Normal Twin Pregnancies Research Articles

Specific changes and clinical significance of plasma D-dimer during pregnancy and puerperium: a prospective study

BackgroundPregnant and puerperal women are high-risk populations for developing venous thromboembolism (VTE). Plasma D-dimer (D-D) is of good value in the diagnosis of exclusion of VTE in the nonpregnant population. Since there is no consensus reference range of plasma D-D applicable to pregnant and puerperal women, the application of plasma D-D is limited. To investigate the change characteristics and the reference range of plasma D-D levels during pregnancy and puerperium and to explore the pregnancy- and childbirth-related factors affecting plasma D-D levels and the diagnostic efficacy of plasma D-D for excluding VTE during early puerperium after caesarean section.MethodsA prospective cohort study was conducted with 514 pregnant and puerperal women (cohort 1), and 29 puerperal women developed VTE 24–48 h after caesarean section (cohort 2). In cohort 1, the effects of the pregnancy- and childbirth-related factors on the plasma D-D levels were analyzed by comparing the differences in plasma D-D levels between different groups and between different subgroups. The 95th percentiles were calculated to establish the unilateral upper limits of the plasma D-D levels. The plasma D-D levels at 24–48 h postpartum were compared between normal singleton pregnant and puerperal women in cohort 2 and women from the cesarean section subgroup in cohort 1, binary logistic analysis was used to analyze the relevance between plasma D-D level and the risk of VTE developing 24–48 h after caesarean section, and a receiver operating characteristic (ROC) curve was used to assess the diagnostic efficacy of plasma D-D for excluding VTE during early puerperium after caesarean section.ResultsThe 95% reference ranges of plasma D-D levels in the normal singleton pregnancy group were ≤ 1.01 mg/L in the first trimester, ≤ 3.17 mg/L in the second trimester, ≤ 5.35 mg/L in the third trimester, ≤ 5.47 mg/L at 24–48 h postpartum, and ≤ 0.66 mg/L at 42 days postpartum. The plasma D-D levels of the normal twin pregnancy group were significantly higher than those of the normal singleton pregnancy group during pregnancy (P < 0.05), the plasma D-D levels of the GDM group in the third trimester were significantly higher than those of the normal singleton pregnancy group (P < 0.05). The plasma D-D levels of the advanced age subgroup at 24–48 h postpartum were significantly higher than those of the nonadvanced age subgroup (P < 0.05), and the plasma D-D levels of the caesarean section subgroup at 24–48 h postpartum were significantly higher than those of the vaginal delivery subgroup (P < 0.05). The plasma D-D level was significantly correlated with the risk of VTE developing at 24–48 h after caesarean section (OR = 2.252, 95% CI: 1.611–3.149). The optimal cut-off value of plasma D-D for the diagnosis of exclusion of VTE during early puerperium after caesarean section was 3.24 mg/L. The negative predictive value for the diagnosis of exclusion of VTE was 96.1%, and the area under the curve (AUC) was 0.816, P < 0.001.ConclusionsThe thresholds of plasma D-D levels in normal singleton pregnancy and parturient women were higher than those of nonpregnant women. Plasma D-D had good value in the diagnosis of exclusion of VTE occurring during early puerperium after caesarean section. Further studies are needed to validate these reference ranges and assess the effects of pregnancy- and childbirth-related factors on plasma D-D levels and the diagnostic efficacy of plasma D-D for excluding VTE during pregnancy and puerperium.

Postpartum takotsubo cardiomyopathy complicated with severe pulmonary edema and cardiogenic shock – a case report

Introduction and aim. Takotsubo cardiomyopathy (TCM) is a rare but life-threatening illness that can affect middle aged, young and pregnant women. It is a cardiac emergency and can mimic many other life threatening conditions like myocardial infarction, acute myocarditis, peripartum cardiomyopathy or dilated cardiomyopathy and is diagnosed by exclusion. Description of the case. Here we report a rare case of takotsubo cardiomyopathy in a young 28 year old female immediately post vaginal delivery of her normal full term twin pregnancy, who was otherwise a healthy female. She went on to develop complication of left ventricular heart failure and cardiogenic shock, which were successfully managed by conservative treatment leading to a full recovery. Conclusion. Takotsubo or stress cardiomyopathy is a rare entity and often a missed diagnosis, which if caught on time and treated leads to great prognosis. Our patient made a full recovery and is living a healthy life.

