Placental pathology, birthweight discordance, and growth restriction in twin pregnancy: results of the ESPRiT Study

Fetal Growth and Antenatal Testing in Uncomplicated Multiple Gestations

Multiple gestations experience a slowing of fetal growth in the third trimester and have been described as having a higher risk of growth restriction. Whether this increased diagnosis of fetal growth restriction is physiological or pathologic is controversial. In an attempt to better identify those fetuses most at risk, twin-specific growth charts have been developed and tested. In addition, there are data to suggest that multiple gestations experience an increased risk of unexpected third-trimester stillbirth in apparently uncomplicated pregnancies. This chapter reviews the current data and recommendations for fetal growth assessment, antenatal surveillance, and delivery timing in uncomplicated multiple gestations.

Relationships between birth weight discordance and maternal and perinatal risks among twin pregnancies conceived following frozen embryo transfer

STUDY QUESTION

Is intertwin birth weight discordance associated with adverse maternal and perinatal outcomes following frozen embryo transfer (FET)?

SUMMARY ANSWER

For twins conceived following FET, intertwin birth weight discordance is related to elevated risks of neonatal mortality irrespective of chorionicity, and the risk of hypertensive disorders of pregnancy (HDP) is elevated for the mothers of dichorionic twins affected by such birth weight discordance.

WHAT IS KNOWN ALREADY

While the relationships between intertwin birth weight discordance and adverse maternal or fetal outcomes have been studied for naturally conceived twins, similarly comprehensive analyses for twins conceived using ART remain to be performed.

STUDY DESIGN, SIZE, DURATION

This was a retrospective cohort study of all twin births from 2007 to 2021 at Shanghai Ninth People's Hospital in Shanghai, China that were conceived following FET (N = 6265).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Intertwin birth weight discordance was defined as a 20% difference in neonatal birth weights. The primary study outcome was the incidence of HDP and neonatal death while secondary outcomes included gestational diabetes, placenta previa, placental abruption, intrahepatic cholestasis of pregnancy, preterm premature rupture of the membranes, Cesarean delivery, gestational age, birth weight, stillbirth, birth defect, neonatal jaundice, necrotizing enterocolitis, and pneumonia incidence. Logistic regression models were used to estimate adjusted odds ratios (aORs) and 95% CIs for maternal and neonatal outcomes. Subgroup analyses were conducted, and Kaplan-Meier survival analysis was used to estimate the survival probability. The sensitivity analysis was performed with a propensity score-based patient-matching model, an inverse probability weighting model, a restricted cubic spline analysis, and logistic regression models using other percentage cutoffs for discordance.

MAIN RESULTS AND THE ROLE OF CHANCE

Of 6101 females that gave birth to dichorionic twins during the study interval, birth weight discordance was observed in 797 twin pairs (13.1%). In this cohort, intertwin birth weight discordance was related to an elevated risk of HDP (aOR 1.56; 95% CI 1.21-2.00), and this relationship was confirmed through sensitivity analyses. Hypertensive disease risk rose as the severity of this birth weight discordance increased. Discordant birth weight was also linked to increased odds of neonatal mortality (aOR 2.13; 95% CI 1.03-4.09) and this risk also increased with the severity of discordance. Of the 164 women with monochorionic twins, the discordant group exhibited an elevated risk of neonatal death compared to the concordant group (crude OR 9.00; 95% CI 1.02-79.3).

LIMITATIONS, REASONS FOR CAUTION

The limitations of this study are its retrospective nature and the fact that the available data could not specify which twins were affected by adverse outcomes. There is a lack of an established reference birth weight for Chinese twins born at a gestational age of 24-41 weeks.

WIDER IMPLICATIONS OF THE FINDINGS

These findings suggest that twins exhibiting a birth weight discordance are related to an elevated risk of adverse maternal and perinatal outcomes, emphasizing a potential need for higher levels of antenatal surveillance in these at-risk pregnancies.

STUDY FUNDING/COMPETING INTEREST(S)

Authors declare no conflict of interest. This study was funded by the Clinical Research Program of Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine (JYLJ202118) and the National Natural Science Foundation of China (Grant Nos 82271693 and 82273634).

TRIAL REGISTRATION NUMBER

N/A.

Fetal growth restriction, neonatal morbidity and placental pathology in dichorionic twins-a comparison of twin-specific versus singleton growth charts‏‏

INTRODUCTION

Fetal growth restriction (FGR) in dichorionic diamniotic (DCDA) twin gestations is a known complication associated with adverse neonatal outcomes. The international guidelines have no consensus on whether to use singleton or twin-specific growth charts. Thus, we aimed to compare growth charts in correlation with pregnancy outcomes and placental histopathology.

METHODS

The medical files of all DCDA twin deliveries between 2010 and 2020 were reviewed. Birthweight percentile for gestational age (GA) for each individual neonate was assigned using the updated local singleton and twin-specific growth chart. We then divided the study population into two groups, neonates that were FGR based on the local singleton charts (FGR-singleton group) versus FGR on both twin-specific and singleton charts (FGR-twin group). Placental lesions were classified as lesions related to maternal or fetal malperfusion lesions (MVM, FVM), vascular and villous changes, and inflammatory lesions.

RESULTS

Overall, 185 neonates met the inclusion criteria. The FGR-twin group (59/185) had a higher rate of PE, lower GA at delivery, lower birthweight, and a higher rate of neonatal composite adverse outcomes compared to the FGR-singleton group. Moreover, placental pathology of the FGR-twin group demonstrated a higher rate of MVM lesions (p = 0.035).

