Amniocentesis in pregnancies at or beyond 24 weeks: an international multicenter study.

BACKGROUND: Amniocentesis for genetic diagnosis is most commonly done between 15 and 22 weeks of gestation but can be performed at later gestational ages. The safety and genetic diagnostic accuracy of amniocentesis have been well-established through numerous large-scale multicenter studies for procedures before 24 weeks, but comprehensive data on late amniocentesis remain sparse. OBJECTIVE: To evaluate the indications, diagnostic yield, safety, and maternal and fetal outcomes associated with amniocentesis performed at or beyond 24 weeks of gestation. STUDY DESIGN: We conducted an international multicenter retrospective cohort study examining pregnant individuals who underwent amniocentesis for prenatal diagnostic testing at gestational ages between 24w0d and 36w6d. The study, spanning from 2011 to 2022, involved 9 referral centers. We included singleton or twin pregnancies with documented outcomes, excluding cases where other invasive procedures were performed during pregnancy or if amniocentesis was conducted for obstetric indications. We analyzed indications for late amniocentesis, types of genetic tests performed, their results, and the diagnostic yield, along with pregnancy outcomes and postprocedure complications. RESULTS: Of the 752 pregnant individuals included in our study, late amniocentesis was primarily performed for the prenatal diagnosis of structural anomalies (91.6%), followed by suspected fetal infection (2.3%) and high-risk findings from cell-free DNA screening (1.9%). The median gestational age at the time of the procedure was 28w5d, and 98.3% of pregnant individuals received results of genetic testing before birth or pregnancy termination. The diagnostic yield was 22.9%, and a diagnosis was made 2.4 times more often for fetuses with anomalies in multiple organ systems (36.4%) compared to those with anomalies in a single organ system (15.3%). Additionally, the diagnostic yield varied depending on the specific organ system involved, with the highest yield for musculoskeletal anomalies (36.7%) and hydrops fetalis (36.4%) when a single organ system or entity was affected. The most prevalent genetic diagnoses were aneuploidies (46.8%), followed by copy number variants (26.3%) and monogenic disorders (22.2%). The median gestational age at delivery was 38w3d, with an average of 59 days between the procedure and delivery date. The overall complication rate within 2 weeks postprocedure was 1.2%. We found no significant difference in the rate of preterm delivery between pregnant individuals undergoing amniocentesis between 24 and 28 weeks and those between 28 and 32 weeks, reinforcing the procedure's safety across these gestational periods. CONCLUSION: Late amniocentesis, at or after 24 weeks of gestation, especially for pregnancies complicated by multiple congenital anomalies, has a high diagnostic yield and a low complication rate, underscoring its clinical utility. It provides pregnant individuals and their providers with a comprehensive diagnostic evaluation and results before delivery, enabling informed counseling and optimized perinatal and neonatal care planning.

A systematic review and meta-analysis of cell-free DNA testing for detection of fetal sex chromosome aneuploidy.

OBJECTIVES: The aim was to determine the accuracy of cell-free DNA testing (cfDNA) for detecting sex chromosome aneuploidies (SCA) in singleton pregnancies. METHODS: A systematic review and meta-analysis was performed to assess cfDNA accuracy for prenatal detection of 45,X, 47,XXY, 47,XXX and 47,XYY. Inclusion was restricted to studies published between January 2010 and December 2021 reporting both cfDNA and confirmatory diagnostic test results. RESULTS: For 45,X, the sensitivity was 98.8% (95%CI 94.6%-100%), specificity 99.4% (95%CI 98.7%-99.9%) and positive predictive value (PPV) 14.5% (95%CI 7.0%-43.8%). For 47,XXY, the sensitivity was 100% (95%CI 99.6%-100%), specificity 100% (95%CI 99.9%-100%) and PPV 97.7% (95%CI 78.6%-100%). For 47,XXX, the sensitivity was 100% (95%CI 96.9%-100%), specificity 99.9% (95%CI 99.7%-100%) and PPV 61.6% (95%CI 37.6%-95.4%). For 47,XYY, the sensitivity was 100% (95%CI 91.3%-100%), specificity 100% (95% CI 100%-100%) and PPV 100% (95%CI 76.5%-100%). All four SCAs had estimated negative predictive values (NPV) exceeding 99.99%, though false negatives were reported. CONCLUSIONS: This analysis suggests that cfDNA is a reliable screening test for SCA, though both false negatives and false positives were reported. These estimates of test performance are derived from pregnancies at high pretest risk for aneuploidy, limiting the generalisability to average risk pregnancies.