Exploration on appropriate fetal weight of twin pregnancies at different gestational weeks and pregnancy complications and outcomes

Objective: To explore the appropriate fetal weight of twin pregnancies at different gestational weeks and the association with pregnancy complications and outcomes. Methods: Fetal weight at different gestational weeks and related pregnancy complications and outcomes from 1 225 twin pregnancies, who gave birth at Peking University First Hospital from January 2004 to December 2020, were analyzed in this study, including hypertensive disorders in pregnancy, gestational diabetes mellitus (GDM), fetal growth restriction (FGR), fetal distress, preterm birth and neonatal asphyxia. The appropriate fetal weight of twin pregnancies at different gestational weeks were analysed based on the information from 616 twin pregnancies without complications (except preterm birth), and were expressed as P10~P90. The chi-square test was used to compare the risk of pregnancy complications and adverse outcomes in large for gestational age (LGA), appropriate for gestational age (AGA) and small for gestational age (SGA) twin pregnancies and the difference in incidence of pregnancy complications and adverse outcomes in different years. Results: The appropriate fetal weights of normal twin pregnancies at 28 to 37 weeks and 38-40 weeks of gestation were 910-1 255 g, 996-1 518 g, 1 105-1 785 g, 1 295-1 825 g, 1 336-2 000 g, 1 754-2 321 g, 1 842-2 591 g, 1 913-2 615 g, 2 150-2 847 g, 2 350-3 130 g and 2 450-3 250 g, respectively. The incidences of hypertensive disorders in pregnancy, FGR, fetal distress and neonatal asphyxia related to SGA twin pregnancies were significantly higher than AGA twin pregnancies (all P<0.05). The incidence of GDM in twin pregnant from 2017 to 2020 was higher than that from 2004 to 2009 or from 2010 to 2016, but the incidence of fetal distress and neonatal asphyxia were lower than those from 2010 to 2016, and the differences were statistically significant (all P<0.05). Conclusions: The appropriate weights of twin fetuses at different gestational weeks are different from singleton. The incidence of pregnancy complications and adverse outcomes in AGA fetuses is significantly lower than that in SGA fetuses under the specific weight standard for twin fetuses, which could provide a practical basis for clinical management of twin pregnancy.

Role of Ultrasound in Early Detection of Molar Pregnancy

OBJECTIVES The objective of this study was to investigate the role of ultrasound in the detection of early pregnancies presenting with placental molar changes. METHODOLOGY This retrospective study was carried out at Radiology department of Hayatabad Medical Complex, Peshawar, between Aug 2020 and July 2021. All cases suspected of molar changes were evaluated from 10-14 weeks of gestation. The patient were referred to our department because of fetal abnormality, maternal disease or age and family or previous pregnancy history or were identified from an ongoing ultrasound screening study for aneuploidy by measurement of fetal nuchal translucency thickness. Transabdominal or transvaginal sonography was used to examine the fetus and placenta. RESULTS Total 85 patients of molar pregnancies were enrolled in the study. Age ranged between 20-45 years with a mean age of 32.5 years. There were 60(70.6%) complete moles (CM) and 25(27.4%) partial moles (PM) were suspected on ultrasound. In case of complete mole coexisting with a normal singleton or twin pregnancy, the molar placenta was clearly separated from the normal placenta, whereas with partial moles the molar structures were dispersed inside the placental mass. CONCLUSION Ultrasound detection of molar pregnancy remains a diagnostic challenge. Data suggest that there has been an increase in both the predictive value and the sensitivity of ultrasound over time; however, the diagnostic criteria remain ill defined. Prior to managing a miscarriage, being aware of the possibility of molar pregnancy will guide treatment and allow for adequate follow-up.

