Natasha L. Hezelgrave

Quantitative Fetal Fibronectin to Predict Preterm Birth in Asymptomatic Women at High Risk

OBJECTIVE: To evaluate the diagnostic accuracy of cervicovaginal fluid quantitative fetal fibronectin, measured by a bedside analyzer, to predict spontaneous preterm birth before 34 weeks of gestation. METHODS: We conducted a prospective masked observational cohort study of cervicovaginal fluid quantitative fetal fibronectin concentration in asymptomatic women at high risk of spontaneous preterm birth (n=1,448; 22–27 6/7 weeks of gestation) measured using a rapid bedside analyzer. The routine qualitative result (positive–negative) was made available to clinicians at the time of testing, but the quantitative result remained blinded until after delivery. RESULTS: Spontaneous preterm birth (less than 34 weeks of gestation) increased from 2.7%, 11.0%, 14.9%, 33.9%, and 47.6% with increasing concentration of fetal fibronectin (less than 10, 10–49, 50–199, 200–499, and 500 ng/mL or greater, respectively). A threshold of 200 ng/mL had a positive predictive value of 37.7 (95% confidence interval [CI] 26.9–49.4) with specificity 96% (95% CI 95.3–97.3). Women with a fetal fibronectin concentration of less than 10 ng/mL had a very low risk of spontaneous preterm birth at less than 34 weeks of gestation (2.7%), no higher than the background spontaneous preterm birth rate of the general hospital population (3.3%). The quantitative fetal fibronectin test predicted birth at less than 34 weeks of gestation with an area under the curve (AUC) of 0.78 (95% CI 0.73–0.84) compared with the qualitative test AUC 0.68 (95% CI 0.63–0.73). Quantitative fetal fibronectin discriminated risk of spontaneous preterm birth at less than 34 weeks of gestation among women with a short cervix (less than 25 mm); 9.5% delivered prematurely less than 10 ng/mL compared with 55.1% greater than 200 ng/mL (P<.001). DISCUSSION: Alternative risk thresholds (less than 10 ng/mL and greater than 200 ng/mL) improve accuracy when using quantitative fetal fibronectin measurements to define risk of spontaneous preterm birth. This is particularly relevant for asymptomatic women with a short cervix. LEVEL OF EVIDENCE: II

Shock index: an effective predictor of outcome in postpartum haemorrhage?

To compare the predictive value of the shock index (SI) with conventional vital signs in postpartum haemorrhage (PPH), and to establish ‘alert’ thresholds for use in low‐resource settings.

Pregnancy after bariatric surgery: a review.

Maternal obesity is a major cause of obstetric morbidity and mortality. With surgical procedures to facilitate weight loss becoming more widely available and demanded and increasing number of women becoming pregnant after undergoing bariatric surgery, it is important and timely to consider the outcome of pregnancy following bariatric surgery. This paper aims to synthesize the current evidence regarding pregnancy outcomes after bariatric surgery. It concludes that bariatric surgery appears to have positive effects on fertility and reduces the risk of gestational diabetes and preeclampsia. Moreover, there appears to be a reduced incidence of fetal macrosomia post-bariatric procedure, although there remains uncertainty about the increased rates of small-for-gestational age and intrauterine growth restricted infants, as well as premature rupture of membranes in this group. A number of case reports highlight that pregnancy following bariatric surgery is not without complications and it must be managed as high risk by the multidisciplinary team.

Vital Sign Prediction of Adverse Maternal Outcomes in Women with Hypovolemic Shock: The Role of Shock Index.