DISCUSSION

In our cohort, neonates considered FGR based on twin-specific charts had worse neonatal outcomes with underlying placental insufficiency demonstrated by a higher rate of placental malperfusion vascular lesions. Our findings support using a twin-specific chart to diagnose FGR that is more clinically relevant.

Maternal paraben exposure and intra-pair thyroid-stimulating hormone difference in twin neonates

Thyroid hormones are essential for fetal growth and neurodevelopment. The recent frequent use of parabens has raised concerns about their endocrine-disrupting potential. However, the effects of maternal paraben exposure on neonatal thyroid hormone levels are still largely unknown. In our study, a co-twin control design was employed to analyze the relationships between maternal paraben exposure and neonatal thyroid-stimulating hormone (TSH) difference. We collected information from 252 mother-twin pairs from a twin birth cohort in Wuhan, China. Concentrations of six parabens were measured in maternal urine samples collected at < 16, 16-28, and > 28 weeks of gestation. Data of neonatal TSH levels were retrieved from medical records. Multiple informant models were applied to explore the time-specific relationships between paraben exposure and intra-twin TSH difference and to determine the susceptible window of exposure. We found that maternal urinary methyl paraben (MeP) during early pregnancy was positively associated with intra-twin TSH difference (%change = 5.96 %; 95 % confidant interval (CI): 0.04 %, 12.2 %). However, no significant differences were observed for exposure to ethyl paraben (EtP) and propyl paraben (PrP), and the associations between parabens and intra-twin TSH difference did not differ materially across pregnancy. Further, a stratified analysis based on twin zygosity and chorionicity and sex types indicated that the positive association between early pregnancy MeP exposure and intra-twin TSH difference was significant in monochorionic diamniotic (MCDA) twins of female-female fetuses and dichorionic diamniotic (DCDA) twins of opposite-sex. The prospective twin study provides first evidence that MeP exposure in early pregnancy was associated with an increased TSH difference in twin neonates, especially in female fetuses.

Pregnancy outcomes and risk factors for preeclampsia in dichorionic twin pregnancies after in vitro fertilization: a five-year retrospective study

Background

Both in vitro fertilization (IVF) and preeclampsia (PE) were associated with placental dysfunction. Although IVF can increase the incidence of PE, the pregnancy outcomes and risk factors for preeclampsia in dichorionic twin pregnancies conceived via IVF remain unclear. This study aimed to investigate the pregnancy outcomes and the risk factors for preeclampsia in dichorionic twin pregnancies conceived through IVF compared to those conceived after natural conception (NC).

Methods

This retrospective observational study enrolled 181 dichorionic twin pregnancy women with preeclampsia from 2016 to 2020. According to the mode of conception, they were allocated into IVF (n = 117) and NC groups (n = 64). The clinical characteristics of preeclampsia and pregnancy outcomes between the two groups were compared by using Student’s t test, chi-square test, and Fisher’s exact test, and logistic regression models were used to obtain adjusted odds ratios (aOR) with 95% confidence intervals (CI) for risk factors of early-onset preeclampsia.

Results

The incidence of early-onset PE and growth discordance in dichorionic twin pregnancies with PE is significantly higher in IVF-PE group than in NC group (78.60% vs 43.80%, P < 0.001, 11.10% vs 25.00%, P = 0.015). We found that IVF (aOR = 4.635, 95% CI: 2.130–10.084, P < 0.001) and growth discordance (aOR = 3.288; 95% CI: 1.090–9.749, P < 0.05) increased the incidence of early-onset PE.

Conclusions

In preeclamptic dichorionic twin pregnancies, IVF and growth discordance were associated with the increased incidence of early-onset PE. The underlying mechanism for the relationship between IVF and early-onset PE or growth discordance may be placental dysfunction.

Is there an impact of fetal sex in dichorionic discordant twins on placental histopathological abnormalities?

INTRODUCTION

Growth discordancy in dichorionic diamniotic (DCDA) twin gestations is a known complication associated with adverse neonatal outcomes. We aimed to study the differences in placental pathology, in relation to fetal sex, in DCDA twin gestations complicated with growth discordancy.

METHODS

The medical files of all DCDA twin deliveries complicated by growth discordancy between 2010 and 2020 were reviewed. Growth discordance was defined as a gap between twin birthweights > 20%. A comparison was made between female vs. male growth discordant twins. Placental lesions were classified as lesions related to maternal or fetal malperfusion lesions (MVM, FVM), vascular and villous changes, and inflammatory lesions.

RESULTS

Included 174 DCDA twins. Eighty-eight were in the discordant female group and eighty-six in the discordant male group. The groups did not differ in maternal demographics, pregnancy characteristics, and neonatal outcome. The discordant male group had a higher rate of placental MVM lesions as compared to the discordant female group (p = 0.003). The increased rate of placental MVM lesions in the discordant male group compared to the discordant female group did not change whether its co-twin was of similar or opposite sex.

DISCUSSION

Higher rate of MVM lesions characterizes growth discordant male neonates in DCDA twin gestations. This finding could represent a different adaptation of male fetuses to a hostile intrauterine environment.

Guideline No. 428: Management of Dichorionic Twin Pregnancies

OBJECTIVE

To review evidence-based recommendations for the management of dichorionic twin pregnancies.

TARGET POPULATION

Pregnant women with a dichorionic twin pregnancy.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in this guideline may improve the management of twin pregnancies and reduce neonatal and maternal morbidity and mortality.

