A signalling protein important in pregnancy can also promote uterine tumour growth in women. High levels of interleukin (IL)-11 protein are found in the placenta of pregnant women who have developed the potentially life-threatening condition of pre-eclampsia. The same protein is also highly expressed in tumours that develop in the endometrium, the inner lining of the uterus. IL-11 may be a new potential therapeutic target for cancer and the pregnancy complication pre-eclampsia.

Invasion of specialised fetal cells, the extravillous trophoblast, into the uterine decidua is critical for the establishment of pregnancy. Overall, there exists an exquisite balance between trophoblast over- and under-invasion. This review summarises what is known about the intrinsic invasive potential of the extravillous trophoblast and the role of maternal cells in regulating invasion. A greater understanding of the mechanisms will lead to therapeutics to treat at-risk pregnancies.

Low antibody titres and the irreversible suppression of spermatogenesis are current hurdles in the contraceptive vaccine field. The purpose of immunocontraception research is to obtain prominent and reversible contraceptive effect through vaccines administered to both males and females. These peptides could be used in the specific diagnosis and treatment of male and female infertility as well as contraceptive vaccine development.

We describe the first technique that makes it possible to analyse the real size and shape of sperm cells. The development and application of this technique must lead to a new classification of human sperm morphology. This new approach will provide a revolutionary tool in the definition of human male fertility.

The recent discovery that prostaglandins are present in the fluid of the female genital tract and increase the motility of human sperm in vitro could lead to a possible treatment to improve male infertility. The findings of this study that incubation of human spermatozoa with low physiological levels of PGE₂ or PGF_2α increases sperm functions could improve conditions for assisted reproduction protocols and help infertile couples seeking medical help, which, according to global estimates, could be as many as 50–80 million people.

In double-yolked duck eggs, the first yolk ovulated achieved a higher level of fertilisation (68.82%) than the second yolk (34.98%), demonstrating a primacy effect. Eggs with larger yolks achieved a higher level of fertilisation, demonstrating an optimal yolk size effect. Both primacy and optimal size have a positive effect on the successful fertilisation of eggs in species with internal fertilisation.

In this study we characterise the ability of environmental oxygen to regulate human embryonic stem cells (hESC). We show that the oxygen concentration influences metabolite use, metabolic gene expression, cell death and free radical production in hESC, without affecting the expression of characteristic hESC markers. Our findings suggest that hESC benefit from culture in a reduced oxygen environment that mimics the physiological paradigm.

Implantation is a critical step of mammalian pregnancy whose progression depends on the quality of embryo and female genital tract. Using cattle as an animal model, gene expression, regulation and cell localization of STAT1 transcription factor were investigated in the endometrium during the oestrous cycle and early pregnancy; direct STAT1 target genes were identified by chromatin immunoprecipitation run with primary cultures of bovine endometrial cells. Altogether our data provide new insights on STAT1 biological functions in the endometrium during pregnancy maternal recognition and implantation.

Standard cryopreservation protocols and modified AI techniques are required to achieve acceptable fertility results with frozen–thawed boar semen. Using simplified procedures, but applying a sublethal hydrostatic pressure to the semen at room temperature before cryopreservation, yielded higher motility and fertility results. The AI dosage still needs to be optimised and, because no direct correlation was found between motility and fertility on an individual basis, the motility results cannot be used to predict potential fertility.

Embryonic loss is one of the major contributors to infertility in humans and domestic animals. This work determined that protein kinase C delta, an intracellular signalling molecule, is involved in several important developmental processes during early embryonic development in cattle. These outcomes implicate this molecule as a principal player in establishing the developmental potential of bovine embryos.

The oocyte-derived growth factors, bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9), play important roles in fertility, but their mechanism of action differs between species. Our aim was to determine the signalling pathways used by human BMP15 and GDF9; we found that they act synergistically and the combinations of pathways used are different from those observed in other species. Understanding the mechanisms of function of these human growth factors may help tailor treatments to improve fertility.

This study revealed the role of auquaporin 2 (AQP2, a water channel) in impaired embryo implantation following ovarian stimulation. It was found that AQP2 was decreased in endometria of ovarian stimulated women and suppressing AQP2 led to impaired implantation. The study indicated the importance of water transportation in embryo implantation and suggested a new way to improve outcome of assisted conception.

Melatonin is a wide-spectrum antioxidant; therefore, the aim of this study was to correlate advanced oxidation protein products (AOPPs) and the total antioxidant capacity (TAC) with melatonin levels in the seminal plasma of men with azoospermia, theratozoospermia and fertile controls. Decreased levels of melatonin and AOPP altered the oxidative–antioxidative balance in the ejaculate, thereby reducing fertility. These parameters may serve as additional markers of semen quality and male reproductive potential.

The effect of seminal plasma on sperm function is yet to be fully explained. This study demonstrates that survival of spermatozoa during cryopreservation is modified by the source of seminal plasma (high or low freezing resilient male) to which they are exposed prior to freezing. These results demonstrate that seminal plasma varies in composition and is the first step in identifying its positive and negative components.