Establishment of reference intervals of complete blood count for twin pregnancy

BackgroundTwin pregnancy poses a high risk, and its incidence has increased in recent years. Establishment of reference intervals of complete blood count (CBC) for women with twin pregnancies during pregnancy may aid in the prognosis of adverse outcomes.MethodsThe incidence of complications and the intensity associated with adverse outcomes were analyzed in 1153 cases of twin pregnancy. A total of 253 cases in the twin pregnancy reference cohort were screened from all candidates after complications and adverse pregnancy outcomes were excluded. Complete blood count data were collected during the mid- and late-term of pregnancy and analyzed using SPSS to establish the reference intervals for peripheral blood in twin pregnancy.ResultsPremature rupture of the membrane and pelvic inflammatory disease were highly positively correlated with adverse outcomes, with OR values of 3.31 and 3.81, respectively. Within the interval population with normal outcomes, red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), and platelet (PLT) values were lower in twin-pregnant women during gestation than in healthy nulligravida women, but the levels of white blood cells (WBC), neutrophils (NEU), and the NEU% increased, especially in the mid-term. The reference intervals of late-term pregnancy were validated using 20 twin pregnancies samples, and then utilized to determine the distinctive CBC characteristics in preterm birth (PTB) pregnancy. Absolute WBC and NEU values increased in PTB pregnancy based on our established reference intervals, which suggests that these may might be prognostic indicators of this adverse outcome.ConclusionEstablishing the reference interval of blood cell-related indicators of normal twin pregnancy is helpful for the monitoring and prognosis of gestation.

Gestational Age-Specific Reference Ranges for the sFlt-1/PlGF Immunoassay Ratio in Twin Pregnancies

Objective: Establish reference ranges for the Elecsys® soluble fms-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PlGF) immunoassay ratio in twin pregnancies. Methods: Data analyzed were from 3 prospective studies: Prediction of Short-Term Outcome in Pregnant Women with Suspected Preeclampsia (PE) (PROGNOSIS), Study of Early-onset PE in Spain (STEPS), and a multicenter case-control study. Median, 5th, and 95th percentiles for sFlt-1, PlGF, and the sFlt-1/PlGF ratios were determined for normal twin pregnancies for 7 gestational windows and compared with the previous data for singleton pregnancies. Results: The reference range analysis included 269 women with normal twin pregnancies. Before 29 weeks’ gestation, median, 5th, and 95th percentiles for sFlt-1/PlGF ratios did not differ between twin and singleton pregnancies. From 29 weeks’ gestation to delivery, median, 5th, and 95th percentiles for sFlt-1/PlGF ratios were substantially higher in twin versus singleton pregnancies. sFlt-1 values were higher in women with twin pregnancies across all gestational windows. PlGF values were similar or higher in twin versus singleton pregnancies; PlGF concentrations increased from 10 weeks + 0 days to 28 weeks + 6 days’ gestation. Conclusions: Reference ranges for the sFlt-1/PlGF ratio are similar in women with twin and singleton pregnancies until 29 weeks’ gestation but appear higher in twin pregnancies thereafter.

The role of umbilical artery velocities in the clinical assessment of twin-twin transfusion syndrome at stage.

To analyze the discordances of the umbilical artery velocities between pregnancies with twin-twin transfusion syndrome (TTTS) at stage I and those with normal monochorionic-diamniotic (MCDA) twins, and investigate the value of their discordances in predicting TTTS at stage I. We recruited 58 twin pregnancies with TTTS at stage I and 60 normal MCDA twin pregnancies in a tertiary referral center retrospectively. The umbilical artery velocities and their discordances were compared between the normal and TTTS twins. The discordances of umbilical artery mean diastolic velocity (UA-MDV), umbilical artery time-averaged maximum velocity (UA-TAmax), umbilical artery peak systolic velocity (UA-PSV), and umbilical artery end-diastolic velocity (UA-EDV) were higher in the TTTS group than in the normal group. In TTTS co-twins, the UA-MDV, UA-TAmax, UA-PSV, and UA-EDV in recipients were higher than those in donors. The discordances of UA-TAmax and UA-PSV were found to be independent predicting factors for TTTS at stage I. Co-twin umbilical artery velocity discordances were significantly associated with stage I TTTS. The results suggest that UA-TAmax and UA-PSV might be new parameters for predicting TTTS at stage I.

