[Assisted reproductive techniques: key procedures and results in Germany and Europe]

The wide application of in vitro fertilization (IVF) since the 1980s years has revolutionized the treatment of infertility. Since then more than four million babies have been born following IVF. Diversification of the original IVF has led to many new techniques. Besides the basic procedures such as intrauterine insemination (IUI), IVF and intracytoplasmic sperm injection (ICSI), new techniques such as cryopreservation and genetic analysis have become an integral part of reproductive medicine. This moves patients into the focus of ART who are not "classic" infertility patients. Cryopreservation of unfertilized oocytes and ovarian tissue offers cancer patients the opportunity to preserve fertility. Genetic analysis on polar bodies or embryonic cells can help patients with genetic diseases or carriers of genetic disorders towards a healthy child.

Clinical effectiveness of elective single versus double embryo transfer: meta-analysis of individual patient data from randomised trials

OBJECTIVE

To compare the effectiveness of elective single embryo transfer versus double embryo transfer on the outcomes of live birth, multiple live birth, miscarriage, preterm birth, term singleton birth, and low birth weight after fresh embryo transfer, and on the outcomes of cumulative live birth and multiple live birth after fresh and frozen embryo transfers.

DESIGN

One stage meta-analysis of individual patient data.

DATA SOURCES

A systematic review of English and non-English articles from Medline, Embase, and the Cochrane Central Register of Controlled Trials (up to 2008). Additional studies were identified by contact with clinical experts and searches of bibliographies of all relevant primary articles. Search terms included embryo transfer, randomised controlled trial, controlled clinical trial, single embryo transfer, and double embryo transfer. Review methods Comparisons of the clinical effectiveness of cleavage stage (day 2 or 3) elective single versus double embryo transfer after fresh or frozen in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) treatments were included. Trials were included if the intervention differed only in terms of the intended number of embryos to be transferred. Trials that involved only blastocyst (day five) transfers were excluded.

RESULTS

Individual patient data were received for every patient recruited to all eight eligible trials (n=1367). A total of 683 and 684 women randomised to the single and double embryo transfer arms, respectively, were included in the analysis. Baseline characteristics in the two groups were comparable. The overall live birth rate in a fresh IVF cycle was lower after single (181/683, 27%) than double embryo transfer (285/683, 42%) (adjusted odds ratio 0.50, 95% confidence interval 0.39 to 0.63), as was the multiple birth rate (3/181 (2%) v 84/285 (29%)) (0.04, 0.01 to 0.12). An additional frozen single embryo transfer, however, resulted in a cumulative live birth rate not significantly lower than the rate after one fresh double embryo transfer (132/350 (38%) v 149/353 (42%) (0.85, 0.62 to 1.15), with a minimal cumulative risk of multiple birth (1/132 (1%) v 47/149 (32%)). The odds of a term singleton birth (that is, over 37 weeks) after elective single embryo transfer was almost five times higher than the odds after double embryo transfer (4.93, 2.98 to 8.18).

CONCLUSIONS

Elective single embryo transfer results in a higher chance of delivering a term singleton live birth compared with double embryo transfer. Although this strategy yields a lower pregnancy rate than a double embryo transfer in a fresh IVF cycle, this difference is almost completely overcome by an additional frozen single embryo transfer cycle. The multiple pregnancy rate after elective single embryo transfer is comparable with that observed in spontaneous pregnancies.

The effect on human sex ratio at birth by assisted reproductive technology (ART) procedures--an assessment of babies born following single embryo transfers, Australia and New Zealand, 2002-2006

OBJECTIVE

To assess the effect on the human sex ratio at birth by assisted reproductive technology (ART) procedures.

DESIGN

Retrospective population-based study.

SETTING

Fertility clinics in Australia and New Zealand.

POPULATION

The study included 13,368 babies by 13,165 women who had a single embryo transfer (SET) between 2002 and 2006.

METHODS

Logistic regression was used to model the effect on the sex ratio at birth of ART characteristics [in vitro fertilisation (IVF) or intracytoplasmic sperm insemination (ICSI) SET, cleavage-stage or blastocyst SET, and fresh or thawed SET] and biological characteristics (woman's and partner's age and cause of infertility).

MAIN OUTCOME MEASURES

Proportion of male births.

RESULTS

The crude sex ratio at birth was 51.3%. Individual ART procedures had a significant effect on the sex ratio at birth. More males were born following IVF SET (53.0%) than ICSI SET (50.0%), and following blastocyst SET (54.1%) than cleavage-stage SET (49.9%). For a specific ART regimen, IVF blastocyst SET produced more males (56.1%) and ICSI cleavage-stage SET produced fewer males (48.7%).

CONCLUSIONS

The change in the sex ratio at birth of SET babies is associated with the ART regimen. The mechanism of these effects remains unclear. Fertility clinics and patients should be aware of the bias in the sex ratio at birth when using ART procedures.

Assisted reproductive technologies (ART) in Canada: 2007 results from the Canadian ART Register

OBJECTIVE

To present a report on assisted reproductive technologies (ART) cycles performed in 2007 in Canada and show trends in outcomes over time. This is the seventh annual report from the Canadian ART Register (CARTR).

DESIGN

Prospective cohort study.

SETTING

Twenty-six of 26 ART centers in Canada.

PATIENT(S)

Couples undergoing ART treatment in Canada during 2007.

INTERVENTION(S)

ART treatments, including in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and frozen embryo transfer (FET).

MAIN OUTCOME MEASURE(S)

Clinical pregnancy, live-birth, and multiple-birth rates.

RESULT(S)

A total of 13,482 ART cycles was reported to CARTR. In 8,972 IVF/ICSI cycles using the woman's own oocytes, per cycle started, the clinical pregnancy rate was 35.6% (41.0% per ET), and the live-birth rate was 28.6%; the multiple-birth rate per delivery was 30.2%, with a high-order multiple-birth rate of 1.1%. In 68% of cycles ICSI was performed. One or two embryos were transferred in 69% of cycles. In 404 IVF/ICSI cycles using donor oocytes, the clinical pregnancy rate was 44.6%, and the live-birth rate was 36.1%; the multiple-birth rate was 26.5%, with no triplet birth. In 3,224 FET cycles using the woman's own oocytes, the clinical pregnancy rate was 23.7%, and the live-birth rate was 17.8%; the multiple-birth rate was 24.1%, with a triplet birth rate of 0.2%. Birth outcomes were unknown for 2.0% of ongoing pregnancies.

CONCLUSION(S)

For 2007, CARTR achieved 100% voluntary participation from Canadian ART centers for the fifth consecutive year. Clinical pregnancy and live-birth rates continued to increase in 2007 compared with previous years, with a decrease in high-order multiple births.