Prediction of chorionicity in twin pregnancies at 10-14 weeks of gestation

Longitudinal hematological change in uncomplicated twin pregnancies: The white blood cell count decreases through pregnancy after the first trimester

OBJECTIVE

Longitudinal hematological changes throughout twin pregnancies have not been reported. This study aimed to reveal longitudinal changes in hematological indices in twin pregnancies.

MATERIALS AND METHODS

We conducted a retrospective chart review of hematological changes in uncomplicated twin pregnancies delivered at ≥37 weeks of gestation between 2010 and 2013 and randomly selected uncomplicated singletons during the same period. A complete blood count and hemogram were performed as blood examinations in the first trimester (9-13 weeks), late second trimester (22-27 weeks), mid-third trimester (33-35 weeks, only in twin pregnancies), and late third trimester (36-38 weeks). We evaluated inter-trimester differences in hematological indices and compared the values between twin and singleton pregnancies in each trimester.

RESULTS

The final analysis group included 60 twin pregnancies and 63 singleton pregnancies. The white blood cell (WBC) count in twin pregnancies decreased throughout the pregnancy after the first trimester and became significantly lower than that in singletons in the late third trimester. The WBC count showed only a slight decrease in the third trimester in singleton pregnancies, whereas it showed a marked decrease throughout the pregnancy in twin pregnancies. The marked decrease in the total WBC count in twin pregnancies is mainly due to a decrease in neutrophils. The red blood cell count and hemoglobin and hematocrit values in twin pregnancies showed more marked decreases in the second trimester than in singletons. No decrease was observed after the second trimester of pregnancy. The platelet count decreased in the third trimester of twin pregnancies.

CONCLUSION

We clarified the longitudinal hematological changes in twin pregnancies that showed augmentation of or differed from those of singleton pregnancies. It should be specifically mentioned that the WBC count markedly decreased through pregnancy after the first trimester, which is a characteristic change in twin pregnancies.

To be born twin: effects on long-term neurodevelopment of very preterm infants-a cohort study

Objective

To examine the effect of twin birth on long-term neurodevelopmental outcomes in a cohort of Italian preterm infants with very low birth weight.

Study design

We performed a retrospective cohort study on children born in a tertiary care centre. We included children born between 1 January 2007 and 31 December 2013 with a gestational age (GA) of ≤32 weeks and birth weight of <1,500 g. The infants born from twin pregnancies complicated by twin-to-twin transfusion syndrome and from higher-order multiple pregnancies were excluded. The children were evaluated both at 2 years corrected age and 5 years chronological age with Griffiths mental development scales revised (GMDS-R). The linear mixed effects models were used to study the effect of being a twin vs. being a singleton on GMDS-R scores, adjusting for GA, being born small for gestational age, sex, length of NICU stay, socio-economic status, and comorbidity score (CS) calculated as the sum of the weights associated with each of the major morbidities of the infants.

Results

A total of 301 children were included in the study, of which 189 (62.8%) were singletons and 112 (37.2%) were twins; 23 out of 112 twins were monochorionic (MC). No statistically significant differences were observed between twins and singletons in terms of mean general quotient and subscales at both 2 and 5 years. No effect of chorionicity was found when comparing scores of MC and dichorionic twins vs. singletons; however, after adjusting for the CS, the MC twins showed lower scores in the hearing and language and performance subscales at 5 years.

Conclusion

Overall, in our cohort of children born very preterm, twin infants were not at higher risk of neurodevelopmental impairment compared with singletons at pre-school age.

