Vanishing twin syndrome is associated with first-trimester intrauterine hematoma in twin pregnancies after in vitro fertilization

RESEARCH QUESTION

Is there an association between intrauterine hematoma (IUH), vanishing twin syndrome (VTS), and subsequent complications in twin pregnancies after in vitro fertilization (IVF)? What are the risk factors for these complications?

DESIGN

Women who presented with two live gestational sacs following double embryo transfer were included. Patients with systematic diseases, artificial fetal reduction, and incomplete data were excluded. Further stratification of IUH pregnancies was performed according to IUH-related characteristics (i.e., volume, changing pattern, and relationship with fetal cardiac activities). The primary outcome was the incidence of VTS, while adverse outcomes in the surviving singleton and the gestational age of VTS were secondary outcomes.

RESULTS

The incidence of IUH was 13.8%. A total of 1,078 twin pregnancies including 539 IUH pregnancies and 539 non-IUH pregnancies were included. IUH pregnancy was associated with higher risks of VTS (26.9% vs. 18.7%, p = 0.001) as well as a higher incidence of preterm birth (p = 0.001, crude OR = 1.98, 95% CI 1.28-3.09, adjusted OR = 1.19, 95% CI 1.09-1.24), threatened abortion (p < 0.001, crude OR = 9.12, 95% CI 2.90-28.69, adjusted OR = 6.63, 95% CI 1.69-14.67), and postpartum hemorrhage (p = 0.024, crude OR = 3.13, 95% CI 1.09-8.99, adjusted OR = 1.16, 95% CI 1.08-1.32) in the surviving singleton. There was no significant difference in risks of other complications. The absence of fetal cardiac activities at the diagnosis of IUH predicted VTS (p < 0.001, crude OR 4.67, 95% CI 3.67-5.78, adjusted OR 3.33, 95% CI 1.56-5.14) and fetal loss at smaller gestational age (7.81 ± 2.10 vs. 11.39 ± 5.60 weeks, p < 0.001), while an IUH with an increasing volume did not increase the risk of VTS but might induce threatened abortion in the surviving fetus (p < 0.001, crude OR 1.84, 95% CI 1.32-2.55, adjusted OR 1.72, 95% CI 1.13-2.13).

CONCLUSIONS

IUH was a risk factor for VTS in twin pregnancies following double embryo transfer and elevated the risks of threatened abortion, preterm birth, and postpartum hemorrhage in the surviving singleton. The absence of fetal cardiac activities at the diagnosis of IUH elevated the risks of VTS, while an IUH with an increasing volume was associated with threatened abortion without elevating the risks of VTS. An IUH diagnosed before the presence of fetal cardiac activities also resulted in an earlier miscarriage. The study suggests that attention be paid to twin pregnancies with first-trimester IUH to prevent VTS and subsequent adverse perinatal outcomes.

HIGHLIGHTS

First-trimester intrauterine hematoma (IUH) following double embryo transfer is associated with a higher incidence of vanishing twin syndrome (VTS) and elevated subsequent risk of threatened abortion, preterm birth, and postpartum hemorrhage in the surviving singleton. Other perinatal outcomes were not associated with the diagnosis of first-trimester IUH. The absence of fetal cardiac activities at the diagnosis of IUH was of predictive value toward VTS, while an IUH with an increasing size was associated with threatened abortion without elevating the risk of VTS. Incomplete fetal cardiac activities and earlier detection of an IUH might also predict miscarriage at smaller gestational age.

The late vanishing of a co-twin contributes to adverse perinatal outcomes in the surviving singleton

STUDY QUESTION

Is the vanishing of a co-twin after or before the ultrasonic registration of cardiac activity at approximately 6-8 weeks of gestation associated with adverse perinatal outcomes?

SUMMARY ANSWER

The timing of the demise of a co-twin after the registration of cardiac activity is an independent risk factor for adverse perinatal outcomes.

WHAT IS KNOWN ALREADY

A significant body of evidence has confirmed that vanishing twin (VT) pregnancies are associated with higher levels of risk for preterm birth (PTB), low birthweight (LBW), small-for-gestational age (SGA) and perinatal mortality, compared with singleton pregnancy. However, the impact of co-twin vanishing, before or after the presence, of cardiac activity, on perinatal outcomes has yet to be extensively investigated.

STUDY DESIGN, SIZE, DURATION

We retrospectively reviewed the medical records of 38 876 singletons delivered from ART cycles between 2006 and 2018, at the Peking University Third Hospital.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 35 188 singletons were delivered from the singleton pregnancy group, 2256 singletons from the VT pregnancy group after that cardiac activity was noted, and 1432 singletons were delivered from the VT pregnancy group before cardiac activity could be registered. Using the Poisson model, the adjusted risk ratio (aRR) was used to estimate the incidence of PTB, LBW, SGA and perinatal mortality, in the pregnancies of two types of VT compared with singleton pregnancies after correction for potential confounding factors.

MAIN RESULTS AND THE ROLE OF CHANCE

The vanishing of a co-twin after the registration of cardiac activity was associated with an increased risk of perinatal mortality when compared with the group of singleton pregnancies (0.5% vs 0.2%; P = 0.006); this association still existed after adjustment for potential confounders (aRR 2.19, 95% CI 1.12-4.30; P = 0.023). Furthermore, it was significantly associated with a higher risk of PTB (all cycles aRR 2.00, 95% CI 1.77-2.24; P < 0.001; fresh transfer aRR 2.06, 95% CI 1.78-2.38; P < 0.001; frozen transfer aRR 1.87, 95% CI 1.52-2.28; P < 0.001), LBW (all cycles aRR 2.47, 95% CI 2.12-2.88; P < 0.001; fresh transfer aRR 2.50, 95% CI 2.07-3.02; P < 0.001; frozen transfer aRR 2.39; 95% CI 1.83-3.12; P < 0.001) and SGA (all cycles aRR 1.56, 95% CI 1.35-1.80; P < 0.001; fresh transfer aRR 1.53, 95% CI 1.29-1.81; P < 0.001; frozen transfer aRR 1.62, 95% CI 1.24-2.11; P < 0.001). However, prior to the presence of cardiac activity, the vanishing of a co-twin was not associated with a higher risk of perinatal mortality (all cycles aRR 0.71, 95% CI 0.17-2.92; P = 0.636; fresh cycles aRR 0.51, 95% CI 0.07-3.70; P = 0.502; frozen cycles aRR 1.29, 95% CI 0.17-9.66; P = 0.803), PTB (all cycles aRR 1.11, 95% CI 0.91-1.34; P = 0.301; fresh cycles aRR 1.10, 95% CI 0.87-1.39; P = 0.447; frozen cycles aRR 1.13, 95% CI 0.81-1.58; P = 0.467), LBW (all cycles aRR 1.19, 95% CI 0.91-1.55; P = 0.207; fresh cycles aRR 1.08, 95% CI 0.77-1.51; P = 0.668; frozen cycles aRR 1.45, 95% CI 0.93-2.25; P = 0.100) and SGA (all cycles aRR 1.09, 95% CI 0.89-1.35; P = 0.405; fresh cycles aRR 0.97, 95% CI 0.75-1.26; P = 0.839). Pregnancies involving the two types of VT were significantly different in terms of PTB (all cycles aRR 1.80, 95% CI 1.45-2.24; P < 0.001; fresh cycles aRR 1.88, 95% CI 1.44-2.45; P < 0.001; frozen cycles aRR 1.65, 95% CI 1.13-2.40; P = 0.009), LBW (all cycles aRR 2.08, 95% CI 1.55-2.79; P < 0.001; fresh cycles aRR 2.32, 95% CI 1.61-3.36; P < 0.001; frozen cycles aRR 1.65, 95% CI 1.01-2.70; P = 0.046) and SGA (all cycles aRR 1.70, 95% CI 1.36-2.11; P < 0.001; fresh cycles aRR 1.87, 95% CI 1.42-2.45; P < 0.001).

