Multiple pregnancy rate and embryo number transferred during in vitro fertilization

Incidence of complications among in vitro fertilization pregnancies

The use of assisted reproductive technology has increased in Romania in the past several years. Although most of these pregnancies are uncomplicated, in vitro fertilization is associated with an increased risk for adverse perinatal outcomes primarily caused by the increased risks of prematurity, gestational diabetes mellitus, and hypertensive disorders. Infertility can be caused by a variety of factors, including both male and female factors, and in some cases, the cause remains unknown. In our clinic, the etiology of infertility was known in most cases and was equally distributed between male and female factors. Women with gestational hypertension were significantly older. Patients with twin pregnancies were significantly younger than those with a single pregnancy. The prevalence of preterm newborns was 2.5 times higher than the global prevalence for prematurity.

Analysis of Factors Associated With Body Mass Index at Ages 18 and 36 Months Among Infants Born Extremely Preterm

IMPORTANCE

The development of neonatology has been associated with improved survival among infants born extremely preterm, and understanding their long-term outcomes is becoming increasingly important. However, there is little information on body mass index (BMI) among these children.

OBJECTIVE

To determine factors associated with BMI at ages 18 months and 36 months among infants born extremely preterm.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, multicenter cohort study was conducted using data from the Neonatal Research Network Japan database for 8838 infants born at gestational ages 23 to 28 weeks with data on BMI at 18 months and 36 months. Data were analyzed from April 2018 through June 2021.

EXPOSURES

BMI and BMI z score at ages 18 months and 36 months were regressed with gestational age, intrauterine growth restriction (IUGR) status, and complications during pregnancy and the neonatal period separately by presence of multiple pregnancy and sex.

MAIN OUTCOMES AND MEASURES

BMI and BMI z score at ages 18 months and 36 months.

RESULTS

Among 16 791 eligible infants born extremely preterm, 8838 infants were included in the analysis. There were 7089 infants born from single pregnancies (mean [SD] gestational age, 26.0 [1.6] weeks; 3769 [53.2%] boys; mean [SD] birth weight, 847 [228] g) and 1749 infants born from multiple pregnancies (mean [SD] gestational age, 26.3 [1.5] weeks; 903 [51.6%] boys; mean [SD] birth weight, 860 [217] g). In single pregnancies, every week of increased gestational age was associated with an increase in BMI of 0.21 (95% CI, 0.17-0.25) among boys and 0.20 (95% CI, 0.15-0.25) among girls at age 18 months and 0.21 (95% CI, 0.18-0.24) among boys and 0.21 (95% CI, 0.18-0.24) among girls at age 36 months. There was an interaction association between gestational age and IUGR among boys at age 36 months, with a decrease in the change associated with gestational age of 0.12 (95% CI, 0.05-0.19). Every week of increased gestational age in single pregnancies was associated with an increase in BMI z score of 0.14 (95% CI, 0.17-0.21) among boys and 0.17 (95% CI, 0.13-0.21) among girls at age 18 months and 0.19 (95% CI, 0.16-0.22) among boys and 0.17 (95% CI, 0.15-0.20) among girls at age 36 months. Among single pregnancies, IUGR was associated with a decrease in BMI among boys (0.59 [95% CI, 0.23-0.95]) and girls (0.75 [95% CI, 0.39-1.11]) and BMI z score among boys 0.85 [95% CI, 0.25-0.95)] and girls (0.67 [95% CI, 0.36-0.97] at age 18 months and BMI among boys (0.44 [95% CI, 0.17-0.18]) and girls (0.84 [95% CI, 0.55-1.12]) and BMI z score among boys (0.46 [95% CI, 0.21-0.71]) and girls (0.77 [95% CI, 0.53-1.01]) at age 36 months. In multiple pregnancies, IUGR was associated with a decrease in BMI z score at age 36 months among boys (0.26 [95% CI, 0.42-0.89]) and girls (0.29 [95% CI, 0.22-0.79]). In single pregnancies intraventricular hemorrhage (IVH) was associated with a decrease in BMI of 0.47 (95% CI, 0.21-0.73) among boys and 0.42 (95% CI, 0.13-0.71) among girls at age 18 months and 0.53 (95% CI, 0.32-0.74) among boys and 0.31 (95% CI, 0.07-0.54) among girls at age 36 months. IVH was associated with a decrease in BMI z score in single pregnancies of 0.63 (95% CI, 0.20-0.41) among boys and 0.35 (95% CI, 0.12-0.60) among girls at age 18 months and 0.53 (95% CI, 0.34-0.71) among boys and 0.30 (95% CI, 0.11-0.50) among girls at age 36 months. Similar associations were seen in multiple pregnancies.

CONCLUSIONS AND RELEVANCE

This study found that gestational age, the presence of IUGR and multiple pregnancy, and IVH complications were associated with infant BMI at ages 18 months and 36 months. These findings suggest that these complicating factors should be considered when setting growth targets and nutrition strategies for infants born extremely preterm.

