A model and scoring system to predict outcome of intrauterine pregnancies of uncertain viability.

OBJECTIVES: To define the incidence and outcome of intrauterine pregnancy of uncertain viability (PUV) and to develop and assess the performance of a model and a scoring system to predict ongoing viability. METHODS: Of 1881 consecutive women undergoing transvaginal ultrasonography, a cohort of 493 women with an empty gestational sac < 20 mm in mean diameter, gestational sac < 25 mm in mean diameter and containing yolk sac only or an embryonic pole < 6 mm in maximum length and without visible heart activity were followed until the end of the first trimester. Women with multiple pregnancies or who underwent termination of pregnancy were excluded. Outcome measures were pregnancy viability at initial 7-14-day follow-up and first-trimester viability at 11-14 weeks. The data were split randomly into two sets (two-thirds and one-third, respectively) in order to first develop and then test a mathematical model and a 'simple' model in the prediction of viability at each outcome point, based on maternal demographics, ultrasound features and symptoms. The performance of each system was assessed by receiver-operating characteristics (ROC) curve analysis and calibration plots on a test dataset. RESULTS: The incidence of PUV in this population was 29.2% (549/1881). Of the 493 pregnancies with initial (7-14 days) follow-up available, 307 (62.3%) were viable at this time and of the 444 pregnancies with follow-up at the end of the first trimester, 225 (50.7%) were still viable. Initial (7-14-day) viability was predicted by the model with an area under the ROC curve (AUC) of 0.837 (95% CI, 0.791-0.884) in the training dataset and 0.821 (95% CI, 0.756-0.885) in the test dataset. First-trimester (11-14-week) viability was predicted by the model with an AUC of 0.788 (95% CI, 0.734-0.842) in the training dataset and 0.774 (95% CI, 0.701-0.848) in the test dataset. The scoring system performed slightly worse than did the model, but had the advantage of being easily applicable. CONCLUSIONS: When early pregnancy viability cannot be established immediately with ultrasound, use of either a logistic regression model or a scoring system allows an individualized prediction of first-trimester outcome.

Functional linear discriminant analysis: a new longitudinal approach to the assessment of embryonic growth.

BACKGROUND: Functional linear discriminant analysis (FLDA) is a new growth assessment technique using serial measurements to discriminate between normal and abnormal fetal growth. We used FLDA to assess and compare growth in live pregnancies destined to miscarry with those remaining viable. METHODS: This was a prospective cohort study of women with ultrasound scans on at least two separate occasions showing live pregnancies. Serial crown-rump length (CRL), mean gestational sac diameter and mean yolk sac diameter measurements were recorded. The ability of FLDA to predict subsequent miscarriage was compared with that of a single CRL measurement. RESULTS: Of 521 included pregnancies, 493 (94.6%) remained viable at 14 weeks and 28 (5.4%) miscarried. The CRL growth rate was significantly lower in those that miscarried (one-sample t-test, P = 2.638E-22). The sensitivity of FLDA in predicting miscarriage from serial CRL measurements was 60.7% and specificity was 93.1% [positive predictive value (PPV) 33.3%, negative predictive value (NPV) 97.7%]. This was significantly better for predicting miscarriage than a single CRL observation of more than 2SD below that expected (sensitivity 53.6%, specificity 72.2%, PPV 9.9%, NPV 96.5%). CONCLUSIONS: FLDA discriminates between normal and abnormal growth to predict miscarriage with high specificity. FLDA predicts miscarriage better than a single observation of a small CRL.

The optimal timing of an ultrasound scan to assess the location and viability of an early pregnancy.

BACKGROUND: The objective of this study was to determine the optimal gestational age at which to establish the location and viability of an early pregnancy using transvaginal ultrasonography (TVS). METHODS: This was a prospective study of 1442 women undergoing initial TVS at no more than 84 days gestation. Logistic regression analysis was performed to determine the relationship between gestational age and the ability to confirm viability or non-viability, in women with and without symptoms of pain and bleeding. RESULTS: The commonest TVS finding prior to 35 days was a pregnancy of unknown location, from 35 to 41 days an early intrauterine pregnancy of uncertain viability and from 42 days a viable intrauterine pregnancy. Miscarriage could only be diagnosed on initial TVS after 35 days. There was no difference between the ability to make a diagnosis for women with certain or uncertain dates (P = 0.719). The chance of confirming viability increased rapidly per day of gestation until 49 days and thereafter plateaued. Of the 29 ectopic pregnancies diagnosed, 72% presented prior to 49 days gestation and all of these women presented with pain, bleeding or a previous ectopic pregnancy history. CONCLUSIONS: The ability to confirm viability or non-viability is significantly related to gestational age. In asymptomatic women with no previous ectopic pregnancy TVS should be delayed until 49 days. Our data suggest that this would reduce the number of inconclusive scans, without an associated increase in morbidity from missed ectopic pregnancies.