LIMITATIONS, REASONS FOR CAUTION

The present data are not able to differentiate between co-twin demise occurring in the first or second trimester. Because the second trimester ultrasound scan is not an integral aspect of IVF assessment, this information was not available in the database.

WIDER IMPLICATIONS OF THE FINDINGS

Adverse perinatal outcomes in ART babies can be avoided by replacing one embryo at a time. It is possible to apply selective single embryo transfer strategy for all while maintaining acceptable success rates.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the National Natural Science Foundation of China for Young Scholars (Reference number: 31801251). No competing interests to declare.

TRIAL REGISTRATION NUMBER

not applicable.

Obstetric and perinatal complications associated with assisted reproductive treatment in Spain

BACKGROUND

Although most newborns conceived through assisted reproductive treatments are healthy, there are concerns about the safety of reproductive techniques and their effect on foetal/maternal well-being.

OBJECTIVE

This study aims to describe the incidence of obstetric and perinatal complications in women undergoing assisted reproductive treatments in the Spanish Health System.

METHOD

This is a cross-sectional observational study aimed at women who have been mothers between 2013 and 2018 in Spain. The data was collected through an online survey of 42 items that was distributed through lactation associations and postpartum support groups. In the data analysis, crude odds ratios (OR) and adjusted odds ratios (AOR) were calculated, through a multivariate analysis with binary logistic regression and multinomial logistic regression.

RESULTS

Five thousand nine hundred forty-two women participated, 2.3% (139) through artificial insemination and 8.2% (486) through in vitro fertilisation (IVF) techniques. Women who underwent IVF had a higher likelihood of suffering problems during pregnancy (OR = 1.71; 95% confidence intervals (95% CI), 1.37-2.13), delivery (OR = 1.43; 95% CI, 1.01-2.02), and postpartum (OR = 1.94; 95% CI, 1.40-2.69) than women with spontaneous pregnancy. No increased likelihood of neonatal problems was observed in this group except for twin pregnancy (OR = 9.17; 95% CI, 6.02-13.96) and prematurity (OR = 1.43; 95% CI, 1.01-2.02). No differences were observed between spontaneous pregnancies and those achieved by artificial insemination.

CONCLUSIONS

Pregnancies achieved through IVF present a higher risk of complications before, during and after delivery. However, there is no increased risk of neonatal problems except for a higher likelihood of twin pregnancy and prematurity.

Cryopreserved embryo replacement is associated with higher birthweight compared with fresh embryo: multicentric sibling embryo cohort study

Birth weight (BW) is higher after frozen embryo transfer (FET) than after fresh embryo replacement. No study has compared the BW of siblings conceived using the same oocyte/embryo cohort. The aim of this study was to determine whether the freezing-thawing procedure is involved in such difference. Multicenter study at Montpellier University Hospital, Clinique Ovo, Canada and Grenoble-Alpes University Hospital. The first cohort (Fresh/FET) included in vitro fertilization (IVF) cycles where the older was born after fresh embryo transfer (n = 158) and the younger after transfer of frozen supernumerary embryos (n = 158). The second cohort (FET/FET) included IVF cycles where older and younger were born after FET of embryos from the same cohort. The mean adjusted BW of the FET group was higher than that of the fresh group (3508.9 ± 452.4 g vs 3237.7 ± 463.3 g; p < 0.01). In the FET/FET cohort, the mean adjusted BW was higher for the younger by 93.1 g but this difference is not significant (3430.2 ± 347.6 g vs 3337.1 ± 391.9 g; p = 0.3789). Our results strongly suggest that cryopreservation is directly involved in the BW variation. Comparing BW difference between Fresh/FET cohort and FET/FET one, it suggests that parity is not the only responsible, increasing the role of cryopreservation step in BW variation.

Perinatal outcomes of singleton live births with and without vanishing twin following transfer of multiple embryos: analysis of 113 784 singleton live births

STUDY QUESTION

Does transfer of multiple embryos affect perinatal outcomes of resulting singleton live births following ART?

SUMMARY ANSWER

There is a higher risk of preterm birth (PTB) and low birthweight (LBW) in singleton live births associated with spontaneous reduction of an initial multiple to singleton gestation following transfer of multiple embryos.

WHAT IS KNOWN ALREADY

Singleton pregnancies following ART are at a higher risk of adverse perinatal outcomes compared to spontaneous conceptions. Earlier studies have found an increased risk of PTB and LBW in singletons following transfer of multiple embryos versus single embryo transfer (SET). However, these studies did not address the specific role of vanishing twin, i.e. spontaneous reduction of an initial multiple to singleton gestation.

STUDY DESIGN, SIZE, DURATION

Anonymised data on all ART cycles performed in the UK were obtained from the Human Fertilization and Embryology Authority. Data from 1991 to 2011 involving 508 410 fresh and 131 157 frozen autologous ART cycles resulting in 95 779 and 18 005 singleton live births, respectively, were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Fresh and frozen ART cycles were analyzed separately to compare perinatal outcomes of PTB and LBW of singleton live births resulting from transfer of multiple (≥2) embryos versus SET. Logistic regression analysis was performed adjusting for confounders. Subgroup analyses were carried out for perinatal outcomes of singleton live births with initial multiple or initial single gestational sacs following transfer of multiple embryos versus singleton live births following SET.

MAIN RESULTS AND THE ROLE OF CHANCE

In fresh cycles, there was a significantly higher risk of PTB (adjusted odds ratio (aOR) 2.70, CI 2.37-3.05) and LBW (aOR 2.76, CI 2.44-3.13) in singleton live births with initial multiple gestational sacs but there was no significant difference in the risk of PTB (aOR 1.08, CI 1.00-1.16) or LBW (aOR 1.08, CI 1.00-1.16) in singleton live births with an initial single gestational sac following transfer of ≥2 embryos compared to those following SET. In frozen cycles, there was a significantly higher risk of PTB (aOR 2.13, CI: 1.55-2.93) and LBW (aOR 2.61, CI: 1.87-3.64) in singleton live births with initial multiple gestational sacs but there was no significant difference in the risk of PTB (aOR 1.02, CI: 0.88-1.18) or LBW (aOR 0.91, CI: 0.77-1.07) in the singleton live births with an initial single gestational sac following transfer of ≥2 embryos compared to those following SET.

LIMITATIONS, REASONS FOR CAUTION

While the analysis was adjusted for a number of known confounders, the dataset had no information for confounders such as smoking, BMI, previous obstetric history and comorbid medical conditions during pregnancy. The lack of information about the timing of occurrence of the vanishing phenomenon is another limitation because poorer perinatal outcomes of a surviving twin have been reported following second trimester fetal demise compared to the first trimester.

WIDER IMPLICATIONS OF THE FINDINGS

The study results suggest that the vanishing twin phenomenon is associated with increased risk of PTB and LBW in the resulting singleton live births and there was no increased risk when there was a single gestational sac from the outset following transfer of multiple embryos.