In vitro fertilization with preimplantation genetic screening improves implantation and live birth in women age 40 through 43

PURPOSE

In Vitro Fertilization is an effective treatment for infertility; however, it has relatively low success in women of advanced maternal age (>37) who have a high risk of producing aneuploid embryos, resulting in implantation failure, a higher rate of miscarriage or birth of a child with chromosome abnormalities. The purpose of this study was to compare the implantation, miscarriage and live birth rates with and without preimplantation genetic screening (PGS) of embryos from patients aged 40 through 43 years.

METHODS

This is a retrospective cohort study, comparing embryos screened for ploidy using trophectoderm biopsy and array comparative genomic hybridization to embryos that were not screened. We compared pregnancy outcomes for traditional fresh IVF cycles with day 5 embryo transfers, Frozen Embryo Transfer (FET) cycles without PGS and PGS-FET (FET of only euploid embryos) cycles of patients with maternal ages ranging from 40 to 43 years, undergoing oocyte retrievals during the period between 1/1/2011 and 12/31/2012.

RESULTS

The implantation rate of euploid embryos transferred in FET cycles (50.9%) was significantly greater than for unscreened embryos transferred in either fresh (23.8%) or FET (25.4%) cycles. The incidence of live birth per transferred embryo for PGS-FET (45.5%) was significantly greater than for No PGS fresh (15.8%) or No PGS FET (19.0 %) cycles. The incidences of live birth per implanted sac for PGS FET cycles (89.3%), No PGS fresh cycles (66.7%) and No PGS FET cycles (75.0%) were not significantly different.

CONCLUSIONS

The present data provides evidence of the benefits of PGS with regard to improved implantation and live birth rate per embryo transferred.

The cumulative probability of liveborn multiples after in vitro fertilization: a cohort study of more than 10,000 women

OBJECTIVE

To estimate the cumulative probability of liveborn multiples after IVF to improve patient counseling regarding this significant morbidity.

DESIGN

Retrospective cohort study.

SETTING

Large academic-affiliated infertility practice.

PATIENT(S)

A total of 10,169 women were followed from their first fresh, nondonor IVF cycle through up to six fresh and frozen IVF cycles from 2000-2010.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Delivery of a liveborn infant(s).

RESULT(S)

After three IVF cycles the cumulative live birth rate (CLBR) was 53.2%. The singleton, twin, and triplet CLBRs were 38.0%, 14.5%, and 0.7%. After six IVF cycles the CLBR was 73.8%, with 52.8%, 19.8%, 1.3% for singletons, twins, and triplets. Of the 5,433 live births, 71.4% were singletons, 27.1% were twins, and 1.5% were triplets. Women more than 39 years had the lowest incidence of liveborn multiples with CLBRs of 5.2% after three cycles and 9.5% after six cycles. The twin CLBR doubled from cycles 1 through 3 with the rate of increase slowing from cycles 3 through 6. Although very low in absolute terms, the triplet CLBR also doubled from cycles 1 through 3 and doubled again from cycles 3 through 6. Of the 1,970 pregnancies that began as multifetal on ultrasound, 77.4% resulted in liveborn multiples.

CONCLUSION(S)

Providers should be aware of the cumulative probability of liveborn multiples to effectively counsel patients on this important issue. With nearly three-quarters of all women having live birth after up to six IVF cycles, it is encouraging to report a low incidence of liveborn multiples.

Constant multiple birth rates in the Czech Republic and the Slovak Republic until recently, 1972–1995

Using vital statistics, yearly changes in the twinning and triplet rates by zygosity were investigated in the Czech Republic and the Slovak Republic during the period 1972–1995. Monozygotic (MZ) twinning rates in both countries had remained nearly constant (about 3 per 1000 total births) during that period. With a few exceptions, the dizygotic (DZ) twinning rates remained constant from 1972 to 1994, and increased in 1995 for both countries. MZ twinning rates for both countries were the lowest in Europe. As for triplet rates, overall rates increased significantly year by year in the Czech Republic, but not in the Slovak Republic. The triplet rate was significantly higher in 1995 than in the period 1972–1982 for both countries. The MZ triplet rate remained constant during that period in the Czech Republic. The trizygotic (TZ) triplet rates increased 3-fold for the Czech Republic and 4-fold for the Slovak Republic in 1972–1976 and 1992–1995. In the later period, the TZ rate was 1.5-fold higher in the Czech Republic than in the Slovak Republic. The quadruplet rate increased 2.3-fold from 2.9 per million births in 1982–1986 to 6.7 in 1992–1995 in the Czech Republic. The corresponding values were 2.7, 2.20 and 5.9-fold in the Slovak Republic. Both the Czech and the Slovak Republics were not affected by fertility drugs and assisted reproductive techniques until recently.

