The decreased rates of triplet births: temporal trends and biologic speculations

One model, two brains: Automatic fetal brain extraction from MR images of twins

Fetal brain extraction from magnetic resonance (MR) images is of great importance for both clinical applications and neuroscience studies. However, it is a challenging task, especially when dealing with twins, which are commonly existing in pregnancy. Currently, there is no brain extraction method dedicated to twins, raising significant demand to develop an effective twin fetal brain extraction method. To this end, we propose the first twin fetal brain extraction framework, which possesses three novel features. First, to narrow down the region of interest and preserve structural information between the two brains in twin fetal MR images, we take advantage of an advanced object detector to locate all the brains in twin fetal MR images at once. Second, we propose a Twin Fetal Brain Extraction Network (TFBE-Net) to further suppress insignificant features for segmenting brain regions. Finally, we propose a Two-step Training Strategy (TTS) to learn correlation features of the single fetal brain for further improving the performance of TFBE-Net. We validate the proposed framework on a twin fetal brain dataset. The experiments show that our framework achieves promising performance on both quantitative and qualitative evaluations, and outperforms state-of-the-art methods for fetal brain extraction.

Outcomes of multiple gestation births compared to singleton: analysis of multicenter KID database

Background

The available data regarding morbidity and mortality associated with multiple gestation births is conflicting and contradicting.

Objective

To compare morbidity, mortality, and length of stay (LOS) outcomes between multiple gestation (twin, triplet and higher-order) and singleton births.

Methods

Data from the national multicenter Kids’ Inpatient Database of the Healthcare Cost and Utilization Project from the years 2000, 2003, 2006, 2009, 2012, and 2016 were analyzed using a complex survey design using Statistical Analysis System (SAS) 9.4 (SAS Institute, Cary NC). Neonates with ICD9 and ICD10 codes indicating singletons, twins or triplets, and higher-order multiples were included. Mortality was compared between these groups after excluding transfer outs to avoid duplicate inclusion. To analyze LOS, we included inborn neonates and excluded transfers; who died inpatient and any neonates who appear to have been discharged less than 33 weeks PMA. The LOS was compared by gestational age groups.

Results

A total of 22,853,125 neonates were analyzed for mortality after applying inclusion-exclusion criteria; 2.96% were twins, and 0.13% were triplets or more. A total of 22,690,082 neonates were analyzed for LOS. Mean GA, expressed as mean (SD), for singleton, twins and triplets, were 38.30 (2.21), 36.39 (4.21), and 32.72 (4.14), respectively. The adjusted odds for mortality were similar for twin births compared to singleton (aOR: 1.004, 95% CI:0.960–1.051, p = 0.8521). The adjusted odds of mortality for triplet or higher-order gestation births were higher (aOR: 1.33, 95% CI: 1.128–1.575, p = 0.0008) when compared to the singleton births. Median LOS (days) was significantly longer in multiple gestation compared to singleton births overall (singletons: 1.59 [1.13, 2.19] vs. twins 3.29 [2.17, 9.59] vs. triplets or higher-order multiples 19.15 [8.80, 36.38], p < .0001), and this difference remained significant within each GA category.

Conclusion

Multiple gestation births have higher mortality and longer LOS when compared to singleton births. This population data from multiple centers across the country could be useful in counseling parents when caring for multiple gestation pregnancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40748-021-00135-5.

Effect of monochorionicity on perinatal outcome and growth discordance in triplet pregnancy: collaborative multicenter study in England, 2000-2013

OBJECTIVES

To compare perinatal outcome and growth discordance between trichorionic triamniotic (TCTA) and dichorionic triamniotic (DCTA) or monochorionic triamniotic (MCTA) triplet pregnancies.

METHODS

This was a multicenter cohort study using population-based data on triplet pregnancies from 11 Northern Survey of Twin and Multiple Pregnancy (NorSTAMP) maternity units and the Southwest Thames Region of London Obstetric Research Collaborative (STORK) multiple pregnancy cohort, for 2000-2013. Perinatal outcomes (from ≥ 24 weeks' gestation to 28 days of age), intertriplet fetal growth and birth-weight (BW) discordance and neonatal morbidity were analyzed in TCTA compared with DCTA/MCTA pregnancies.

RESULTS

Monochorionic placentation of a pair or trio in triplet pregnancy (n = 72) was associated with a significantly increased risk of perinatal mortality (risk ratio, 2.7 (95% CI, 1.3-5.5)) compared with that in TCTA pregnancies (n = 68), due mainly to a much higher risk of stillbirth (risk ratio, 5.4 (95% CI, 1.6-18.2)), with 57% of all stillbirth cases resulting from fetofetal transfusion syndrome, while there was no significant difference in neonatal mortality (P = 0.60). The associations with perinatal mortality and stillbirth persisted when considering only pregnancies not affected by a major congenital anomaly. DCTA/MCTA triplets had lower BW and demonstrated greater BW discordance than did TCTA triplets (P = 0.049). Severe BW discordance of > 35% was 2.5-fold higher in DCTA/MCTA compared with TCTA pregnancies (26.1% vs 10.4%), but this difference did not reach statistical significance (P = 0.06), presumably due to low numbers. Triplets in both groups were delivered by Cesarean section in over 95% of cases, at a similar gestational age (median, 33 weeks' gestation). The rate of respiratory (P = 0.28) or infectious (P = 0.08) neonatal morbidity was similar between the groups.