STUDY FUNDING/COMPETING INTERESTS

Nil.

Comparison of perinatal outcomes following blastocyst and cleavage-stage embryo transfer: analysis of 10 years' data from a single centre

RESEARCH QUESTION

Are there greater risks of adverse perinatal outcomes, in particular of congenital malformations, after blastocyst transfer compared with cleavage-stage embryo transfer in IVF?

DESIGN

This was a retrospective cohort analysis from a centre for assisted reproduction at a public hospital in China over the period 2006-2015. The analysis covered all women who conceived (15,254) and newborns (16,213) from IVF/intracytoplasmic sperm injection (ICSI) cycles with cleavage-stage embryo transfer or blastocyst transfer. The principal outcome measures were congenital malformations, preterm birth (PTB), low birthweight (LBW), small for gestational age (SGA) and large for gestational age (LGA).

RESULTS

Logistic regression analysis showed that the sex ratio was imbalanced towards male neonates after blastocyst transfer (P=0.001; adjusted OR 1.17, 95%CI 1.07-1.30) but there were no differences in rates of miscarriage, ectopic pregnancy, stillbirth, very preterm birth (<32 weeks), PTB (<37 weeks), LBW, SGA or LGA between blastocyst transfer and cleavage-stage embryo transfer. A total of 176 congenital malformations (123 cleavage-stage embryos versus 53 blastocysts) were identified both in newborns and aborted fetuses, but the difference between groups was not statistically significant.

CONCLUSIONS

There was no difference in the risks of adverse perinatal outcomes, and in particular of congenital malformation, after blastocyst transfer compared with cleavage-stage transfer, although there was a sex ratio imbalance towards male neonates after blastocyst transfer.

Neonatal outcomes among twins following assisted reproductive technology: an Australian population-based retrospective cohort study

Background

While their incidence is on the rise, twin pregnancies are associated with risks to the mothers and their babies. This study aims to investigate the likelihood of adverse neonatal outcomes of twins following assisted reproductive technology (ART) compared to non-ART twins.

Methods

A retrospective population study using the Australian National Perinatal Data Collections (NPDC) which included 19,662 twins of ≥20 weeks gestational age or ≥ 400 g birthweight in Australia. Maternal outcomes and neonatal outcomes (preterm birth, low birth weight, resuscitation and neonatal death) were compared. Generalized Estimating Equations were used to assess the likelihood of any neonatal outcomes, with adjusted odds ratio (AOR) and 95% confidence intervals (CI) presented. Weinberg’s differential rule was used to estimate monozygotic twin rate.

Results

ART mothers were 3.3 years older than non-ART mothers. The rates of pregnancy-induced hypertension and gestational diabetes were significantly higher for ART mothers than non-ART mothers (12.2% vs. 8.4%, p <  0.01) and (9.7% vs. 7.5%, p <  0.01) respectively. The incidence of monozygotic twins was 2.0% for ART twins and 1.1% for non-ART twins. Compared with non-ART twins, ART twins had higher rates of preterm birth (AOR 1.13, 95% CI: 1.05–1.22), low birth weight (AOR 1.13, 95% CI: 1.05–1.22), and resuscitation (AOR 1.26, 95% CI: 1.17–1.36). Liveborn ART twins had 28% (AOR 1.28, 95% CI 1.09–1.50) increased odds of having any adverse neonatal outcome compared to liveborn non-ART twins, especially for opposite-sex ART twins (AOR 1.42, 95% CI 1.11–1.82).

Conclusion

As ART twins had higher rates of adverse outcome, special prenatal care is recommended. Couples accessing ART should be fully informed of the risk of adverse outcome of twin pregnancies.

Morbidity and mortality among very preterm singletons following fertility treatment in Australia and New Zealand, a population cohort study

BACKGROUND

Due to high rates of multiple birth and preterm birth following fertility treatment, the rates of mortality and morbidity among births following fertility treatment were higher than those conceived spontaneously. However, it is unclear whether the rates of adverse neonatal outcomes remain higher for very preterm (<32 weeks gestational age) singletons born after fertility treatment. This study aims to compare adverse neonatal outcomes among very preterm singletons born after fertility treatment including assisted reproductive technology (ART) hyper-ovulution (HO) and artificial insemination (AI) to those following spontaneous conception.

METHODS

The population cohort study included 24069 liveborn very preterm singletons who were admitted to Neonatal Intensive Care Unit (NICU) in Australia and New Zealand from 2000 to 2010. The in-hospital neonatal mortality and morbidity among 21753 liveborn very preterm singletons were compared by maternal mode of conceptions: spontaneous conception, HO, ART and AI. Univariate and multivariate binary logistic regression analysis was used to examine the association between mode of conception and various outcome factors. Odds ratio (OR) and adjusted odds ratio (AOR) and 95% confidence interval (CI) were calculated.

RESULTS

The rate of small for gestational age was significantly higher in HO group (AOR 1.52, 95% CI 1.02-2.67) and AI group (AOR 2.98, 95% CI 1.53-5.81) than spontaneous group. The rate of birth defect was significantly higher in ART group (AOR 1.71, 95% CI 1.36-2.16) and AI group (AOR 3.01, 95% CI 1.47-6.19) compared to spontaneous group. Singletons following ART had 43% increased odds of necrotizing enterocolitis (AOR 1.43, 95% CI 1.04-1.97) and 71% increased odds of major surgery (AOR 1.71, 95% CI 1.37-2.13) compared to singletons conceived spontaneously. Other birth and NICU outcomes were not different among the comparison groups.

CONCLUSIONS

Compared to the spontaneous conception group, risk of congenital abnormality significantly increases after ART and AI; the risk of morbidities increases after ART, HO and AI. Preconception planning should include comprehensive information about the benefits and risks of fertility treatment on the neonatal outcomes.

Risk of adverse pregnancy and perinatal outcomes after high technology infertility treatment: a comprehensive systematic review

In the literature, there is growing evidence that subfertile patients who conceived after infertility treatments have an increased risk of pregnancy and perinatal complications and this is particularly true for patients who conceived through use of high technology infertility treatments. Moreover, high technology infertility treatments include many concomitant clinical and biological risk factors. This review aims to summarize in a systematic fashion the current evidence regarding the relative effect of the different procedures for high technology infertility treatments on the risk of adverse pregnancy and perinatal outcome. A literature search up to August 2016 was performed in IBSS, SocINDEX, Institute for Scientific Information, PubMed, Web of Science and Google Scholar and an evidence-based hierarchy was used to determine which articles to include and analyze. Data on prepregnancy maternal factors, low technology interventions, specific procedures for male factor, ovarian tissue/ovary and uterus transplantation, and chromosomal abnormalities and malformations of the offspring were excluded. The available evidences were analyzed assessing the level and the quality of evidence according to the Oxford Centre for Evidence-Based Medicine guidelines and the Grading of Recommendations Assessment, Development, and Evaluation system, respectively. Current review highlights that every single procedure of high technology infertility treatments can play a crucial role in increasing the risk of pregnancy and perinatal complications. Due to the suboptimal level and quality of the current evidence, further well-designed studies are needed.

