Pregnancy: The influence of the number of embryos transferred in 1060 in-vitro fertilization pregnancies on miscarriage rates and pregnancy outcome

To assess the incidence of miscarriage, multiple pregnancy andoutcome of pregnancy in relation to the number of embryos transferredduring in-vitro fertilization (IVF), an analysis was performedof 1060 pregnancies conceived in a tertiary-referral IVF clinic.There was no difference in the miscarriage rate after transferof one or two embryos (37.7% and 34.6%), or after three or fourembryos (22.5% and 25.2%). The miscarriage rate was, however,higher when one or two embryos were transferred compared withthree (P < 0.01) or four embryos (P < 0.02). Of the 724ongoing pregnancies, 524 (72.3%) were singleton, 164 (22.7%)twin, 33 (4.6%) triplet and three (0.4%) quadruplet. The mean(±SD) ages of women with singleton, twin, triplet andquadruplet pregnancies were 32.5 (±3.8), 32.0 (±3.5),29.76 (±4.3) and 29.67 (±2.5) years respectively.The mean age of women with singleton and twin pregnancies wassimilar and both were greater than that of triplet pregnancies(P < 0.007). The overall perinatal mortality rate (PNMR)was 39.7/1000. The PNMR for singletons was 17.2/1000, for twins80.0/1000 and for triplets 30.6/1000. All of the babies fromthe three quadruplet pregnancies survived. There were more babieslost in the twin pregnancies than any other group, althoughthis only reached significance for singletons versus twins (P< 0.00005). We conclude that the incidence of miscarriageis increased in women in whom one or two embryos are transferred.Multiple pregnancies are more likely to occur in younger womenand are associated with a significantly higher rate of perinatalmortality.     

Fertilization and early embryology: The applicability of the cumulative embryo score system for embryo selection and quality control in an in-vitro fertilization/embryo transfer programme

The cumulative embryo score system involves three aspects ofrelevance in pregnancy achievement during in-vitro fertilization(IVF) and embryo transfer: cleavage rates, morphological qualitiesand the number of embryos transferred. The scores of 602 IVF/embryotransfer trials were calculated and analysed to determine thesystem's relationship to pregnancy rate, pregnancy outcome andthe incidence of twin and triplet pregnancies. The system wasalso applied to cycles where endotoxins were either presentin or absent from culture medium, in order to evaluate its validityin quality control analyses. Pregnancy rates were found to increasefrom 4%, with scores between 1 and 10, to 35% in the 41–50group. The score of 20 was the criterion for separating patientsinto poor and good pregnancy prognosis groups (P = 0.00001).Biochemical abortions occurred more frequently with scores <20(P = 0.00978), but a similar relationship was not found in clinicalabortion rates (P = 0.62206). Birth rates below and above ascore of 20 (2.8 and 19.2%, respectively) differed significantly(P = 0.0005). The scores of twins overlapped extensively withthose of singleton births, but those of all triplets were >40. The system did not reflect a correlation between embryoquality and the presence of endotoxins in culture medium.     

Impact of patients' choice for single embryo transfer of a top quality embryo versus double embryo transfer in the first IVF/ICSI cycle

BACKGROUND: The aim of this study was to evaluate the impact of transferring a single top quality embryo in the first IVF/ICSI cycle of patients <38 years old who chose to have one or two embryos transferred. METHODS: A total of 262 patients participated in the study, and 243 transfers were performed: 156 (64%) patients chose the transfer of a single top quality embryo, if available, and two non-top quality embryos if not available; 87 (36%) patients chose to have a double embryo transfer regardless of embryo quality. RESULTS: In the first group an ongoing pregnancy rate of 40% (63/156) with a twin pregnancy rate of 2% (1/63) was achieved. In the second group the ongoing pregnancy rate was 44% (38/87) with 26% (10/38) twin pregnancies. In the patient group with only one embryo transferred, irrespective of the patient's choice, the ongoing pregnancy rate was 43% (54/127) with no twin pregnancies. For the study population as a whole, the ongoing pregnancy rate was 42% (101/243) with 11% (11/101) twins. CONCLUSION: We conclude that the introduction of single embryo transfer in the first IVF/ICSI cycle is highly acceptable in women <38 years old.     

