Objectives To assess whether early fetal growth restriction in a twin, expressed as the intertwin discrepancy in crown-rump length (CRL) between two viable twins at 16.9% discrepancy (sensitivity, 88.9%; 95% CI, and specificity, 86.7%; 95% CI,. ConclusionThere is a significant relationship between CRL discrepancy at 7 + 0 to 9 + 6 weeks and the likelihood of subsequent single intrauterine fetal loss. This suggests that spontaneous fetal demise of one twin may be preceded by growth restriction in the first trimester.

Objectives To assess the agreement in the diagnosis of chorionicity and amnionicity between transvaginal ultrasound examination at 7-9 weeks' gestation and at the 11-14-week transabdominal scan. Methods

Objectives: The differential diagnosis of fetal renal or suprarenal pathology includes severe or life-threatening conditions such as infantile renal polycystosis or bilateral renal agenesis as well as potentially malignant forms such as a Wilms' tumor, suprarenal neuroblastomas or lymphangiomas. The nature and exact location of these lesions are important for diagnosis and optimal perinatal management and cannot always be made conclusively on ultrasound. This report evaluated the added value of fetal Magnetic Resonance Imaging (fMRI) in the differential diagnosis of fetuses with renal or suprarenal pathology. Methods: All fetuses with suspected but inconclusive ultrasound diagnosis of (supra)renal lesions underwent fMRI during the study period (2001)(2002)(2003)(2004)(2005)(2006). The fMRI scanning protocol consisted of T1, T2 and diffusion weighed images (DWI) in the three orthogonal axes. Results: During the study period 547 fMRI examinations were performed. There were 28 cases (5.1%) with (supra)renal pathology suspected on ultrasound examination. Antenatal MRI was performed at a median gestational age of 24 (range 17-39) weeks. The tentative sonographic diagnosis was confirmed by fMRI and postnatal imaging studies in 22 cases (78.5%). In 5 cases (17.8%) MRI added relevant information. In one case (3.8%) the MRI was of no value due to the poor image quality. Conclusions: MRI can have an additive value in the perinatal workup of renal and suprarenal pathology of unclear origin on prenatal ultrasound. It is especially helpful to differentiate renal from adrenal origin of the lesions and offers good image quality in the presence of oligo-or anhydramnios. OP04: EARLY PREGNANCY IOP04.01 Has ultrasound eliminated the need for a vaginal speculum examination in the assessment of women with bleeding in early pregnancy? Department of Early Pregnancy and Gynaecological Ultrasound, St George's Hospital, London, United KingdomObjectives: Vaginal bleeding affects around 20% of women in the first trimester. These women often attend emergency departments or general practitioners, where a vaginal speculum examination (VSE) is performed before referral to an early pregnancy unit (EPU) for assessment and a transvaginal scan (TVS). This study aimed to investigate whether a VSE improves diagnosis or management in women complaining of bleeding prior to TVS. Methods: This was a prospective study performed over six months in a 'walk-in' EPU by a single investigator. Women with bleeding prior to 14 weeks' gestation were asked to describe bleeding as heavy, moderate or light and consent to VSE prior to TVS. The presence of vaginal bleeding or evidence of cervical pathology was documented. TVS was performed to obtain a final diagnosis of miscarriage (early fetal demise, empty sac, complete or incomplete) or a viable (or early ongoing) intrauterine pregnancy (IUP). Results: 221/223 women consented to VSE. In women complaining of heavy bleeding, blood was seen in all VSE, 27(84%) had a miscarriage and five (16%) had an IUP diagnosed on T...

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Oral communication abstracts odds ratio (OR) for each previous delivery 1.48 (95% CI, 1.22-1.80), P < 0.0001; OR for each previous miscarriage 1.34 (95% CI, 1.07-1.68), P = 0.01. Excluding women with any previous miscarriage and adjusting for parity we found a U-shaped relationship between maternal age and miscarriage (P = 0.04). Conclusions: In singleton pregnancies with an estimated risk of Down syndrome < 1 : 250 according to NT screening at 12-14 weeks, the spontaneous fetal loss rate before 25 weeks is likely to be around 0.5%. NT thickness up to 3 mm does not seem to affect the risk of miscarriage in such pregnancies. Instead, the risk seems to increase with number of previous miscarriages and deliveries, and possibly the risk is highest in the youngest and oldest women. OC57 Enlarged nuchal translucency in the same woman in different pregnancies

