ≤5 or >5, and CD rates were compared across Bishop score categories using chi-square or Fisher exact tests at each gestational week beginning at 37 weeks. RESULTS: In all, 171 patients were prospectively followed. The overall CD rate was 27.5%. The prevalence of unfavorable Bishop scores, categorized as ≤5, decreased with increasing gestation age until 41 weeks. CD rates for the cohort with unfavorable Bishop scores was higher than those with favorable scores at each week. The likelihood ratio for CD was 1.35-2.00, depending on gestational age. The Bishop score that best predicted subsequent vaginal delivery following expectant management was >3 at 37 weeks and >5 at 39 weeks. CONCLUSION: A Bishop score ≤5 between 37 and 39 weeks gestation predicts a higher CD rate compared to patients with a Bishop score >5 implying an intrinsically higher CD risk despite expectant management.

Postpartum cerebral venous thrombosis.

BACKGROUND: Cerebral venous thrombosis is a rare entity in pregnancy and the postpartum period, with an incidence of 1:10,000 to 1:25,000. CASE: A 19-year-old woman, gravida 1, para 1, presented to the emergency department on postpartum day 7, having experienced seizures. Severe preeclampsia had been diagnosed during the antepartum period. The patient initially was diagnosed with postpartum eclampsia and started on magnesium sulfate for seizure prophylaxis. Magnetic resonance imaging later showed cerebral venous thrombosis of the left transverse sinus and right frontal and left frontoparietal cortical veins. CONCLUSION: Cerebral venous thrombosis and eclampsia may manifest in a similar manner. Physicians can optimize the care of patients presenting with seizures by considering etiologies rarer than eclampsia and pursuing tests that may distinguish them.

Determining uterine blood flow in pregnancy with magnetic resonance imaging.

OBJECTIVE: The purpose of this study is to determine the feasibility of measuring total uterine blood flow in pregnancy using magnetic resonance imaging (MRI) technique. METHODS: Uterine blood flow was determined in pregnant women in whom MRI was being carried out to assess a fetal anomaly. A two-dimensional time-of-flight magnetic resonance (MR) angiogram sequence was performed. Scout images and a peripherally gated phase contrast MR sequence were planned to study simultaneous blood flow in the uterine and ovarian arteries. RESULTS: The MR pelvic angiogram sequence was completed in 13 women. The uterine arteries were visualized and their cross-sectional area determined. The complexity of the pelvic blood supply prevented the calculation of blood flow velocity and, thus, total uterine blood flow. CONCLUSION: The measurement of total uterine blood flow during pregnancy was not possible using our MR technique. The ovarian vessels were not consistently visualized. Doppler ultrasonography remains the best modality by which to estimate total uterine blood flow in pregnancy.

The appendix in pregnancy: confirming historical observations with a contemporary modality.

OBJECTIVE: To estimate the position of the appendix in term pregnancy using magnetic resonance imaging (MRI) technique. METHODS: Appendiceal distance from the iliac crest and axis rotation were determined in women between 39 and 40 weeks of gestation who were undergoing scheduled repeat cesarean delivery. A single-shot fast spin-echo MRI sequence of the maternal pelvis was performed without gadolinium contrast. A board-certified radiologist interpreted the MRIs and measured the distance from the base of appendix (or cecum) to the iliac crest in centimeters as well as the axis of the appendix using clock position annotation. RESULTS: Seventy-two women had optimal imaging for interpretation. The mean displacement of the appendix above the iliac crest was 45 mm and was significantly higher than previously described in the term pregnant woman (P<.001). CONCLUSION: Despite recent studies supporting the contrary view, the upward displacement of the appendix in term pregnancy is confirmed in this study. LEVEL OF EVIDENCE: II.

Predicting macrosomia.

OBJECTIVE: The purpose of this study was to evaluate the prediction of fetal macrosomia based on ultrasound estimates of fetal weight and amniotic fluid volume combined with clinical risk factors. METHODS: A retrospective cohort study of women undergoing indicated obstetric ultrasound examinations within 7 days of delivery was conducted. RESULTS: A total of 3115 women gave birth within 7 days of ultrasound examinations that included an estimated fetal weight (EFW) and an amniotic fluid index (AFI). Clinical risk factors were associated with an 8% positive predictive value for a birth weight of 4000 g or higher. Adding an ultrasound EFW of 4000 g or higher increased the positive predictive value to 62%. Adding an AFI of 20 cm or higher to the clinical risk factors and the ultrasound EFW further increased the positive predictive value to 71%. CONCLUSIONS: An ultrasound EFW of 4000 g or higher within 1 week of delivery combined with clinical risk factors and an increased AFI is associated with macrosomia at birth in 71% of cases.

Magnetic resonance signal characteristics of the cervix as pregnancy advances.