The cumulative embryo score: a predictive embryo scoring technique to select the optimal number of embryos to transfer in an in-vitro fertilization and embryo transfer programme.

In order to achieve a clinical pregnancy rate higher than that achieved following initial adoption of in-vitro fertilization embryo transfers, more than one embryo is transferred. This has led to a substantial increase in unwanted multiple pregnancy rates with IVF as compared with natural conception. What is therefore required is a simple, clinically useful embryo scoring system, to reflect embryo developmental potential, which will enable the selection of the optimal number of embryos to transfer in order to achieve the maximum pregnancy rate with a low incidence of high order multiple pregnancies. We believe that the Cumulative Embryo Score (CES) achieves these aims. On the day of embryo transfer the grade of each embryo transferred was multiplied by the number of blastomeres to produce a score for each embryo, and summation of the scores obtained for all the embryos transferred gave the CES. The grouped pregnancy rates obtained rose as the CES increased to maximum of 42. A continued increase in the CES above 42 did not result in any further rise in the pregnancy rate. However, an analysis of all our IVF pregnancies showed that the multiple pregnancy rate continued to rise above a CES of 42. By restricting the CES per embryo transfer to 42, 78% of triplet pregnancies and 100% of the quadruplet IVF pregnancies could have been predicted and potentially avoided.     

One year's experience with elective transfer of two good quality embryos in the human in-vitro fertilization and intracytoplasmic sperm injection programmes

High incidences of multiple pregnancies, after transferringa maximum of three embryos, were observed after in-vitro fertilization(IVF) treatment. In a randomized study, it was demonstratedthat, after taking into account embryo quality and other positivelyinterfering parameters, an elective transfer of two good qualityembryos does not significantly influence the pregnancy rate.The intracytoplasmic sperm injection (ICSI) technique was successfullydeveloped in the meantime and high incidences of multiple pregnancieswere also obtained after ICSI. The question arose whether afterICSI there was also room for elective double embryo transferin a well-defined patient group. This report covers 1 year of IVF and ICSI treatment and theresults are presented in relation to the number of embryos transferred.The embryo development is similar for zygotes obtained afterIVF and ICSI; for both techniques 63% of the zygotes developto type A-B embryos and 13% to type C embryos. There is alsono difference in the pregnancy rate after ICSI or IVF. Globally,after IVF, 307 out of the 766 double and triple transfers (40.1%)and 317 out of 774 double and triple transfers (40.9%) afterICSI resulted in a positive HCG. After IVF, 73.9% (227) andafter ICSI 76.3% (242) of the pregnancies were evolutive. Neitherwas there any difference between the two techniques as regardsthe implantation rate per transferred embryo. After IVF, 22.8%of the transferred embryos implanted compared with 21.8% afterICSI. When the elective double embryo transfers were compared,no difference was found between IVF and ICSI. After IVF, 102of the 211 elective double transfers (48.1%) resulted in a pregnancyversus 93 out of 225 (41.3%) after ICSI [not significant (NS)].A high implantation rate per transferred embryo (IVF: 33.2%;ICSI: 26.9%, NS) was obtained in this elective double transfercategory, as was also reported in the randomized study. Thesedata confirm the results obtained in our randomized study andthe effectiveness of the elective double embryo transfer forIVF as well as for ICSI.     