Evaluation of possible criteria for elective single embryo transfer

Purpose

A major problem of assisted reproductive technology (ART) is multiple gestation, which impacts neonatal and perinatal medicine. The literature contains a number of reports that elective single embryo transfer (eSET) is effective for the control of multiple pregnancies; however, to date, uniform criteria have not been established.

Methods

Using logistic regression analysis based on the results of ART in our department from January 2005 to July 2006, our eSET criteria were established. We conducted a comparative study of the clinical pregnancy rate, multiple gestation rate, and delivery rate before and after eSET (before-eSET and after-eSET groups, respectively).

Results

As a result of the analysis, our eSET criteria included all three of the following: (A) patient age ≤37, (B) previous IVF/ICSI trials ≤5, and (C) acquisition of two or more good-quality embryos. Based on our criteria, the after-eSET group was not found to have a decrease in the pregnancy rate; however, the multiple gestation rate decreased as compared to the before-eSET group. In addition, as a result of various evaluations of the eSET group, interesting findings were revealed.

Conclusions

In the after-eSET group, our eSET criteria achieved a decrease in the multiple pregnancy rate without a decrease in the pregnancy rate.

Single embryo transfer in clinical practice

The high incidence of multiple pregnancies is the main reason for adverse treatment outcome in assisted reproduction. A good strategy to avoid multiple pregnancies is elective single embryo transfer and cryopreservation of spare embryos. Important factors in an elective single embryo transfer programme are good counselling of the patients and the selection of embryos with high implantation potential. In the infertility clinic at Helsinki University Central Hospital the elective single embryo transfer programme was started in 1997 and in 2000 the transfer policy turned to single embryo transfer as primary option. In 2003 60% of fresh transfers were elective single embryo transfers and 66% of frozen transfers were single embryo transfers. It has been shown that an elective single embryo transfer programme can be adopted in daily practice and that it decreases the multiple pregnancy rate, in our programme to around 7% with acceptable overall pregnancy and delivery rates. In Finland the increased use of single embryo transfer has reduced the proportion of multiple births. Finally, a good cryopreservation programme is essential to achieve a good cumulative delivery rate without multiple pregnancies.

Success of infertility treatments in Finland in the period 1992-2005

OBJECTIVES

The objective was to study the success rates of infertility treatments in the period 1992-2005 in public and private clinics.

STUDY DESIGN

Aggregate IVF statistics (1992-2005) and nationally representative cross-sectional survey (2002).

RESULTS

The success rates of infertility treatments remained stable, despite a substantial increase in single-embryo transfers. In 2005, the clinical pregnancy rate was 23/100 initiated cycles and a live birth rate of 17/100 cycles. The proportions of term singletons and singletons weighing at least 2500g improved over time and both rates were 14/100 in 2005. Pregnancy rates improved most among older women during the study period. The success rate in the private sector was significantly better than that in the public sector among women younger than 35 years.

CONCLUSION

The single-embryo policy has not decreased pregnancy and birth rates. The proportions of term singletons per initiated cycle and singletons weighing at least 2500g per initiated cycle have improved over time. The higher success rate in the private sector may be because of different clientele.

Cumulative live birth rates following IVF in 41- to 43-year-old women presenting with favourable ovarian reserve characteristics

For women aged 41-43 years old, success rates in IVF are generally poor. This study aimed to assess cumulative live birth rate related to treatment costs over a maximum of three IVF cycles in selected women who were considered to still have adequate ovarian reserve. Fifty-five patients (38% of the total cohort, n = 144) were excluded from IVF treatment based on low antral follicle count (<5 follicles) and/or elevated basal FSH (>15 IU/l). Of those admitted, 66 (74%) actually started and completed a total of 125 IVF/intracytoplasmic sperm injection cycles. Treatment resulted in 10 live births (8% per cycle). Kaplan-Meier survival analysis revealed a realistic cumulative live birth rate after three cycles of 17%. The direct medical costs per live birth were calculated to be approximately 44,000 euro. These results show that selection towards favourable ovarian reserve status in the female age group 41-43 years yielded disappointing results in terms of cumulative live birth rates after IVF. In view of the costs raised per live birth, improvement of selection parameters for treatment in this age group is warranted.

Guidelines for the number of embryos to transfer following in vitro fertilization

OBJECTIVE

To review the effect of the number of embryos transferred on the outcome of in vitro fertilization (IVF), to provide guidelines on the number of embryos to transfer in IVF-embryo transfer (ET) in order to optimize healthy live births and minimize multiple pregnancies.

OPTIONS

Rates of live birth, clinical pregnancy, and multiple pregnancy or birth by number of embryos transferred are compared.

OUTCOMES

Clinical pregnancy, multiple pregnancy, and live birth rates.