Prenatal phenotype of 47, XXY (Klinefelter syndrome).

OBJECTIVE: There is a paucity of knowledge regarding the prenatal presentation of Klinefelter syndrome, or 47, XXY. Accurate prenatal counseling is critical and in utero diagnosis is currently limited by a poor understanding of the prenatal phenotype of this condition. METHODS: This is a case series of fetuses with cytogenetically confirmed 47, XXY in the prenatal period or up to age 5 years, with prenatal records available for review from four academic institutions between 2006 and 2019. Ultrasound reports were reviewed in detail to assess for increased nuchal translucency and structural abnormalities. Additionally, we reviewed results of cell-free DNA and serum analyte testing when performed to inform our understanding of the detection of fetal 47, XXY through standard genetic screening tests. RESULTS: Forty-one cases with confirmed cytogenetic diagnosis of 47, XXY and prenatal records available for review were identified: 37 had a prenatal diagnosis and 4 had a postnatal diagnosis. Nuchal translucency was increased ≥3.0 mm in 23.1% (6/26) of cases with a documented measurement. In 29.2% (7/24) of cases with a second trimester anatomical ultrasound available for review, a fetal abnormality was identified (3 brain anomalies, 1 cardiac abnormality, 1 echogenic bowel, and 2 limb abnormalities). Among those who had cell-free DNA and serum analytes performed, 92.6% (25/27) and 36.3% (4/11) had an abnormal result respectively. CONCLUSION: This case series expands our knowledge of the prenatal presentation of 47, XXY by identifying first and second trimester fetal sonographic abnormalities. Prenatal identification of this condition enables accurate counseling, focused prenatal management, and early postnatal interventions to ameliorate some of the known complications.

Understanding Preterm Birth in Pregnancies Complicated by Nonimmune Hydrops Fetalis.

OBJECTIVE: Nonimmune hydrops fetalis (NIHF) is associated with poor perinatal outcomes including preterm birth (PTB). However, the frequency and causes of PTB in this population are not well understood. We hypothesized that NIHF frequently results in PTB due to medically indicated delivery for fetal distress. STUDY DESIGN: This was a secondary analysis of a prospectively enrolled cohort of pregnancies with NIHF that underwent exome sequencing if standard testing was nondiagnostic. The primary outcome was frequency of PTB at <37 weeks' gestation. Secondary outcomes were reasons for PTB, fetal predictors of PTB, and frequency of neonatal death following PTB. RESULTS: Fifty-six cases were included, with a median gestational age at delivery of 32.8 weeks (interquartile range [IQR]: 30.3-35.0). Overall, 86% (48/56) were delivered preterm. Among 48 PTBs, 18 (38%) were spontaneous, 9 (19%) were medically indicated for maternal indications (primarily preeclampsia), and 21 (44%) were medically indicated for fetal indications (nonreassuring antenatal testing or worsening effusions). Neither fetal genetic diagnosis nor polyhydramnios was associated with PTB. CONCLUSION: More than four-fifths of pregnancies with NIHF result in PTB, often due to nonreassuring fetal status. These data are informative for counseling patients and for developing strategies to reduce PTB in pregnancies with NIHF. KEY POINTS: · Pregnancies complicated by nonimmune hydrops fetalis often result in preterm birth.. · Preterm birth in these cases is most often medically indicated for fetal benefit.. · Fetal genetic conditions and polyhydramnios may be associated with preterm birth in cases of NIHF..

Disparities in the acceptance of chromosomal microarray at the time of prenatal genetic diagnosis.