The optimal number of embryos to be transferred in shared oocyte donation: walking the thin line between low pregnancy rates and multiple pregnancies

There has been growing concern about the number of multiple gestations resulting from assisted reproductive technologies. For in-vitro fertilization (IVF), there are guidelines concerning the number of embryos to be transferred. In oocyte donation, however, there is a paucity of studies addressing this issue and common practice is extrapolated from standard IVF procedures. This may not be correct since endometrial receptivity has been shown to be altered in oocyte donation. Thus the purpose of this study was to assess the optimal number of embryos to be transferred in oocyte donation. The study population included 254 patients with ovarian failure who underwent a total of 601 embryo transfers in a single shared oocyte donation programme. Pregnancy rates (PRs), multiple pregnancies, triplet pregnancy rates, and implantation rates were evaluated according to the number of embryos transferred. A significant linear increase in PRs was noted with the increasing number of embryos transferred up to five (11.1% for one embryo, 36.7% for five embryos). Multiple pregnancies increased significantly from 15.8% for two embryos transferred, to 44.4% for five embryos. The rate of triplet pregnancies also increased from 2.7% for three embryos transferred, to 8.3% for five embryos. Optimization of the number of embryos to be transferred is discussed.      

Assisted reproductive technology in Europe, 2004: results generated from European registers by ESHRE

BACKGROUND: European results of assisted reproductive techniques from treatmentsinitiated during 2004 are presented in this eighth report. METHODS: Data were mainly collected from existing national registers.From 29 countries, 785 clinics reported 367 066 treatment cyclesincluding: IVF (114 672), ICSI (167 192), frozen embryo replacement(FER, 71 997), egg donation (ED, 10 334), preimplantation geneticdiagnosis/screening (PGD/PGS, 2701) and in vitro maturation(IVM, 170). Overall, this represents only a marginal increasesince 2003, due to a huge reduction in treatments in Germany.European data on intrauterine insemination using husband/partner’ssemen (IUI-H) and donor semen (IUI-D) were reported from 20countries. A total of 115 980 cycles (IUI-H, 98 388; IUI-D,17 592) were included. RESULTS: In 14 countries where all clinics reported to the IVF register,a total of 248 937 ART cycles were performed in a populationof 261.6 million, corresponding to 1095 cycles per million inhabitants.For IVF, the clinical pregnancy rates per aspiration and pertransfer were 26.6% and 30.1%, respectively. For ICSI, the correspondingrates were 27.1% and 29.8%. After IUI-H, the clinical pregnancyrate was 12.6% in women below 40. After IVF and ICSI, the distributionof transfer of 1, 2, 3 and 4 or more embryos was 19.2%, 55.3%,22.1% and 3.3%, respectively. Compared with 2003, fewer embryoswere transferred, but huge differences still existed betweencountries. The distribution of singleton, twin and triplet deliveriesafter IVF and ICSI combined was 77.2%, 21.7% and 1.0%, respectively.This gives a total multiple delivery rate of 22.7% comparedwith 23.1% in 2003 and 24.5% in 2002. After IUI-H in women below40 years of age, 11.9% were twin and 1.3% triplet gestations. CONCLUSIONS: Compared with earlier years, the reported number of ART cyclesin Europe increased and the pregnancy rates increased marginally,even though fewer embryos were transferred and the multipledelivery rates were reduced.     

The couple's decision-making in IVF: one or two embryos at transfer?

BACKGROUND: The aim of this study was to evaluate the decision-making process and factors that contribute to the decision of IVF participants to choose one or two embryos at transfer. METHODS: Two hundred and seventy-four IVF patients equally distributed in males and females were personally interviewed using a semi-structured questionnaire which included 82 items. RESULTS: In the whole study population, previous childbirth [odds ratio (OR) 2.1; 95% confidence interval (CI) 1.9-3.6], and spare embryos to freeze (OR 23.6; 95% CI 11.2-54.5) emerged as the most important variables in patients who had one embryo transferred, while previous IVF treatments (OR 0.3; 95% CI 0.1-0.6) and the assumed increased pregnancy chance (OR 0.1; 95% CI 0.05-0.3) were the most important decision-making factors among those who had two embryos. The women were more satisfied with the information (83 versus 71%; P = 0.02), and more aware of the risks with twin pregnancies (77 versus 66%; P = 0.03) than the males. The women were also more concerned about their age. Knowledge about risks of multiple pregnancies was higher in females (77%) than in males (66%, P = 0.03). CONCLUSION: The results of this study indicate that despite good information about the risks for complications with multiple pregnancies, many patients wish to have two embryos transferred. Spare embryos to freeze, improvement of pregnancy rate in single embryo transfer and young age of the woman are predictive of choosing single embryo transfer. However, the final decision must always be made in agreement with the physician.     