CONCLUSIONS

Despite close antenatal surveillance, monochorionic placentation of a pair or trio in triamniotic triplet pregnancy was associated with a significantly increased stillbirth risk, mainly due to fetofetal transfusion syndrome, and with greater size discordance. In liveborn triplets, there was no adverse effect of monochorionicity on neonatal outcome. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Risks of miscarriage or preterm delivery in trichorionic and dichorionic triplet pregnancies with embryo reduction versus expectant management: a systematic review and meta-analysis

STUDY QUESTION

Is pregnancy outcome in triplet pregnancies improved with embryo reduction (ER) to twins compared to expectant management?

SUMMARY ANSWER

In trichorionic triplet pregnancies, ER to twins reduces the risk of preterm birth (<34 weeks) without significantly increasing the risk of miscarriage (<24 weeks), whereas in dichorionic triplet pregnancies, the results are inconclusive.

WHAT IS KNOWN ALREADY

Triplet pregnancies are associated with a high risk of miscarriage and preterm birth. ER can ameliorate these conditions in higher order multiple gestations but is still controversial in triplets.

STUDY DESIGN, SIZE, DURATION

This study aimed to conduct a systematic review, following the PRISMA guidelines, and critically appraise ER at 8-14 weeks of gestation in both trichorionic triamniotic (TCTA) and dichorionic triamniotic (DCTA) pregnancies. Selective ER to twins was compared with expectant management, focusing on the risks of miscarriage and preterm birth. The computerized database search was performed on 8 January 2017. Overall, from 25 citations of relevance, eight studies with a total of 249 DCTA and 1167 TCTA pregnancies fulfilled the inclusion criteria.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A comprehensive computerized systematic literature search of all English language studies between 2000 and 2016 was performed in PubMed, EMBASE, Scopus, Evidence Based Medicine Reviews (Cochrane Database and Cochrane Central Register of Controlled Trials) and Google Scholar. Relevant article reference lists were hand searched. The management options were compared for rates of miscarriage <24 weeks and preterm birth <34 weeks. Only studies with both expectant management and ER to twins were included in the analysis. The quality of each individual article was critically appraised and appropriate statistical methods were used to extract results.

MAIN RESULTS AND THE ROLE OF CHANCE

In TCTA pregnancies managed expectantly (n = 501), the rates of miscarriage and preterm birth were 7.4 and 50.2%, respectively. Meta-analysis demonstrated that ER to twins in TCTA pregnancies (n = 666) was associated with a lower risk (17.3 versus 50.2%) of preterm birth (RR = 0.36, 95% CI: 0.28-0.48), whereas the risk of miscarriage (8.1% versus 7.4%) did not significantly increase (RR = 1.08, 95% CI: 0.58-1.98). In DCTA triplets managed expectantly (n = 200), the rates of miscarriage and preterm birth were 8.5 and 51.9%, respectively. Although the meta-analysis was inconclusive, it suggested that ER to twins in DCTA triplets, either of the foetus with a separate placenta (n = 15) or one of the monochorionic pair (n = 34), was neither significantly associated with an increased risk of miscarriage (8.5 versus 13.3%, P = 0.628 and RR = 1.22, 95% CI: 0.38-3.95, respectively) nor with a lower risk of preterm birth (51.9 versus 46.2%, P = 0.778 and RR = 0.5, 95% CI: 0.04-5.7, respectively).

LIMITATIONS, REASONS FOR CAUTION

No randomized controlled trials of ER versus expectant management in TCTA or DCTA pregnancies were identified from our literature search. We were able to include only a handful of papers with small sample sizes and suffering from bias, and non-English publications were missed. Irrespective of the strict inclusion and exclusion criteria, publication bias was evident.

WIDER IMPLICATIONS OF THE FINDINGS

The greatest strength of our systematic review is that, contrary to the existing literature, it only included studies with both the intervention and expectant arm. Our results are in agreement with current literature. In TCTA pregnancies, ER to twins is associated with a lower risk of preterm birth but is not associated with a higher risk of miscarriage. In the absence of a randomized trial, the data from systematic reviews appear to be the best existing evidence for counselling in the first trimester on the different options available. Finally, in DCTA pregnancies, indications exist that ER (of one of the MC pair) to twins could possibly reduce the risk of preterm birth without increasing the risk of miscarriage.

STUDY FUNDING/COMPETING INTEREST(S)

None to declare.

REGISTRATION NUMBER

N/A.

Perinatal outcome of dichorionic-triamniotic as compared to trichorionic triplets

OBJECTIVE

To evaluate if the perinatal outcomes of dichorionic-triamniotic (DC) triplets are significantly different than that of trichorionic (TC) triplets.

STUDY DESIGN

Comparison of maternal and neonatal data of 44 DC to 46 TC triplets, using univariate analysis.