Maternal and Live-birth Outcomes of Pregnancies following Assisted Reproductive Technology: A Retrospective Cohort Study

This study was carried out to explore associations between assisted reproductive technology (ART) and maternal and neonatal outcomes compared with similar outcomes following spontaneously conceived births. We conducted a retrospective cohort study of pregnancies conceived by ART (N = 2641) during 2006–2014 compared to naturally conceived pregnancies (N = 5282) after matching for maternal age and birth year. Pregnancy complications, perinatal complications and neonatal outcomes of enrolled subjects were investigated and analysed by multivariate logistic regression. We found that pregnancies conceived by in vitro fertilization (IVF) were associated with a significantly increased incidence of gestational diabetes mellitus, gestational hypertension, preeclampsia, intrahepatic cholestasis of pregnancy, placenta previa, placental abruption, preterm premature rupture of membranes, placental adherence, postpartum haemorrhage, polyhydramnios, preterm labour, low birth weight, and small-for-date infant compared with spontaneously conceived births. Pregnancies conceived by intracytoplasmic sperm injection (ICSI) showed similar elevated complications, except some of the difference narrowed or disappeared. Singleton pregnancies or nulliparous pregnancies following ART still exhibited increased maternal and neonatal complications. Therefore, we conclude that pregnancies conceived following ART are at increased risks of antenatal complications, perinatal complications and poor neonatal outcomes, which may result from not only a higher incidence of multiple pregnancy, but also the manipulation involved in ART processes.

Costs of achieving live birth from assisted reproductive technology: a comparison of sequential single and double embryo transfer approaches

OBJECTIVE

To assess treatment and pregnancy/infant-associated medical costs and birth outcomes for assisted reproductive technology (ART) cycles in a subset of patients using elective double embryo (ET) and to project the difference in costs and outcomes had the cycles instead been sequential single ETs (fresh followed by frozen if the fresh ET did not result in live birth).

DESIGN

Retrospective cohort study using 2012 and 2013 data from the National ART Surveillance System.

SETTING

Infertility treatment centers.

PATIENT(S)

Fresh, autologous double ETs performed in 2012 among ART patients younger than 35 years of age with no prior ART use who cryopreserved at least one embryo.

INTERVENTION(S)

Sequential single and double ETs.

MAIN OUTCOME MEASURE(S)

Actual live birth rates and estimated ART treatment and pregnancy/infant-associated medical costs for double ET cycles started in 2012 and projected ART treatment and pregnancy/infant-associated medical costs if the double ET cycles had been performed as sequential single ETs.

RESULT(S)

The estimated total ART treatment and pregnancy/infant-associated medical costs were $580.9 million for 10,001 double ETs started in 2012. If performed as sequential single ETs, estimated costs would have decreased by $195.0 million to $386.0 million, and live birth rates would have increased from 57.7%-68.0%.

CONCLUSION(S)

Sequential single ETs, when clinically appropriate, can reduce total ART treatment and pregnancy/infant-associated medical costs by reducing multiple births without lowering live birth rates.

Impact of single embryo transfer policy on perinatal outcomes in fresh and frozen cycles-analysis of the Japanese Assisted Reproduction Technology registry between 2007 and 2012

OBJECTIVE

To investigate whether the introduction of single embryo transfer (SET) policy in Japan has improved perinatal outcomes.

DESIGN

A retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

A total of 140,718 live births and 510 stillbirths (after 22 weeks of gestation) conceived by assisted reproductive technology in Japan between 2007 and 2012 were reviewed.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Preterm birth (PTB), low birth weight (LBW), very low birth weight (VLBW), small for gestational age (SGA), large for gestational age (LGA), perinatal mortality, and other pregnancy complications.

RESULT(S)

The rate of SET increased significantly from 52.2% in 2007 to 82.6% in 2012, while the rate of multiple pregnancy decreased significantly from 10.7% to 4.1% over the same period. The rates of PTB, LBW, and SGA decreased significantly, while that of LGA increased. Perinatal mortality decreased from 0.70% to 0.40% in fresh cycles, while that of frozen cycles did not change. Double ET or more was associated with a significantly increased risk for multiple pregnancy, placenta accreta, preterm premature rupture of membrane, cesarean section (CS), PTB, LBW, SGA, and early neonatal death compared with SET. Compared with before the SET policy was launched, the risks of multiple pregnancy, CS, early PTB before 32 weeks, LBW, VLBW, and SGA were significantly decreased after the policy was launched, with significant interactions of fresh/frozen status.

CONCLUSION(S)

The results suggest that the SET policy improved perinatal outcomes in Japan. The impact of SET policy was different in fresh and frozen cycles for several perinatal outcomes.

Risk of preterm birth after blastocyst embryo transfer: a large population study using contemporary registry data from Australia and New Zealand

OBJECTIVE

To investigate whether there is an increased risk of preterm birth with blastocyst transfer compared with cleavage-stage embryo transfer (ET) after assisted reproductive technology (ART).

DESIGN

A retrospective, population-based study.

SETTING

Not applicable.

PATIENT(S)

A total of 50,788 infants conceived after ART treatment performed from 2009 to 2012.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The rates of preterm birth, low birth weight (LBW), and small for gestational age (SGA) for 43,952 singleton and 3,418 twin deliveries after transfers of blastocyst or cleavage-stage embryos.

RESULT(S)

Among singletons, there was no significant difference in the odds of preterm birth between blastocyst and cleavage-stage ET (9.1% compared with 9.3%, respectively, adjusted odds ratio 1.00, 95% confidence interval 0.94-1.08). Among twins, the crude rates of preterm birth were similar after blastocyst and cleavage-stage ETs (61.5% and 64.4%, respectively). However, after adjusting for potential confounders, blastocyst transfer was associated with a lower odds of preterm birth among twins (adjusted odds ratio 0.80, 95% confidence interval 0.70-0.93). There was no difference in risks of LBW and SGA between blastocyst and cleavage-stage ETs for both singletons and twins after adjusting for potential confounders.

CONCLUSION(S)

In contrast with the findings from a number of other studies, blastocyst culture in Australian and New Zealand is not associated with an increased risk of preterm, LBW, and SGA for singletons. Further studies are needed to assess longer-term outcomes of children born after ART treatment and possible biological or treatment factors related to adverse outcomes.

Trends in Morbidity and Mortality of Extremely Preterm Multiple Gestation Newborns

OBJECTIVES

To examine the risk of mortality and major morbidities in extremely preterm multiple gestation infants compared with singletons over time.

METHODS

This is a retrospective study of 15,402 infants born ≤27 weeks' gestation, admitted to NICUs in the Australian and New Zealand Neonatal Network from 1995 to 2009. Mortality and major morbidities were compared between singletons and multiples across three 5-year epochs.

RESULTS

Extreme preterm multiples were more likely to have lower birth weight; higher maternal age; and higher rates of assisted conception, antenatal steroid use, and cesarean delivery compared with singletons. The mortality rate was significantly higher in multiples compared with singletons even as there was a trend of decreasing gestational-age stratified mortality in multiples over the time period investigated. The rates of major morbidities or composite adverse outcomes were not different between multiples and singletons across all epochs. The adjusted odds ratio (AOR) for mortality in multiples was significantly higher in multiples compared with singletons (AOR 1.20, 95% confidence interval [CI] 1.08-1.34). There were no differences in the adjusted odds for poor outcomes in multiples compared with singletons in the most recent epoch: mortality (AOR 1.00, 95% CI 0.84-1.19), major morbidity (0.95, 95% CI 0.81-1.10), and composite adverse outcome (0.96, 95% CI 0.83-1.11).