Of 1000 women attending an early pregnancy unit over 3 months who had at least two ultrasound examinations confirming singleton viability, two classes of pregnancies are considered: ongoing pregnancies and early pregnancy losses. Our objective was to discriminate between these two classes to predict early pregnancy loss. We considered the rate of growth of the crown-rump length (CRL), the mean sac diameter (MSD) and the difference between MSD and CRL as a function of the gestational age (GA). Methods: Classical linear discriminant analysis (LDA) classifies data by maximizing the ratio of the between-class variation to the within-class variation. FLDA is an extension where the predictor variables are curves (e.g. a variable measured multiple times during pregnancy). Serial observations from each individual are modeled with a spline function (a curved line formed by two or more vertices), parameterized with a basis function multiplied by a 5-dimensional coefficient vector. A training set was used to estimate the mean coefficient vector for each class. New patients can then be classified by determining the class with the closest mean coefficient vector. Results: 270 patients had at least two measurements for CRL and GA. Nine of these subsequently resulted in early pregnancy loss. It was not possible to discriminate between classes with FLDA using CRL alone. Using MSD we could include 99 patients and mean growth curves of MSD as function of GA for ongoing pregnancies and pregnancy losses did not overlap (P < 0.0001). The MSD for early pregnancy loss was smaller at all gestational ages. Moreover, the difference between MSD and CRL could be used to discriminate between ongoing pregnancies and pregnancies destined to fail (P < 0.0001). Conclusions: Using FLDA it is possible to predict early pregnancy loss on the basis of MSD or difference between MSD and CRL for patients in whom MSD and CRL have been measured on at least two occasions.

Oral poster abstracts OP04.07 Predicting early pregnancy loss with functional linear discriminant analysis (FLDA)AObjectives: Of 1000 women attending an early pregnancy unit over 3 months who had at least two ultrasound examinations confirming singleton viability, two classes of pregnancies are considered: ongoing pregnancies and early pregnancy losses. Our objective was to discriminate between these two classes to predict early pregnancy loss. We considered the rate of growth of the crown-rump length (CRL), the mean sac diameter (MSD) and the difference between MSD and CRL as a function of the gestational age (GA). Methods: Classical linear discriminant analysis (LDA) classifies data by maximizing the ratio of the between-class variation to the within-class variation. FLDA is an extension where the predictor variables are curves (e.g. a variable measured multiple times during pregnancy). Serial observations from each individual are modeled with a spline function (a curved line formed by two or more vertices), parameterized with a basis function multiplied by a 5-dimensional coefficient vector. A training set was used to estimate the mean coefficient vector for each class. New patients can then be classified by determining the class with the closest mean coefficient vector. Results: 270 patients had at least two measurements for CRL and GA. Nine of these subsequently resulted in early pregnancy loss. It was not possible to discriminate between classes with FLDA using CRL alone. Using MSD we could include 99 patients and mean growth curves of MSD as function of GA for ongoing pregnancies and pregnancy losses did not overlap (P < 0.0001). The MSD for early pregnancy loss was smaller at all gestational ages. Moreover, the difference between MSD and CRL could be used to discriminate between ongoing pregnancies and pregnancies destined to fail (P < 0.0001). Conclusions: Using FLDA it is possible to predict early pregnancy loss on the basis of MSD or difference between MSD and CRL for patients in whom MSD and CRL have been measured on at least two occasions. OP04.08Does the location of a subchorionic hematoma in early pregnancy affect the miscarriage rate? St Georges Hospital, London, United KingdomObjectives: Subchorionic hematomas (SCH) are observed on ultrasound in early pregnancy in 0.5% to 22% of women, and some studies suggest that the presence of an SCH may increase the risk of miscarriage. However, the relationship between the location of SCH and subsequent pregnancy outcome has not been examined. We have postulated that the gestational sac (GS) may be more likely to become disrupted by blood tracking from an SCH above it, than if the SCH is near the cervix. The aim of this study was to examine whether the location of the SCH has a bearing on the likelihood of subsequent miscarriage before 12 weeks. Methods: This was a prospective cohort study of an unselected early pregnancy population. Women attending for a transvaginal scan (TVS) with a singleton viable pregnancy before 12 weeks of gestation were included. ...

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