RESULTS

DC triplets were significantly more common after spontaneous conception but all other maternal characteristics as well complications and cesarean section rates were similar. Both groups had similar incidence of birth at <32 and <28 weeks as well as similar incidence of very low and extremely low birth weight. There was similar incidence of neonatal morbidity except for twin-twin transfusion syndrome (13.6%) in the DC group. The stillbirth rate was 45/1000 and 29/1000, the early neonatal mortality rates were 63/1000 and 45/1000, and the perinatal mortality rate was 106/1000 and 72/1000 for DC and TC triplets, respectively (all not significantly different).

CONCLUSIONS

Our data indicate that DC twins are not significantly disadvantaged compared to TC triplets and the similar outcomes might be reassuring for those who consider continuing their DC triplet pregnancy.

Recommendations for Fetal Echocardiography in Twin Pregnancy in 2016

Progress in the fields of fetal cardiology and fetal surgery have been seen not only in singleton pregnancies but also in multiple pregnancies. Proper interpretation of prenatal echocardiography is critical to clinical decision making, family counseling and perinatal management for obstetricians, maternal fetal medicine specialists, neonatologists and pediatric cardiologists. Fetal echocardiography is one of the most challenging and time-consuming prenatal examinations to perform, especially in multiple gestations. Performing just the basic fetal exam in twin gestations may take an hour or more. Thus, it is not practical to perform this exam in all cases of multiple gestations. Therefore our review and recommendations are related to fetal echocardiography in twin gestation.

The effectiveness of multifetal pregnancy reduction in trichorionic triplet gestation

OBJECTIVE

The objective of the study was to assess in trichorionic triplet pregnancies the effectiveness of elective reduction to twins.

STUDY DESIGN

This was a nationwide retrospective cohort study. We compared the time to delivery and perinatal mortality in trichorionic triplet pregnancies electively reduced to twins with ongoing trichorionic triplets and primary dichorionic twins.

RESULTS

We identified 86 women with reduced trichorionic triplet pregnancies, 44 with ongoing trichorionic triplets, and 824 with primary twins. Reduced triplets had a median gestational age at delivery of 36.1 weeks (interquartile range [IQR], 33.3-37.5 weeks) vs 33.3 (IQR, 28.1-35.2) weeks for ongoing triplets and 37.1 (IQR, 35.3-38.1) weeks for primary twins (P < .001). The total number of surviving children in the reduced group was 155 (90%) vs 114 (86%) in the ongoing triplet group. After reduction, 75 of women (87%) had all their fetuses surviving, compared with 36 (82%) (relative risk [RR], 1.3; 95% confidence interval [CI], 0.72-2.3) for ongoing triplets and 770 (93%) (RR, 0.91; 95% CI, 0.82-1) for primary twins. There were 6 women without any surviving children (7%) after reduction vs 5 (11.4%) (RR, 0.81; 95% CI, 0.47-1.4) among women with ongoing triplets and 32 (3.9%) (RR, 1.7; 95% CI, 0.8-3.7) in women with primary twins.

CONCLUSION

In women with a triplet pregnancy, fetal reduction increases gestational age at birth with 3 weeks as compared with ongoing triplets. However, there the impact on neonatal survival is limited.

The economic implications of multiple pregnancy following ART

The clinical risks to mothers and babies associated with assisted reproductive technology (ART) multiple birth pregnancies are well described and widely recognized. In contrast, the long-term economic consequences that follow are less appreciated. The few economic analyses that do exist consistently demonstrate the greater patient, healthcare and societal costs associated with twins and higher-order multiples when compared with singleton infants, and convincingly add to the argument that single embryo transfer should be standard practice in most patient groups. Several recent studies have shown that the relative price paid by patients for ART treatment not only has implications for who can afford to access treatment, but also plays an important role in incentivizing embryo transfer practices and thus ART multiple birth rates. This review summarizes the current literature on the costs and consequences of ART multiple births, the contribution of ART multiple births to the economic burden associated with preterm birth, the evidence for the cost-effectiveness of single embryo transfer, and the association between the cost of treatment and the downstream costs associated with multiple births.

Perinatal death of triplet pregnancies by chorionicity

OBJECTIVE

The purpose of this study was to evaluate the perinatal risk of death by chorionicity at >22 weeks of gestation of triplet pregnancies.

STUDY DESIGN

In a retrospective cohort study, the perinatal data were collected from triplet pregnancies in Japanese perinatal care centers between 1999 and 2009. We included maternal characteristics and examined the following factors: prenatal interventions, pregnancy outcome, and neonatal outcome. The association between fetal or neonatal death of triplets and chorionicity was evaluated by logistic regression analysis.