OBJECTIVE: Chromosomal microarray (CMA) increases the diagnostic yield of prenatal genetic diagnostic testing but is not universally performed. Our objective was to identify provider and patient characteristics associated with the acceptance of CMA at the time of prenatal genetic diagnostic testing. METHODS: Retrospective cohort study of patients undergoing prenatal genetic diagnostic testing (chorionic villus sampling or amniocentesis) at a single institution between 2014 and 2020. Primary outcome was the acceptance of CMA based on the genetic counselor ,GC who saw the patient. Secondary analyses assessed patient characteristics associated with the acceptance of CMA. RESULTS: 2372 participants were included. Fifty-eight percent of participants accepted CMA. Acceptance of CMA varied significantly by GC, ranging from 31% to 90%. Patients with public insurance and those who identified as Black or Hispanic/Latina were less likely to have CMA performed (aOR 0.24, 95% CI 0.20-0.30, and 0.68, 95% CI 0.50-0.92). Even among those with a structural anomaly present, public insurance was associated with significantly lower odds of CMA being performed (aOR 0.39, 95% CI 0.25-0.61). CONCLUSIONS: Acceptance of CMA at the time of prenatal genetic diagnostic testing varied based on the GC performing the counseling. Public insurance was associated with lower frequency of accepting CMA.

The utility of pathologic examination and comprehensive phenotyping for accurate diagnosis with perinatal exome sequencing.

OBJECTIVE: Exome sequencing (ES) offers the ability to assess for variants in thousands of genes and is particularly useful in the setting of fetal anomalies. However, the ES pipeline relies on a thorough understanding of an individual patient's phenotype, which may be limited in the prenatal setting. Additional pathology evaluations in the pre- and postnatal settings can add phenotypic details important for clearly establishing and characterizing a diagnosis. METHODS: This is a case series of prenatal ES performed at our institution in which pathology evaluations, including autopsy, dysmorphology examination, histology, and peripheral blood smear, augmented the understanding of the fetal phenotype. ES was performed at our institution and a multidisciplinary panel reviewed and classified the variants for each case. RESULTS: We present four cases wherein pathology evaluations were beneficial for supporting a perinatal diagnosis identified with ES. In each of these cases, pathology findings provided additional data to support a more complete understanding of the relationship between the perinatal phenotype and variants identified with ES. CONCLUSION: These cases highlight challenges of perinatal ES related to incomplete prenatal phenotyping, demonstrate the utility of pathology evaluations to support diagnoses identified with ES, and further characterize the disease manifestations of specific genetic variants.

Preference for secondary findings in prenatal and pediatric exome sequencing.

OBJECTIVE: We aimed to determine the frequency of accepting secondary findings in families undergoing exome sequencing in prenatal and pediatric settings. METHODS: This was a secondary analysis of prospectively enrolled patients undergoing trio exome sequencing for congenital anomalies or developmental disorders in prenatal and pediatric settings, in which families were offered receiving secondary findings (initially assessed in the proband and, if identified, then in the parents). The primary outcome was frequency of accepting secondary findings. Secondary outcomes included frequency of acceptance in prenatal versus pediatric settings, and sociodemographic differences between those who accepted versus declined secondary findings. RESULTS: There were 682 families included in the cohort (289 prenatal and 393 pediatric). Overall, 84% (576/682) of families accepted secondary findings: 86.2% (249/289) of families undergoing prenatal versus 83.2% (327/393) pediatric (p = 0.30) testing. Secondary findings were identified in 2.6% (15/576) of cases, with no difference between prenatal and pediatric settings. There were no differences in sociodemographics between families that accepted versus declined secondary findings. CONCLUSION: The majority of families undergoing exome sequencing accepted secondary findings; this did not differ in prenatal versus pediatric settings. This highlights the need for guidance surrounding the offer of secondary findings in the prenatal setting.

Duration of Exposure to General Endotracheal Anesthesia during Cesarean Deliveries at Term and Perinatal Complications.