Assisted reproductive technology in Europe, 2002. Results generated from European registers by ESHRE

European results of assisted reproductive techniques (ART) from treatments initiated during 2002 are presented in this sixth report. Data was mainly collected from already existing national registers. From 25 countries, 631 clinics reported 324,238 treatment cycles with: IVF 122,634, ICSI 135,048, frozen embryo replacement (FER) 57 162, egg donation (ED) 7677, preimplantation genetic diagnosis/screening (PGD/PGS) 1563 and in vitro maturation (IVM) 154. Overall this represents a 12% increase since year 2001. For the second time, results on European data on intrauterine inseminations were reported from 17 countries. A total of 93,284 cycles [IUI-husband/partner (H), 78 505 and IUI-donor (D), 14,779] were included. In 13 countries where all clinics reported to the register, a total of 177,429 cycles were performed in a population of 193.7 million, corresponding to 916 cycles per million inhabitants. For IVF the clinical pregnancy rate per aspiration and per transfer was 26.0 and 29.5%, respectively. For ICSI the corresponding rates were 27.2 and 29.4%. These figures are marginally better than in 2001. After IUI-H the clinical pregnancy rate was 11.6% in women below 40 and 7.8% in women>or=40 years of age. After IVF and ICSI the distribution of transfer of 1, 2, 3 and 4 or more embryos was 13.7, 54.8, 26.9 and 4.7%, respectively. Compared with year 2001, less embryos were transferred, but huge differences existed between countries. The distribution of singleton, twin and triplet deliveries for IVF and ICSI combined was 75.5, 23.2 and 1.3%, respectively. This gives a total multiple delivery rate of 24.5%, compared with 25.5% in year 2001. The range of triplet deliveries after IVF and ICSI varied from 0.0 to 5.2% between countries. After IUI-H in women below 40 years of age, 10.2% were twin and 1.3% triplet gestations.     

One versus two embryo transfer after IVF and ICSI: a randomized study

BACKGROUND: The main reason for adverse treatment outcome in assisted reproduction is the high rate of multiple pregnancies. The only strategy to avoid dizygotic twins is to transfer one embryo at a time. METHODS: A total of 144 women, who had had at least four good quality embryos available after IVF/intracytoplasmic sperm injection (ICSI) and who had no more than one previous failed treatment cycle, were randomized to have either one or two embryos transferred. The treatment outcomes including those after frozen embryo transfer were compared between these groups. RESULTS: The clinical pregnancy rate per transfer was 32.4% in the one embryo transfer group and 47.1% in the two embryo transfer group, the difference being not significant. Eleven twin deliveries (n = 39) occurred in the two embryo transfer group and there was one pair of monozygotic twins in the one embryo transfer group. The cumulative pregnancy rate per patient after transfer of fresh and frozen embryos was 47.3% in the one embryo transfer group and 58.6% in the two embryo transfer group. CONCLUSIONS: Our results indicate that among women who have good quality embryos in their first IVF/ICSI, good treatment results can be achieved. They support the idea of changing embryo transfer policy towards one embryo transfer without any remarkable decrease in the success rate, while dizygotic twins can be avoided.     