EVIDENCE

The Cochrane Library and MEDLINE were searched for English language articles from 1990 to April 2006. Search terms included embryo transfer (ET), assisted reproduction, in vitro fertilization (IVF), ntracytoplasmic sperm injection (ICSI), multiple pregnancy, and multiple gestation. Additional references were identified through hand searches of bibliographies of identified articles.

VALUES

Available evidence was reviewed by the Reproductive Endocrinology and Infertility Committee and the Maternal-Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada and the Board of the Canadian Fertility and Andrology Society, and was qualified using the Evaluation of Evidence Guidelines developed by the Canadian Task Force on the Periodic Health Exam.

BENEFITS, HARMS, AND COSTS

This guideline is intended to minimize the occurrence of multifetal gestation, particularly high-order multiples (HOM), while maintaining acceptable overall pregnancy and live birth rates following IVF-ET.

Birthweight of singletons after assisted reproduction is higher after single- than after double-embryo transfer

BACKGROUND

Single-embryo transfer (SET) has proven efficient in reducing multiple pregnancy rates after assisted reproduction technologies (ART). This study compares outcome of singletons after SET and double-embryo transfer (DET).

METHODS

We studied 404 SET and 431 DET patients, who delivered a singleton child of >500 g after fresh embryo transfer in a first, second or third cycle. Preterm birth and low birthweight incidences and gestational age and birthweight were compared between both groups. Adjustments were made for maternal age, parity, cycle rank number, treatment indication, ART method, embryo characteristics and sex of the child.

RESULTS

Singletons born after DET have a significantly lower birthweight than that after SET (3204.3 +/-617.5 g versus 3324.6+/-509.7 g , P<0.01). Also preterm birth (<37 weeks) [odds ratio (OR) 1.77, 95% confidence interval (CI) 1.06-2.94] and low birthweight (<2500 g) (OR 3.38, 95% CI 1.86-6.12) are significantly more common in DET singletons.

CONCLUSIONS

Singleton birth after SET is advantageous compared with DET. This sheds new light on the reasons why singleton births following ART do worse than spontaneously conceived singletons in IVF programs, where double- or multiple-embryo transfer is standard.

Influence of embryo quality and number of previous cycles on pregnancy and multiple pregnancy rates in women aged 35 to 37 years who received two or three embryos

Women aged 35-37 years undergoing IVF-ET with fresh embryos at a university infertility center were analyzed to evaluate factors useful in determining whether two or three embryos should be transferred in this age group. Embryo quality and number, but not number of previous failed cycles, were important in determining outcome, and all triplet pregnancies could have been avoided at our program in this age group by limiting the transfer to two good-quality embryos, without reducing pregnancy rates.

Impact of infertility characteristics and treatment modalities on singleton pregnancies after assisted reproduction

Obstetric and neonatal outcomes of assisted reproduction and control singletons were evaluated after taking into account treatment characteristics and infertility background. The elective single embryo transfer (eSET) group (n = 45) was compared with the compulsory single embryo transfer (cSET; n = 52), double embryo transfer (DET; n = 227) and control (n = 304) groups. Infertility-related prognostic factors for neonatal outcomes were also analysed. Data were collected with structured questionnaires at gestational week 20 and 8 weeks after delivery. Spontaneous onset of delivery was more typical of the eSET group than of cSET and DET groups (68.9 versus 52.0%, P = 0.02). Mean (+/-SD) gestation at birth (39.3 +/- 1.6 weeks) and mean birth weight (3,470 +/- 505 g) of eSET singletons were comparable with other assisted reproduction groups, but gestational duration was lower than in the eSET group than in the control group (39.9 +/- 1.4; P < 0.05). However, numbers of preterm births and low birth weight infants were similar between groups. History of induced abortion increased risk of preterm birth (OR 4.5 and 95% CI 1.2-17.1) in assisted reproduction singletons. A small though clinically unimportant difference in gestational age at birth and birth weight between assisted reproduction and control singletons was found regardless of the number of embryos transferred.

Effects of competition among fertility centers on pregnancy and high-order multiple gestation rates

OBJECTIVE

To measure the effect of competition among fertility centers on pregnancy and high-order multiple (HOM) gestation rates after IVF.

DESIGN

Retrospective cohort study.

SETTING

Four hundred eight fertility clinics registered with the Society for Assisted Reproductive Technology as providing IVF services in 2000. Competition was defined as number of clinics in a geographically defined area. Demand for services was based on the population of reproductive-aged women.

PATIENT(S)

Three hundred eighty-one fertility clinics reporting clinical outcomes.

INTERVENTION(S)

Pregnancy rates, HOM gestation rates, population of reproductive-aged women, and number of competing clinics were calculated for each clinic from Society for Assisted Reproductive Technology and census data.

MAIN OUTCOME MEASURE(S)

The clinic HOM gestation rate (percentage of pregnancies that were HOM) and age-adjusted pregnancy rate.