Molecular Characterization of a Rare Case of Monozygotic Dichorionic Diamniotic Twin Pregnancy after Single Blastocyst Transfer in Preimplantation Genetic Testing (PGT)

Preimplantation genetic testing (PGT) is widely used to select unaffected embryos, increasing the odds of having a healthy baby. During the last few decades, it was accepted that monozygotic dichorionic diamniotic twin pregnancies occurred from the embryo splitting before Day 3 postfertilization according to Corner’s dogma. Hence, the occurrence of a dichorionic diamniotic twin pregnancy after a single blastocyst transfer was considered a dizygotic pregnancy resulting from blastocyst transfer and concurrent natural fertilization. In our study, we have provided for the first time molecular proof that a single blastocyst transfer can result in a monozygotic dichorionic diamniotic twin pregnancy, invalidating Corner’s dogma. In this case, we recommend systematically assessing the genetic status of dichorionic twins after single blastocyst transfer using prenatal diagnosis to exclude the risk from a potential concurrent spontaneous pregnancy and to ensure that both fetuses are unaffected. To achieve this goal, we have developed here an innovative noninvasive prenatal diagnosis by exclusion of paternal variants with droplet digital PCR, maximizing the reliability of genetic diagnosis. Further multicentric prospective studies using genetic testing are now required to establish the rate of blastocyst splitting leading to dichorionic pregnancy in PGT and to identify the risk factors.

Twin to twin transfusion syndrome

Twin to twin transfusion syndrome (TTTS) is a common complication that typically presents in the second trimester of pregnancy in 10-15% of monochorionic twins due to net transfer of volume and hormonal substances from one twin to the other across vascular anastomoses on the placenta. Without recognition and treatment, TTTS is the greatest contributor to fetal loss prior to viability in 90-100% of advanced cases. Ultrasound diagnosis of monochorionicity is most reliable in the first trimester and sets the monitoring strategy for this type of twins. The diagnosis of TTTS is made by ultrasound with the findings of polyhydramnios due to volume overload and polyuria in one twin and oligohydramnios due to oliguria of the co-twin. Assessment of bladder filling as well as arterial and venous Doppler patterns are required for staging disease severity. Assessment of fetal cardiac function also provides additional insight into the fetal cardiovascular impacts of the disease as well as help identify fetuses that may require postnatal follow up. Fetoscopic laser ablation of the communicating vascular anastomoses between the twins is the standard treatment for TTTS. It aims to cure the condition by interrupting the link between their circulations and making them independent of one another. Contemporary outcome data after laser surgery suggests survival for both fetuses can be anticipated in up to 65% of cases and survival of a single fetus in up to 88% of cases. However, preterm birth remains a significant contributor to postnatal morbidity and mortality. Long term outcomes of TTTS survivors indicate that up to 11% of children may show signs of neurologic impairment. Strategies to minimize preterm birth after treatment and standardized reporting by laser centers are important considerations to improve overall outcomes and understand the long-term impacts of TTTS.

Selective fetal reduction in complicated monochorionic twin pregnancies: A comparison of techniques

OBJECTIVE

To compare perinatal outcomes associated with three methods of selective reduction in complicated monochorionic (MC) twin pregnancies: bipolar cord coagulation (BC), fetoscopic or ultrasound guided laser cord occlusion and radiofrequency ablation (RFA).

METHODS

Retrospective cohort study of complicated MC twin pregnancies undergoing selective fetal reduction at a tertiary fetal center over a 20-year period. Obstetric and perinatal outcomes were compared.

RESULTS

105 procedures met inclusion criteria: 74 RFAs, 17 lasers and 14 BCs. Procedure duration was significantly shorter for RFA (27.4 ± 15.8 minutes) compared to BC (91.7 ± 38.7 minutes) and laser (83.4 ± 40.4 minutes), P < .0001). The incidence of preterm prelabor rupture of membranes (PPROM) and co-twin demise did not differ between groups, however preterm delivery <34 weeks occurred less frequently following RFA (29.7%), compared to laser (64.7%) or BC (42.9%) (P = .02); delivery <37 weeks was also less frequent following RFA (45.9%), compared to laser (76.5%) or BC (78.6%)(P = .01). The difference in preterm birth<34 weeks between RFA and laser was maintained after adjusting for cord occlusion indication and amnionicity (OR 3.96, 95% CI 1.27-12.31).

CONCLUSIONS

In our experience, RFA procedures were simpler, faster and associated with a lower risk of preterm delivery <34 and <37 weeks, compared to laser or BC.