Cost-effectiveness analysis of in-vitro fertilization: estimated costs per successful pregnancy after transfer of one or two embryos

Standard protocols for in-vitro fertilization (IVF) include transfer of two or three embryos. Not surprisingly, the rate of twin pregnancy after IVF is high (about 24% of all pregnancies). Routine transfer of one, rather than two, embryos would be expected to result in a much lower rate of twin pregnancies at the cost of a lower take-home baby rate. The aim of this study was to compare hypothetical costs to society incurred by pregnancies achieved with IVF protocols based on the transfer of one or two embryos. We compared actual (for two-embryo transfers) and hypothetical (for one-embryo transfers) take-home baby rates; risks of twin pregnancies; and costs of sick leave and hospitalization during pregnancy, deliveries, neonatal intensive care, and handicap care after transfer of one or two embryos. The study showed that even when more treatments might be needed to achieve similar baby take-home rates after transfer of one compared with two embryos, the lower twin pregnancy rate of the former approach caused it to be more cost-efficient than the latter. In conclusion, IVF costs are the sum of fertilization treatment costs and the costs for health care of the pregnant women and their offspring. Considering the association of the latter costs with numbers of embryos transferred, studies of one- embryo transfer protocols are urgently needed.      

Assisted reproductive technology in Europe, 2003. Results generated from European registers by ESHRE

BACKGROUND: European results of assisted reproductive techniques (ARTs) from treatments initiated during 2003 are presented in this seventh report. METHODS: Data were mainly collected from already existing national registers. From 28 countries, 725 clinics reported 365 103 treatment cycles with: IVF 132 932, ICSI 162 149, frozen embryo replacement (FER) 60 412, oocyte donation (OD) 7548, PGD/PGS 1956 and IVM 109. Overall, this represents a 13% increase since 2002. For the third time, results on European data on intrauterine inseminations (IUIs) were reported from 19 countries. A total of 99 577 cycles (IUI-H, 82 834; IUI-D, 16 743) were included. RESULTS: In those 15 countries where all clinics reported to the register, a total of 284 765 cycles were performed in a population of 278.7 million, corresponding to 1022 cycles per million inhabitants. For IVF, the clinical pregnancy rates per aspiration and per transfer were 26.1 and 29.6%, respectively. For ICSI, the corresponding rates were 26.5 and 28.7%. After IUI-H, the clinical pregnancy rate was 12.2% in women below 40 years and 8.8% in women > or =40 years. After IVF and ICSI, the distribution of transfer of one, two, three and four or more embryos was 15.7, 55.9, 24.9 and 3.5%, respectively. Compared to the year 2002, fewer embryos were transferred, but huge differences still exist between countries. The distribution of singleton, twin and triplet deliveries for IVF and ICSI combined was 76.7, 22.0 and 1.1%, respectively. This gives a total multiple delivery rate of 23.1% compared with 24.5% in 2002. The range of triplet deliveries after IVF and ICSI varied from 0.0 to 4.4% between countries. After IUI-H in women below 40 years of age, 11.4% were twin and 2.2% triplet gestations.     

Elective single embryo transfer: the value of cryopreservation

In-vitro fertilization is associated with a high rate of multiple pregnancies, a consequence of the number of embryos transferred. There is a challenge in avoiding even twin pregnancies in assisted reproduction, and this can be accomplished with elective single embryo transfer and a good cryopreservation programme. In our follow-up study, we analysed all our elective single embryo transfers during 1998-1999. In all these cycles at least one embryo was frozen. A total of 127 elective single embryo transfers were performed with a clinical pregnancy rate of 38.6%. The highest implantation rate was obtained with four-cell embryos with <10% fragmentation (39.8%). Thirty-four patients have delivered (26.8%), one of these being a monozygotic pregnancy. In total 129 frozen-thawed cycles have been achieved in 83 patients. One frozen-thawed embryo has been transferred in 46 cycles with a clinical pregnancy rate of 17.4%, and two embryos have been transferred in 83 cycles, with a clinical pregnancy rate of 37.3%. Up until now, 66 of 125 patients in our single embryo transfer programme have delivered or have on-going pregnancies, and 77 still have embryos frozen. The cumulative delivery rate per oocyte retrieval is 52.8% and the twin rate 7.6%. We conclude that elective single embryo transfer with a good cryopreservation programme results in very acceptable pregnancy rates with a low risk of twins. This is a cost-effective practice that substantially reduces all risks associated with multiple pregnancies and lowers the cost per delivery.     