RESULTS

After the exclusion of 253 cases, the study group comprised 701 cases: 507 trichorionic triamniotic (TT) triplet pregnancies, 144 diamniotic triamniotic (DT) triplet pregnancies, and 50 monochorionic triamniotic (MT) triplet pregnancies. The mortality rate (fetal death at >22 weeks of gestation; neonatal death) in triplets was 2.6% and included 2.1% of TT triplet pregnancies, 3.2% of DT triplet pregnancies, and 5.3% of MT triplet pregnancies. No significant risk of death was identified in DT triplet pregnancies; however, MT triplet pregnancies had a 2.6-fold greater risk (adjusted odds ratio, 2.60; 95% confidence interval, 1.17-5.76; P = .019) compared with TT triplet pregnancies. Prophylactic cervical cerclage did not reduce the perinatal mortality rate at >22 weeks of gestation in triplets.

CONCLUSION

The risk of death for MT triplet pregnancies is significantly higher than that of TT triplet pregnancies; however, the risk of death for DT triplet pregnancies is not.

Puerperal morbidity following repeat cesarean delivery in twin pregnancies

OBJECTIVE

To evaluate the puerperal complications following twin deliveries.

STUDY DESIGN

We conducted a population-based analysis of puerperal delivery-related complications of twins born in Slovenia for comparing three groups of births (vaginal, elective and emergent cesarean).

RESULTS

A total of 1,001 elective, 1,109 emergent cesarean sections, and 2,204 vaginal twin births were evaluated. No differences were found between the complications after emergent and elective cesareans. Uterine atony was more frequent after vaginal births (OR 1.8-2.0, 95 % CI 1.1-1.2, 2.9-3.3). Vaginal births had a higher frequency of endometritis compared with elective cesarean (OR 4.1, 95 % CI 1.2, 13.6). Conversely, vaginal deliveries were less frequently associated with anemia, hematoma formation, and need for blood transfusion as compared to both modes of cesarean deliveries.

CONCLUSION

No solid data exist to show a clear advantage or disadvantage in terms of puerperal complications of an elective cesarean over vaginal birth for twins.

Clinical features and short-term outcomes of triplet pregnancies in Japan

OBJECTIVE

To review clinical features and short-term outcomes of triplet pregnancies among Japanese women.

METHODS

A retrospective analysis was carried out among 320 Japanese women with triplet pregnancies (8 monochorionic, 75 dichorionic, and 150 trichorionic triplets; 87 with unknown placental chorionicity) who delivered at 22 gestational weeks or more between January 2005 and December 2008.

RESULTS

Delivery was by cesarean for 315 (98%) women. Gestational age at delivery was 32.3±2.8 weeks (mean±SD) and 33.2 weeks (median), and 97%, 61%, and 14% of women delivered at less than 37, less than 34, and less than 30 gestational weeks, respectively. For live-born infants, mean birth weight was 1762±437 g, 1608±396 g, and 1406±380 g for the heaviest, middle, and lightest triplet, respectively. Eighteen (5.6%) women experienced perinatal mortality (3 triplets for 1 woman, 2 triplets for 4 women, and 1 triplet for 13 women). Perinatal mortality was 25 deaths per 1000 deliveries, and decreased with increasing number of chorionic membranes (125, 44, and 20 per 1000 mono-, di-, and trichorionic triplet deliveries, respectively).

CONCLUSION

Short-term outcomes were good among triplet pregnancies in Japan. The data may be useful for counseling Japanese women with triplet pregnancies.

Temporal trends in the frequency of twins and higher-order multiple births in Canada and the United States

BACKGROUND

The dramatic increase in multiple births is an important public health issue, since such births have elevated risks for adverse perinatal outcomes. Our objective was to explore the most recent temporal trends in rates of multiple births in Canada and the United States.

METHODS

Live birth data from Canada (excluding Ontario) and the United States from 1991-2009 were used to calculate rates of twins, and triplet and higher-order multiples (triplet+). Temporal trends were assessed using tests for linear trend and absolute and relative changes in rates.

RESULTS

Twin live births in the United States increased from 23.1 in 1991 to 32.2 per 1,000 live births in 2004, remained stable between 2004 and 2007, and then increased slightly to an all-time high of 33.2 per 1,000 live births in 2009. In Canada, rates also increased from 20.0 in 1991 to 28.3 per 1,000 live births in 2004, continued to increase modestly between 2004 and 2007, and rose to a high of 31.4 per 1,000 in 2009. Rates of triplet+ live births in the United States increased dramatically from 81.4 in 1991 to 193.5 per 100,000 live births in 1998, remained stable between 1998 and 2003 and then decreased to 148.9 per 100,000 in 2007. The rate declined marginally in 2008, but then rose again in 2009 to 153.5 per 100,000. Rates of triplet+ live births were much lower in Canada, although the temporal pattern of change was similar.

CONCLUSION

The rate of twin live births in the United States and Canada continues to increase, though more modestly than during the 1990s. Recent declines in rates of triplet+ live births in both countries have been followed by unstable trends.