CONCLUSIONS

Over the 15-year period, the odds for mortality in extremely preterm NICU infants of multiple gestation was significantly higher compared with singletons. The adjusted odds of poor outcomes in multiples were not significantly different from that of singletons in the most recent epoch.

Application of a validated prediction model for in vitro fertilization: comparison of live birth rates and multiple birth rates with 1 embryo transferred over 2 cycles vs 2 embryos in 1 cycle

OBJECTIVE

The purpose of this study was to use a validated prediction model to examine whether single embryo transfer (SET) over 2 cycles results in live birth rates (LBR) comparable with 2 embryos transferred (DET) in 1 cycle and reduces the probability of a multiple birth (ie, multiple birth rate [MBR]).

STUDY DESIGN

Prediction models of LBR and MBR for a woman considering assisted reproductive technology developed from linked cycles from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System for 2006-2012 were used to compare SET over 2 cycles with DET in 1 cycle. The prediction model was based on a woman's age, body mass index (BMI), gravidity, previous full-term births, infertility diagnoses, embryo state, number of embryos transferred, and number of cycles.

RESULTS

To demonstrate the effect of the number of embryos transferred (1 or 2), the LBRs and MBRs were estimated for women with a single infertility diagnosis (male factor, ovulation disorders, diminished ovarian reserve, and unexplained); nulligravid; BMI of 20, 25, 30, and 35 kg/m2; and ages 25, 35, and 40 years old by cycle (first or second). The cumulative LBR over 2 cycles with SET was similar to or better than the LBR with DET in a single cycle (for example, for women with the diagnosis of ovulation disorders: 35 years old; BMI, 30 kg/m2; 54.4% vs 46.5%; and for women who are 40 years old: BMI, 30 kg/m(2); 31.3% vs 28.9%). The MBR with DET in 1 cycle was 32.8% for women 35 years old and 20.9% for women 40 years old; with SET, the cumulative MBR was 2.7% and 1.6%, respectively.

CONCLUSION

The application of this validated predictive model demonstrated that the cumulative LBR is as good as or better with SET over 2 cycles than with DET in 1 cycle, while greatly reducing the probability of a multiple birth.

The type of culture medium and the duration of in vitro culture do not influence birthweight of ART singletons

STUDY QUESTION

Does the type of in vitro culture medium or the duration of in vitro culture influence singleton birthweight after IVF/ICSI treatment?

SUMMARY ANSWER

In a comparison of two culture media, neither the medium nor the duration of culture (Day 3 versus Day 5 blastocyst transfer) had any effect on mean singleton birthweight.

WHAT IS KNOWN ALREADY

Previous studies indicated that in vitro culture of human embryos may affect birthweight of live born singletons. Both the type of culture medium and the duration of culture may be implicated. However, these studies are small and report conflicting results.

STUDY DESIGN, SIZE, DURATION

A large retrospective analysis was performed including all singleton live births after transferring fresh Day 3 or Day 5 embryos. IVF and ICSI cycles performed between April 2004 and December 2009 at a tertiary care centre were included for analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 2098 singleton live births resulting from singleton pregnancies were included for analysis. Two different sequential embryo culture media were concurrently used in an alternating way: Medicult (n = 1388) and Vitrolife (n = 710). Maternal age, maternal and paternal BMI, maternal parity, maternal smoking, main cause of infertility, cycle rank, stimulation protocol, method of fertilization (IVF or ICSI), time in culture and number of embryos transferred were taken into account. Embryo transfers were performed either on Day 3 (n = 1234) or on Day 5 (n = 864). Singleton birthweight was the primary outcome parameter. Gestational age and gender of the newborn were accounted for in the multiple regression analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

No significant differences in mean singleton birthweight were observed between the two culture media: Medicult 3222 g (±15 SE) and Vitrolife 3251 g (±21 SE) (P = 0.264). The mean singleton birthweight was not different between Day 3 embryo transfers (3219 ± 16 g) and Day 5 blastocyst transfers (3250 ± 19 g; P = 0.209). Multiple regression analysis controlling for potential maternal, paternal, treatment and newborn confounders confirmed the non-significant differences in mean singleton birthweight between the two culture media. Likewise, the adjusted mean singleton birthweight was not different according to the duration of in vitro culture (P = 0.521).

LIMITATIONS, REASONS FOR CAUTION

The conclusions are limited by its retrospective design; however, the two different sequential culture systems were used in an alternating way during the same time period. Pregnancy-associated factors possibly influencing birthweight (such as diabetes, hypertension, pre-eclampsia) were not included in the analysis.

WIDER IMPLICATIONS OF THE FINDINGS

This large retrospective study does not support earlier concerns that both the type of culture medium and the duration of embryo culture influence singleton birthweight. However, a continuous surveillance of human embryo culture procedures (medium type, culture duration and other culture conditions) should remain a priority within assisted reproduction technology.

STUDY FUNDING/COMPETING INTERESTS

None.

Outcomes of surrogacy undertaken by Australians overseas

OBJECTIVES

To describe the outcomes of surrogacy among Australian intended parents who engage in compensated surrogacy overseas.

DESIGN, SETTING AND PARTICIPANTS

Members of two Australian parenting support forums who were considering surrogacy or were currently or previously in a surrogacy arrangement were invited to complete an anonymous online survey during July 2013.

MAIN OUTCOME MEASURES

Destination countries; source of eggs; number of surrogates and embryo transfers; proportions who experienced pregnancy loss after 12 weeks' gestation, multiple pregnancy, prematurity, and live birth by destination country; and intentions regarding disclosure to children about the way they were conceived.

RESULTS

Of 1135 potential participants 259 (23%) completed the survey. Of these, 112 (43%) had undertaken at least one surrogacy attempt overseas. India and the United States were the two most common destination countries. Most respondents (95/112; 85%) had used donor eggs; half (57/112; 51%) had used more than one surrogate; and the mean number of embryo transfer procedures was 2.9. As a result of surrogacy, 85% (95/112) had at least one child; 55% (62/112) reported that their surrogate had a multiple pregnancy; 10% (11/112) reported that a pregnancy had ended in a late miscarriage or perinatal death; and 45% of births (35/78) were premature. Most respondents (80/112; 71%) were most comfortable with using an identity-release donor, and 87% (97/112) believed that this would also be in their child's best interests. Almost universally, parents were planning to disclose the use of a surrogate and/or a donor to their child.

CONCLUSIONS

Almost half of the intended parents via surrogacy who completed this survey had undertaken compensated surrogacy overseas; most of these used donor eggs, but few considered Australian donors. A high proportion of surrogates had multiple pregnancies and there was a high rate of premature birth. These adverse outcomes could be avoided if the surrogacy was undertaken in Australia. Removing some of the existing barriers to surrogacy in Australia may reduce the number of surrogacy arrangements carried out overseas.

Birth and perinatal outcomes and complications for babies conceived following ART

Children born after assisted reproductive techniques (ART) have an increased risk of several adverse perinatal outcomes compared with their naturally conceived peers. This has various causes such as higher multiple birth rates, parental characteristics and higher maternal age, with more being nulliparous. Furthermore the in-vitro techniques, the controlled ovarian stimulation, culture media, and possibly additional freezing or vitrification procedures seem to play a role. However, when analyzing the perinatal trends over time, the differences between ART and naturally conceived children appear to have diminished. This is probably due to ART being more accessible and therefore couples have shorter duration of infertility before referral to ART; hence couples are nowadays less reproductively ill than in the past. A refinement of both clinical and laboratory skills during the past three decades of assisted reproduction may be another explanation. However, caution should be taken, as we do not yet know the full consequences of the observed increase in fetal growth and potential epigenetic changes in the early embryonic stages of fetal development.