Recurrent GTD and GTD coexisting with normal twin pregnancy

Hydatidiform mole (HM) affects around 1/1000 pregnancies, and in such cases the recurrence risk is around 1%, being greater for those with complete HM (CHM). Whilst most cases appear sporadic with unknown mechanisms, there is a distinct subgroup of patients who suffer recurrent pregnancy loss, including multiple recurrent CHM (familial recurrent biparental HM syndrome). The majority of these cases are related to maternal genetic mutations in genes related to the control of imprinting, specifically NALP7 and KHDC3L. Oocyte donation is an effective treatment allowing these patients to have successful pregnancies. Approximately 1 in 50,000 pregnancies are complicated by twin pregnancy comprising normal foetus and HM, the majority of reported cases being CHM. Such pregnancies are at significantly increased risk of complications, including pregnancy loss, early-onset preeclampsia and severe preterm delivery, but when managed conservatively the delivery of a liveborn healthy infant occurs in around one-third of cases. Regardless of management, the risk of persistent GTD in such cases appears similar to that following singleton CHM. Rarely, other conditions mimic prenatal ultrasound appearances of twin pregnancy with HM, CHM mosaicism and placental mesenchymal dysplasia, both of which have distinctive histological and genetic features.

Longer distance between umbilical cord insertions is associated with spontaneous twin anemia polycythemia sequence.

The aim of the study was to investigate the placental characteristics in spontaneous twin anemia polycythemia sequence. A retrospective case-control study of spontaneous twin anemia polycythemia sequence, twin-to-twin transfusion syndrome and normal monochorionic diamniotic twin pregnancies was performed. The primary outcome was placental characteristics. The prevalence of artery-artery anastomoses in spontaneous twin anemia polycythemia sequence and twin-to-twin transfusion syndrome groups was significantly lower than in the normal monochorionic diamniotic twin group (40.0% vs 33.3% vs 88.8%, respectively, P<.001). The total number of vascular anastomoses in the spontaneous twin anemia polycythemia sequence group (with range given in parentheses) was significantly lower than in the two control groups (3 [1-6] vs 5 [1-14] vs 6 [1-20], P=.001/<.001/.794). The number of artery-vein anastomoses in the spontaneous twin anemia polycythemia sequence was significantly lower than in the two control groups (2 [1-5] vs 4 [1-13] vs 5 [1-19], P=.011/.001/1.000). The total diameter of all vascular anastomoses was significantly smaller in the spontaneous twin anemia polycythemia sequence than in the two control groups (0.9mm [0.3-4.7] vs 5.2mm [0.8-24.6] vs 7.3mm [1.0-25.1], P<.001/<.001/.104), as was the total diameter of artery-to-artery anastomoses (0.5mm [0.3-1.3] vs 2.0mm [0.5-11.8] vs 2.3mm [0.7-9.7], P=.003/<.001/1.000) and the total diameter of artery-to-vein anastomoses (0.8mm [0.3-2.1] vs 4.6mm [0.8-15.3] vs 4.0mm [0.2-21.8], P<.001/<.001/1.000). The ratio between the distance of the two umbilical cords insertion points and the placental maximum diameter in the spontaneous twin anemia polycythemia sequence group was significantly larger than in the two control groups (0.78 [0.49-0.99] vs 0.64 [0.32-1.00] vs 0.55 [0.05-1.00], P=.033/<.001/.138). In spontaneous twin anemia polycythemia sequence placentas, the number of superficial vascular anastomoses is lower, their diameter is smaller and the distance between the two umbilical cord insertion points is longer.

Aggressive Thoracic Hemangioma Leading to Secondary Kyphosis with Paraparesis in the Postpartum Period. A Case Report

Aggressive vertebral hemangioma is rare, and its management can be very challenging. In this report, we present the case of a 30-year-old female with a normal twin pregnancy. She had been complaining of midthoracic pain after the seventh month of pregnancy with no other symptoms. Normal delivery was done under spinal anesthesia, but the patient's back pain worsened after the delivery, and she left the hospital on Day 4 with the onset of an unsteady gait. She was seen in the spinal clinic on Day 14, referred by her gynecologist, with a paraparetic presentation that was rapidly worsening. Urgent magnetic resonance imaging (MRI) was done and revealed aggressive hemangioma of T6 with kyphosis and significant cord compression. The patient was admitted and was operated the following morning. Posterior decompression with fixation from T4 to T8 and kyphosis correction was done. Samples from the vertebrae were sent to the lab for pathology analysis, and the results confirmed the diagnosis of vertebral hemangioma. She could walk on Day 1 with progressive neurological recovery, but distal junctional kyphosis in the form of a "chance fracture" of T8 occurred at 2 months and was treated conservatively. She showed a satisfactory clinical and radiological result at 2 years with no recurrence. Literature is sparse on the management of vertebral hemangioma in the context of pregnancy and postpartum, with only case reports, and its presentation as a kyphotic fracture is extremely rare. The current case shows how, in the context of delivery, a benign procedure such as spinal anesthesia should be done with extreme caution, as it may play a role in aggravating an undiagnosed aggressive hemangioma; rapid management after the onset of paraparetic symptoms enables a full neurological recovery, but close monitoring later on with regular MRI is mandatory for detection of any recurrence.