Perinatal Outcome and Change in Body Mass Index in Mothers of Dichorionic Twins: A Longitudinal Cohort Study

We used a prospective cohort to analyze the effect of change in BMI rather than change in weight, in mothers carrying dichorionic twins from a population that did not receive any dietary intervention. A total of 269 mothers (150 nulliparas and 119 multiparas) were evaluated. The average change (%) from the pre-gravid BMI was 7.2 ± 6.1, 17.4 ± 8.2, and 28.7 ± 10.8, at 12–14, 22–25, and 30–34 weeks, respectively, without difference between nulliparas and multiparas. The comparison between maternities below or above the average change from the pregravid BMI failed to demonstrate an advantage (in terms of total twin birthweight and gestational age) of an above average change from the pregravid BMI, even when the lower versus upper quartiles were compared. Our observations reached different conclusions regarding the recommended universal dietary intervention in twin gestations. A cautious approach is advocated towards seemingly harmless excess weight gain, as normal weight women may turn overweight, or even obese, by the end of pregnancy, and be exposed to the untoward effects of obesity on future health and body image.

The effect of the 2004 Italian legislation on perinatal outcomes following assisted reproduction technology

OBJECTIVE

To assess the perinatal outcomes of the first three years under the 2004 Italian reproductive legislation obligating transfer of all embryos resulting from insemination of < or =3 oocytes.

STUDY DESIGN

We compared the perinatal results of clinical assisted reproductive technology (ART) pregnancies during the three years following the new Italian legislation with the previous three years.

RESULTS

There were 583 and 571 clinical pregnancies during the respective periods. Before the law, the overall embryonic and fetal loss rates were significantly higher resulting in a significantly lower rate of live born infants and significantly fewer clinical pregnancies with at least one live born infant. Quadruplet and quintuplet pregnancies were entirely eliminated following the 2004 law but the neonatal mortality rate was not different between the two study periods.

CONCLUSION

The 2004 Italian infertility legislation led to improved quantitative and qualitative outcomes of ART.

Increasing rates of sex-discordant twins no longer correspond to decreasing perinatal mortality rates

OBJECTIVE

To analyze dizygotic twinning rates and outcomes over a 25-year period.

METHODS

Birth and fetal death certificates from 1980-2004 in Washington State, USA, were analyzed retrospectively to find factors associated with the increase in sex-discordant twins through time. "Low" and "high" fertility treatment groups were defined according to demographic traits. Perinatal mortality was defined as fetal or neonatal death of one or both twins and Weinberg's rule was used to estimate mortality for monozygotic and dizygotic pairs.

RESULTS

Controlling simultaneously for maternal age, race, parity, and education did not eliminate the trend of increasing sex-discordant twins from 1992-2004 (M-H chi2 P=0.001). The "low" fertility group had a non-significant decline in sex-discordant twins (M-H chi2 P=0.24), whereas the "high" fertility group had a significant increase (M-H chi2 P=0.001). Perinatal mortality decreased for monozygtic twin pairs throughout the study period, but decreased until the mid-1990s and then increased slightly through 2004 for the dizygotic twin pairs.

CONCLUSION

Advancing maternal age and increasing use of fertility treatments are largely responsible for the increase in dizygotic twins from 1980-2004 and may also be responsible for the stalling of the decline in perinatal mortality rate.

Global epidemiology of multiple birth

Multiple births, which account for approximately 3% of births and 14% of infant deaths, are increasing in frequency. Multiple birth rates began to decline in the 1950s, reaching a minimum in the 1970s and rising since then. Both twin and triplet rates followed the same rising trend until 1998, after which triplet birth rates began to decline while twin birth rates continued to rise. Rising maternal age is associated with rising frequency of dizygotic twinning up to 37 years of age. Older maternal age, associated with the social trend to delayed child bearing, accounts for 25- 30% of the rise in multiple birth rates since 1970. The resulting rise in the prevalence of infertility has given rise to unprecedented use of ovarian stimulation treatments that stimulate the development of multiple oocytes. Assisted reproduction technology and ovulation stimulation with clomiphene citrate or gonadotrophins without assisted reproduction account for similar proportions of both twin births (20- 30%) and triplet births (30- 40%). The fall in triplet rates since 2000 is reassuring, but fetal reduction of high order pregnancies may be a factor in rising twin rates. Continuing attention is needed to all possible means of minimizing triplet pregnancies.

The association between maternal characteristics and different types and levels of discordance in triplet pregnancies

OBJECTIVE

This study evaluated the association of maternal factors known to influence outcomes of triplets, different discordance levels (-25, 25.1-35, and )35%), and three types (according to the birth weight of the middle-sized triplet) of birth weight discordance in triplets.

METHODS

We used data collected by the Women's Health Division of Matria Healthcare, Inc. (Marietta, GA). We analyzed a cohort of 2706 triplet sets, to calculate the frequencies of different levels and types of birth weight discordance by maternal age, parity, weight, height, body mass index and weight gain at 24 weeks of gestation.

RESULTS

We found a positive association between maternal parity and birth weight discordance level but no clear association between the other maternal factors and the level of discordance as well as the type of discordance. However, a trend was seen whereby overweight women had a trend towards the low-skew (a set comprising one large and two small triplets) type of birth weight discordance and an opposite trend in underweight women.

CONCLUSIONS

These results corroborate previous findings that nulliparity is associated with aberrant growth in triplet pregnancies.