The objective of this study is to describe magnetic resonance (MR) signal intensity (SI) changes in the cervix during pregnancy. This is an observational cohort study of women with a history of preterm delivery. MR imaging sequences were performed every 3 to 4 weeks. Using 8 regions of interest, the SIs are quantified and analyzed with respect to gestational age. Twenty-seven MR studies were performed on a cohort of 8 women. The SIs of the external os are significantly greater than those of the internal os ( P = .035). Similarly, the SIs of the outer stroma are greater than those of the inner stroma (P = .002). As gestational age advances, the inner to outer stromal SI ratio increases, primarily because of a decreasing SI in the outer stromal layer (P = .03). The MR SIs of the cervical stromal zones display variability during pregnancy and decrease with advancing gestation.

Uterine contractions preceding labor.

OBJECTIVE: To evaluate whether 12 contractions in 1 hour is a meaningful signal that spontaneous labor has begun or is imminent. METHODS: This prospective observational cohort study includes all women reporting contractions who presented to a labor and delivery triage unit between August 1 and October 31, 2006, who met the following criteria: 1) 36 0/7 to 41 6/7 weeks of gestation, 2) cervical dilation less than 4 cm, 3) intact membranes, and 4) no other medical or obstetric complications that might influence admission. Each woman received external fetal monitoring for a minimum of 1 hour. Women were discharged home if cervical dilation did not advance and the fetal heart rate pattern was reassuring. Women who progressed to a cervical dilation of 4 cm were admitted with the diagnosis of labor. RESULTS: Among 768 women studied, labor was diagnosed within 24 hours in 268 (76%) with 12 or more contractions per hour compared with 216 (52%) of 416 women with fewer than 12 contractions per hour, P<.001. Cervical condition and fetal station were more advanced on presentation in women with 12 or more contractions per hour. CONCLUSION: Twelve contractions or more per hour at term is a meaningful signal that true labor has either begun or is imminent. LEVEL OF EVIDENCE: II.

Determining cervical ripeness and labor outcome: the efficacy of magnetic resonance T2 relaxation times.

OBJECTIVE: To determine whether the magnetic resonance assessment of cervical water content using the T2 relaxation time correlated with cervical ripening, as evidenced by the time to onset of spontaneous labor, need for induction, and the incidence of cesarean delivery in women whose pregnancy reached 41 weeks of gestation. METHODS: The cervical T2 relaxation time was calculated from magnetic resonance data obtained in a previous study of magnetic resonance pelvimetry. After consent was obtained, the patients underwent a magnetic resonance imaging (MRI) protocol consisting of a dual fast spin echo T2-weighted scan. From images of a single slice, the cervical T2 relaxation time was calculated from two different regions of interest (anterior and posterior) on the cervix. The average cervical T2 relaxation time was then correlated to obstetric outcomes linked with cervical ripening. RESULTS: A total of 119 patients gave their consent for the study. Of these patients, 93 had optimal imaging of the cervical stroma and were included in the analysis. There was no significant correlation between the cervical T2 relaxation time and any individual component of the Bishop score or the total score. The cervical T2 relaxation time did not predict whether labor was spontaneous or induced and whether or not a woman underwent cesarean delivery. CONCLUSION: Cervical magnetic resonance T2 relaxation times did not correlate with the clinical Bishop score or predict labor outcome in our series of women whose pregnancies reached 41 weeks of gestation. Quantifying the magnetic resonance T2 relaxation time does not appear to be useful in the assessment of cervical ripening. LEVEL OF EVIDENCE: III.

Prenatal diagnosis and management of hydronephrosis.

Congenital hydronephrosis is frequently amenable to prenatal diagnosis, often as early as the second trimester. Most clinicians use a renal pelvis anterior-posterior (AP) diameter of 4 mm or more prior to 20 weeks of gestation as a threshold for identifying pyelectasis. If mild dilation of the renal pelvis is an isolated finding in the second trimester, evaluation performed later in gestation is used to guide postnatal management. Since the normal renal pelvis dimensions may increase with advancing gestation, thresholds for the diagnosis are larger in the third trimester. Neonatal follow-up is typically recommended only if the fetal renal pelvis diameter exceeds a specified cut-off (e.g. 7 or 10 mm) at or beyond 34 weeks. If the measurement is less, most deem the pyelectasis physiologic or normal. However, it has been suggested that fetuses with early renal pelvis dilation that resolved during pregnancy might also benefit from postnatal surveillance. The newborn evaluation for hydronephrosis may be time consuming, invasive, and costly; however, it can often prevent sequelae from congenital uropathy.

The use of radiographic modalities to diagnose infection in pregnancy.

The usefulness of sonography, plain film, CT, and MRI in diagnosing infections in pregnancy is discussed. Imaging modality choices for specific clinical indications in pregnancy are reviewed. The overall safety of most techniques in pregnancy is emphasized.

Active management of labor.

A source of great controversy, the active management of labor as classically defined, is routinely misunderstood and misapplied in many clinical settings. Aggressive induction protocols, early amniotomy, operative delivery, epidural analgesia, and even early admission to labor and delivery units are actions frequently thought to be synonymous with "active management of labor". To regain an understanding of the active management of labor, one needs to examine the goal of this management scheme and become more familiar with its components.