Objective To determine the optimal vital sign predictor of adverse maternal outcomes in women with hypovolemic shock secondary to obstetric hemorrhage and to develop thresholds for referral/intensive monitoring and need for urgent intervention to inform a vital sign alert device for low-resource settings. Study Design We conducted secondary analyses of a dataset of pregnant/postpartum women with hypovolemic shock in low-resource settings (n = 958). Using receiver-operating curve analysis, we evaluated the predictive ability of pulse, systolic blood pressure, diastolic blood pressure, shock index, mean arterial pressure, and pulse pressure for three adverse maternal outcomes: (1) death, (2) severe maternal outcome (death or severe end organ dysfunction morbidity); and (3) a combined severe maternal and critical interventions outcome comprising death, severe end organ dysfunction morbidity, intensive care admission, blood transfusion ≥ 5 units, or emergency hysterectomy. Two threshold parameters with optimal rule-in and rule-out characteristics were selected based on sensitivities, specificities, and positive and negative predictive values. Results Shock index was consistently among the top two predictors across adverse maternal outcomes. Its discriminatory ability was significantly better than pulse and pulse pressure for maternal death (p<0.05 and p<0.01, respectively), diastolic blood pressure and pulse pressure for severe maternal outcome (p<0.01), and systolic and diastolic blood pressure, mean arterial pressure and pulse pressure for severe maternal outcome and critical interventions (p<0.01). A shock index threshold of ≥ 0.9 maintained high sensitivity (100.0) with clinical practicality, ≥ 1.4 balanced specificity (range 70.0–74.8) with negative predictive value (range 93.2–99.2), and ≥ 1.7 further improved specificity (range 80.7–90.8) without compromising negative predictive value (range 88.8–98.5). Conclusions For women with hypovolemic shock from obstetric hemorrhage, shock index was consistently a strong predictor of all adverse outcomes. In lower-level facilities in low resource settings, we recommend a shock index threshold of ≥ 0.9 indicating need for referral, ≥ 1.4 indicating urgent need for intervention in tertiary facilities and ≥ 1.7 indicating high chance of adverse outcome. The vital sign alert device incorporated values 0.9 and 1.7; however, all thresholds will be prospectively validated and clinical pathways for action appropriate to setting established prior to clinical implementation.

Development and validation of a tool incorporating cervical length and quantitative fetal fibronectin to predict spontaneous preterm birth in asymptomatic high‐risk women

To develop a predictive tool for spontaneous preterm birth (sPTB) in asymptomatic high‐risk women that includes quantification of fetal fibronectin (fFN) along with cervical length (CL) measurement and other clinical factors.

Development and validation of a predictive tool for spontaneous preterm birth incorporating cervical length and quantitative fetal fibronectin in asymptomatic high‐risk women

To develop a predictive tool for spontaneous preterm birth (sPTB) in asymptomatic high‐risk women that includes quantification of fetal fibronectin (fFN) along with cervical length (CL) measurement and other clinical factors.

Advising on travel during pregnancy

#### Summary points As travel increases,1 the number of pregnant women who travel will probably rise. Women often ask if travel is safe in pregnancy and seek advice from a range of healthcare professionals. Travel related maternal and fetal morbidity and mortality can be completely avoided only by postponing travel until after delivery, but travel may be necessary or desirable during pregnancy. Most women are “low risk” and can expect no problems with travel during pregnancy. However, there are particular risks to be considered with each stage of pregnancy, especially if the pregnancy is complicated by comorbidity. Medical concerns can be divided into risks of travel itself (in particular air travel), difficulties related to negotiating different healthcare systems and insurance, and specific risks of acquiring infectious diseases in particular countries. Some travel companies place restrictions on travel in pregnancy. Limited robust evidence or disseminated guidelines makes it difficult to provide definitive advice. When asked to advise a woman regarding travel in pregnancy a careful risk assessment will help to inform the advice given. We outline an approach to considering risks associated with travel during pregnancy and discuss preparation for travel, advice on managing illness while abroad, and relevant post-travel considerations. This article is relevant to all who provide care during pregnancy, particularly general practitioners, who may be the primary source of advice for women with uncomplicated pregnancies who are considering travel. #### Sources and selection criteria We searched PubMed and the …

Development and validation of a tool incorporating quantitative fetal fibronectin to predict spontaneous preterm birth in symptomatic women

To develop a reliable and validated tool for prediction of spontaneous preterm birth (sPTB) in symptomatic women that incorporates quantitative measurements of fetal fibronectin (qfFN) and other relevant risk factors.

