C. Zanardini

The effect of fetal sex on customized fetal growth charts

Abstract Objective: To evaluate the effect of fetal sex on singleton pregnancy growth charts customized for parental characteristics, race, and parity Methods: In a multicentric cross-sectional study, 8070 ultrasonographic examinations from low-risk singleton pregnancies between 16 and 40 weeks of gestation were considered. The fetal measurements obtained were biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL). Quantile regression was used to examine the impact of fetal sex across the biometric percentiles of the fetal measurements considered together with parents’ height, weight, parity, and race. Results: Fetal gender resulted to be a significant covariate for BDP, HC, and AC with higher values for male fetuses (p ≤ 0.0009). Minimal differences were found among sexes for FL. Parity, maternal race, paternal height and maternal height, and weight resulted significantly related to the fetal biometric parameters considered independently from fetal gender. Conclusion: In this study, we constructed customized biometric growth charts for fetal sex, parental, and obstetrical characteristics using quantile regression. The use of gender-specific charts offers the advantage to define individualized normal ranges of fetal biometric parameters at each specific centile. This approach may improve the antenatal identification of abnormal fetal growth.

Rapid cervical phIGFBP-1 test in asymptomatic twin pregnancies: role in mid-pregnancy prediction of spontaneous preterm delivery.

This study aimed to assess the accuracy of a second‐trimester rapid cervical phosphorylated insulin‐like growth factor binding protein‐1 (phIGFBP‐1) test to predict spontaneous preterm delivery in asymptomatic twin pregnancies.

Early prediction of twin-to-twin transfusion syndrome: systematic review and meta-analysis.

To assess the role of first‐ and early second‐trimester markers in the prediction of twin‐to‐twin transfusion syndrome (TTTS) in monochorionic twin pregnancies.

Changes in ductus venosus velocity ratios after fetoscopic laser surgery for twin–twin transfusion syndrome

Wohlmuth et al.1 described changes in ductus venosus waveforms (DV-FVW) in 149 pairs of monochorionic diamniotic (MCDA) twin pregnancies referred for twin-twin transfusion syndrome (TTTS) requiring fetoscopic laser surgery. We hypotesize that DV-FVW might also change after placental laser ablation.

Management of monochorionic twin pregnancy discordant for body‐stalk anomaly

A 31-year-old woman, gravida 4 para 1 was referred to our center at 11+1 weeks of gestation: the ultrasound examination revealed a monochorionic monoamniotic twin pregnancy, and one fetus was affected by body stalk anomaly. Chorionic villus sampling revealed a 46,XX karyotype. Extensive counselling about the prognosis of the affected fetus and possible complications of the pregnancy was provided.

Maternal functional hemodynamics in uncomplicated twin pregnancies: a longitudinal study using impedance cardiography

Longitudinal studies of maternal hemodynamics in twin pregnancy are scarce and preload reserve in twin pregnancies has not been studied. Thus, we aimed to investigate serial changes in maternal systemic hemodynamics from the first to third trimester, and cardiovascular response to passive leg raising to evaluate preload reserve using impedance cardiography in a cohort of uncomplicated twin pregnancies.

Fetoscopic cord transection for treatment of monoamniotic twin reversed arterial perfusion sequence

We read with interest two articles discussing the role and timing of intrafetal procedures, particularly interstitial laser therapy, for the treatment of twin reversed arterial perfusion (TRAP) sequence1,2. In both case series and in the systematic review by Pagani et al.1, no case appeared to involve a monoamniotic twin pregnancy. However, approximately 3−4% of cases of TRAP sequence are monoamniotic3. Since the umbilical cord of the parasitic twin is often very short, this does not usually affect treatment modality. However, when the cord is long enough to allow cord entanglement with the pump twin, this can pose a major challenge. Although cord entanglement per se is not associated with increased risk of complications in monoamniotic pregnancies4, occlusion of blood flow to the abnormal twin may be associated with increased risk of intrauterine death of the surviving twin and has been described as a cause of intrauterine demise in TRAP sequence5. It is possible that the unperfused cord undergoing involution may easily act as a band constricting the cotwin’s cord more than a normally perfused cord with an adequate amount of Wharton’s jelly. To avoid such risks, it is feasible to transect the umbilical cord with laser after its occlusion, thus allowing release of the entanglement; this has been reported in only one case of TRAP sequence5. We describe here two further cases of TRAP sequence in monoamniotic twin pregnancies with cord entanglement (Figures 1 and 2), treated by fetoscopic laser cord coagulation and transection. Procedures were performed between March 2012 and March 2013, both with a single-entry technique using a 2-mm fetoscope inserted under ultrasound guidance in the amniotic cavity through a sheath with an outer diameter of 3 mm (Karl Storz, Tuttlingen, Germany). The umbilical cord of the parasitic Figure 1 Ultrasound image of Case 1 at 23 + 2 weeks, showing entanglement of the two cords (long arrow) and a very short length of free parasitic twin umbilical cord at abdominal insertion (short arrow). Asterisk indicates the parasitic twin.