The Impact of Assisted Reproductive Technology in Twin Pregnancies Complicated by Intrahepatic Cholestasis of Pregnancy: a Retrospective Cohort Study.

Our study aims to evaluate the perinatal outcomes in twin pregnancies diagnosed with intrahepatic cholestasis of pregnancy (ICP) and to compare these with normal healthy twin pregnancies for perinatal outcomes. The second outcome of the study was to determine whether in vitro fertilization-embryo transfer (IVF-ET) affects the perinatal outcome in ICP patients. In this study, 59 ICP and 641 healthy twin pregnancies were compared for perinatal outcomes retrospectively. According to the mode of conception, the twin pregnancies with ICP were divided into 2 groups. The twin pregnancies with ICP who were conceived with IVF were referred to as the IVF-ET group. The twin pregnancies with ICP who were conceived spontaneously or by ovulation induction and intrauterine insemination (IUI) were referred to as the non-IVF-ET group. Twin pregnancies with ICP give birth significantly earlier than normal twin pregnancies (p ˂ 0.001). The diagnosis of ICP occurred significantly earlier in the IVF-ET pregnancy with ICP than in the non-IVF-ET group. In twin pregnancies with IVF-ET, patients delivered significantly earlier than in the non-IVF-ET group (p=0.002). Twin pregnancies with ICP were found to have significantly higher rates of meconium-stained amniotic fluid, postnatal intubation, and admission to the neonatal intensive care unit (NICU) than healthy twin pregnancies. ICP is a risk factor for preterm delivery in twin pregnancies. In addition, ICP develops earlier and more frequently in twin pregnancies from IVF-ET than in those from non-IVF twin pregnancies, and the disease may be more serious.

Blood Coagulation Indices in Twin Pregnancy Complicated with Preeclampsia.

To determine the regular changes of blood coagulation indices in twin pregnancy complicated with preeclampsia (PE). Descriptive study. Fujian Provincial Maternity and Children Hospital from January 2014 to December 2017. A total of 180 twin pregnancies were enrolled in this study, including 40 diagnosed as PE, 50 as severe PE (SPE), and 90 as normal twin pregnancies. The changes of coagulation parameters of twin pregnant women in different gestational states and periods were retrospectively analysed. During the middle and late pregnancies in all groups, the PT (prothrombin time) decreased, and D-Di (D-dimers) increased gradually compared to early pregnancy (p <0.05). When D-Di increased abnormally, adverse pregnancy outcomes increased. APTT (activated partial thromboplastin time) and TT (thromoplastin time) were shortened first and then significantly prolonged (p <0.05). In the normal twin group, FIB was increased gradually from early pregnancy to midlate pregnancy; in the PE group, FIB was increased and then decreased, especially in the sPE group (p <0.05). There was no significant difference in coagulation function in early pregnancy (p >0.05). FIB in sPE group was lower than that in other two groups in late pregnancy. TT in sPE group was higher than that in other two groups. D-Di and APTT in PE group and sPE group were higher than those in normal group (p <0.05). The TT sensitivity was 68.8% with specificity 72.4%, at cut-off value of 13.48 s (p <0.01). The regular changes of blood coagulation indices in twin pregnancy complicated with PE had great predictive and diagnostic value of preeclampsia.