The effects of co-culture with human fibroblasts on human embryo development in vitro and implantation

In a human in-vitro fertilization (IVF) programme, the effect of co- culture of embryos with human fibroblasts was evaluated with respect to pregnancy rate and embryo development. Patients were included in the study after giving informed written consent. The IVF treatments were randomly assigned by stratification of both age (<36 versus > or =36 years) and previous IVF attempts (yes versus no). After fertilization was established, the zygotes were transferred to a 4-well dish with or without fibroblasts and cultured for 2 days. On the third day after ovum pick-up (OPU), cell number and quality [5 (good) to 1 (poor)] of the embryos were scored and a maximum of three embryos was transferred. Supernumerary embryos of good quality were cryopreserved. The design of this study was a group sequential trial with the objective of detecting differences between pregnancy rates following IVF with conventional incubation or incubation in co-culture with fibroblasts. This design included one evaluation at half-way data collection. In the study, 148 patients had an OPU, of whom 77 were allocated to the co-culture group. There was no statistically significant difference in pregnancy rate, cell number and embryo quality between the two groups. The ongoing pregnancy rate per embryo transfer was 27% in co-culture and 30% in the conventional culture group. The implantation rates per transferred embryo were 17 and 18% respectively. Using a multivariate logistic regression model for the probability of ongoing pregnancies, the odds ratio of co-culture, adjusted for age and previous IVF attempts, was not statistically significant. In conclusion, co-culture with human fibroblasts does not contribute to an improvement of embryo quality nor to a higher pregnancy rate after IVF in an unselected group of patients.      

Assisted reproductive technology in Europe, 2001. Results generated from European registers by ESHRE

European results of assisted reproductive techniques from treatments initiated during 2001 are presented in this fifth report. Data were collected mainly from already existing national registers. From 23 countries, 579 clinics reported 289 690 cycles with: IVF 120 946, ICSI 114 378, frozen embryo transfer (FER) 47 195 and egg donation (ED) 7171. Overall this represents a 4% increase since the year 2000. For the first time, results on European data on intra-uterine inseminations (IUIs) were reported from 15 countries. A total of 67 124 cycles [IUI husband'sperm (IUI-H) 52 949 and IUI donor sperm (IUI-D) 14 185] were included. In 12 countries where all clinics reported to the register, a total of 108 910 cycles were performed in a population of 131.4 million, corresponding to 829 cycles per million inhabitants. For IVF, the clinical pregnancy rate per aspiration and per transfer was 25.1 and 29.0%, respectively. For ICSI, the corresponding rates were 26.2 and 28.3%. These figures are similar to the results from 2000. After IUI-H, the clinical pregnancy rate was 12.8% in women <40 and 9.7% in women > or =40 years of age. After IVF and ICSI, the distribution of transfer of one, two, three and > or =4 embryos was 12.0, 51.7, 30.8 and 5.5%, respectively. Compared with the year 2000, fewer embryos were transferred, but huge differences existed between countries. The distribution of singleton, twin and triplet deliveries for IVF and ICSI combined was 74.5, 24.0 and 1.5%, respectively. This gives a total multiple delivery rate of 25.5%, compared with 26.9% in the year 2000. The range of triplet deliveries after IVF and ICSI differed from 0.0 to 8.2% between countries. After IUI-H in women <40 years of age, 10.2% were twin and 1.1% were triplet gestations.     