Quantitative Fetal Fibronectin at 18 Weeks of Gestation to Predict Preterm Birth in Asymptomatic High-Risk Women.

OBJECTIVE: To compare quantitative fetal fibronectin measurement from 18 to 21 weeks of gestation to measurement at 22–27 weeks of gestation for the prediction of spontaneous preterm birth. METHODS: In a prospective cohort study, we studied the accuracy of cervicovaginal fluid quantitative fetal fibronectin concentrations measured between 18 0/7 weeks of gestation and 21 6/7 weeks of gestation in high-risk asymptomatic women to predict spontaneous preterm birth before 34 weeks of gestation. Predefined fibronectin thresholds were 10 or greater, 50 or greater, and 200 ng/mL or greater. Diagnostic accuracy of the early test (n=898) was compared with the standard test performed between 22 0/7 and 27 6/7 weeks of gestation (n=691) in the same cohort. Subgroup analysis was performed according to cervical length measurement. RESULTS: Of 898 women, 8.7% delivered spontaneously before 34 weeks of gestation. Only 3.8% of the women with concentrations less than 10 ng/mL (65% of test results) delivered before 34 weeks of gestation. A concentration threshold of 10 ng/mL measured at 18 and 22 weeks of gestation had comparably high sensitivity (early 0.71, 95% confidence interval 0.60–0.81; standard 0.76, 0.63–0.87) and negative predictive value (early 0.96, 0.94–0.98; standard 0.97, 0.95–0.99) for delivery before 34 weeks of gestation. Specificity was also comparable (early 0.69, 0.65–0.72; standard 0.70, 0.66–0.74). A threshold of 200 ng/mL had high specificity (early 0.96, 0.94–0.98; standard 0.96, 0.94–0.97) with lower sensitivity (early 0.26, 0.17–0.37; standard 0.35, 0.22–0.49). Consideration of cervical length strengthened prediction. CONCLUSION: Quantitative cervicovaginal fetal fibronectin measured from 18 to 21 weeks of gestation has similar predictive value as measurement at 22–27 weeks of gestation for prediction of spontaneous preterm birth. Low fibronectin concentrations are associated with spontaneous preterm birthrates approaching population background levels.

Endocervical and high vaginal quantitative fetal fibronectin in predicting preterm birth

Abstract Objective: Accurate prediction of spontaneous preterm birth (sPTB) is essential to target interventions. Fetal fibronectin (fFN) is a leading predictor. A quantitative fFN (qfFN) test has improved prediction, based on high vaginal swabs (HVS). It is not known how endocervical (ECS) fFN levels compare, or which has the best predictive value. Our principal aim was to determine the difference in fFN concentration between HVS and ECS and compare their ability to predict sPTB. Methods: Asymptomatic high risk women (18+0–30+0 weeks gestation) had secretions sampled from the endocervix (ECS) and vaginal fornix (HVS), analyzed by the quantitative fFN analyzer (Hologic). Mean concentrations were compared; ROC curves were calculated using area under the curve (AUC) for prediction of delivery <30 and 37 weeks. Results: Mean HVS value was lower than ECS (80 ng/ml (SD142) versus 217 (SD 212) (p < 0.05). Predictive ability was similar: AUC of 0.92 and 0.94, respectively, for prediction of sPTB < 37 and 0.84 and 0.82 for <30 weeks. Conclusions: Endocervical qfFN is higher than HVS and clinicians should avoid ECS if using traditional thresholds. ECS and HVS are both useful predictors, but require different threshold values. Further work is needed to determine whether ECS is a better and safe test to justify the difficulty in sampling.