The impact of assisted reproductive technologies on intra-uterine growth and birth defects in singletons

Pooled odds ratios from meta-analyses of infants born following assisted reproductive technologies (ART) compared with non-ART singletons show increases in low birth weight, preterm birth, small for gestational age, and birth defects. Although there have been small reductions in recent data, odds associated with these outcomes are still higher for ART singletons. Both ART procedures and underlying infertility contribute to these increased risks. Outcomes appear better for frozen-thawed compared with fresh embryo transfers, but are poorer than for non-ART infants. There is a concerning increase in large-for-gestational-age infants born following frozen-thawed embryo transfer and limited data on the effects of embryo vitrification used instead of slow-freezing techniques. Using large datasets, we now need to investigate risks of individual birth defects and disentangle the inter-related effects of different types of infertility and the multiple aspects of ART. Greater understanding of the causes of adverse ART outcomes and identification of modifiable risk factors may lead to further reductions in the disparities in outcome between ART and non-ART infants.

Neonatal outcome after preimplantation genetic diagnosis

OBJECTIVE

To examine whether embryo biopsy for preimplantation genetic diagnosis (PGD) influences neonatal outcomes.

DESIGN

Prospective follow-up cohort.

SETTING

Tertiary university-affiliated medical center.

PATIENT(S)

242 children born after PGD, 242 children born after intracytoplasmic sperm injection (ICSI) (158 singletons and 42 twins pairs in each group), and 733 children born after a spontaneous conception (SC) (493 singletons, 120 twins pairs), matched for maternal age, parity, and body mass index.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Gestational age, birth weight, prematurity (<37 and <34 weeks), low birth weight (<2,500 g, very low birth weight, <1,500 g), and intrauterine growth restriction (<10th percentile for gestational age).

RESULT(S)

For singletons, the mean birth weight was higher after SC compared with ICSI but not compared with PGD. Mean gestational ages were lower after PGD and ICSI compared with SC. The low birth weight and intrauterine growth restriction rates were 4.4%, 12.0%, and 5.7% and 5.1%, 9.5%, and 5.5% for PGD, ICSI, and SC, respectively. Similar results were found when controlled for the number of embryos transferred and cryopreservation. The results for twins exhibited similar but less statistically significant trends. Polar body and blastomere biopsies provided similar outcomes.

CONCLUSION(S)

Embryo biopsy itself did not cause intrauterine growth restriction or low birth weight compared with SC, despite lower gestational ages with PGD. The worsened outcomes in ICSI compared with PGD pregnancies may be due to the infertility itself.

An international survey of assisted reproductive technologies (ARTs) policies and the effects of these policies on costs, utilization, and health outcomes

OBJECTIVES

The purpose of this study was to compare existing policies regarding access to 7 assisted reproductive technologies (ARTs) and to examine the effects of these policies on costs, utilization, and health outcomes in 14 countries and 2 Canadian provinces based on publicly available information.

METHODS

A systematic review of publicly available information from peer-reviewed literature (using biomedical and social science databases) and grey literature (e.g., health ministry websites, health technology assessment agency websites, etc.) was performed.

RESULTS

ARTs services permitted or funded vary across jurisdictions. The goals and eligibility restrictions (e.g., on maternal age, number of embryos transferred, and number of cycles) defined in ARTs policies also vary across jurisdictions. Studies on the impact of such policies have primarily been retrospective and focused on short-term service utilization. Nevertheless, they suggest that the policies have achieved specific outcomes, such as reductions in multiple births and in costs to payers.

CONCLUSIONS

Based on the evidence reviewed, policies aimed at reducing public coverage of ARTs or restricting the number of embryos transferred have achieved these goals. However, their effects on maternal and infant health outcomes have not been well explored.

Embryo selection strategy in sibling oocytes: a novel approach to measuring the likelihood of single‑embryo transfer using a mouse embryo transfer model

The present study investigated the effect of embryo transfer on post-implantation development using different fertilization approaches in sibling oocyte procedures. C57BL/6, DBA/2, C3H/HeJ and ICR mice were used at 8-10 weeks of age. Mature oocytes were collected, divided into two groups and fertilized using in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Different numbers of the resulting blastocysts were then transferred into recipients and designated as either: The single embryo transfer (SET) I model (one transferred embryo), the SET II model (six transferred embryos) or the multiple embryo transfer (MET) model (24 transferred embryos). The development efficiency, cell number, number of apoptotic cells in blastocysts, pregnancy efficiency, delivery rate and cumulative pregnancy efficiency were analyzed. IVF-fertilized embryos exhibited higher blastocyst development competence and embryo quality compared with ICSI embryos. The pregnancy and delivery efficiency was not identified to be significantly different between the two SET models, but it was lower in these two models than in the MET model. The cumulative pregnancy efficiency in SET models, calculated using a mathematical equation, was not decreased. In conclusion, embryo quality was shown to be the primary factor in selecting embryos prior to embryo transfer using sibling oocytes. In addition, single blastocyst transfer can be performed in sibling oocytes without compromising cumulative pregnancy rates, independent of the fertilization approach.

Perinatal mortality following assisted reproductive technology treatment in Australia and New Zealand, a public health approach for international reporting of perinatal mortality

BACKGROUND

There is a need to have uniformed reporting of perinatal mortality for births following assisted reproductive technology (ART) treatment to enable international comparison and benchmarking of ART practice.

METHODS

The Australian and New Zealand Assisted Reproduction Database was used in this study. Births of ≥ 20 weeks gestation and/or ≥ 400 grams of birth weight following embryos transfer cycles in Australia and New Zealand during the period 2004 to 2008 were included. Differences in the mortality rates by different perinatal periods from a gestational age cutoff of ≥ 20, ≥ 22, ≥ 24, or ≥ 28 weeks (wks) to a neonatal period cutoff of either < 7 or < 28 days after birth were assessed. Crude and specific (number of embryos transferred and plurality) rates of perinatal mortality were calculated for selected gestational and neonatal periods.

RESULTS

When the perinatal period is defined as ≥ 20 wks gestation to < 28 days after birth, the perinatal mortality rate (PMR) was 16.1 per 1000 births (n = 630). A progressive contraction of the gestational age groups resulted in marked reductions in the PMR for deaths at < 28 days (22 wks 11.0; 24 wks 7.7; 28 wks 5.6); and similarly for deaths at < 7 days (20 wks 15.6, 22 wks 10.5; 24 wks 7.3; 28 wks 5.3). In contrast, a contraction of the perinatal period from < 28 to < 7 days after birth only marginally reduced the PMR from 16.2 to 15.6 per 1000 births which was consistent across all gestational ages.The PMR for single embryo transfer (SET) births (≥ 20 weeks gestation to < 7 days post-birth) was significantly lower (12.8 per 1000 SET births) compared to double embryo transfer (DET) births (PMR 18.3 per 1000 DET births; p < 0.001, Fisher's Exact Test). Similarly, the PMR for SET births (≥ 22 weeks gestation to < 7 days post-birth) was significantly lower (8.8 per 1000 SET births, p < 0.001, Fisher's Exact Test) when compared to DET births (12.2 per 1000 DET births). The highest PMR (50.5 per 1000 SET births, 95% CI 36.5-64.5) was for twins following SET births (≥ 20 weeks gestation to < 7 days post-birth) compared to twins following DET (23.9 per 1000 DET births, 95% CI 20.8-27.1).