OC09.04: Crown–rump length and abdominal circumference discrepancy as early predictors of late adverse pregnancy outcome in monochorionic diamniotic pregnancies

the last 10 years. Chorionicity and indication for invasive testing were retrieved from the clinical notes. The following outcomes were analysed: fetal loss within 4 weeks from the procedure and < 24 weeks’ gestation; preterm premature rupture of membranes (PPROM) within 4 weeks from the procedure and < 34 weeks’ gestation; spontaneous preterm delivery (PTD) < 32 weeks of gestation. Results: A total of 267 twin pregnancies underwent invasive prenatal diagnosis during the study period, 212 dichorionic diamniotic and 55 monochorionic diamniotic. Amniocentesis was the most frequent procedure in both groups. Indications for invasive testing, type of procedure used, and pregnancy outcomes are described in Table 1 and reported with their 95% confidence intervals. Conclusions: We observed a fetal loss rate < 24 weeks of 1.5% (95% CI, 0.3–4.3). As expected, monochorionic pregnancies had a higher incidence of adverse pregnancy outcome.

OP16.10: Role of uterine artery Doppler velocimetry in the third trimester of pregnancy

Objectives: Thrombophilia has been reported be more frequent in pregnancies affected by placental insufficiency. The aim of this study was to evaluate the usefulness of abnormal uterine artery Doppler at 22–24 weeks to identify patients with thrombophilia. Methods: Case-control study, involved pregnant women attending our Unit at 22–24 weeks gestation. Uterine artery (UA) Doppler velocimetry was routinely performed in this patients and the pulsatility index in uterine artery (UA-PI) calculated. We identified those patients with abnormal UA Doppler (UA-PI > 95th centile) to perform haematological test; 20 ml blood sample was obtained to investigate genetic and acquired thrombophilia. The control group were patients at 22–24 weeks gestation, with normal UA Doppler and complete study for thrombophilia. Results: There were 33 pregnant women included in the study. There were 18 patients enrolled with abnormal UA -Doppler and 15 patients in the control group. In 12 of 18 patients (67%) in the study group, and 9 of 15 (60%) in the other group, we found haematological changes characteristic of thrombophilia; there was no a statistically significant difference between both groups in the frequency of thrombophilic conditions. The most frequent thrombophilic conditions observed in the study group were: Protein S deficiency and elevated fibrinogen levels. Combined thrombophilic changes were observed more frequently in the study group: 6 patients (33%) versus 1 patient (7%) in the control group (t student; P < 0.06). Conclusions: Our study suggests that an abnormal uterine artery Doppler at 22–24 weeks of gestation could identify pregnant patients with increased risk of combined thrombophilia, but we believe the number of cases was too small to show a statistically significant difference. This situation could be clinically relevant and be associated to increased risk of perinatal complications associated a thrombosis. It is necessary largest studies to definitive conclusions.

OC09.02: Complications and outcome of invasive prenatal diagnosis in twin pregnancies

Objectives: In first trimester risk assessment, crown–rump length has been utilized as the gold standard for dating pregnancies and interpreting screening results. Other fetal biometric measurements have been employed to confirm gestational age, but not to interpret screening results. The purpose of this study is the compare the accuracy and precision of crown–rump length and other fetal biometric measurements in the interpretation of first trimester nuchal translucency. The goal is to determine which measurement leads to the least variability when an observed nuchal translucency measurement is related to the expected level for the observed biometry value (MoMs). Methods: Women presenting to an academic fetal diagnostic center between 11+0 and 13+6 weeks were examined by one sonographer followed by one physician. Each examiner obtained 3 independent measurements of fetal biometric parameters, and NT. Patients were excluded for fetal malformations or demise. Biometry-specific expected NT values were calculated using regression models, and the results were converted into MoMs. The standard deviation of log MoM was compared, and the smallest value was regarded as reflecting the biometric measure with the greatest accuracy and precision. Results: Measurements were obtained on 135 fetuses. Abdominal circumference yielded MoMs with the smallest standard deviation, significantly lower than for CRL, the next smallest (P < 0.0001). The standard deviation of AC remained the smallest when results from sonographers and physicians were considered separately, and when the mean of the three exams was used rather than the individual exam results. Conclusions: Abdominal circumference is the most accurate and precise biometric measurement for the interpretation of nuchal translucency screening results. Since crown rump length is currently utilized to calculate NT MoMs in order to place fetuses in categories of risk for aneuploidy, consideration should be given to an alternative model for calculation of NT MoMs using other fetal biometric measurements. OC09: COMPLICATIONS OF TWIN PREGNANCY