Weight gain and pregnancy outcomes in underweight women with twin gestations

Background: Adherence to minimum weight gain recommendations in twin pregnancies as defined by the Institute of Medicine (IOM) guidelines is associated with improved pregnancy outcomes; however, these recommendations have yet to be made for underweight women (BMI < 18.5 kg/m2).Objective: To determine if existing pregnancy weight gain recommendations in twin gestations apply to women with underweight prepregnancy body mass index (BMI), and if these women have similar pregnancy outcomes to women with normal prepregnancy BMI.Methods: This is a retrospective cohort study of women with underweight (BMI < 18.5 kg/m2) and normal prepregnancy BMI (18.5–24.9 kg/m2) and twin pregnancies delivered > 24 weeks by a single Maternal Fetal Medicine (MFM) practice between 2005–2017. Weight gain patterns and pregnancy outcomes were compared between women with underweight prepregnancy BMI and normal prepregnancy BMI. The primary outcomes of the study were gestational age at delivery and intrauterine growth restriction.Results: A total of 664 women met inclusion criteria during the study period, 55 (8.3%) of whom had an underweight prepregnancy BMI, and 609 (91.7%) of whom had a normal prepregnancy BMI. There were no differences in baseline clinical and demographic characteristics between the groups, nor any differences in overall weight gain or weight gain patterns between the two groups. There were no significant differences between the groups in birthweight of the larger twin (2415 versus 2489 g, p = .26) or the smaller twin (2150 versus 2190 g, p = .55), gestational age at delivery (35.8 versus 35.8 weeks, p = .96), incidence of preterm birth < 34 weeks (16.4 versus 16.3%, p = .98), spontaneous preterm birth < 34 weeks (9.1 versus 11.7%, p = .57), or the incidence of either twin with a birthweight < 10% for gestational age (60.0 versus 56.0%, p = .57) or < 5% for gestational age (36.4 versus 30.9%, p = .40).Conclusions: Women with underweight prepregnancy BMI who gain equal weight to women with normal prepregnancy BMI have similar pregnancy outcomes. The recommendations for adequate weight gain in women with underweight prepregnancy BMI should therefore not exceed those for women with normal prepregnancy BMI.

Three-dimensional power Doppler ultrasound evaluation of placental blood flow in normal monochorionic diamniotic twin pregnancies

BackgroundMonochorionic diamniotic (MCDA) twin pregnancies are at higher risk of adverse outcomes and complications, which are attributed to the influence of placental morphology in MCDA twins. Monitoring of placental function is an important index for clinical decisions. The aim of our study was to evaluate the placental blood flow estimated using three-dimensional power Doppler (3D-PD) ultrasound and the vascular indices distribution with gestational age (GA) in normal MCDA twin pregnancies.MethodsOne hundred four MCDA twin pregnancies and 106 singleton pregnancies (GA range, 14–32 weeks) were included in this prospective study. 3D-PD volume data of each fetus was obtained separately from the placenta at the site of umbilical cord insertion. We analyzed the volume data using sonobiopsy technique. The placental vascularization index (VI), flow index (FI) and vascularizationflow index (VFI), were auto-calculated. The means and standard deviation values of three vascular indices per fetus were calculated and regression analysis of the vascular indices as a function of GA was performed in twin pregnancies. The vascular indices of twin and singleton pregnancies were compared using independent t-test.ResultsThere were no significant differences in VI, FI or VFI among the fetuses of twins (p > 0.05). These vascular indices increased over the course of pregnancy (p < 0.05). We obtained the regression equations for the indices as a function of GA in days: VI = exp. (4.369–28.533/GA) (R2 = 0.699, p < 0.05), FI = exp. (3.916–13.003/GA) (R2 = 0.511, p < 0.05), and VFI = exp. (3.577–37.468/GA) (R2 = 0.675, p < 0.05). There were no significant differences in three vascular indices between MCDA twin and singleton groups (p > 0.05).Conclusions3D-PD placental data using sonobiopsy technique could reflect the placental blood flow of each twin, which could be applied to the study of placental perfusion in MCDA twin pregnancies. This study also presented the vascular indices distribution with GA in normal twin pregnancies, which might be useful for early detection of MCDA complications.

Performance and outcomes of noninvasive prenatal testing for twin pregnancies in Japan.

The purpose of this study was to describe the characteristics of women with twin pregnancies who undergo noninvasive prenatal testing (NIPT) as well as the post-partum and neonatal outcomes of such cases in Japan. The study population consisted of women who were pregnant with twins and who underwent NIPT using massively parallel sequencing (MPS) at Nagoya City University Hospital between April 2013 and June 2016. Questionnaires were completed pre-NIPT and post-partum. Among 4009 women who underwent NIPT during the study period, 75 women (1.9%) were pregnant with twins. Fifteen women (20%) experienced vanishing twin/intrauterine fetal deaths at <22 weeks, and 60 women (80%) had normal twin pregnancies at the time of genetic counseling for NIPT. The use of NIPT was correlated with increased proportions of women using assisted reproductive technology (ART). The test had a high performance, with a false-positive rate of 1.7% and no false negatives. In this study, NIPT had a high performance, with a false positive rate of 1.7% and no false negatives. When treating women with twin pregnancies, the efficacy of NIPT should be explained during genetic counseling. Further larger studies are required to assess the reliability and validity of NIPT in twin pregnancies.