RESULT(S)

The number of clinics in an area of competition ranged from 1 to 22. The HOM gestation rate per clinic ranged from 0% to 50%. As demand increased, competition increased. As competition increased, the number of HOM pregnancies per clinic decreased. In areas of low competition (1 to 2 clinics) the clinic HOM gestation rate was 8.43%, in areas of intermediate competition (3-7 clinics) 8.39%, and in areas of high competition (8-22 clinics) 8.24%. In areas with intermediate demand, high levels of competition resulted in fewer HOM pregnancies than intermediate competition (relative risk 0.56, 95% confidence interval 0.36-0.89) or low levels of competition (RR 0.57, 95% confidence interval 0.35-0.94). Age-adjusted pregnancy rates did not differ by level of competition.

CONCLUSION(S)

According to these data, the risk of HOM gestation decreases with increasing competition among clinics; however, pregnancy rates are unaffected.

Single or multiple embryo transfer following in vitro fertilisation for improved neonatal outcome: A systematic review of the literature

BACKGROUND

The aim of the current review was to determine if single versus two or more embryos, or double versus three or more embryos, transferred to the woman of a subfertile couple at in vitro fertilisation (IVF) maximises the likelihood of pregnancy, while minimising the likelihood of multiple pregnancy and adverse sequelae.

METHODS

Studies were identified that reported maternal, infant and cost outcomes following embryo transfer at IVF.

RESULTS

Three randomised trials and 17 cohort studies were included. From two randomised trials, single embryo transfer was found to result in decreased incidence of clinical pregnancy, multiple pregnancy and low birthweight. In the cohort studies for single embryo transfer compared with transfer of two or more embryos the incidence of live birth and singleton pregnancies was unchanged, and the incidence of multiple pregnancies and low birthweight was reduced. For double embryo transfer compared with the transfer of three or more embryos, the incidence of clinical pregnancy, live birth, preterm birth and low birthweight babies was reduced.

CONCLUSIONS

Information on neonatal and maternal outcomes following transfer of different numbers of embryos is limited. Transfer of one embryo does not alter the likelihood of a singleton pregnancy or birth when compared to transfer of two or more embryos. Transfer of one or two embryos decreases the risk of a multiple pregnancy, preterm birth and low birthweight. Further large, well-designed randomised trials are required to provide maternal and neonatal outcomes of relevance to a couple undergoing IVF.

Use of outcomes-based data in reducing high-order multiple pregnancies: the role of age, diagnosis, and embryo score

OBJECTIVE

To identify high-risk categories for high-order multiple pregnancy (HMP) in in vitro fertilization (IVF), establish clinic-specific HMP risk data for counseling use, and verify their utility in reducing HMP.

DESIGN

Before and after intervention study.

SETTING

Two IVF programs using the same embryology laboratory and IVF protocols.

PATIENT(S)

All IVF patients undergoing fresh embryo transfers.

INTERVENTION(S)

Use of clinic-specific age, diagnosis, and embryo score (ES) risk data in assessing individual HMP risk during informed consent.

MAIN OUTCOME MEASURE(S)

HMP and pregnancy outcomes.

RESULT(S)

In determining clinic-specific high risk categories and developing outcomes-based HMP risk data for counseling, the good outcome rate (GR) was defined as the percentage of singleton or twin deliveries per cycle and the bad outcome rate included no pregnancy or nondelivered pregnancies (miscarriages, multifetal reduction) and HMP per cycle. During 1995 to 1999, age <35 years, calculated morphologic ES, and donor egg (DE) cycles were factors shown by logistic regression to statistically significantly affect the GR. The optimal GRs for DE <35 and >or=35 years (donor age), and non-DE cycles <35 years were achieved with two (57.7%), three (43.2%), and three (43.2%) embryos transferred, respectively. A DE <35 years with >or=3 embryos transferred had the highest risk for HMP. The GR correlated (0.91) with the ES according to the formula: GR = 3.3 + 2.0 ES, when ES range was between 4 and 26. Clinic-specific risks for HMP based on age, diagnosis, and ES were developed and considered while counseling for ET during 2004. The clinic-specific HMP risk data made for a reduction in the HMP rate of 90.9% for DE-IVF (11.8% to 1%) and 53.8% for all IVF (9.1% to 4.2%), without decreases in clinical pregnancy or delivery rates. Physicians showing the greatest decline (64%) in HMP had no reduction in pregnancy or delivery rates.

CONCLUSION(S)

The use of clinic-specific HMP risk data in counseling based on age, diagnosis, and ES provided a 53% to 64% reduction in HMP without affecting rates of pregnancy or delivery. The clinic-specific ES system correlated closely with good outcomes. A standardized ES system may provide useful information for counseling during ET informed consent.

