Effect of parental and ART treatment characteristics on perinatal outcomes.

STUDY QUESTION: Do parental characteristics and treatment with ART affect perinatal outcomes in singleton pregnancies? SUMMARY ANSWER: Both parental and ART treatment characteristics affect perinatal outcomes in singleton pregnancies. WHAT IS KNOWN ALREADY: Previous studies have shown that singleton pregnancies resulting from ART are at risk of preterm birth. ART children are lighter at birth after correction for duration of gestation and at increased risk of congenital abnormalities compared to naturally conceived children. This association is confounded by parental characteristics that are also known to affect perinatal outcomes. It is unclear to which extent parental and ART treatment characteristics independently affect perinatal outcomes. STUDY DESIGN, SIZE, DURATION: All IVF clinics in the Netherlands (n = 13) were requested to provide data on all ART treatment cycles (IVF, ICSI and frozen-thawed embryo transfers (FET)), performed between 1 January 2000, and 1 January 2011, which resulted in a pregnancy. Using probabilistic data-linkage, these data (n = 36 683) were linked to the Dutch Perinatal Registry (Perined), which includes all children born in the Netherlands in the same time period (n = 2 548 977). PARTICIPANTS/MATERIALS, SETTING, METHODS: Analyses were limited to singleton pregnancies that resulted from IVF, ICSI or FET cycles. Multivariable models for linear and logistic regression were fitted including parental characteristics as well as ART treatment characteristics. Analyses were performed separately for fresh cycles and for fresh and FET cycles combined. We assessed the impact on the following perinatal outcomes: birth weight, preterm birth below 37 or 32 weeks of gestation, congenital malformations and perinatal mortality. MAIN RESULTS AND THE ROLE OF CHANCE: The perinatal outcomes of 31 184 out of the 36 683 ART treatment cycles leading to a pregnancy were retrieved through linkage with the Perined (85% linkage). Of those, 23 671 concerned singleton pregnancies resulting from IVF, ICSI or FET. Birth weight was independently associated with both parental and ART treatment characteristics. Characteristics associated with lower birth weight included maternal hypertensive disease, non-Dutch maternal ethnicity, nulliparity, increasing duration of subfertility, hCG for luteal phase support (compared to progesterone), shorter embryo culture duration, increasing number of oocytes retrieved and fresh embryo transfer. The parental characteristic with the greatest effect size on birth weight was maternal diabetes (adjusted difference 283 g, 95% CI 228-338). FET was the ART treatment characteristic with the greatest effect size on birth weight (adjusted difference 100 g, 95% CI 84-117) compared to fresh embryo transfer. Preterm birth was more common among mothers of South-Asian ethnicity. Preterm birth was less common among multiparous women and women with 'male factor' as treatment indication (compared to 'tubal factor'). LIMITATIONS, REASONS FOR CAUTION: Due to the retrospective nature of our study, we cannot prove causality. Further limitations of our study were the inability to adjust for mothers giving birth more than once in our dataset, missing values for several variables and limited information on parental lifestyle and general health. WIDER IMPLICATIONS OF THE FINDINGS: Multiple parental and ART treatment characteristics affect perinatal outcomes, with birth weight being influenced by the widest range of factors. This highlights the importance of assessing both parental and ART treatment characteristics in studies that focus on the health of ART-offspring, with the purpose of modifying these factors where possible. Our results further support the hypothesis that the embryo is sensitive to its early environment. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by Foreest Medical School, Alkmaar, the Netherlands (grants: FIO 1307 and FIO 1505). B.W.M. reports grants from NHMRC and consultancy for ObsEva, Merck KGaA, iGenomics and Guerbet. F.B. reports research support grants from Merck Serono and personal fees from Merck Serono. A.C. reports travel support from Ferring BV. and Theramex BV. and personal fees from UpToDate (Hyperthecosis), all outside the remit of the current work. The remaining authors report no conflict of interests. TRIAL REGISTRATION NUMBER: N/A.

The use of artificial gynogenesis in studies on the immune system of carp (Cyprinus carpio L.).

Gynogenetic carp were obtained by using gamma-irradiated sperm for fertilization followed by a cold shock. The gynogenetic fish and normal siblings of the same parents were analysed for 3 genetic markers: scale pattern, transferrin (Tf) and allograft rejection. Gynogenetic offspring showed only the maternal scale pattern (scattered). In the majority of the gynogenetic fish a heterozygous Tf pattern identical to the mother was observed. Animals homozygous for Tf were rare in this group. A typical paternal Tf band was only seen in normal siblings. An exchange of skin grafts between normal animals was always followed by rejection (median survival time, 12 days at 23 OC). However, the rejection was delayed in the gynogenetic group (MST, 19,6 days). There were even signs of acceptance in some animals. This approach can be used for the identification of 2nd and 3rd generation gynogenetic fish, which are homozygous for certain MHC haplotypes.

Influence of group culture and culture volume on the formation of human blastocysts: a prospective randomized study.

The optimal culture conditions for embryos to reach the blastocyst stage are under investigation. One factor is the putative influence of autocrine or paracrine factors produced by the embryo itself. Studies in mice blastocysts showed a beneficial influence of micro-cultures and communal growth on pregnancy and implantation rates, attributed to these growth or survival factors. In humans, studies have only involved embryos up to day 2 or 3 without consistent results. Therefore a prospective, randomized study was designed to assess whether group culture or incubation volume would influence day 3 human embryos to develop into blastocysts. Embryos were initially cultured in groups until day 3, after which patients were randomly allocated to four groups. Group 1: group culture in a small volume; group 2: single culture in a small volume; group 3: single culture in a large volume; group 4: group culture in a large volume. No significant differences in blastocyst formation could be found between the four groups (35, 45, 36 and 36% respectively). Therefore any of the four modes can be used, whichever is most convenient. The only factor which made a statistically significant contribution was the number of embryos on day 3. An increase in the number of embryos by one embryo decreased the odds of obtaining a blastocyst by 6%. The overall pregnancy rate per transfer was 40%, and the implantation rate was 28%. Single culture in a small volume allows a direct and individual assessment of embryo morphology, and as such it seems preferable.

The predictive value of day 3 embryo morphology regarding blastocyst formation, pregnancy and implantation rate after day 5 transfer following in-vitro fertilization or intracytoplasmic sperm injection.

The transfer of blastocysts has been associated with a very high implantation rate. However, not all embryos achieve the blastocyst stage. Our study was set up to demonstrate whether embryo morphology on day 3 predicts subsequent blastocyst formation. A prospective study was carried out in 48 patients with a mean of 2.9 failed in-vitro fertilization (IVF) attempts. In this new cycle, the morphology of the embryos on day 3 was noted. After pre-selection of the embryos which would have been transferred on day 3, all embryos were cultured individually and allowed to develop further until transfer on day 5. The clinical pregnancy rate per transfer was 46%, and the overall implantation rate was 24%. When only blastocysts were transferred the pregnancy rate was 53% with an implantation rate of 30%. Thirty-nine per cent of all embryos reached the blastocyst stage on day 5; 47% of class 1 and 2 embryos (good quality) in contrast to 21% of class 3 and 4 embryos (poor quality). Respectively 45% of class 1 and 2 embryos and 69% of class 3 and 4 embryos arrested in development or degenerated. Only 51% of the embryos that were transferred on day 5 had been pre-selected for transfer on day 3. In conclusion, it appears that the predictive value of embryo morphology on day 3 for subsequent blastocyst formation is limited.