[The maternal and fetal outcome of 122 triplet pregnancies]

INTRODUCTION

The wide use of infertility drugs and assisted reproduction has resulted in 4- to 5-fold increase in the incidence of triplet pregnancies, which carry an extremely high risk of maternal complications and adverse perinatal outcome. In Hungary, reduction of multifetal pregnancies is available for all pregnant women with multifetal gestation since 1998. The goal of the procedure is to ensure better outcome for surviving fetuses. Counseling of pregnant patients should include the maternal and fetal risks of triplet gestation without multifetal pregnancy reduction.

AIM

To assess the risk of maternal complications, stillbirth, perinatal and neonatal mortality rates, and risk of neonatal morbidity in non-reduced triplets in a large case series, representing the Hungarian triplet population.

METHODS

The study population consisted of triplets delivered between July 1st, 1990 and June 30th, 2006, at the 1st Department of Obstetrics and Gynecology. All three fetuses had to be alive on the 18th-week ultrasound scan to be eligible.

RESULTS

Out of the 122 cases, 8 (6.6%) ended in midtrimester miscarriage, 114 (93.4%) ended in delivery. There were no maternal deaths. The most common antepartum maternal complications were pregnancy-induced hypertension (16.7%), gestational diabetes mellitus (18.4%), thrombocytopenia (20.2%), anemia (16.7%) and intrahepatic cholestasis (9.7%). Preterm labor requiring tocolysis occurred in 57.9%, preterm premature rupture of membranes in 32.5%. Prophylactic cerclage was performed in 15.8% of cases, and 69.3% of patients received steroid prophylaxis. The mean gestational age at delivery was 32.3 +/- 3.2 weeks. The rates of very early (<28 weeks) and early (<32 weeks) preterm deliveries were 8.8% and 42.1%, respectively. The mean 5-minute Apgar score was 9.2 +/- 0.8, and the mean birth weight at delivery was 1664 +/- 506 g. 38.0% of infants were very low birth weight (<1500 g). Stillbirth, crude perinatal mortality and corrected perinatal mortality rates were 23.4 per thousand, 64.3 per thousand and 27.4 per thousand, respectively. 11.7 per thousand of infants had some major congenital anomaly. 54.4% of infants required ventilation or oxygen therapy or both. The most common neonatal complication were respiratory distress (17.1%), transitory tachypnea (5.2%), sepsis or pneumonia (25.5%), intraventricular hemorrhage (4.3%) and jaundice (11.4%).

CONCLUSIONS

Both the maternal and neonatal risks should be considered when patients with triplets are counseled before the decision to continue the triplet gestation or to choose multifetal pregnancy reduction is made.

The effect of legislation on outcomes of assisted reproduction technology: lessons from the 2004 Italian law

OBJECTIVE

To evaluate the effect of the 2004 Italian regulations (insemination of <or=3 oocytes/cycle, transfer of all embryos, prohibition of embryo cryopreservation) on outcomes of assisted reproduction treatment (ART).

DESIGN

Case-control study.

SETTING

The Center of Reproductive Medicine, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.

PATIENT(S)

Women undergoing ART for the first time.

INTERVENTION(S)

Comparing outcomes of ART between 2 years before (n = 900) and after (n = 936) the law's implementation (March 10, 2004).

MAIN OUTCOME MEASURE(S)

Rates of fertilization, pregnancy, "take-home baby," and multiple pregnancies.

RESULT(S)

During the pre-law period, statistically significantly more patients reached embryo transfer (odds ratio 1.9; 95% CI, 1.5, 2.5), and embryo transfer rate per cycle was statistically significantly higher (3.1 +/- 1.7 vs. 2.2 +/- 0.7), but the overall transfer of good embryos was lower (OR 0.6; 95% CI, 0.5, 0.8). The pregnancy rates per aspiration cycle were similar between the periods, but the pregnancy rate per embryo transfer and birth rate with at least one liveborn baby per embryo transfer were statistically significantly lower in the pre-law period (OR 0.7; 95% CI, 0.5, 0.9). The multiple births rate was not different between the two periods.

CONCLUSION(S)

In contrast to prior pessimistic expectations, the obligation to transfer all available embryos produced from <or=3 inseminated oocytes neither reduced success rates of ART nor increased the multiple births rate.

Puerperal complications following elective Cesarean sections for twin pregnancies

OBJECTIVE

To estimate the maternal puerperal morbidity in elective and emergent cesareans in twins.

STUDY DESIGN

We evaluated postpartum complications among patients who underwent elective cesarean birth for twin pregnancy. This group was compared to matched singletons and to emergent cesareans in twins.

RESULTS

During the period September 1994-March 2006 there were 299 (47.4%) elective and 80 (12.7%) emergent cesarean sections in twin pregnancies, for a total of 379 (60.1%) cesarean births for both twins. Controls included 299 cases of elective cesareans in singletons. The comparison between elective and emergent cesareans and between elective cesareans in twins and in singletons found no significant differences in postpartum fever, scar infection, and postpartum hemorrhage. Venous thromboembolism occurred in two twin pregnancies, one in the elective and one in the emergent cesarean group. Postpartum hysterectomy was required in a singleton pregnancy following an elective cesarean birth.