EVIDENCE

Published literature was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary (e.g., twin, preterm birth). Results were restricted to systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date limits, but results were limited to English- or French-language materials.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the principal authors. The Board of the SOGC approved the final draft for publication. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED AUDIENCE

Obstetricians, family physicians, nurses, midwives, maternal-fetal medicine specialists, radiologists, and other health care providers who care for women with twin pregnancies.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Twin Growth Discordance and Risk of Postpartum Hemorrhage: A Retrospective Cohort Study

Background

In recent years, the incidence of postpartum hemorrhage has increased globally. Multiple pregnancies and cesarean sections are well-known risk factors for postpartum hemorrhage. No studies have evaluated the associations between fetal growth anomalies and postpartum hemorrhage in women with twin pregnancies undergoing cesarean section. This study aimed to identify the relationship between fetal growth anomalies and postpartum hemorrhage in women with twin pregnancies undergoing cesarean section.

Methods

This retrospective single-center study included 3,180 women with twin pregnancies at a tertiary hospital between August 2013 and July 2020. Singleton reference charts were used to assess fetal growth restriction at birth. Discordant growth was defined as an intertwin birth weight difference of ≥20%. Logistic regression analyses were used to evaluate the association between fetal growth anomalies and postpartum hemorrhage. Additionally, sensitivity analysis of abnormal placenta and stratification by twin chorionicity were conducted.

Results

The overall incidence of postpartum hemorrhage was 4.3%. Twin growth discordance, especially with fetal growth restriction, was associated with an increased risk of postpartum hemorrhage (adjusted odds ratio [AOR] = 1.62, 95% confidence interval [CI], 1.05-2.51, P = 0.031; AOR = 1.71; 95% CI, 1.08-2.70, P = 0.022; AOR = 1.98, 95% CI, 1.21-3.25, P = 0.006, respectively). After stratification, this relationship persisted in dichorionic twins (OR = 1.71, 95% CI, 1.04-2.82, P = 0.036; OR = 1.90, 95% CI, 1.13-3.21, P = 0.016; OR = 2.48, 95% CI, 1.41-4.38, P = 0.002, respectively). However, no significant association was observed in monochorionic twin pregnancies.

Conclusion

Growth discordance, especially complicated by fetal growth restriction, was associated with an increased risk of postpartum hemorrhage in women with twin pregnancies undergoing cesarean section, and was more evident in patients with dichorionic twins.

Hepatic and Adrenocortical Choristomas in the Placenta

Background Hepatic and adrenocortical choristomas are unusual findings in the placenta. This meta-analysis includes our own case report and 23 previously reported cases. We searched for patterns of associated placental, fetal and maternal aberrations in order to determine whether these choristomas are clinically relevant. Case report: In our case, abortion was induced due to fetal central nervous system and renal malformations. In the placenta a hepatic choristoma (<0.1 cm), thrombangiitis obliterans and a single umbilical artery were found. Results: In the literature, the majority of lesions were ≤1.0 cm (n = 21/24, 87.5%) and two hepatic choristomas manifested within chorangiomas. In a subfraction of cases, we found an association with twin/triple pregnancies (n = 6/24, 25%) and heterogeneous non-hepatic/non-adrenal malformations in fetuses (n = 4/24, 17%). Conclusion: Hepatic and adrenocortical choristomas are benign, could be based on focal epigenetic changes and might be related to chorangiomas but are not associated with a particular disease pattern or risk profile.

What fetal medicine specialists should know about the monochorionic placenta

Monochorionic twins are at risk of transfusion imbalances as long as they are connected to the shared placenta during their intrauterine journey. This review article addresses the macroscopic examination of the monochorionic placenta at the time of birth and explains placental dye injection studies to document the vascular anastomoses and placental sharing. We elaborate on the different types of anastomoses, the importance of how the placenta is divided between the twins, and the angioarchitecture in twin-twin transfusion syndrome, twin anemia polycythemia sequence and selective fetal growth restriction.

Gestational hypertensive disease and birthweight discordance in twin pregnancies: a systematic review and meta-analysis

INTRODUCTION

The objective of this systematic review was to explore the association between gestational hypertensive disease (GHD) and birthweight discordance in twin pregnancies.

METHODS

PubMed, Embase, Web of Science and Cochrane Library were systematically searched for studies reporting the risk of birthweight discordance in twin pregnancies complicated compared with those not complicated by GHD from establishment until July 2021. Risk of bias was assessed with the Newcastle-Ottawa Scale. According to the classification of GHD, sub-group analyses reporting cases with gestational hypertension (GH), chronic hypertension (CH) and preeclampsia (PE) were performed separately. Stratification by twin chorionicity (dichorionic (DC) and monochorionic (MC)) was also conducted. When there was substantial heterogeneity (I² ≥ 50%), the random effect mode was used to estimate the pooled risk ratio, otherwise the fixed effect model was used.

RESULTS

Nine studies (303,204 twin pregnancies) were included. GHD (OR 1.45, 95% CI 1.41-1.49) was a risk factor for intertwin birthweight discordance [PE (OR 1.69, 95% CI 1.33-2.16); CH (OR 1.59, 95% CI 1.46-1.73); GH (OR1.45, 95%Cl 1.10-1.92]. After stratification, birthweight discordance was related to GHD (OR 2.51, 95% CI 2.01-3.14), GH (OR 2.08, 95% CI 1.33-3.25) and PE (OR 2.74, 95% CI 2.09-3.61) in DC pregnancies, but no longer associated with GHD and PE in MC group.

CONCLUSIONS

Twin gestations complicated with GHD, especially in DC pregnancies, were at significantly higher risk of birthweight discordance.