OBJECTIVE: To examine whether the duration of time from initiation of general endotracheal anesthesia (GETA) to delivery for cesarean deliveries (CDs) performed is related to perinatal outcomes. STUDY DESIGN: This is a retrospective study of patients with singleton nonanomalous gestations undergoing CD ≥37 weeks of gestation under GETA with reassuring fetal status at a single tertiary care center from 2000 to 2016. Duration from GETA initiation until delivery was calculated as the time interval from GETA induction to delivery (I-D), categorized into tertiles. Outcomes for those in the tertile with the shortest I-D were compared with those in the other two tertiles. The primary perinatal outcome was a composite of complications (continuous positive airway pressure or high-flow nasal cannula for ≥2 consecutive hours, inspired oxygen ≥30% for ≥4 consecutive hours, mechanical ventilation, stillbirth, or neonatal death ≤72 hours after birth). Secondary outcomes were 5-minute Apgar score <7 and a composite of maternal morbidity (bladder injury, bowel injury, and extension of hysterotomy). Bivariable and multivariable analyses were used to compare outcomes. RESULTS: Two hundred eighteen maternal-perinatal dyads were analyzed. They were dichotomized based on I-D ≤4 minutes (those in the tertile with the shortest duration) or >4 minutes. Women with I-D >4 minutes were more likely to have prior abdominal surgery and less likely to have labored prior to CD. I-D >4 minutes was associated with significantly increased frequency of the primary perinatal outcome. This persisted after multivariable adjustment. In bivariable analysis, 5-minute Apgar <7 was more common in the group with I-D >4 minutes, but this did not persist in multivariable analysis. Frequency of maternal morbidity did not differ. CONCLUSION: When CD is performed at term using GETA without evidence of nonreassuring fetal status prior to delivery, I-D interval >4 minutes is associated with increased frequency of perinatal complications. KEY POINTS: · Cesarean delivery under general anesthesia is associated with increased perinatal complications.. · Perinatal complications are increased with increasing duration of exposure to general anesthetics.. · Maternal complications were not increased with shorter duration of exposure to general anesthesia..

Patient Decisions Regarding Fetal Monitoring in the Periviable Period and Perinatal and Maternal Outcomes.

OBJECTIVE: Management of delivery at periviable gestation requires complex counseling and decision making, including difficult choices about monitoring and potential cesarean delivery (CD) for fetal benefit. Our objective was to characterize decisions that patients make regarding fetal monitoring and potential CD for fetal benefit when delivering in the periviable period, and associations with perinatal and obstetric outcomes. We hypothesize that a significant number of patients forgo monitoring and potential CD for fetal benefit in the periviable period when offered the opportunity to do so. STUDY DESIGN: Retrospective cohort study of nonanomalous singleton pregnancies delivering between 230/7 and 256/7 weeks at a tertiary care center from 2015 to 2020 as based on our institutional clinical practice. Since 2015, these patients are offered the ability to accept or decline fetal monitoring, potential CD for fetal benefit, and active resuscitation of a liveborn neonate. The frequency of patients desiring potential CD for fetal benefit was identified, and associations with CD and intrapartum demise were analyzed. RESULTS: Fifty subjects were included. Seventy-eight percent (n = 39) desired monitoring and potential CD for fetal benefit, and 84% (n = 42) desired resuscitation if the neonate was born alive. This varied by gestational age: 55% (6/11) of patients delivering between 230/7 and 236/7 weeks desired fetal monitoring and potential CD for fetal benefit, while 90% (19/21) of patients delivering between 250/7 and 256/7 weeks desired fetal monitoring and potential CD for fetal benefit (p = 0.02). Sixty-nine percent of pregnancies in which potential CD for fetal benefit was desired resulted in CD (27/39), of which 85% were classical (23/27). Intrapartum fetal demise occurred in 45% (5/11) of pregnancies in which monitoring was not performed. CONCLUSION: While a majority of patients delivering between 230/7 and 256/7 weeks desired monitoring and potential CD for fetal benefit, this varied significantly by gestational age. The decision to perform monitoring and potential CD for fetal benefit was associated with a high frequency of CD, while the decision to forgo monitoring was associated with high frequency of intrapartum demise. KEY POINTS: · Patients desires vary in the setting of periviable delivery.. · Periviable monitoring is associated with cesarean delivery.. · Forgoing monitoring is associated with intrapartum demise..

Is Preimplantation Genetic Testing Associated with Increased Risk of Abnormal Placentation After Frozen Embryo Transfer?