CONCLUSION

At present, no data exist to show a disadvantage for a planned cesarean birth for twins.

Litigation in multiple pregnancy and birth

Multiple birth rates have increased in most developed countries. The potential of a medical legal dispute increases when complications are common. Failure to perform the basic and standard care follow-up often misses the complication and the chance of a timely referral to a center experienced in the diagnosis and management of these complexities of a multiple pregnancy. In this article, several examples are discussed in which departure from the standard of care of multiple pregnancies were the basis of the allegation.

Does assisted reproduction technology, per se, increase the risk of preterm birth?

There is little doubt that all methods of assisted reproduction increase the likelihood of multiple pregnancy and, as a result, increase the likelihood of preterm birth. Data from the East Flanders Prospective Twin Study clearly show that the proportion of spontaneous to iatrogenic twins has changed from 25:1 to 1:1 over the past two decades. Data from the very low birthweight (VLBW) Infant Database of the Israel Neonatal Network showed that 10% of VLBW singletons were a result of assisted reproduction compared with 60% of the VLBW twins and 90% of the VLBW triplets. Irrespective of plurality, an association between preterm birth and assisted reproduction has long been suspected and was related to causes such as iatrogenic preterm birth (in the so-called 'premium' pregnancies), fertility history, past obstetric performance and to underlying medical conditions of the female partner. With more data available, a clearer picture is defined. Two different, recent meta-analyses showed that singleton pregnancies resulting from in vitro fertilisation (IVF) have increased rates of preterm birth at <33 weeks of gestation (OR 2.99; 95% CI 1.54-5.80), at <37 weeks of gestation (OR 1.93; 95% CI 1.36-2.74) and a relative risk of 1.98 (95% CI 1.77-2.22) for preterm birth in singleton pregnancies resulting from in vitro fertilisation embryo transfer/gamete intra fallopian transfer (IVF-ET/GIFT) compared with naturally conceived pregnancies. Since there is no way to predict which pregnant woman is at increased risk of preterm birth, it may be advisable to consider all pregnancies after assisted reproduction as being at risk. In any case, the most appropriate endpoint after assisted reproduction should also include preterm or term birth as measure of success.

Early weight gain does not decrease the incidence of low birth weight and small for gestational age triplets in mothers with normal pre-gestational body mass index

OBJECTIVE

To examine if the recommended weight gain of >680 g/week during the first 24 weeks of pregnancy decreases the frequency of adverse birth weight outcomes in triplet mothers with a normal pregravid BMI.

STUDY DESIGN

Retrospective observational study of a large sample of triplet mothers with a normal (19.8-26) pregravid BMI. Adequate, average, and inadequate weight gains were defined as >680, 500-680, and <500 g/week. Outcome measures were the incidence of >or=1 SGA infant and total triplet birth weight <4500 g.

RESULTS

Of the 1166 triplet mothers, 208 (17.8%) gained >680 g/week during their pregnancy. This presumed adequate weight gain did not reduce the incidence of SGA triplets or that of total birth weight <4500 g, irrespective of parity. These adverse birth weight outcomes were 2 to 3.5 times lower among multiparous compared to nulliparous mothers.

CONCLUSION

Early weight gain of >680 g/week in triplet mothers with a normal pre-pregnancy BMI is not associated with a decrease in the incidence of adverse outcomes. Weight gain recommendations in triplet pregnancies should be realistic and associated with a low risk-benefit ratio.

Non-selective fetal reduction is malpractice

Non-selective multifetal pregnancy reduction is carried out to reduce healthy higher order multiple fetuses to one or two fetuses. No studies exist to show any benefit of this practice and a Cochrane review, as well as investigators in the field, have not found any justification for such practice. From a medical point of view, this non evidence-based practice is not following good clinical practice. Any practice that transfers more than one or two embryos, for instance due to commercial interests, should be abandoned by the international medical community because multifetal pregnancies can, to a large extent, be avoided by transferring only one or a maximum of two fertilized eggs by in vitro fertilization. Further, ovarian stimulating programs should strictly adhere to protocols aiming at mono-ovulation.

The effect of ICSI, maternal age, and embryonic stage on early clinical loss rate of twin versus singleton pregnancies

OBJECTIVES

To compare early loss rates between twin and singleton pregnancies following ART.

STUDY DESIGN

First-trimester sonography counted the number of embryos with positive heartbeat in women undergoing IVF/ICSI and transfer of one to three embryos. The number of lost pregnancies was calculated from a second-trimester sonogram. Loss rates of the entire pregnancy were related to maternal age <38 or > or = 38 years, IVF or ICSI, and cleavage or blastocyst stage embryo transfers (in ICSI cases).

RESULTS

Patients underwent IVF with (n = 672) and without (n = 189) ICSI. The overall odds of miscarrying the entire singleton pregnancy were 2.6 times that of a twin gestation (95% CI 1.5, 4.5). The disadvantage for singletons compared to twins seems more apparent in pregnancy after ICSI in the subgroup of patients <38 years (OR 2.9, 95% CI 1.5, 5.8). In this subgroup, the disadvantage conferred to singletons appeared only among days 2-3 embryo transfers (OR 3.0, 95% CI 1.3, 7.2).