Patterns of discordant growth and adverse neonatal outcomes in twins

BACKGROUND

Intertwin size discordance is an independent risk factor for adverse neonatal outcomes in twin pregnancies. However, size discordance at a given point in gestation fails to take into consideration information, such as the timing of onset and the rate of progression of discordance, that may be of prognostic value.

OBJECTIVE

In this study, we aimed to identify distinct patterns of discordant fetal growth in twin pregnancies and to determine whether these patterns are predictive of adverse pregnancy outcomes.

STUDY DESIGN

This was a retrospective cohort study of women with twin pregnancies in a single tertiary referral center between January 2011 and April 2020, who had at least 3 ultrasound examinations during pregnancy that included assessment of fetal biometry. Size discordance was calculated at each ultrasound examination, and pregnancies were classified into 1 of 4 predetermined patterns based on the timing of onset and the progression of discordance: pattern 1, no significant discordance group (referent); pattern 2, early (<24 weeks' gestation) progressive discordance group; pattern 3, early discordance with plateau group; or pattern 4, late (≥24 weeks' gestation) discordance group. The associations of discordance pattern (using pattern 1 as referent) with preterm birth, preeclampsia, size discordance at birth, and birthweight<10th percentile were expressed as adjusted relative risk with 95% confidence intervals and were compared with those observed for a single measurement of size discordance at 32 weeks' gestation.

RESULTS

Of 2075 women with a twin gestation who were identified during the study period, 1059 met the study criteria. Of the 1059 women, 599 (57%) were classified as no significant discordance (pattern 1), 23 (2%) as early progressive discordance (pattern 2), 160 (15%) as early discordance with plateau (pattern 3), and 277 (26%) as late discordance (pattern 4). The associations of discordance pattern with preterm birth at <34 weeks' gestation and preeclampsia were strongest for pattern 2 (rates of 43% [adjusted relative risk, 3.43; 95% confidence interval, 2.10-5.62] and 17% [adjusted relative risk, 5.81; 95% confidence interval, 2.31-14.60], respectively), intermediate for pattern 3 (rates of 23% [adjusted relative risk, 1.82; 95% confidence interval, 1.28-2.59] and 6% [adjusted relative risk, 2.08; 95% confidence interval, 1.01-4.43], respectively), and weakest for pattern 4 (rates of 12% [adjusted relative risk, 0.96; 95% confidence interval, 0.65-1.42] and 4% [adjusted relative risk, 1.41; 0.68-2.92], respectively). In contrast, a single measurement of size discordance at 32 weeks' gestation showed no association with preeclampsia and only a weak association with preterm birth at <34 weeks' gestation.

CONCLUSION

We identified 4 distinct discordance growth patterns among twins that demonstrated a dose-response relationship with adverse outcomes and seemed to be more informative than a single measurement of size discordance.

Pathologic Basis for the Definition of Discordant Growth in Dichorionic Twins

OBJECTIVE

The aim of the current study was to identify the optimal cutoff that should define discordance in dichorionic twin gestations through correlation with abnormal placental pathology as a specific measure of fetal growth restriction of the smaller twin.

METHODS

We performed a retrospective cohort study of all women with dichorionic twin pregnancies who gave birth in a single center between 2002 and 2015. We investigated the association between the level of growth discordance and maternal vascular malperfusion (MVM) pathology in the placenta of the smaller twin, with and without adjustment for whether the smaller twin is small for gestational age (SGA).

RESULTS

A total of 1,198 women with dichorionic twin gestation met the study criteria. The rate of MVM pathology in the placenta of the smaller twin increased with the level of discordance and was most obvious for discordance ≥25% (rate of MVM 12.0% compared with 2.8% in cases with discordance <10%, adjusted relative risk [aRR] 3.71, 95% confidence interval [CI] 1.97-6.99). When the analysis was adjusted for SGA of the smaller twin, discordance was independently associated with MVM pathology only when growth discordance was ≥25% (aRR 2.18, 95%-CI 1.01-4.93), while SGA was strongly associated with MVM pathology irrespective of the level of discordance.

CONCLUSION

Our findings suggest that discordant growth in dichorionic twins should raise the concern of fetal growth restriction of the smaller twin, irrespective of whether the smaller twin is SGA, only when the discordance s ≥25%. The association of lower levels of discordance with abnormal placental pathology is mainly driven by the confounding effect of SGA of the smaller twin.

Placental T2* estimated by magnetic resonance imaging and fetal weight estimated by ultrasound in the prediction of birthweight differences in dichorionic twin pairs

INTRODUCTION

Intertwin birthweight (BW) difference is associated with an increased risk of adverse outcome. Ultrasound estimated fetal weight (EFW) is the current method to predict intertwin BW difference, however, the sensitivity is poor. Therefore, new methods are needed. Placental T2* estimated by magnetic resonance imaging (MRI) provides non-invasive information about the placental function. This study aimed to investigate placental T2* difference as a new predictor of BW difference, and to compare it to the EFW.

METHODS

We included 25 dichorionic twin pairs at 19-38 weeks' gestation. Placental T2* was obtained by MRI and EFW by ultrasound. Correlations between each predictor and BW difference were examined by simple linear regression, and the combined model was analyzed by multiple linear regression and likelihood ratio test.

RESULTS

Strong positive correlations were demonstrated between intertwin differences in placental T2* and BW (r = 0.80, p < 0.005), and EFW and BW (r = 0.64, p < 0.005). Placental T2* difference was a strong independent predictor of BW difference (p < 0.001), and the combined model performed better than each predictor alone (p < 0.0001).

