Can growth in dichorionic twins be monitored with individualized growth assessment?

OBJECTIVE

To characterize fetal growth in dichorionic twins using individualized growth assessment (IGA), a method based on individual growth potential estimates.

METHODS

This secondary analysis included 286 fetuses/neonates from 143 dichorionic twin pregnancies that were part of the ESPRiT (Evaluation of Sonographic Predictors of Restricted Growth in Twins) study. The sample was subcategorized according to birth weight into appropriate-for-gestational-age (AGA) (n = 243) and small-for-gestational-age (SGA) (n = 43) cohorts. Serial biometric scans evaluating biparietal diameter, head circumference (HC), abdominal circumference, femur diaphysis length and estimated weight at 2-week intervals were used to evaluate fetal growth, while measurements of birth weight, crown-heel length and HC determined neonatal growth outcome. Six abnormalities (hypoxic ischemic encephalopathy, periventricular leukomalacia, necrotizing enterocolitis, respiratory distress, sepsis and death) constituted the evaluated adverse neonatal outcomes (ANO). IGA was used to: evaluate differences in second-trimester growth velocities between singletons (from a published dataset) and dichorionic twins (138 AGA twins with normal third-trimester growth); describe the degree to which actual third-trimester growth in twins followed expected growth (111 AGA twins, normal fetal growth and neonatal growth outcomes); determine if the fetal growth pathology score 1 (-FGPS1) could detect, quantify and classify twin growth pathology (224 AGA, 42 SGA); and assess the relationship between -FGPS1 and ANO (24 SGA twins with progressive growth restriction confirmed by abnormal neonatal growth outcome).

RESULTS

The differences in second-trimester growth velocity between singletons and twins (means and variances) were small and not statistically significant. Percent deviations from the expected third-trimester size trajectories were within the 95% reference ranges derived from singletons at 95.7% (1677/1752) of timepoints studied. Abnormal growth was detected in 37.9% of AGA twins and 85.7% of SGA twins. Growth restriction was more heterogeneous in AGA twins, while in SGA twins progressive growth restriction was the principal type (66.7%). -FGPS1 patterns previously defined in singletons classified 97.5% of pathological twin cases. In our most severe form of growth restriction (progressive), there were only three (12.5%) ANOs related to growth abnormalities, all in cases with -FGPS1 values more negative than -2.0%. Using these criteria, the frequency of ANO was 33%.

CONCLUSIONS

With respect to growth, dichorionic twins can be considered as two singletons in the same uterus. Normally growing dichorionic twins have the same growth potential as singletons with normal growth outcome. These twins also follow expected third-trimester growth trajectories with the same precision as do singletons. Third-trimester growth pathology can be detected, quantified and classified using -FGPS1 as in singletons. Limited evidence of a relationship between fetal growth abnormalities and adverse neonatal outcome was found. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Umbilical and fetal middle cerebral artery Doppler reference ranges in a twin population followed longitudinally from 24 to 38 weeks' gestation

OBJECTIVE

To construct monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA) twin reference ranges for umbilical artery (UA) pulsatility index (PI), UA resistance index (RI), fetal middle cerebral artery (MCA) PI and peak systolic velocity (PSV) and cerebroplacental ratio (CPR) from 24 weeks' to 38 weeks' gestation and compare these with published normal values for singleton pregnancies.

METHODS

This prospective multicenter cohort study included 1028 unselected twin pairs recruited over a 2-year period. Participants with dichorionic twins underwent fortnightly ultrasound surveillance from 24 weeks' gestation, with monochorionic twins being followed every 2 weeks from 16 weeks until delivery. A total of 7536 fetal Doppler examinations in 618 twin pregnancies were included in the analysis, with reference ranges for MCDA and DCDA pregnancies constructed for each of the Doppler indices using multilevel modeling.

RESULTS

UA-PI and UA-RI appear to be higher in twins than in singletons, and MCA-PI and MCA-PSV appear to be lower. The CPR also appears to be lower in twins than in singletons. Similar MCA indices were observed in MCDA and DCDA twins.

CONCLUSION

We have established longitudinal reference ranges for UA-PI and UA-RI, MCA-PI and MCA-PSV and CPR in twin pregnancies, which appear to differ from those in singleton pregnancies. The derived twin-specific reference ranges may be more appropriate in the surveillance of these high-risk pregnancies. Applying the singleton CPR cut-off of ≤ 1.0 may lead to a large number of false-positive diagnoses of cerebral redistribution in twin fetuses.