Case series of a single centre's treatment of ovulatory infertility with clomiphene citrate and intrauterine insemination in 2002

The present paper reports a single department's retrospective case series of all clomiphene citrate (CC) combined with intrauterine insemination (IUI) treatment cycles for ovulatory infertility performed during 2002. Thirty-eight couples with unexplained, endometriosis, male or unilateral tubal factor infertility had undergone 71 cycles of CC and IUI. The clinical and ongoing cycle pregnancy rates were 20 and 17%, respectively. Seven percent of the clinical pregnancies were multiple pregnancies, with all multiple pregnancies being twin gestations. The current use of CC and IUI is an effective early treatment option in couples with ovulatory infertility presenting to our department.

Selected single blastocyst transfers maintained pregnancy outcome and eliminated multiple pregnancies

Background:  Transfer of more than one embryo following in vitro fertilization/intracytoplasmic sperm injection cycles have increased pregnancy rate at the cost of increasing the incidence of triplets and twins. It has been proposed that prolonged culture to the blastocyst stage would automatically result in the selection of good quality embryos for transfer and minimize the incidence of triplets and twins. Methods and Results:  The objectives of the present retrospective analysis were to examine the pregnancy outcome, multiple pregnancy and related data following: (i) single blastocyst transfer (BT) and double BT; (ii) single BT in patients belonging to different age groups; and (iii) good, fair or poor quality of BT. A total of 260 BT were carried out between August 1998 and July 2002 and they are included in the current study. Sixty of the 260 BT patients received a single BT, and 41 of them received selected single good quality BT (SSBT). The implantation rate has no significant difference between following single BT (53.3%) and double BT (42.8%). No multiple pregnancy occurred following single BT, while significantly higher (P < 0.05) multiple pregnancy rate was observed following a double BT (45.8%). The clinical pregnancy and implantation rates following a single BT were similar (P > 0.05) in patients belonging to <30 years (62.5%), 30-34 years (57.9%) and 35-39 years old (35.8%). Conclusion:  Selected single good quality BT maintained pregnancy and avoided multiple pregnancies. It is recommended for patients with a risk for high-order multiple pregnancy. (Reprod Med Biol 2004; 3: 13-18).

Cause and risk of stillbirth in twin pregnancies: a retrospective audit

BACKGROUND

The epidemiology of twin pregnancies complicated by stillbirth of one or both fetuses is a scarcely examined area. The risk of perinatal death in twin pregnancies is increased 2-5 times compared to singletons, and the identification of preventable risk factors becomes increasingly important as the number of multiple pregnancies is rising. We report the causes of death in twin pregnancies and their respective risk factors.

METHODS

Twin pregnancies (n = 54) complicated by antepartum or intrapartum stillbirth of one or both twins (n = 68) and twin pregnancies with normal outcome (n = 103) in the counties of Oslo and Akershus, Norway, from 1986 to 1995 were included. The cases were classified and compared to the controls in multiple logistic regression analyses with regard to risk factors.

RESULTS

The risk of stillbirth increased with monochorionicity, non-Western origin and assisted reproduction techniques (ART). The cases could be divided into eight different groups according to the primary diagnosis. The groups did not fit any of the existing cause-of-death classifications used on singleton stillbirths.

CONCLUSIONS

The identification of monochorionic gestation should be made early in pregnancy to designate the level of risk. Assisted reproduction techniques leading to a high incidence of twins should be avoided. Health care professionals in the immigrant population should address the detrimental effects of consanguinity on reproductive outcome. We emphasize the need of a new cause-of-death classification for twin stillbirths.

Ethical considerations in newer reproductive technologies

Ethics is an essential dimension of newer reproductive technologies. In this rapidly evolving field, there is a need for an ethical framework to guide both clinical practice and research. In this article, we provide such a framework that incorporates ethical principles, professional virtues, and the concept of the fetus as a patient. We then apply this framework to an important current clinical issue: the number of embryos to be transferred during in vitro fertilization; in addition to an emerging research issue: gene transfer research on in vitro embryos.

Pregnancy and birth after assisted reproduction

Pregnancy and birth after IVF has attracted much critical attention. Overall, pregnancy rates are about 30-40% with three transferred embryos. Abortion rates are high before 19 weeks of gestation, at 8% of established pregnancies, and ectopic pregnancies are regular occurrences. Pregnancy rates are highest (35%) in women aged 20-24 years, declining to 10% at and above age 40. The use of intracytoplasmic sperm injection (ICSI) and blastocyst transfer has transformed the establishment of pregnancies for couples with differing indications. High rates of implantation are achieved with blastocyst transfers, although many embryos die in vitro before this stage. Twins and triplets can result in up to 50% of pregnancies. Heterotopic pregnancies are rare. Abortion afflicts fetuses before 12 weeks (vanishing fetuses). Rates of spontaneous abortion can be as high as 50% with quadruplets and quintuplets, and may be even higher in cases of fetal aneuploidy. At birth, prematurity is high, especially with twins or higher multiple pregnancies. Fetal reduction is used to reduce multiple pregnancies for singletons. Ovarian hyperstimulation is a risk associated with multiple pregnancy.