Andrology: Successful treatment of severe male factor infertility in 100 consecutive cycles using intracytoplasmic sperm injection

In this report, we present the results of our first 100 consecutivecycles of intracytoplasmic sperm injection (ICSI). Overall,fertilization occurred in 98% of cycles and embryos were transferredin 94% (2.6 embryos per cycle). About 50% of patients had embryosfrozen. The overall fertilization rate was 71%, of which 4%were abnormally fertilized (three pronuclei). A total of 30clinical pregnancies were established (32% per transfer), resultingin 18 singleton, six twin and one triplet ongoing pregnancies.The implantation rate per embryo was 15%. There were no significantdifferences in the fertilization or pregnancy rates betweenpatients Who had only occasional motile spermatozoa in the ejaculate,semen that was too poor for routine in-vitro fertilization (IVF),or who had failed routine IVF and/or subzonal sperm injection(SUZI). A group of 18 patients were treated with both ICSI androutine IVF on their first cycle because of the high likelihoodof failed fertilization due to poor sperm morphology (<20%normal). In this group, ICSI oocytes had a fertilization rateof 76% compared to only 15% for the routine IVF (control) oocytes,and six patients conceived after transfer of ICSI embryos (33%),indicating that ICSI can be used successfully on 50% of theoocytes if fertilization failure is expected. Similarly, patientswho had failed to become pregnant with SUZI achieved excellentresults after ICSI. There were no significant differences betweenICSI and routine IVF in the proportions of grade 1, 2 or 3 embryoson day 3 post-oocyte recovery. In conclusion, we have achievedresults comparable to those reported from Belgium and we havefound that ICSI is universally applicable to all forms of severemale factor infertility. ICSI produces fertilization, pregnancyand freezing rates comparable to routine IVF with normozoospermicsamples and has none of the drawbacks of other assisted fertilizationtechniques.     

Birth characteristics and perinatal outcome of babies conceived from cryopreserved embryos

The objective of this retrospective study was to compare thebirth characteristics and perinatal mortality of babies conceivedfrom the use of cryopreserved embryos with those resulting fromin-vitro fertilization (IVF) and fresh embryo transfer. A totalof 232 consecutive births, one pregnancy termination and a totalof 283 babies in the cryopreserved group were studied. The IVFdata included 763 births, three terminations and 961 babies,based on a previous analysis. There was no difference in theincidence of twin (18 versus 19%) and triplet births (2 versus3%) in the cryopreserved and IVF groups respectively. The meangestational age and birthweight of singleton, twin and tripletbirths were not significantly different between the groups.No difference was found in the perinatal mortality rates. Theincidence of major congenital malformations in the cryopreservedgroup (1%) was significantly lower than that in the IVF group(3%, P < 0.05). It is concluded that the birth characteristicsof babies conceived from cryopreserved/thawed embryos are similarto those from fresh embryos. There are fewer congenital malformationsin the cryopreserved group.     

Prospective evaluation of simple morphological criteria for embryo selection in double embryo transfer cycles

Preventing the occurrence of high-rank multiple pregnancieswithout reducing the pregnancy rate remains a high priorityof in-vitro fertilization and embryo transfer programmes. Ourprevious study demonstrated that, if there is at least one embryowith a good morphological grade, then the transfer of two (adouble embryo transfer) instead of three embryos does not resultin a lower pregnancy rate, and that the influence of the numberof embryos transferred becomes significant only when poor-qualityembryos are transferred. This result allowed us to employ thesimple policy of systematically selecting double embryo transfercycles without affecting the pregnancy rate. Since January 1994,when patients <37 years of age had more than two embryosavailable for transfer, only two instead of three embryos weretransferred if at least one of the embryos demonstrated a goodmorphological grade. After a 1 year application of this policy,of the 147 cycles (group A) that fulfilled the above criteria,two embryos were transferred in 92 cycles, while three embryoswere transferred in the other 55 cycles. The results of thesecycles were compared to those of the control 144 cycles (groupB) in which three embryos were transferred, prior to the applicationof this policy. The on-going pregnancy rates and the incidenceof multiple and triplet pregnancies were 24% and 28%, 22% and23%, and 2% and 9% in groups A and B respectively. The rateswere not significantly different. In conclusion, although ourprospective trial demonstrated a tendency of decreasing pregnancyrate and an invariable incidence of multiple pregnancies, thevery low occurrence of triplets during this period indicatedthat this policy provided a practical compromise between achievinga high pregnancy rate and an acceptable incidence of tripletpregnancies.     

