Donor age is a major determinant of success of oocyte donation/recipient programme.

BACKGROUND: In recent years, particularly in developed countries, women have tended to delay childbirth until over 40 years of age. Our study aims to identify whether the donor's age or recipient's age influences the pregnancy and live birth rate following oocyte recipient cycles. METHODS: A population study included 3889 fresh oocyte recipient cycles. Pregnancy and live delivery rates were compared in recipient age groups (<35, 35-39, 40-44 and ≥45 years) and donor age groups (<30, 30-34, 35-39 and ≥40 years). RESULTS: The highest live birth rate was of cycles in donors aged 30-34 years (25.0%), it decreased (P< 0.05) to 24.1% in donors aged <30 years, 20.7% in donors aged 35-39 years and 11.5% in donors aged ≥40 years. The multivariate analysis showed no significant differences in the success by recipient's age. Compared with cycles in donors aged 30-34 years, cycles in donors aged 35-39 years had 14 and 18% less chance to achieve a pregnancy [adjusted rate ratio (ARR) 0.86, 95% confidence interval (CI) 0.75-0.98] and a live delivery (ARR 0.82, 95% CI 0.71-0.96), while cycles in donors aged 40 years or older had 42 and 54% less chance to achieve a pregnancy (ARR 0.58, 95% CI 0.41-0.84) and a live delivery (ARR 0.46, 95% CI 0.29-0.73). CONCLUSIONS: Older recipients with younger donors did not have a poorer pregnancy outcome compared with younger recipients with younger donors. Choosing a donor aged <35 years would increase the chance of pregnancy and live delivery for older recipients.

Transfers of fresh blastocysts and blastocysts cultured from thawed cleavage embryos are associated with fewer miscarriages.

The literature shows an inconsistent relationship between miscarriage and assisted reproduction treatment factors. This study assessed the association between miscarriage and transfer of fresh or thawed embryos at cleavage/blastocyst stages. A population study included 52,874 pregnancies following autologous cycles. The miscarriage rate was compared by groups of transferred embryos (fresh cleavage embryo, fresh blastocyst, thawed cleavage embryo, blastocyst from thawed cleavage embryo, thawed blastocyst), IVF/intracytoplasmic sperm injection procedures, number of embryos transferred and woman's demographics. The overall miscarriage rate was 18.7%. Women aged 35-39 years and ≥40 years had a 51% and 177% increased hazard of miscarriage, respectively, compared with women <35 years. Women with history of miscarriage had 1.22 times hazard of miscarriage compared with those without previous miscarriage. Singleton pregnancies following fresh double-embryo transfer had 1.43 times higher rate of miscarriage than fresh single-embryo transfer. Fresh blastocyst transfer was associated with 8% less hazard of miscarriage than fresh cleavage-embryo transfer. Compared with pregnancies following thawed cleavage-embryo transfers, thawed blastocyst transfers were at 14% higher hazard of miscarriage. This study suggests that a practice model that includes transferring blastocysts and freezing cleavage embryos in fresh cycles would result in better outcomes.

Transfer of a selected single blastocyst optimizes the chance of a healthy term baby: a retrospective population based study in Australia 2004-2007.

BACKGROUND: The practice of single embryo transfer (SET) is highly accepted by clinicians in Australia. This study investigates whether the SET of blastocysts results in optimal perinatal outcomes. METHODS: This retrospective population-based study included 34 035 single or double embryo transfer cycles in women who had their first fresh autologous treatment in Australia during 2004-2007. Pregnancy, live delivery and 'healthy baby' (live born term singleton of > or = 2500 g birthweight and survived for at least 28 days without a notified/reported congenital anomaly) rates per transfer cycle were compared in four groups: selective single embryo transfer (SSET), unselective single embryo transfer (USSET), selective double embryo transfer (SDET) and unselective double embryo transfer (USDET). Live delivery and 'healthy baby' rates per transfer following SSET were further compared by number of embryos available. The analysis was stratified by woman's age and stage of embryo development. RESULTS: The highest rates of live delivery and 'healthy baby' per transfer cycle (46.2 and 38.0%) were achieved with transfer of a single blastocyst in women aged younger than 35 years. In women aged younger than 40 years, SSET had a significantly higher rate of 'healthy baby' per transfer cycle than did SDET regardless of stage of embryo development. In woman aged younger than 35 years who had SSET, there was no significant difference in live delivery and 'healthy baby' rates per transfer cycle whether two, three, four or five embryos were available. For all of these women, SSET of a cleavage embryo had significantly lower rates of live delivery and 'healthy baby' per transfer cycle compared with SSET of a blastocyst where only two blastocysts were available. CONCLUSIONS: Consultation with the patient with respect to the advantage of extended culture and selective single blastocyst transfer will result in better success rates following assisted reproductive technology treatment in Australia.