Obstetric outcome and follow-up of children born after in vitro fertilization (IVF)

In vitro fertilization (IVF) is a well established and effective method for the treatment of infertility, but there is concern about the health of children born as a result of this procedure. The introduction of new technologies, such as intracytoplasmic sperm injection (ICSI), has increased concern that the offspring from such techniques may be at increased risk, particularly of malformations. Studies on obstetric and neonatal outcome and early infant development after IVF obtained from a Medline search were reviewed. Children born after IVF had a considerably higher risk of being born pre-term and with a lower birth weight than children conceived naturally. A high incidence of multiple births and maternal characteristics were the main factors responsible for the increase in adverse outcome. Novel strategies in assisted reproduction, including the development of single embryo transfer regimens and avoidance of multiple births, are required. There is also a need for further developmental follow-up of children born after assisted conception, especially those born after ICSI.

Trends in the incidence of births and multiple births and the factors that determine the probability of multiple birth after IVF treatment

BACKGROUND

We aimed to review trends in the probability of birth and multiple birth before and after the legal restriction limiting the maximum allowable number of embryos transferred, and to examine factors that determine the probability of multiple birth following IVF treatment.

METHODS

We analysed data relating to 7170 IVF and 530 intracytoplasmic sperm injection cycles reaching embryo transfer undertaken by 4417 women at a single tertiary referral assisted conception centre in the UK between 1984 and 1997. Probability of birth, and of proportion of multiple births among those who gave birth, was explored using logistic regression analysis.

RESULTS

Between 1984 and 1997 there was a significant increase in probability of birth but no change in the probability of multiple birth. The trend in probability of birth was almost wholly explained by the significant increase in number of embryos created per cycle. Pooling all the data, risk factors for increased chance of birth and multiple birth were: younger age (<35 years), diagnoses other than tubal infertility, fewer than three previous unsuccessful cycles, previous IVF live birth and a large number of embryos created. Given these factors, increasing the number of embryos transferred did not increase the chance of a birth, but did increase the chance of a multiple birth.

CONCLUSIONS

The probability of birth has increased and the probability of multiple birth has remained unchanged, despite legislation limiting the number of embryos transferred in the UK. Efforts should be made to reduce the incidence of multiple births by transferring fewer embryos, especially in the presence of good prognostic factors for birth.

A comparative study of twinning and triplet rates in 17 countries, 1972-1996

Secular changes in twinning and triplet rates were analyzed using vital statistics in Austria, the Czech Republic, the Slovak Republic, England and Wales, Germany, the Netherlands, Switzerland, Denmark, Finland, Norway, Sweden, Canada, Australia, Hong Kong, Israel, Japan, and Singapore during the period from 1972 to 1996. Among those 17 countries, the twinning and triplet rates in the Czech Republic and in the Slovak Republic remained constant from 1972 to 1994, whereas these rates increased significantly year by year in the other 15 countries during the examined period in each country. Twinning rates increased from 1.2-fold in Austria to 2-fold in Denmark from 1972 to 1996. As for triplets, the rate increased from 3-fold in Denmark to 9-fold in Norway during that period. With one exception, that being the Slovak Republic, the triplet rate was highest in the Scandinavian countries, followed by the other European and Asian countries. The rising twinning and triplet rates have been attributed to the higher proportion of mothers treated with ovulation-inducing hormones and partially attributed to IVF.

Predictors of success after embryo transfer: experience from a single provider

OBJECTIVE

Our goal was to examine the variables present at the time of embryo transfer and to determine their effects on the clinical pregnancy rate.

STUDY DESIGN

All fresh and frozen embryo transfers during a 3-year period in a university-based in vitro fertilization program were examined. Female age, previous in vitro fertilization attempt, diagnosis, embryo number and quality, transfer technique, and presence of a clinical pregnancy were recorded for each couple. Logistic regression analyses were performed both univariately and multivariately to determine the association between a clinical pregnancy and the independent variables.

RESULTS

All transfers during the study period were included in the analysis. The four primary diagnoses were pelvic or tubal disease, male factor infertility, unexplained infertility, and endometriosis. The 46 frozen embryo transfers had a clinical pregnancy rate similar to that among the 159 fresh embryo transfers and were therefore included in the analysis. One variable was found to significantly affect the outcome, the number of high-grade embryos placed. The presence of a previous failed embryo transfer tended to lower the success rate for future attempts; however, this result did not reach statistical significance. The catheter type and the transfer difficulty did not affect outcome.

CONCLUSION

The two most important variables for predicting a clinical pregnancy are a first-time transfer and the number of high-grade embryos placed. Neither the type of embryo transfer catheter used nor the diagnosis affected outcome. In this small sample difficult embryo transfers did not diminish the chance for a successful outcome.