OBJECTIVE: This study aimed to assess the association of preimplantation genetic testing (PGT) with abnormal placentation among a cohort of pregnancies conceived after frozen embryo transfer (FET). STUDY DESIGN: This is a retrospective cohort study of women who conceived via FET at the University of California, San Francisco from 2012 to 2016 with resultant delivery at the same institution. The primary outcome was abnormal placentation, including placenta accreta, retained placenta, abruption, placenta previa, vasa previa, marginal or velamentous cord insertion, circumvallate placenta, circummarginate placenta, placenta membranacea, bipartite placenta, and placenta succenturiata. Diagnosis was confirmed by reviewing imaging, delivery, and pathology reports. Our secondary outcome was hypertensive disease of pregnancy. RESULTS: A total of 311 pregnancies were included in analysis; 158 (50.8%) underwent PGT. Baseline demographic characteristics were similar between groups except for age at conception and infertility diagnosis. Women with PGT were more likely to undergo single embryo transfer (82.3 vs. 64.1%, p < 0.001). There were no statistically significant differences in the rate of the primary outcome (26.6 vs. 27.4%, p = 0.86) or hypertensive disorders of pregnancy (33.5 vs. 33.3%, p = 0.97), which remained true after multivariate analysis was performed. CONCLUSION: Among pregnancies conceived after FET, PGT is not associated with a statistically significant increased risk of abnormal placentation or hypertensive disorders of pregnancy. KEY POINTS: · In pregnancies conceived by FET, PGT is not associated with increased risk of abnormal placentation.. · In pregnancies conceived by FET, PGT is not associated with increased risk of hypertensive disorders.. · Differences in outcomes of PGT pregnancies may be related to FET rather than trophectoderm biopsy..

Association of multifetal gestation with obstetric and neonatal outcomes in gestational carrier pregnancies.

OBJECTIVE: Multifetal gestation is more frequent among gestational carrier pregnancies than non-surrogacy IVF pregnancies. We aimed to evaluate the association between multifetal gestation and obstetric and neonatal morbidity among gestational carrier pregnancies. METHODS: Pooled cross-sectional study of birth certificate data from gestational carrier pregnancies in Utah from 2009 to 2018. Our primary outcome was a composite of severe obstetric morbidity; secondary outcomes included cesarean delivery (CD), hypertensive disorders of pregnancy, preterm birth (PTB), and a neonatal morbidity composite. Logistic regression was utilized to compare odds of these outcomes between gestational carrier pregnancies with and without multifetal gestation. RESULTS: A total of 361 gestational carrier pregnancies resulted in the delivery of 435 neonates during the study period. Of these, 284 were singleton pregnancies, and 77 were multifetal, a multifetal gestation rate of 21.3%. Baseline demographic characteristics did not differ between singleton and multifetal gestations. Multifetal gestation was not associated with higher rates of severe obstetric morbidity (odds ratio [OR] 1.87, 95% confidence interval [CI] 0.34-10.39). Multifetal gestation was associated with increased odds of neonatal morbidity (OR 9.49, 95% CI 5.35-15.83); PTB < 37, 34, and 32 weeks (OR 21.88, 95% CI 11.64-41.12; OR 11.67, 95% CI 5.25-25.91; OR 8.79, 95% CI 3.41-22.68); and CD (OR 4.82, 95% CI 2.81-8.27). CONCLUSION: Severe obstetric morbidity did not differ between singleton and multifetal gestations among gestational carrier pregnancies. However, multifetal gestation was associated with increased odds of neonatal morbidity, CD, and PTB. This information may be useful when counseling prospective gestational carriers and intended parents.

Obstetric morbidity in gestational carrier pregnancies: a population-based study.

PURPOSE: We sought to characterize severe obstetric morbidity among women who are gestational carriers compared to other patients. METHODS: This was a population-based study comparing gestational carrier pregnancies to non-surrogate pregnancies (non-surrogate IVF pregnancies, all non-gestational carrier pregnancies, and a cohort of matched controls) delivering in Utah between 2009 and 2018, using birth certificate data. Our primary outcome was a composite of severe morbidity, including death, ICU admission, eclampsia, HELLP syndrome, transfusion, and unplanned hysterectomy. Our secondary outcomes were cesarean delivery (CD) and hypertensive disorders of pregnancy. RESULTS: During the study period, 361 gestational carrier pregnancies and 509,015 other pregnancies resulted in live births. Severe morbidity was less common among gestational carrier pregnancies than IVF pregnancies (1.7% versus 5.5%, odds ratio [OR] 0.29, 95% confidence interval [CI] 0.12-0.70), but was not different when compared to all other pregnancies (1.0%, OR 1.61, 95% CI 0.72-3.60), or a cohort of matched controls (1.0%, OR 1.37, 95% CI 0.55-3.40). CD was less common among gestational carrier pregnancies than IVF pregnancies, but not different than all other pregnancies or matched controls. While frequency of hypertensive disorders of pregnancy was lower among gestational carrier pregnancies than IVF pregnancies, it was higher than all other women who delivered and comparable to matched controls. CONCLUSION: Severe obstetric morbidity is uncommon among gestational carrier pregnancies. Women who are gestational carriers are at lower risk of morbidity and CD than others who conceive through IVF and do not appear to be at increased risk compared to matched controls.