CONCLUSION

A significantly lower early spontaneous loss rate of twin pregnancies seems related to ICSI followed by cleavage stage embryo transfer in patients <38 years.

Temporal changes in rates of stillbirth, neonatal and infant mortality among triplet gestations in the United States

OBJECTIVE

The purpose of this study was to examine temporal changes in stillbirth, neonatal and infant mortality rates among triplet births in the US, and to assess the contributions of triplet delivery at < 34 weeks to these changes.

STUDY DESIGN

Data on triplet live births, and fetal and infant deaths (1990-2002) delivered at > or = 22 weeks and fetuses weighing > or = 500 g (n = 66,986) were derived from the US linked birth/infant death data files. Relative risk (RR), quantifying changes in triplet stillbirth, neonatal (death within the first 28 days) and infant mortality (death within the first year) rates between 1990 and 1991 and 2001 and 2002, were derived. Temporal changes in triplet births at < 34 weeks, and changes in stillbirth, and neonatal and infant mortality rates were examined through logistic regression models before and after adjusting for confounders.

RESULTS

Triplet births at < 34 weeks increased by 25% between 1990 and 1991 (48.7%) and 2001 and 2002 (60.9%). Stillbirth, neonatal and infant mortality rates declined by 52% (RR 0.48, 95% confidence interval [CI] 0.36-0.63), 32% (RR 0.68, 95% CI 0.58-0.80), and 38% (RR 0.62, 95% CI 0.53-0.71), respectively, between 1990 and 1991 and 2001 and 2002. The increase in triplet births at < 34 weeks was not associated with the stillbirth decline, but was associated with an excess 14% and 12% increase in neonatal and infant deaths, respectively.

CONCLUSION

Our findings suggest that the increase in triplet births at < 34 weeks' gestation is not associated with changes in triplet stillbirths, but is associated with increases in triplet neonatal and infant mortality.

The management of multiple pregnancy

The epidemic of multiple pregnancy continues albeit in a different form with twin pregnancies predominating. Determination of chorionicity is the key to management and regular monitoring by ultrasound is a hallmark of quality care. All multiple pregnancies should be offered first trimester screening by nuchal translucency for aneuploidy. MC twins should be scanned at fortnightly intervals to allow complications such as twin-twin transfusion or IUGR to be detected and referral made to a fetal medicine centre. Maternal complications are common and vigilance is required for their detection. Although planned vaginal delivery can often be achieved, mothers must be prepared for the substantial risk of requiring a caesarean section as this currently occurs in the majority.

Plurality-dependent risk of severe intraventricular hemorrhage among very low birth weight infants and antepartum corticosteroid treatment

OBJECTIVE

This study was undertaken to compare the effect of antenatal corticosteroid therapy on the risk for severe intraventricular hemorrhage (IVH grade III-IV) in preterm singleton and multiple very low birth weight (VLBW) infants.

STUDY DESIGN

The occurrence of severe IVH was recorded in 5022 singleton, 2032 twin, and 582 triplet infants, delivered at 24 to 32 weeks' gestation, registered in the Israeli National VLBW infant database. Antenatal corticosteroid therapy was defined as complete, partial, or none.

RESULTS

The incidence of IVH grade III-IV ranged from 6.8% among singletons receiving complete course to 29.3% in triplets without antenatal corticosteroid treatment. Complete treatment significantly reduced the incidence of IVH in all plurality groups. The adjusted risk for IVH among multiple infants who received a complete course compared with singletons was not significantly different, odds ratio (OR) 1.3, 95% CI 1.0-1.7 for twins and OR 1.5, 95% CI 0.9-2.3 for triplets.

CONCLUSION

Complete course of antenatal corticosteroid therapy was independently associated with decreased risk for severe IVH in singleton and in multiple preterm VLBW infants.

The association between small-for-gestational age triplet pregnancies and neonatal mortality: a novel approach to growth assessment in multiple gestations

It is customary to estimate the uteroplacental function in singletons by defining appropriateness of birth weight by gestational age. Such a measure, however, is not available for the entire multiple pregnancy set. We evaluate a new index, total triplet birth weight, expressed as multiples of the median (MOM) birth weight of singleton gestations. We categorized triplet sets as small-, appropriate-, and large-for-gestational age pregnancies (SGA, AGA, and LGA, respectively), defined as <1 SD, +/-1 SD, and >1 SD from the mean MOM birth weight of singleton gestations. We used the 1995-1998 US matched multiple dataset to evaluate this index and to explore the association between the three categories in terms of risk of neonatal mortality. The mean +/- SD MOM value was 2.3 +/- 0.4. There was an inverse correlation between mean MOM and gestational age. LGA pregnancy status was associated with multiparity, race (being white), and high social status (education). Maternal age did not influence MOM scores. Compared with the LGA pregnancy category, the risk for neonatal mortality was more than doubled in the AGA pregnancy group and more than 9-fold in the SGA pregnancy category. We propose that this new measure could be a useful proxy for the uteroplacental efficiency in a similar way that the SGA designation works for singleton infants.