US Evaluation of Twin Pregnancies: Importance of Chorionicity and Amnionicity

The twin birth rate is increasing in the United States. Twin pregnancies can be dichorionic or monochorionic (MC). MC twins account for 20% of twin pregnancies but 30% of all-cause pregnancy-related complications. This article describes the imaging findings that establish chorionicity and amnionicity. Ideally, these are established in the first trimester when accuracy is high, but they can also be determined later in pregnancy. Complications unique to MC twin pregnancy include twin-twin transfusion syndrome, twin anemia polycythemia sequence, twin reversed arterial perfusion sequence, and selective fetal growth restriction. The US features, staging systems, and management of these complications are reviewed, and the consequences of MC twin demise are illustrated. Ongoing surveillance for these conditions starts at 16 weeks gestation. Monoamniotic (MA) twins are a small subset of MC twins. In addition to all of the MC complications, specific MA complications include cord entanglement and conjoined twinning. Radiologists must be able to determine chorionicity and amnionicity and should be aware of potential complications so that patients may be referred to appropriate regional specialized centers. A proposed algorithm for referral to specialized fetal treatment centers is outlined. Online supplemental material is available for this article. ^©RSNA, 2019.

Impact of different prenatal management strategies in short- and long-term outcomes in monochorionic twin pregnancies with selective intrauterine growth restriction and abnormal flow velocity waveforms in the umbilical artery Doppler: a retrospective observational study of 108 cases

OBJECTIVES

To review perinatal and neurodevelopmental outcome (NDO) following selective fetoscopic laser coagulation (SFLC), cord coagulation (CC) or expectant management of monochorionic diamniotic twin pregnancies complicated with selective intrauterine growth restriction (sIUGR) and absent or reverse end-diastolic flow (AREDF) in the umbilical arteries (UA).

DESIGN AND SETTING

Single-centre retrospective observational study.

POPULATION

108 cases of sIUGR diagnosed before 26⁺⁶  weeks' gestation with AREDF in the UA.

METHODS

Survival rate and potential risk factors were analysed. NDO was assessed using parental questionnaires.

MAIN OUTCOMES MEASURES

Survival, gestational age at delivery and NDO.

RESULTS

SFLC, CC and EM were performed in 13, 50 and 45 cases, respectively, with an overall survival of 23.1, 40 and 77.8% and intrauterine demise of the co-twin of 30.8, 10 and 6.7% respectively. Intrauterine demise of the sIUGR twin occurred in 76.9 and 17.8% following SFLC and EM, respectively. The discordance in EFW at diagnosis was higher and absent/negative a-wave in the ductus venosus (DV) was more prevalent in the surgical groups. NDO in survivors at follow up was abnormal in 0 and 18% in the smaller twin following SFLC and EM, respectively, and in 25, 24 and 21% in the larger twin following SFLC, CC and EM, respectively.

CONCLUSION

SFLC yielded a poor result. EM seems a valid option when EFW discordance is <30% and a-wave in DV is positive. Otherwise, CC should be considered to protect the AGA co-twin. The long-term outcome of both small and large twins seems unaffected by the choice in primary prenatal management strategy.

TWEETABLE ABSTRACT

In type II sIUGR in MC twins, long-term neurodevelopment is normal in over 80% of the survivors.

An ultrasonographic estimated fetal weight reference for Japanese twin pregnancies

Purpose

The purpose was to establish an estimated fetal weight (EFW) reference for twin pregnancies in Japan and to compare the growth of twins with singletons.

Methods

We retrospectively investigated Japanese women who delivered live-born twins at our center during the period from 2010 to 2016. The main exclusion criteria were monoamniotic twins, fetal reduction, maternal complications, twin–twin transfusion syndrome, fetal congenital anomalies, and patients with their first visit after 16 weeks’ gestation. The EFW was measured longitudinally from 16 to 37 weeks’ gestation. We calculated the posterior predictive distribution using hierarchical Bayesian models and determined the EFW corresponding to each Z-score.

Results

A total of 364 women (190 dichorionic and 174 monochorionic) were included, and the total number of examinations was 3952. The EFWs of a Z-score of 0 for twins at 20, 28, and 36 weeks’ gestation were 308, 1070, and 2294 g, respectively. The EFW of a Z-score of 0 for twins was 98–101% that of singletons until 21 weeks, gradually becoming lower than that of singletons and reaching 90–93% that of singletons after 27 weeks.