CONCLUSION

Reporting of perinatal mortality of ART births is an essential component of quality ART practice. This should include measures that monitor the impact on perinatal mortality of multiple embryo transfer. We recommend that reporting of perinatal deaths following ART treatment, should be stratified for three gestation-specific perinatal periods of ≥ 20, ≥ 22 and ≥ 28 completed weeks to < 7 days post-birth; and include plurality specific rates by SET and DET. This would provide a valuable international evidence-base of PMR for use in evaluating ART policy, practice and new research.

Refuting a misguided campaign against the goal of single-embryo transfer and singleton birth in assisted reproduction

Much recent progress has been made by assisted reproductive technology (ART) professionals toward minimizing the incidence of multiple pregnancy following ART treatment. While a healthy singleton birth is widely considered to be the ideal outcome of such treatment, a vocal minority continues a campaign to advocate the benefits of multiple embryo transfer as treatment and twin pregnancy as outcome for most ART patients. Proponents of twinning argue four points: that patients prefer twins, that multiple embryo transfer maximizes success rates, that the costs per infant are lower with twins and that one twin pregnancy and birth is associated with no higher risk than two consecutive singleton pregnancies and births. We find fault with the reasoning and data behind each of these tenets. First, we respect the principle of patient autonomy to choose the number of embryos for transfer but counter that it has been shown that better patient education reduces their desire for twins. In addition, reasonable and evidentially supported limits may be placed on autonomy in exchange for public or private insurance coverage for ART treatment, and counterbalancing ethical principles to autonomy exist, especially beneficence (doing good) and non-maleficence (doing no harm). Second, comparisons between success rates following single-embryo transfer (SET) and double-embryo transfers favor double-embryo transfers only when embryo utilization is not comparable; cumulative pregnancy and birth rates that take into account utilization of cryopreserved embryos (and the additional cryopreserved embryo available with single fresh embryo transfer) consistently demonstrate no advantage to double-embryo transfer. Third, while comparisons of costs are system dependent and not easy to assess, several independent studies all suggest that short-term costs per child (through the neonatal period alone) are lower with transfers of one rather than two embryos. And, finally, abundant evidence conclusively demonstrates that the risks to both mother and especially to children are substantially greater with one twin birth compared with two singleton births. Thus, the arguments used by some to promote multiple embryo transfer and twinning are not supported by the facts. They should not detract from efforts to further promote SET and thus reduce ART-associated multiple pregnancy and its inherent risks.

The longer-term health outcomes for children born as a result of IVF treatment: Part I--General health outcomes

BACKGROUND Several million children have been born from in vitro fertilization (IVF) treatment, but limited data exist regarding their health and development beyond the first year of life. It has been alleged that IVF may lead to long-term adverse consequences, in addition to the documented worse perinatal outcome and increased risk of congenital abnormalities in children born resulting from IVF treatment. METHODS A search strategy restricted to studies relating to the medical condition of children of at least 1 year of age born as a result of IVF treatment was performed to include case series, data linkage and prospective studies published 1 January 2000-1 April 2012. RESULTS Limited long-term follow-up data suggest that there is potentially an increase in the incidence of raised blood pressure, elevated fasting glucose, increase in total body fat composition, advancement of bone age and potentially subclinical thyroid disorder in the IVF offspring. Whether these potential associations are related to the IVF treatment per se, the adverse obstetric outcomes associated with IVF treatment or are related to the genetic origin of the children is yet to be determined. CONCLUSIONS This review provides evidence to suggest that the short-term health outcome for children born from IVF treatment is positive. However, it is expected that the cardiovascular and metabolic risk factors found in childhood and tracking into adulthood could be worse in later life, and may be responsible for chronic cardiometabolic disease. These observations need to be addressed by further studies.

Increased risk of preterm birth in singleton pregnancies after blastocyst versus Day 3 embryo transfer: Canadian ART Register (CARTR) analysis

STUDY QUESTION

Are the fetal outcomes of singleton pregnancies that result from cleavage stage embryo transfer (ET) different from the outcomes from Day 5/6 blastocyst stage ET?

SUMMARY ANSWER

There was a significantly higher risk of preterm birth (<37 weeks) in singletons after extended embryo culture (Day 5/6) compared with cleavage stage (Day 3) transfer.

WHAT IS KNOWN ALREADY

Two recent studies, from Sweden and the USA, reported an increased risk of preterm birth in singleton pregnancies after Day 5/6 ET compared with Day 3 ET. The US study also showed increased early preterm births and the Swedish study showed increased fetal malformations in this group.

STUDY DESIGN, SIZE AND DURATION

A retrospective cohort study was performed. Data were collected from the Canadian ART Register database for all singleton births after fresh IVF/ICSI ET cycles (2001-2009).

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 12 712 singleton births were included. Of these, 9506 resulted from a Day 3 ET and 3206 resulted from a blastocyst (Day 5/6) ET.

MAIN RESULTS AND THE ROLE OF CHANCE

Preterm birth rate <37 weeks (unadjusted by potential confounding factors) was higher with Day 5/6 versus Day 3 transfers (17.2 versus 14.1%, P < 0.001). Using logistic regression analysis to adjust for confounding factors, preterm birth rate <37 weeks was the only outcome significantly increased after Day 5/6 compared with Day 3 transfer (odds ratio 1.32, 95% confidence interval 1.17-1.49). The following confounding factors were adjusted for: year of treatment (2001-2009), maternal age (continuous), parity (0 versus ≥1 birth), diagnosis category, number of oocytes retrieved [≤20 versus >20 (high responder group)], insemination method (IVF versus ICSI), number of embryos transferred (1, 2 or ≥3) and the presence of a vanishing twin (≥1 fetal heart on the initial ultrasonographic examination).

LIMITATIONS, REASONS FOR CAUTION

Post-natal follow-up studies will be required to determine if this difference we observed translates into adverse long-term effects on these offspring. The rate of early preterm births (<32 weeks) was higher in Day 5/6 versus Day 3, but the low number of cases in this category did not have the power to show a difference (3.0 versus 2.7%, P = 0.34).

WIDER IMPLICATIONS OF THE FINDINGS

We found a significantly higher risk of preterm birth (<37 weeks) in singletons after extended embryo culture (Day 5/6) compared with cleavage stage (Day 3) transfer, even when adjusting for confounding factors. Our findings are in agreement with the previous two studies; however, we did not show a difference in the very preterm deliveries (unlike the US study) or in fetal malformations (as in the Swedish study). We hypothesize that there may be a deleterious effect of prolonged in vitro embryo culture on subsequent placentation. Longer term follow-up studies will be required to determine if prolonged in vitro culture to the blastocyst stage has an adverse effect on the long-term health of offspring when compared with shorter cleavage stage culture.

STUDY FUNDING/COMPETING INTEREST(S)

None.

Why do singletons conceived after assisted reproduction technology have adverse perinatal outcome? Systematic review and meta-analysis

BACKGROUND

Assisted reproduction technology (ART) is used worldwide, at increasing rates, and data show that some adverse outcomes occur more frequently than following spontaneous conception (SC). Possible explanatory factors for the well-known adverse perinatal outcome in ART singletons were evaluated.