Better perinatal outcomes following transfer of fresh blastocysts and blastocysts cultured from thawed cleavage embryos: a population-based study.

BACKGROUND: Fresh embryo transfer results in higher live birth rates, while thawed embryo transfer appears to result in healthier babies. This study aims to investigate the association between the transfer of fresh or thawed embryos at the cleavage or blastocyst stage and the perinatal outcomes. METHODS: This analysis is a retrospective population-based study of 150 376 autologous embryo transfer cycles in Australia during 2002-2006. The rates of pregnancy, live delivery and 'healthy baby' delivery (a single baby born live at term, weighing >or=2500 g, surviving for at least 28 days post birth and not having congenital anomalies) were compared after transfer of fresh cleavage embryos, fresh blastocysts, thawed cleavage embryos, blastocysts from thawed cleavage embryos and thawed blastocysts. RESULTS: The live delivery rate was significantly higher for transfer of fresh blastocysts (27.9%) than for blastocysts cultured from thawed cleavage embryos (22.0%), fresh cleavage embryos (21.7%), thawed blastocysts (16.3%) and thawed cleavage embryos (15.2%). Compared with the transfer of fresh blastocysts, the likelihood of a 'healthy baby' was significantly lower for blastocysts from thawed cleavage embryos [adjusted odds ratios (AOR) 0.73, 95% confidence intervals (CI) 0.65-0.82], fresh cleavage embryos (AOR 0.67, 95% CI 0.64-0.69), thawed blastocysts (AOR 0.57, 95% CI 0.53-0.62) and thawed cleavage embryos (AOR 0.53, 95% CI 0.51-0.56). Of thaw cycles, transfers of thawed blastocysts (AOR 0.79, 95% CI 0.70-0.89) and thawed cleavage embryos (AOR 0.71, 95% CI 0.63-0.79) had significantly lower odds of 'healthy baby' than transfer of blastocysts from thawed cleavage embryos. CONCLUSIONS: These data suggest that an optimum practice model to maximize the outcomes of the birth of a 'healthy baby' is the transfer of blastocysts and the freezing of cleavage embryos in fresh cycles and subsequent transfer of blastocysts cultured from these thawed cleavage embryos.

Term breech singletons and caesarean section: a population study, Australia 1991-2005.

OBJECTIVE: To describe the method of birth of term breech singletons in Australia. DESIGN, SETTING AND PARTICIPANTS: A retrospective population-based study of women who gave birth to term breech singletons in Australia between 1 January 1991 and 31 December 2005 using data from the National Perinatal Data Collection. MAIN OUTCOME MEASURES: Caesarean section, vaginal breech birth. RESULTS: Method of birth changed for term breech singletons from 1991 (vaginal breech birth 23.1% versus caesarean (no labour 55.6%, labour 21.2%)) to 2005 (vaginal breech birth 3.7% versus caesarean (no labour 76.6%, labour 19.7%)). Overall, the population attributable risk percentage of term breech singletons for all caesarean sections declined from 10.2% in 1991 to 6.9% in 2005. CONCLUSION: Planned caesarean section is the standard method of birth for term breech singletons in Australia. Active measures including external cephalic version should be supported to reduce the rate of caesarean section where clinically indicated. Retention of a skilled clinical workforce is essential in the provision of the latter and to assist the minority of women having vaginal breech births. Breech presentation is not a major factor in the overall rise in caesarean section experienced by Australia since 1996.