Evaluation of placental vascularization indices in monochorionic diamniotic and dichorionic diamniotic twin pregnancies

ObjectivesWe aimed to investigate and compare placental vascularization indices between monochorionic-diamniotic, dichorionic-diamniotic normal twin pregnancies, and normal singular pregnancies. We hypothesized that there is correlation between placental three-dimensional power Doppler vascularization indices and birth weight in case of twin pregnancies, and that normal singular pregnancies have higher placental vascularization indices than normal twin pregnancies. Study designPlacental three-dimensional power Doppler vascularization indices, such as vascularization index, flow index, and vascularization-flow index were measured in monochorionic-diamniotic (N = 15) and dichorionic-diamniotic (N = 36) normal twin pregnancies, and in normal singular (N = 109) pregnancies. Correlations were analyzed between vascularization indices, and birth weight, APGAR score, umbilical pH, umbilical venous bicarbonate, lactate, and base excess. ResultsVascularization indices and birth weight were significantly (p < 0.01) higher in normal singular gestations (vascularization index = 10.36, flow index = 46.08, vascularization-flow index = 4.08, average birth weight = 3377 g at 38.2 weeks average gestational age) compared to monochorionic-diamniotic and dichorionic-diamniotic normal twin pregnancies. No significant differences were found in vascularization indices between monochorionic-diamniotic and dichorionic-diamniotic normal twins. There were no significant differences in APGAR score, umbilical pH, umbilical venous bicarbonate, lactate, and base excess between groups examined (p < 0.01). We found strong linear correlations between placental vascularization indices and birth weight in both twin groups. ConclusionPlacental three-dimensional power Doppler vascularization indices seem appropriate for predicting birth weight in monochorionic-diamniotic and dichorionic-diamniotic normal twin pregnancies. Our pilot study revealed reference values for vascularization indices in case of twin pregnancies examined.

Gestational hypertensive disease in twin pregnancy: Influence on outcomes in a large national prospective cohort.

Gestational hypertensive disease (GHD) is associated with pregnancy-related complications and poor maternal and fetal outcomes in singleton pregnancies. We sought to examine the influence of GHD in a large prospective cohort of twin pregnancies. The ESPRIT study was a national multicenter observational cohort study of 1028 structurally normal twin pregnancies. Each pregnancy underwent sonographic surveillance with two-week ultrasound from 24 weeks for dichorionic and from 16 weeks for monochorionic gestations. Characteristics and demographics as well as labour and delivery outcome data were prospectively recorded. Perinatal mortality, admission to the neonatal intensive care unit (NICU) and a composite of morbidity of respiratory distress syndrome, hypoxic ischaemic encephalopathy, periventricular leukomalacia, necrotising enterocolitis and sepsis were documented for all cases. Outcomes for patients with documented GHD (pre-eclampsia and gestational hypertension) were compared with those without GHD. Perinatal outcome data were recorded for 977 patients. Women with GHD had a higher body mass index (27.1 ± 6.4 vs 25.2 ± 4.5, P < 0.0001) than those without and were more likely to be nulliparous (65% (59/92) vs 46% (407/885), P = 0.001). Both groups had similar mean birthweights, but those with GHD were more likely to have a birthweight discordance ≥18% (35% (32/92) vs 20% (179/885), P = 0.001). Rates of caesarean delivery were higher in those twin pregnancies affected by GHD, and while the rate of composite morbidity was similar in both groups, twins in the GHD group had higher rates of NICU admission. In twin gestations, gestational hypertension independently confers an increased risk for emergency caesarean delivery, birthweight discordance and NICU admission, such that intensive maternal-fetal monitoring is justified when hypertension develops in a twin pregnancy.

Second trimester maternal serum triple screening marker levels in normal twin and singleton pregnancies.