DISCUSSION

This pilot study demonstrates that placental T2* difference may be a predictor of intertwin BW difference irrespectively of fetal size. The clinical potential of this method deserves further investigation in a larger clinical study.

Twin pregnancy outcomes after metabolic and bariatric surgery

BACKGROUND

The effect of bariatric surgery (BS) on twin pregnancy outcomes is unclear.

OBJECTIVES

We examined associations of BS with maternal and perinatal outcomes among women with twin gestation.

SETTING

A university hospital.

METHODS

A retrospective case-control study of twin deliveries during 2006 through 2017. The study group comprised all women with twin pregnancy who had undergone BS and delivered during the study period. A control group was established by matching preoperative body mass index, age, parity, and delivery year.

RESULTS

Data from 66 women with twin gestation were analyzed, 22 postBS and 44 matched control parturients. Compared with the control group, the study group had lower rates of gestational diabetes (9.1% versus 36.4%, P = .02) and gestational hypertensive disorders (0% versus 25.0%, P = .01); hemoglobin levels were lower at both early pregnancy (median 12.3 versus 13.4 g/dL, P < .001) and after delivery (9.3 versus 10.5 g/dL, P < .001). Median neonatal birthweights and the proportion of small-for-gestational-age infants were comparable between the groups. The degree of birth weight discordance between the twins was higher (17.2% versus 8.8%, P < .001) in the control group.

CONCLUSIONS

In this study involving twin gestations, pregnancy outcomes were more positive among women who had undergone BS; as noted by reduced prevalences of gestational diabetes and gestational hypertensive disorders as well as a lesser degree of birth weight discordance. Nevertheless, BS was associated with lower hemoglobin levels during pregnancy and the postpartum period. Future studies are warranted to confirm our findings and evaluate the long-term outcomes of newborns of postBS mothers.

Neonatal morbidity and mortality among growth-discordant dichorionic twins, classified according to birth weight of the smaller twin: a population-based cohort study

Objective: To examine the outcomes among discordant dichorionic (DC) twins, where the smaller twin is small for gestational age (SGA) or non-SGA.Materials and methods: We used the national perinatal registry to compare the relationship between selected maternal characteristics (age, parity, body mass index, gestational diabetes, hypertensive disorders, and gestational age at delivery) and neonatal outcomes in discordant >25% DC twins. Chorionicity was established by standard ultrasound criteria and confirmed postpartum. The smaller of the twins was further classified as SGA or non-SGA. The neonatal outcomes included 5-min Apgar score <7, admission to neonatal intensive care unit, early neonatal death and neonatal morbidities.Results: We identified 377 pairs of DC discordant twins >25% born during the 15 years study period, 270 (71.6%) of which included an SGA smaller twin and 107 (28.4%) were non-SGA smaller twin. Maternal characteristics and neonatal morbidities were unrelated to the smaller discordant twin being SGA. A significantly increased incidence of stillbirth was found in the SGA group. Early neonatal deaths were only found in the SGA group.Conclusion: When the smaller twin is SGA, the growth discordant DC twin pair is associated with increased incidence of perinatal deaths. These appear unrelated to maternal characteristics and neonatal morbidity.

Ultrasound surveillance in twin pregnancy: An update for practitioners

Ultrasound has revolutionised the management of multiple pregnancies and their complications. Increasing frequency of twin pregnancies mandates familiarity of all clinicians with the relevant pathologies and evidence-based surveillance and management protocols for their care. In this review, we summarise the latest evidence relating to ultrasound surveillance of twin pregnancies including first trimester assessment and screening, growth surveillance and the detection and management of the complications of monochorionic pregnancies including twin-to-twin-transfusion syndrome, selective fetal growth restriction, twin reversed arterial perfusion sequence and conjoined twinning.

The differences in placental pathology and neonatal outcome in singleton vs. twin gestation complicated by small for gestational age

OBJECTIVE

We aimed to compare placental histopathology and neonatal outcome between dichorionic diamniotic (DCDA) twins and singleton pregnancies complicated by small for gestational age (SGA).

METHODS

Medical files and placental pathology reports from all deliveries between 2008 and 2017 of SGA neonates, (birthweight < 10th percentile), were reviewed. Comparison was made between singleton pregnancies complicated with SGA (singletons SGA group) and DCDA twin pregnancies (Twins SGA group), in which only one of the neonates was SGA. Placental diameters were compared between the groups. Placental lesions were classified into maternal and fetal vascular malperfusion lesions (MVM and FVM), maternal (MIR) and fetal (FIR) inflammatory responses, and chronic villitis. Neonatal outcome parameters included composite of early neonatal complications.

RESULTS

The twins SGA group (n = 66) was characterized by a higher maternal age (p = 0.011), lower gestational age at delivery (34.9 ± 3.1 vs. 37.7 ± 2.6 weeks, p < 0.001), and a higher rate of preeclampsia (p = 0.010), compared to the singletons SGA group (n = 500). Adverse composite neonatal outcome was more common in the twins SGA group (p < 0.001). Placental villous lesions related to MVM (p < 0.001) and composite MVM lesions (p = 0.04) were more common in the singletons SGA group. On multivariate logistic regression analysis, the singletons SGA group was independently associated with placental villous lesions (aOR 3.6, 95% CI 1.9-7.0, p < 0.001) and placental MVM lesions (aOR 2.44, 95% CI 1.29-4.61, p = 0.006).

CONCLUSION

Placentas from SGA singleton pregnancies have more MVM lesions as compared to placentas from SGA twin pregnancies, suggesting different mechanisms involved in abnormal fetal growth in singleton and twin gestations.