Fetoscopic laser treatment of twin-to-twintransfusion syndrome (TTTS)

The aim of this study was to report the results of the first 10 cases of fetoscopic laser surgery for twin-to-twin transfusion syndrome by the Rotunda Hospital Fetal Treatment Programme. All cases of severe TTTS managed by our team from 2006 to 2007 were included. All fetoscopic laser surgeries were performed by a single specialist in fetal medicine. All pregnancies were followed up to pregnancy completion and a minimum of six weeks neonatal life. Laser surgeries were performed with ultrasound guidance and percutaneously using local anaesthesia via a 2.8mm rigid fetoscope. Selective laser ablation of placental vessels was accomplished with a neodymium:YAG laser. The first 10 cases of severe TTTS managed by our team are reported. Laser ablation of placental vessels was accomplished successfully in all cases. Two pregnancies were complicated by preterm premature rupture of membranes before 22 weeks and both pregnancies were lost. Of the remaining 16 fetuses, one was diagnosed with significant ventriculomegaly postoperatively and underwent selective termination in the United Kingdom. The overall intact neonatal survival rate was 65%. Fetoscopic laser ablation of placental vessels for severe twin-to-twin transfusion syndrome is now available in Ireland, and our programme has delivered results that are in keeping with international best practices in this regard.

A retrospective review of visual outcome and complications in the treatment of retinoblastoma

The aim of this study was to look at the visual outcome and treatment complications of children diagnosed with Retinoblastoma during the years 1985-2003 inclusive. A retrospective review of all patients records was performed. Patient characteristics, treatment methods and complications were recorded. Twenty eight children presented to Temple street Hospital between 1985-2003. Six of these infants had bilateral tumours. The mean age at presentation was 23.7 months. Sixty-nine percent presented with Leucocoria, of these 33% also had a squint. The mean duration of symptoms was only known in 58% and this figure was approximately 19.8 months. Enucleation was performed in 24 eyes of 24 patients. Three patients required adjuvant chemotherapy post enucleation. Two eyes was treated with external beam radiation and one eye with plaque radiotherapy. One eye (second eye) was treated with systemic chemotherapy and radiation. Five eyes of three patients were treated with systemic chemotherapy followed by adjuvant Argon laser, cryotherapy and diode laser to each eye.The complications of each treatment group was recorded. The visual outcome in the salvaged eyes was favourable. There were no deaths recorded. Though chemotherapy with adjuvant local treatments provide adequate treatment for early tumours, enucleation still plays a major role in the treatment of Retinoblastoma. The total eye salvage rate in this study was 29% with an enucleation rate of 90% in unilateral cases and 33% in bilateral cases. Sixty-six percent of bilateral eyes affected were salvaged. Seventy-one percent of tumours were diagnosed after a parent noticed a gross abnormality of the eye. This highlights the possible need for screening for retinoblastoma in the infant population.

Air travel in pregnancy: the 'air-born' study

An increasingly common question posed by patients antenatally is whether air travel can be considered safe in pregnancy. The aim of this study was to assess whether any agreed standards or policies exist between airlines with respect to flying in pregnancy. Sixty-eight international airlines were surveyed, of whom seventeen (25%) replied. Three of seventeen (17.5%) airlines applied no restrictions at all to pregnant passengers; the remainder applied restrictions to air travel with varying gestations (28 to 36 weeks). A full delivery kit was carried by 5/17 airlines (29%), and some form of training in the management of a delivery was provided to the cabin crew in 12/17 airlines (70%). Experience of in-flight obstetric emergencies was reported by 11/17 airlines (65%). This study highlights a lack of consensus regarding restrictions on air travel in pregnancy. The low response rate also suggests an unwillingness on the part of the airline industry to openly declare their policy on this issue.

"In-situ" Teicoplanin for central venous catheter infection

Infection of central venous catheters (CVC) is a relatively common occurrence in immunocompromised patients, management of which has included I.V. antibiotics +/- removal of catheter. We have previously demonstrated that intracatheter administration of Amikacin empirically, successfully eradicated all bacterial infections except those due to S. epidermidis. A study was subsequently undertaken to treat gram positive cocci infections of CVC with intracatheter Teicoplanin. Eleven patients attending a single institution with documented gram positive cocci infection of CVC over a one year period were included in the study. Teicoplanin was instilled with heparinised saline once daily into the infected lumen of the CVC and allowed to remain for 24 hours. Treatment was continued for 48 hours after negative cultures were reported. Teicoplanin was successful in eradicating infection in 100% of cases. Mean duration of treatment was six days (range 4-9 days). Four patients subsequently developed a further infection, a mean of 13 weeks from first infection, only one of which was due to the same organism and this was successfully treated by a further course of Teicoplanin. No side effects were reported and catheter life was prolonged a mean of 132 days after completion of treatment. The use of Teicoplanin in this way for treatment of gram positive cocci infection of CVC is highly effective; once daily administration of antibiotic enables treatment to be given on an outpatient basis, thereby minimising hospital admission.