METHODS

PubMed and Cochrane databases from 1982 to 2012 were searched. Studies using donor or frozen oocytes were excluded, as well as those with no control group or including <100 children. The main outcome measure was preterm birth (PTB defined as delivery <37 weeks of gestation), and a random effects model was used for meta-analyses of PTB. Other outcomes were very PTB, low-birthweight (LBW), very LBW, small for gestational age and perinatal mortality.

RESULTS

The search returned 1255 articles and 65 of these met the inclusion criteria. The following were identified as predictors for PTB in singletons: SC in couples with time to pregnancy (TTP) > 1 year versus SC singletons in couples with TTP ≤ 1 year [adjusted odds ratio (AOR) 1.35, 95% confidence interval (CI) 1.22, 1.50]; IVF/ICSI versus SC singletons from subfertile couples (TTP > 1 year; AOR 1.55, 95% CI 1.30, 1.85); conception after ovulation induction and/or intrauterine insemination versus SC singletons where TTP ≤ 1 year (AOR 1.45, 95% CI 1.21, 1.74); IVF/ICSI singletons versus their non-ART singleton siblings (AOR 1.27, 95% CI 1.08, 1.49). The risk of PTB in singletons with a 'vanishing co-twin' versus from a single gestation was AOR of 1.73 (95% CI 1.54, 1.94) in the narrative data. ICSI versus IVF (AOR 0.80, 95% CI 0.69-0.93), and frozen embryo transfer versus fresh embryo transfer (AOR 0.85, 95% CI 0.76, 0.94) were associated with a lower risk of PTB.

CONCLUSIONS

Subfertility is a major risk factor for adverse perinatal outcome in ART singletons, however, even in the same mother an ART singleton has a poorer outcome than the non-ART sibling; hence, factors related to the hormone stimulation and/or IVF methods per se also may play a part. Further research is required into mechanisms of epigenetic modification in human embryos and the effects of cryopreservation on this, whether milder ovarian stimulation regimens can improve embryo quality and endometrial conditions, and whether longer culture times for embryos has a negative influence on the perinatal outcome.

Single embryo transfer reduces the risk of perinatal mortality, a population study

STUDY QUESTION

Do births following single embryo transfers (SET) have a reduced risk of perinatal mortality compared with those following double embryo transfers (DET)?

SUMMARY ANSWER

SET is associated with reduced risk of perinatal mortality compared with DET.

WHAT IS KNOWN ALREADY

Fetal, neonatal and perinatal mortality are important indicators for monitoring pregnancy and childbirth, particularly for births following assisted reproductive technology (ART) treatments. Following the introduction of SET, there has been a decline in the perinatal mortality rate (PMR) among babies born after ART in Australia and New Zealand.

STUDY DESIGN, SIZE, DURATION

This population study (census) included 50,258 births of ≥ 20 weeks gestation and/or ≥ 400 g of birthweight following embryos transfer cycles in Australia and New Zealand during the period 2004-2008.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The PMR was calculated according to the number of embryos transferred and other demographic and treatment-related factors. Perinatal deaths were defined as the number of fetal deaths (stillbirths) plus the number of neonatal deaths (deaths that occur before 28 days after birth).

MAIN RESULTS AND THE ROLE OF CHANCE

The PMR was 16.2 per 1000 births (n= 813). Of the 813 perinatal deaths, 630 were fetal deaths and 183 neonatal deaths. Twins had a significantly higher PMR (27.8 per 1000 births) than singletons (12.4 per 1000 births). The risk of perinatal mortality for all births following DET was 53% higher than for all births following SET (adjusted risk ratio 1.53, 95% confidence interval (95% CI): 1.29-1.80). Births following fresh DET had a 58% increased risk of perinatal mortality compared with births following fresh SET (risk ratio 1.58, 95% CI: 1.32-1.90).

LIMITATIONS, REASONS FOR CAUTION

Information on outcomes was missing from <1% of clinical pregnancies recorded in Australian and New Zealand Assisted Reproduction Database for the study period. There are no data on the timing of fetal death, the cause of perinatal death or on late termination of pregnancy at ≥ 20 weeks' gestation.

WIDER IMPLICATIONS OF THE FINDINGS

Double and higher order embryo transfer is associated with a higher risk of perinatal mortality when compared with SET. The number of embryos transferred is determined by the clinician with consent of the patient and is a modifiable treatment factor. SET should be advocated as the first-line management in ART as it is the single most effective public health intervention for preventing excess perinatal mortality among ART pregnancies.

STUDY FUNDING/COMPETING INTEREST(S)

Nil.

Obstetric outcome and long-term follow up of children conceived through assisted reproduction

Most children born after assisted reproduction techniques are healthy. The most important risk associated with in-vitro fertilisation is the higher multiple birth rate, which may result in increased child morbidity because several embryos are transferred at each cycle. Single-embryo transfer reduces this risk dramatically. Large registry studies and meta-analyses have indicated a small but statistically significantly increased risk of congenital malformations among children born after in-vitro fertilisation. Other risks, such as preterm birth and low birth weight seem to be associated more with parental characteristics than the in-vitro fertilisation technique. All knowledge about children conceived through in-vitro fertilisation is based on observational studies, with risks of bias and confounders. It is possible that pregnancies and children resulting from in-vitro fertilisation are more carefully monitored and seek health care more frequently, resulting in more health problems being discovered. Continuous follow up of children after in-vitro fertilisation is of great importance, particularly as new techniques are constantly being introduced.

Factors affecting obstetric outcome of singletons born after IVF

BACKGROUND

Singletons born after IVF have an adverse perinatal outcome when compared with singletons in the general population. This study investigates maternal characteristics and IVF- treatment-related variables, for a possible influence on obstetric outcomes.

METHODS

Data from all IVF clinics in Sweden, including all IVF singletons born after fresh treatment cycles and own oocytes during 2002-2006, were included (n = 8941) and cross-linked with the Swedish Medical Birth Registry. Four major outcomes were investigated: very preterm birth (<32 weeks), small for gestational age (SGA), placenta previa and placental abruption. Maternal characteristics (age, parity, BMI, smoking and years of infertility) and treatment-related variables (number of oocytes retrieved, number of embryo culture days, number of transferred and cryopreserved embryos, 'vanishing twin') were investigated for independent association with the four selected outcomes. Adjusted odds ratios (AORs) were calculated by logistic regression.

RESULTS

Primiparity, smoking, BMI and 'vanishing twin' were associated with an increased risk of very preterm birth. Maternal age, primiparity, smoking, BMI and years of infertility were associated with an increased risk of SGA. Maternal age and blastocyst transfer were associated with an increased risk, and primiparity with a decreased risk, of placenta previa. Smoking was significantly associated with placental abruption.

CONCLUSIONS

In singletons born after fresh IVF, certain maternal characteristics and the number of embryos transferred, when there was a 'vanishing twin' affected the obstetric outcome negatively. An increased rate of placenta previa was observed after blastocyst transfer. The results support the use of single embryo transfer and indicate that lifestyle factors are important for obstetric outcome.

Epidemiology of multiple pregnancy and the effect of assisted conception

Multiple pregnancy is one of the greatest perinatal challenges facing clinicians today. In a society of rising expectations among fertility and maternity service users, the potential for adverse outcomes associated with multiple pregnancy is a source of concern. This article examines the impact of assisted conception on the incidence of multiple pregnancies and associated complications. It explores some of the reasons for the strong association between assisted reproductive technology and multiple pregnancies and suggests possible ways of addressing this continuing problem.