The Association of Intrapair Birth-Weight Differences With Internalizing and Externalizing Behavior Problems

Problem behaviors are of increasing public health concern. Twin studies have revealed substantial genetic and environmental influences on children's behavior, and examining birth-weight difference could allow the identification of the specific contribution of multiple non-shared prenatal environmental factors. The Twins and Multiple Births Association Heritability Study, a UK, volunteer-based study, recruited mothers of twins aged 18 months to 5 years; 960 twins (480 pairs) were included in the analysis. Twins' mothers answered questions relative to their pregnancy and their twins' characteristics, and completed the Child Behavior Checklist (CBCL) 1½-5. The association between the absolute birth-weight difference and each CBCL scale's score difference was analyzed by means of multiple linear regressions. Expected mean CBCL score differences were calculated. In monozygotic (MZ) twins, statistically and clinically significant associations were found between intrapair birth-weight difference and difference in total problems, internalizing problems, and emotional reactiveness. No significant results were observed neither in dizygotic (DZ) twins when analyzed as a separate group nor in MZ and DZ twins combined. The results of the present study suggest that with increasing the absolute birth-weight difference, the intrapair difference in total problems, internalizing behaviors and emotionality increases, with smaller twins being at major risk for later behavior problems. Moreover, these results suggest a causal association between birth weight and behavior development.

Placental Histopathology Differences and Neonatal Outcome in Dichorionic-Diamniotic as Compared to Monochorionic-Diamniotic Twin Pregnancies

OBJECTIVE

We aimed to compare the differences in placental histopathology lesions and pregnancy outcome in dichorionic-diamniotic (DCDA) versus uncomplicated monochorionic-diamniotic (MCDA) twin gestations.

STUDY DESIGN

Maternal characteristics, neonatal outcome, and placental histopathology reports of all twin deliveries between 24 and 41 weeks were reviewed. Excluded were pregnancies complicated by twin-to-twin transfusion syndrome, twin anemia-polycythemia sequence, selective intrauterine growth restriction, placenta previa, intrauterine fetal death, and malformation. Placental lesions were classified to maternal/fetal vascular malperfusion lesions. Umbilical cord abnormalities included hypo-/hypercoiling and abnormal insertion. Composite adverse neonatal outcome was defined as 1 or more early complications. Small for gestational age (SGA) was defined as birth weight ≤10th percentile.

RESULTS

The DCDA group (n = 362) was characterized by higher rates of assisted reproductive techniques ( P < .001) and nulliparity ( P = .03) as compared to the MCDA group (n = 65). Gestational age at delivery was similar between groups. Placental maternal vascular malperfusion lesions were more common in placentas from DCDA group (38.2% vs 23.1%; P = .016), while fetal vascular malperfusion lesions and abnormal cord insertion were more common in placentas from MCDA group ( P = .027; P< .001). The SGA and composite adverse neonatal outcome were more common in the MCDA group ( P = .031 and P = .038, respectively). By multivariate regression analysis, composite adverse neonatal outcome was found to be independently associated with the MCDA group, adjusted odds ratio (aOR) = 1.2, 95% confidence interval (CI) = 1.04 to 1.89, P = .041, and with placental fetal malperfusion lesions aOR = 1.3, 95% CI = 1.1 to 2.09, P = .038.

CONCLUSION

Placental pathology differs between MCDA and DCDA twin pregnancies. Adverse neonatal outcome in uncomplicated MCDA twins, as compared to DCDA twins, could be related to increased placental fetal malperfusion lesions and abnormal cord insertion.

Growth discordance of monoamniotic twin because of difference of cords diameter in forked umbilical cord: Case report

A case of monochorionic-monoamniotic (MCMA) twin pregnancy with growth discordance because of difference of cord diameter in forked umbilical cord is reported.MCMA twins were diagnosed at 12 weeks of gestation and twin growth discordance was considered during the follow-up twice-weekly visits to the ultrasound and prenatal care units. The pregnancy was terminated at 34 weeks. Two live female babies weighing 2510 g and 1940 g were delivered. Examination of placenta and umbilical cords after birth showed that the 2 cords merged into a conjoint cord 1 cm from insertion to the placenta (forked umbilical cord). Placental color injection showed that the 2 fetuses shared the same placenta area. The diameters of the 2 cords were significantly different (1.5 vs 0.8 cm). This caused an unequal distribution of blood and nutrients, which is the real reason of twin growth discordance in this case.This case reveals that the diameter discordance of cords can be an important factor for twin growth discordance. Few relevant cases have previously been reported. Cords diameter measurement is suggested for ultrasound surveillance of twin growth discordance.

Birth weight discordance and adverse perinatal outcomes

OBJECTIVE

Our purpose was to examine the association between discordant growth and perinatal mortality and morbidity among twins with careful adjustment for maternal confounding factors.

STUDY DESIGN

Two cohorts with and without chorionicity data were compared using generalized estimating modeling.

RESULTS

Our population-based dataset consisted of 12,656 individual twins from whom 4% (452/12,656) had≥30% growth discordance. A subgroup of this population with chorionicity information had an incidence of 7.3%≥30% growth discordance. In growth-discordant twins, perinatal mortality and morbidity were higher than concordant pairs (P<0.01). Low Apgar score and perinatal mortality were more frequent in growth-discordant twins compared with growth-concordant ones (all P<0.01).

CONCLUSION

Birth weight discordance (BWD) places twins at increased risk of perinatal mortality. Growth discordance was also an independent risk factor for lower Apgar score of 5 min less than 5.