The aim of the present study was to evaluate the serum levels of α-fetoprotein (AFP), free-β-human chorionic gonadotropin (free-β-hCG) and unconjugated estriol (uE3) in second trimester maternal serum and comparative analysis of serum markers levels in normal twin and singleton pregnancies, and to evaluate the feasible methods for the screening performances of triple markers in twin pregnancy. The levels of maternal serum markers were measured by magnetic microparticle chemiluminescence immunoassay in the second trimester. TCSoft was used for calculating the risk of Down's syndrome (DS). The marker levels were compared between the twin and singleton pregnancies, along with gestational age, and the weight or age of the pregnant women. The concentrations of the maternal serum markers were higher on average in twin compared to in singleton pregnancies in the second trimester of the gestation. The levels of AFP were 2-fold higher in twin compared to those in singleton pregnancies in weeks 16, 17 and total gestational weeks. For free-β-hCG, the levels were higher in 15 and 18 gestational weeks. However, significant differences were found in all the gestational weeks for uE3. There was no correlation between the levels of markers and weight or age in the twin pregnancies. The serum marker levels of AFP, free-β-hCG and uE3 in normal twins were not all 2-fold higher compared to singleton pregnancies. The current singleton gestational age-specific model for DS screening requires further correction so that it is feasible for screening in twin pregnancies.

The thy-box for sonographic assessment of the fetal thymus: nomogram and review of the literature.

To assess the feasibility and reproducibility of fetal thy-box visualization and to set normative data for the fetal thymus using this technique. We performed a cross-sectional observational study in pregnant women in their second trimester of pregnancy who attended the fetal medicine unit of the Hospital Gregorio Marañón from March 2011 to March 2013. Using thy-box sonography, which sets boundaries within the thymus, we assessed the feasibility of the thy-box and analyzed the factors related to its visualization. Measurements of the thy-box anteroposterior and transverse diameters were performed in healthy fetuses. Interobserver agreement was studied for both items. We set normative data for the thy-box diameters in singleton and twin pregnancies. A total of 337 patients from 15 to 37 weeks were recruited after exclusion criteria. Thy-box feasibility was 74.2% (250 of 337). Nonfeasible cases were related to the fetal anterior spine and advanced gestational age. Assessment of the thy-box anteroposterior and transverse diameters was achievable in 250 fetuses. Interobserver agreement was good for feasibility and measurements (κ = 0.80). Linear growth of the thy-box in both diameters was observed in relation to gestational age during the second half of pregnancy. Thy-box diameters did not show significant differences according to the type of gestation, fetal sex, or chorionicity. Thy-box diameters are achievable and reproducible by sonography in normal singleton and twin pregnancies during the second trimester; however, although feasible, the thy-box transverse diameter measurement is not reliable beyond 28 weeks. Further studies are needed to evaluate thy-box diameters in pathologic cases, especially conotruncal anomalies.

3D Ultrasonography to Evaluate Fetal Urinary Production Rates in Twin Gestation: Construction of a Normal Value Curve

The aim of this study was to assess fetal urinary production rates (FUPR) in twin gestations using 3D ultrasonography with VOCAL® (virtual organ computer-aided analysis) and to develop a curve of normal values for the target population. A cross-sectional study was performed in 30 normal twin pregnancies with gestational ages ranging from 20 to 34 weeks. FUPR was measured using a three-dimensional ultrasound (3D US) virtual organ computer-aided analysis (VOCAL) system. FUPR (ml/hour) was calculated during the filling phase using the equation UPR = (VFB(2) - VFB(1))/time. The values for UPR were plotted as a function of fetal biometry (biparietal diameter) to generate a nomogram. A total of 41 normal twin fetuses with gestational ages between 20 and 34 weeks were investigated. Eleven were excluded because of inadequate bladder contour image quality and/or the observation of micturition in one or both fetuses. Linear regression analysis of FUPR as a function of biparietal diameter (BPD) shows the normal range for UPR by fetal biometry and is expressed by the following equation: Ln(UPR) = -5.0121 + 0.0548 BPD (R(2) 0.3386, p value <.001). There was no statistically significant difference when the UPR was stratified by chorionicity. The use of biometric parameters to predict fetal FUPR seems to be useful. In twin pregnancies, BPD is the variable that is most closely related to FUPR. For each 1 mm increase in BPD, there is a 5% increase in FUPR. Chorionicity did not affect FUPR.