Understanding gestational surrogacy in the United States: a primer for obstetricians and gynecologists.

As gestational surrogacy (a process by which intended parents contract with a woman to carry a fetus that the intended parents will raise) increases across the United States, it is imperative that obstetrician/gynecologists understand the unique nuances of caring for patients who are gestational surrogates. Gestational surrogacy offers a route to parenthood for individuals and families who may otherwise have limited options. Understanding surrogacy requires multiple ethical considerations about the potential medical and psychosocial effects on gestational surrogates as well as the families built through surrogacy. There is a dearth of research on the subject, particularly in the United States and other countries that practice compensated surrogacy. Here we seek to review the process of gestational surrogacy in the United States, including the legal landscape, current trends in gestational surrogacy use, and what is known about the medical and social effects of this process on all participants. We also aim to highlight the limitations of available data and to identify topics for future research to provide optimal evidence-based and just care for these patients.

Is Uterocervical Angle Associated with Gestational Latency after Physical Exam Indicated Cerclage?

OBJECTIVE: Prediction of gestational latency after placement of physical exam indicated cerclage (PEIC) is limited. Uterocervical angle (UCA) has been associated with spontaneous preterm delivery in the general population. Our objective was to examine whether UCA is associated with gestational latency in women with PEIC. STUDY DESIGN: This retrospective cohort included women with a singleton gestation who had PEIC placed at a single tertiary care center between January 2010 and September 2015. Ultrasound images of the cervix obtained prior to placement of PEIC were reviewed. Spearman's correlation coefficient for the relationship between UCA and gestational latency was estimated. UCA was dichotomized at 95° and 105°. Survival analyses were performed and Cox proportional hazard ratios were calculated. RESULTS: Sixty women met the inclusion criteria. Median gestational latency was 93 days (IQR 39-121 d). There was no significant correlation between UCA and gestational latency (Spearman's rho 0.08, p = 0.54). Survival analyses demonstrated no significant difference in gestational latency stratified by UCA ≥ 95° (HR 1.19, 95% CI 0.70-2.04) or UCA ≥ 105° (HR 0.95, 95% CI 0.56-1.63). Findings persisted after adjusting for potential confounders (aHR 1.29, 95% CI 0.74-2.23 for UCA ≥ 95° and aHR 1.04, 95% CI 0.60-1.82). CONCLUSION: UCA is not associated with gestational latency in women with PEIC.

Labor Curves in Multiparous Women Related to Interbirth Intervals.

OBJECTIVE: Previous studies have shown that risk of cesarean section increases among multiparous women as interbirth interval increases. One possibility is that progress of labor may vary with interbirth interval, such that with longer intervals, labor curves of multiparas more closely resemble those of nulliparas. We sought to define labor curves among a cohort of multiparas with varying interbirth intervals. STUDY DESIGN: This was a retrospective cohort study of term multiparas with known interval from last delivery and only vaginal deliveries. Subjects were grouped by interval between the studied pregnancy and the most recent birth: 0 to 59, 60 to 119, and ≥120 months. Statistical analysis was performed using linear mixed effects model. Group slopes and intercepts were compared using model t-tests for individual effects. Length of second stage was compared using a Wilcoxon's rank-sum test. RESULTS: Groups did not differ significantly in demographic or obstetrical characteristics. Rate of dilation was similar between the 0 to 59 and 60 to 119 month groups (p = 0.38), but faster in the ≥120 month group compared with the 60 to 119 month group (p = 0.037). Median duration of second stage increased slightly with increased interbirth interval (p = 0.003). CONCLUSION: Prolonged interbirth interval is not associated with slower active phase of labor.

Can venous cord gas values predict fetal acidemia?