Nonpresenting Dichorionic Twins and Placental Vascular Malperfusion

OBJECTIVE

To explore the hypothesis that selective placental pathology affecting the nonpresenting twin is a significant contributory factor mediating the smaller size at birth of nonpresenting dichorionic twins.

METHODS

We conducted a retrospective cohort study of all dichorionic twin deliveries in a single tertiary center between 2002 and 2015 where by departmental policy, all placentas from multifetal gestations are routinely sent for pathologic examination. Maternal charts, neonatal charts, and pathology reports were reviewed. Placental abnormalities were classified into lesions associated with maternal vascular malperfusion, fetal vascular malperfusion, placental hemorrhage, and chronic villitis. Comparison of neonatal outcomes and placental abnormalities was made between all nonpresenting and all presenting twins as well as within twin pairs.

RESULTS

A total of 1,322 women with dichorionic twins were studied. Nonpresenting twins were smaller at birth compared with the presenting cotwin starting at 32 weeks of gestation (birth weight [±standard deviation] 2,224±666 g compared with 2,278±675 g, P=.036). Nonpresenting twins had smaller placentas (361±108 g compared with 492±129 g, P<.001) as early as 24 weeks of gestation. Nonpresenting twins had higher odds for any placental abnormality (adjusted odds ratio [OR] 1.91, 95% confidence interval [95% CI] 1.63-2.23), small placenta (adjusted OR 4.69, 95% CI 3.75-5.88), and maternal vascular malperfusion (OR 2.75, 95% CI 2.32-3.27) compared with their presenting cotwins. In nonpresenting twins, the presence of maternal vascular malperfusion pathology was associated with lower birth weight compared with their presenting cotwin during the third trimester.

CONCLUSION

The lower birth weight of nonpresenting fetuses in dichorionic twin pregnancies is correlated with a higher rate of placental maternal vascular malperfusion pathology.

Placental weight and birth weight to placental weight ratio in monochorionic and dichorionic growth-restricted and non-growth-restricted twins

OBJECTIVE:

The aim of the present study was to compare the placental weight and birth weight/placental weight ratio for intrauterine growth-restricted and non-intrauterine growth-restricted monochorionic and dichorionic twins.

METHODS:

This was a retrospective analysis of placentas from twin pregnancies. Placental weight and the birth weight/placental weight ratio were compared in intrauterine growth-restricted and non-intrauterine growth-restricted monochorionic and dichorionic twins. The association between cord insertion type and placental lesions in intrauterine growth-restricted and non-intrauterine growth-restricted monochorionic and dichorionic twins was also investigated.

RESULTS:

A total of 105 monochorionic (intrauterine growth restriction=40; non-intrauterine growth restriction=65) and 219 dichorionic (intrauterine growth restriction=57; non-intrauterine growth restriction=162) placentas were analyzed. A significantly lower placental weight was observed in intrauterine growth-restricted monochorionic (p=0.022) and dichorionic (p<0.001) twins compared to non-intrauterine growth-restricted twins. There was no difference in the birth weight/placental weight ratio between the intrauterine growth restriction and non-intrauterine growth restriction groups for either monochorionic (p=0.36) or dichorionic (p=0.68) twins. Placental weight and the birth weight/placental weight ratio were not associated with cord insertion type or with placental lesions.

CONCLUSION:

Low placental weight, and consequently reduced functional mass, appears to be involved in fetal growth restriction in monochorionic and dichorionic twins. The mechanism by which low placental weight influences the birth weight/placental weight ratio in intrauterine growth-restricted monochorionic and dichorionic twins needs to be determined in larger prospective studies.

Intertwin estimated fetal weight or crown rump length discordance and adverse perinatal outcome

AIM

In the current review study, we present recent data regarding the importance of intertwin estimated fetal weight (EFW) and crown rump length (CRL) discordance for the prediction of adverse perinatal outcome both in monochorionic and in dichorionic diamniotic gestations.

RESULTS

Twins with significant weight disparity are associated with higher rates of perinatal morbidity and mortality, regardless of gestational age at delivery. However, there is no agreement regarding as to the cut off value above which the perinatal outcome is unfavorably affected and the threshold range from 10 to 30%. On the other hand, CRL discrepancy has proved to be a weak predictor of adverse outcomes, such as fetal or neonatal death in fetuses without chromosomal and structural abnormalities. In clinical practice, decisions about obstetric surveillance of discordant twin gestations, frequency of fetal sonographic monitoring and time of delivery are usually based on amniotic fluid volume and Doppler assessments on a weekly basis.

CONCLUSION

Significant EFW discordance leads to adverse perinatal outcome, although the cut-off value has not yet been estimated. CRL discrepancy is not correlated well with adverse perinatal outcome. However, increased monitoring of women with EFW and CRL discrepancy is suggested.

Optimal threshold for birth weight discordance: Does knowledge of chorionicity matter?

OBJECTIVE

To establish the optimal threshold of birth weight discordance (BWD) for prediction of stillbirth, perinatal mortality and morbidity in twins born in British Columbia with or without chorionicity information.

STUDY DESIGN

This is a retrospective population-based cohort study of twins born in British Columbia from 2000 to 2010. Data from one hospital was used to adjust for chorionicity. Multivariate generalized estimating equation and receiver operating characteristic curve analyses were performed to evaluate the predictability of BWD in comparison with other fetal anthropometric measurements. Positive likelihood ratio is used to estimate test accuracy. Survival analysis was conducted to take gestational age and other confounders into account.