Conclusion

We established an EFW reference for Japanese twin pregnancies. The EFW of twins is similar to that of singletons until the mid-second trimester, gradually becoming lower than that of singletons and reaching about 90% that of singletons in the third trimester.

Twin births: cesarean section or vaginal delivery?

OBJECTIVE

To assess morbidity and mortality in twin pregnancy deliveries, according to chorionicity and mode of delivery.

DESIGN

Population-based retrospective cohort.

SETTING

Fourteen obstetric departments in Denmark.

POPULATION

One thousand one hundred and seventy-five twin pregnancies with two live fetuses at 36(+0) weeks of gestation.

METHODS

Pregnancy outcomes assessed according to chorionicity and mode of delivery.

MAIN OUTCOME MEASURES

Poor outcome defined as five min Apgar score ≤ 7, umbilical artery pH < 7.10, admission to neonatal unit for more than three days or death.

RESULTS

Dichorionic (DC) twins, delivered after 36 gestational weeks, with intended vaginal delivery (n= 689) compared with DC twins with planned cesarean section (n= 371) had an increased risk of poor outcome [odds ratio (OR) 1.47, p= 0.037] after adjustment for body mass index, parity and weight discordance. There was no increased risk for poor outcome in monochorionic (MC) twins with intended vaginal delivery (n= 63) compared with planned cesarean section (n= 52; OR 0.87, 95% confidence interval 0.26-2.96). Nulliparity increased the risk of poor outcome in DC (OR 1.5, p= 0.03) and in MC twins (OR 4.01, p= 0.02), as well as birthweight discordance >300 g (DC, OR 1.50, p= 0.02; and MC, OR 6.02, p= 0.002). For DC twins, we found a significantly higher risk of poor outcome of the second-born twin compared with the first (OR 1.64, p= 0.001).

CONCLUSIONS

Dichorionic twins born after 36 weeks of gestation had a higher risk of poor outcome by intended vaginal delivery than by planned cesarean section. For MC twins, statistical differences in outcome by mode of delivery could not be seen.

A successful birth of healthy monozygotic dichorionic diamniotic (DD) twins of the same gender following a single vitrified-warmed blastocyst transfer

PURPOSE

To report the world's first case of live monozygotic dichorionic diamniotic (DD) twins after a single vitrified-warmed blastocyst transfer in a cycle during which hormone supplements were given.

METHODS AND RESULTS

The patient was a 39-year-old woman with tubal factor infertility. Six oocytes were retrieved and three blastocysts were vitrified after insemination with her husband's sperm. Two months later, a single warmed blastocyst was transferred on the fifth day after progesterone supplementation during the luteal phase. Two gestational sacs and fetuses with heartbeats showing lambda sign under ultrasonography were recognized at 7 weeks of gestation and the patient gave birth to two female infants at gestational 33 weeks. The pathological examination demonstrated that the DD twin placentas fused in the third trimester.

CONCLUSIONS

This report suggests that the splitting of the transferred embryo took place after the blastocyst stage and the popular credo that the timing of embryo division governs the placental configuration of monozygotic twins (MZT) must be re-examined as to its veracity.

Ultrasound Evaluation of Pregnancy in the First Trimester

Improvements in ultrasound technology, including transvaginal sonography and higher frequency probes, have led to a better understanding of early pregnancy development. These advances and the increasing availability of ultrasound allow women to have an earlier and more accurate assessment of their pregnancy. First trimester sonographic signs have been identified that can be used to reassure women that their pregnancy is progressing normally or counsel them that their pregnancy will fail. In addition, first trimester ultrasound can accurately predict the type of twinning in multiple gestations, allowing for appropriate counseling and management.

Objectives

Know the first trimester ultrasound findings of a normal intrauterine pregnancy

Understand the ultrasound findings that diagnose an early pregnancy failure

Know the ultrasound criteria used to diagnose a multifetal gestation