Obstetric outcome among women with unexplained infertility after IVF: a matched case-control study

BACKGROUND: Infertility itself and also assisted reproductive treatment increase the incidence of some obstetric complications. Women with unexplained infertility are reported to be at an increased risk of intrauterine growth restriction during pregnancy, but not for other perinatal complications. METHODS: A matched case-control study was performed on care during pregnancy and delivery, obstetric complications and infant perinatal outcomes of 107 women with unexplained infertility, with 118 clinical pregnancies after IVF or ICSI treatment. These resulted in 90 deliveries; of these, 69 were singleton, 20 twin and one triplet. Two control groups were chosen from the Finnish Medical Birth Register, one group for spontaneous pregnancies (including 445 women and 545 children), matched according to maternal age, parity, year of birth, mother's residence and number of children at birth, and the other group for all pregnancies after IVF, ICSI or frozen embryo transfer treatment (FET) during the study period (including 2377 women and 2853 children). RESULTS: Among singletons, no difference was found in the mean birthweight, and the incidence of low birthweight (<2500 g) was comparable with that of the control groups. No differences were found in gestational duration, major congenital malformations or perinatal mortality among the groups studied. Among singletons in the study group, there were more term breech presentations (10.1%) compared with both spontaneously conceiving women and all IVF women (P < 0.01). The rate of pregnancy-induced hypertension was significantly lower among singletons in the study group (P < 0.05) compared with other IVF singletons. The multiple pregnancy rate was 23.3% in the study group. The obstetric outcome of the IVF twins was similar to both control groups. CONCLUSIONS: The overall obstetric outcome among couples with unexplained infertility treated with IVF was good, with similar outcome compared with spontaneous pregnancies and IVF pregnancies generally.     

In unselected patients, elective single embryo transfer prevents all multiples, but results in significantly lower pregnancy rates compared with double embryo transfer: a randomized controlled trial

BACKGROUND: Elective single embryo transfer (eSET) in a selected group of patients (i.e. young patients with at least one good quality embryo) reduces the number of multiple pregnancies in an IVF programme. However, the reduced overall multiple pregnancy rate (PR) is still unacceptably high. Therefore, a randomized controlled trial (RCT) was conducted comparing eSET and double embryo transfer (DET) in an unselected group of patients (i.e. irrespective of the woman's age or embryo quality). METHODS: Consenting unselected patients were randomized between eSET (RCT-eSET) (n = 154) or DET (RCT-DET) (n = 154). Randomization was performed just prior to the first embryo transfer, provided that at least two 2PN zygotes were available. Non-participants received our standard transfer policy [SP-eSET in a selected group of patients (n = 100), otherwise SP-DET (n = 122)]. RESULTS: The ongoing PR after RCT-eSET was significantly lower as compared with RCT-DET (21.4 versus 40.3%) and the twin PR was reduced from 21.0% after RCT-DET to 0% after RCT-eSET. The ongoing PRs after SP-eSET and SP-DET did not differ significantly (33.0 versus 30.3%), with an overall twin PR of 12.9%. CONCLUSION: To avoid twin pregnancies resulting from an IVF treatment, eSET should be applied in all patients. The consequence would be a halving of the ongoing PR as compared with applying a DET policy in all patients. The transfer of one embryo in a selected group of good prognosis patients leads to a less drastic reduction in PR but maintains a twin PR of 12.9%.