BACKGROUND: Umbilical cord arterial blood gas values are used to diagnose fetal acidemia; however, arterial cord blood specimens are frequently not available. OBJECTIVE: We sought to assess whether umbilical cord venous blood gas values can be used to reliably predict fetal acidemia. STUDY DESIGN: This is an observational study of women with a singleton gestation at a single tertiary care hospital who delivered from September 2010 through August 2015 and had both umbilical cord arterial and venous blood gas samples measured. Fetal acidemia was defined in 2 ways: (1) umbilical cord arterial pH <7.0, and (2) umbilical cord arterial base deficit ≥12 mEq/L. Receiver operating characteristic curves for fetal acidemia were generated using umbilical cord venous blood gas values and the areas under the curve were calculated. Umbilical cord venous blood gas cutoffs associated with <1%, <5%, <10%, and <50% probability of acidemia were calculated. RESULTS: Of the 36,325 women who met inclusion criteria, 563 (1.5%) had an umbilical cord arterial pH <7.0 and 1535 (4.2%) had an umbilical cord arterial base deficit ≥12 mEq/L. Umbilical cord venous pH was highly predictive of umbilical cord arterial pH <7.0 (area under the curve, 0.955; 95% confidence interval, 0.946-0.965). Similarly, umbilical cord venous base deficit was highly predictive of umbilical cord arterial base deficit ≥12 mEq/L (area under the curve, 0.967; 95% confidence interval, 0.963-0.971). While the combination of venous pH and base deficit was statistically significantly more predictive of umbilical cord arterial pH <7.0 (area under the curve, 0.961; 95% confidence interval, 0.952-0.969; P < .001), this difference has negligible clinical meaning. Similarly, the combination of venous pH and base deficit (area under the curve, 0.967; 95% confidence interval, 0.962-0.971) was no more predictive than venous base deficit alone in the prediction of umbilical cord arterial base deficit ≥12 mEq (P = .622). The likelihood of an arterial cord venous pH <7.0 was <1%, <5%, <10%, and <50% with cord venous pH of 7.22, 7.16, 7.14, and 7.07, respectively. The likelihood of an arterial cord base deficit ≥12 mEq/L was <1%, <5%, <10%, and <50% with cord venous base deficit of 7.0, 8.5, 9.2, and 11.3, respectively. CONCLUSION: Umbilical cord venous pH and base deficit are each highly predictive of fetal acidemia, and can be used to evaluate the likelihood of fetal acidemia in the absence of umbilical cord arterial blood gas values.

HIV Risk Behaviors and Correlates of Inconsistent Condom Use Among Substance Using Migrants at the Mexico/Guatemala Border.

This study assessed correlates of inconsistent condom use with casual partners and the prevalence of sexual risk behaviors and STIs in the Mexico/Guatemala border region using a sample of 392 migrants (303 men, 85 women) who reported current substance use or problem drinking. We ran separate univariate logistic regression models for men and women, and multivariate logistic regression models for men only. Prevalence of syphilis was 1.2% among women and 2.3% among men; HIV prevalence was 2.4% among women and 1.3% among men. Inconsistent condom use with casual partners was higher in women with greater education and lower among women who sold sex. In men, less access to free condoms, drug use with sexual partners, and drug use before sex were independently associated with inconsistent condom use with casual partners. Sexual and substance use risk behaviors were common, and HIV/STI prevention efforts should target both genders and expand beyond most-at risk populations.

The Association between the Intertwin Interval and Adverse Neonatal Outcomes.

Objective Previous data examining the association between the interval between the delivery of the first and second twin (intertwin interval) and adverse neonatal outcomes are conflicting. We sought to evaluate whether intertwin interval is associated with adverse neonatal outcomes for the second twin in a contemporary U. S. cohort. Methods This is a cohort study of women who delivered twins at or after 32 weeks gestation between 2006 and 2014 and whose first twin was delivered vaginally vertex. The intertwin interval was dichotomized as < 10 minutes or ≥ 10 minutes. Adverse outcomes included arterial cord pH ≤ 7.1, admission to the neonatal intensive care unit, respiratory distress, intraventricular hemorrhage, and death. Results Of the 171 subjects, 61 (35.7%) had an intertwin interval of ≥ 10 minutes. There were no differences in maternal characteristics. Intertwin interval of ≥ 10 minutes was associated with an increased frequency of arterial pH ≤ 7.1 (22.0 vs. 8.2%, p = 0.03), which persisted after adjusting for confounders (adjusted odds ratio, 2.94; 95% confidence interval, 1.04-8.33). Other adverse outcomes did not differ. Conclusion Intertwin interval of ≥ 10 minutes was associated with increased frequency of arterial pH ≤ 7.1 in the second twin, but no other adverse neonatal outcomes.