Evidence of early first-trimester growth restriction in pregnancies that subsequently end in miscarriage.

OBJECTIVES: To examine whether viable early pregnancies that subsequently end in miscarriage exhibit evidence of first-trimester growth restriction. DESIGN: Prospective cohort study. SETTING: Early pregnancy unit (EPU) of a teaching hospital. POPULATION: Women attending EPU between 5 and 10 weeks of gestation. METHODS: Women with spontaneously conceived intrauterine, viable singleton pregnancies with certain last menstrual period and regular cycles were included. The deviation between the observed and expected crown-rump length (CRL) for gestation was calculated and expressed as a z score. Pregnancies were followed up until the 11-14 week scan, and the deviation between those that remained viable and miscarried subsequently was calculated. MAIN OUTCOME MEASURES: Viability at 11-14 week scan. RESULTS: Over 6 months, 316 women met the inclusion criteria. Twenty-four (7.4%) women were excluded. Of the remaining 292, the pregnancy remained viable in 251 (86%) and 41 (14%) suffered a miscarriage. At the first transvaginal ultrasound, the z score of the mean measured CRL for pregnancies that remained viable was -0.82, SD 1.46, while in pregnancies that subsequently miscarried the z score was -2.42 and the CRL was significantly smaller, SD 1.31 (P < 0.0001). In the latter group, the initial CRL was below the expected mean for gestational age in all women, while in 61% (25/41), the CRL was at least 2 SDs below the expected mean. CONCLUSIONS: CRL was significantly smaller in pregnancies that subsequently ended in miscarriage. This suggests that early first-trimester growth restriction is associated with subsequent intrauterine death.

Impact of the availability of sonography in the acute gynecology unit.

OBJECTIVE: The initial assessment of acute gynecology patients is usually based on history and clinical examination and does not involve ultrasound. The aim of this study was to investigate the impact of the availability of transvaginal sonography at the time of initial assessment of the emergency gynecology patient. METHODS: This was a prospective observational study carried out over a 5-month period in the acute gynecology unit of an inner London teaching hospital. Women were assessed in the routine manner by history-taking and clinical examination and questionnaires were completed by the doctors, including details of the intention to treat. Transvaginal ultrasound examinations were then performed and a second diagnosis and management plan were made utilizing the extra information from the scan. The plans for clinical management before and after the ultrasound examination were compared. RESULTS: We originally recruited 1000 consecutive women to the study. The mean age was 31.1 (SD, 9.81) years. Complete data were available for 920 (92%). 84 (9.1%) women did not require a scan. Of the 521 women with a positive pregnancy test, 75.6% were reassured immediately that their pregnancy was intrauterine. 143 women (27.4%) were given the diagnosis of a suspected ectopic pregnancy before sonography, compared with 29 (5.6%) after. Following the ultrasound examination there was a change in clinical management in 54.1% of the women with a positive pregnancy test and a reduction in admissions (including inpatient theater admissions) (from 40.3% to 17.1%) and outpatient follow-up examinations (from 41.1% to 35.5%). In 90 (23.8%) non-pregnant women a significant ovarian cyst (> 5 cm) was suspected clinically; 28/90 (31.1%) were confirmed on sonography. Following the ultrasound examination there was a change in clinical management for 38.1% of non-pregnant women and a reduction in admissions (from 37.1% to 19.4%) and outpatient follow-up examinations (from 25.7% to 18.1%). CONCLUSION: It appears that the availability of transvaginal sonography at the time of initial assessment of emergency gynecology patients improves diagnostic accuracy and reduces unnecessary admissions and follow-up examinations.