A historical perspective of the clinical evolution of the assisted reproductive technologies

The practice of assisted reproduction technology today is the result of the dedicated patient care, observation, research, and experimentation undertaken by previous generations of physicians. The building blocks of progress have been assembled over past decades, by scientists whose primary objective has been to push forward the frontiers of knowledge, in order to offer more effective methods of infertility treatment. And fortunately that process continues today. Amongst the many scientific developments that have led to the modern practice in assisted reproductive technology, a small number stand out as having had a unique importance. This historical review redraws the path through which in vitro fertilization went from an experimental to an accepted infertility treatment.

Elective transfer of one embryo results in an acceptable pregnancy rate and eliminates the risk of multiple birth

To avoid multiple pregnancies without compromising pregnancy rates (PR) is a challenge in assisted reproduction. We have compared pregnancy results among 74 elective one-embryo transfers (group 2) and 94 transfers where only one embryo was available (group 1). All the fresh embryo cycles during 1997 in two clinics in Helsinki were analysed, and cumulative PR among these couples after frozen-thawed embryo transfers up to June 1998 were counted. In group 2, where at least two embryos were available for transfer, and only one was transferred on day 2 or 3, the PR per embryo transfer was 29.7%. In group 1, the PR per embryo transfer was 20.2%. In group 2, the cumulative PR after frozen-thawed embryo transfers was 47.3% per oocyte retrieval. Over the same time, 742 two-embryo transfers were carried out. The PR per embryo transfer was 29.4% in these subjects, but 23.9% of these pregnancies were twins. The implantation rates, as well as the PR, were highest when the embryos were at the four- to five-cell stage on day 2 (35.8 versus 9.7% compared with the two- to three-cell stage, P < 0.001) or at the six- to eight-cell stage on day 3 (45.5%). The PR per embryo transfer was higher when a grade 1 or 2 embryo was transferred compared with a grade three embryo (34. 0 and 26.7% versus 8.8% respectively, P < 0.05). In women 35 years or younger, the PR per elective one-embryo transfer was 32.8%. The corresponding figure in women older than 35 years was 18.8%. On the basis of these results, elective one-embryo transfer can be highly recommended, at least in subjects who are younger than 35 years of age, and who have grade one or grade two embryos available for transfer.

Probabilities for singleton and multiple pregnancies after in vitro fertilization

OBJECTIVE

To help physicians provide risk estimates for specific pregnancy outcomes.

DESIGN

Computation of exact binomial probabilities for singleton and multiple pregnancies as a function of two inputs: the number of embryos transferred and the implantation rate. Inputs were varied over the range of values reported in the literature.

MAIN OUTCOME MEASURE(S)

Probabilities for a singleton pregnancy (none), a multiple pregnancy (Pmult), and no pregnancy (Pnone) after one IVF cycle.

RESULT(S)

Given a 30% implantation rate and three embryos transferred, Pone=.44, Pmult=.22, and Pnone=.34. Although further increasing the number of embryos transferred increases the chance of pregnancy, it also raises the probability of a multiple pregnancy and lowers the chance of a singleton pregnancy. Although varying the implantation rate changes the specific probability estimates, the same trade-off persists.

CONCLUSION(S)

Those who consider an IVF "success" to be a singleton pregnancy should be attentive to the number of embryos transferred. Infertility therapy may be one area in medicine where more is not necessarily better.

Outcome comparison of in vitro fertilization treatment with highly purified subcutaneous follicle-stimulating hormone (Fertinex, a urofollitropin) versus intramuscular menotropins

OBJECTIVE

The aim of this study was to investigate various outcome measures of stimulation with highly purified subcutaneous follicle-stimulating hormone (Fertinex, a urofollitropin) compared with first- and second-generation urinary human menopausal gonadotropin standards (Pergonal, Metrodin).

STUDY DESIGN

Retrospective analysis was restricted to our most efficient in vitro fertilization age group (23-34 years). Data from Institute for Assisted Reproduction in vitro fertilization cycles 1 through 11 with Pergonal, Metrodin, or both were tabulated for hormonal values, oocyte quality, and embryo outcome as baseline data. Patients in cycles 12 through 13 were treated with Fertinex and Pergonal or Fertinex alone and then reviewed for the same parameters.

RESULTS

Two hundred thirty-eight in vitro fertilization records with embryo transfer were analyzed. Clinical pregnancy rates per embryo transfer in an optimal age group were similar despite use of first- through third-generation urinary gonadotropin preparations: Pergonal and Metrodin, 67%; Metrodin, 64%; Fertinex and Pergonal, 62%; and Fertinex, 54%. There were no discernible differences in hormonal response, oocyte recovery, or embryonic growth.

CONCLUSION

Administered subcutaneously, the third-generation urinary gonadotropin preparation Fertinex is effective in in vitro fertilization treatment in young women.