RESULTS

We analyzed two cohorts, with (pairs=1493) and without (pairs=6328) chorionicity information, of which 1.5% experienced stillbirth, 2.9% suffered perinatal mortality and 22.6% identified with perinatal morbidities. BWD was a significant predictor of stillbirth. Standard receiver operating characteristic curve analysis and survival analysis suggested that BWD of ⩾30% is the optimal thresholds for stillbirth and perinatal mortality irrespective of chorionicity. However, the P-value for predictive accuracy of BWD was nonsignificant for perinatal morbidity, after adjusting for confounding variables engaging multivariate analysis. Sex discordance can be used as a proxy for chorionicity.

CONCLUSION

BWD is a good predictor for stillbirth. A BWD cutoff limit of 30% and higher has optimal accuracy for detecting perinatal mortality.

Anomalies of the placenta and umbilical cord in twin gestations

The frequency of twin gestations has increased over the last few decades, mainly due to maternal age at childbearing, and the use of assisted reproductive technologies. Twins are at higher risk of aneuploidy, structural anomalies, and placental abnormalities. Some of the placental and umbilical cord abnormalities found in twin gestations are nonspecific and can be found in singleton gestations (ie, placenta previa, placental abruption, single umbilical artery, velamentous cord insertion, vasa previa, etc). However, other anomalies are unique to twin gestations, and are mainly associated with monochorionic twins-these include intraplacental anastomosis and cord entanglement. Most of these conditions can be diagnosed with ultrasound. An accurate and early diagnosis is important in the management of twin gestations. Determination of chorionicity, amnionicity, and the identification of placental anomalies are key issues for the adequate management of twin pregnancies. Pathologic placental examination after delivery can help in assessing the presence of placental and umbilical cord abnormalities, as well as providing information about chorionicity and gaining insight into the potential mechanisms of disease affecting twin gestations.

[Birth weight discordance in dichorionic twins: diagnosis, obstetrical and neonatal prognosis]

OBJECTIVE

To describe neonatal and obstetrical prognosis in dichorionic (DC) twins with a birth weight discordance under 20% and evaluate the influence of intrauterine growth restriction on the management.

PATIENTS AND METHODS

We studied retrospectively 67 DC twins birth between July 2002 and July 2012 at our university labour ward. Birth weight discordance was considered slight between 20-25%, moderate between 25-30%, and severe over 30%.

RESULTS

Prevalence of birth weight discordance in DC twins is estimated at 11.4% in our study. Eighty percent of severe discordance was diagnosed before delivery, 41% for moderate discordance and 20% for slight discordance. We note 30% of pre eclampsia in our population with 44% in the severe discordance group. Mean gestational age was 35.1 weeks for slight and moderate discordances, and 33 weeks for severe discordance. Caesarean section rate was 48% for severe discordance and only 36% for slight discordance. Vaginal delivery rate is 56.7%. More than half of patient with a severe discordance gave birth vaginally. Intrauterine growth restriction rate under the 10th percentile was 18.7%. Prevalence of IUGR was 24% in sever discordance group, 23.5% in the moderate discordance group and 10% in the slight group. Neonatal morbidity rate was 20.8% mainly in children with IUGR.

DISCUSSION AND CONCLUSION

Neonatal mortality and morbidity rate are mainly increased in severe discordant twins. These pregnancies are at high risk of maternal morbidity. Vaginal delivery must be preferred for slight and moderate discordances. In case of severe discordance, vaginal delivery should be considered depending on the degree of intrauterine growth retardation.

Degree and rate of growth discordance in dichorionic twins conceived by in vitro fertilization

Objective. Our objective was to estimate degree and rate of discordant growth and its impact on perinatal outcome in dichorionic twin pregnancies conceived by in vitro fertilization (IVF) compared to those conceived spontaneously. Study Design. Growth discordance was defined as 90th percentiles for the study population. Adverse perinatal outcome was defined as 5-minute Apgar score <7 and/or admission to neonatal intensive care unit. Results. In the total study population of dichorionic twins (176 conceived by IVF and 215 spontaneously), 30% discordant growth represented the 90th percentile. After adjusting for gestational age, discordant twins conceived by IVF or spontaneously were at higher risk for adverse perinatal outcome (hazard ratio 4.4; 95% CI 2.4-8.3, P < 0.0001; hazard ratio 2.5; 95% CI 1.5-4.4, P = 0.001, resp.). Similar rates of 5-minute Apgar score <7, admission to neonatal intensive care unit, and delivery <34 weeks were found between discordant twins conceived by IVF and those conceived spontaneously. Conclusion. Dichorionic twins conceived by IVF are at similar risk for the rate and degree of discordant growth and adverse perinatal outcome compared to dichorionic twins conceived spontaneously.

The winding road to understanding the neonatal origins of inflammatory gastrointestinal disorders

Beginning with the observation that birth weight correlates with increased risk of cardiovascular disease, the concept of neonatal programming, that the environmental influence on fetal and neonatal development results in modification of the risk profile for adult disease, has begun to emerge as an important component to understanding the origin of chronic diseases of many different organ systems. Until recently, the gastrointestinal system has not been considered. Our understanding of the pathogenesis of many intestinal inflammatory disorders is still incomplete; however, a brief review of what is known reveals several opportunities for the early intraluminal environment to affect the development of the intestinal immune system. Early clinical observations such as the increased risk of celiac disease observed in those born by cesarean section and the protective effect of breast-feeding against inflammatory bowel disease and celiac disease support the role of neonatal programming in the development of chronic inflammatory gastrointestinal disease. Additional, more robust clinical studies are needed to confirm this role. Furthermore, examination of the possible mechanisms of immune phenotype modification is necessary.