Is premature ovarian ageing a cause of unexplained recurrent miscarriage?

Do ovarian reserve markers predict the subsequent pregnancy outcomes in women with recurrent pregnancy loss?

Objective(s):

Chromosomal abnormalities are more commonly seen in embryos with decreased oocyte quality. Therefore aneuploidy due to diminished ovarian reserve may be one of the causative reasons of RPL. We investigated the relationship between ovarian reserve markers especially serum antimullerian hormone (AMH) level and antral follicle count (AFC) and recurrent pregnancy loss (RPL).

Materials and methods:

This prospective cross-sectional clinical trial including 88 women with RPL and 84 age-matched women without RPL.

Results:

There were statistically significant differences in body mass index, live birth number, menstrual cycle length, AFC and serum AMH level between groups. There was no statistically significant difference between groups regarding age, menstrual cycle regularity and serum follicle stimulating hormone (FSH) and estradiol (E2) levels. The percentage of women with levels of AMH<1 was 21.4% in the RPL group and 11.4% in the control group. AFC <7 in both ovaries was lower in the RPL group when compared with the control group (73.8% vs 44.3%, respectively).

Conclusion(s):

Serum AMH levels and AFC can be assessed in patients with RPL as a part of the work up parameters. Lower Serum AMH levels and AFC especially may predict the quantity of oocytes that may be consequently be related with RPL.

The T helper type 17/regulatory T cell paradigm in pregnancy

T helper type 17 (Th17) and regulatory T (Treg) cells are active players in the establishment of tolerance and defence. These attributes of the immune system enmesh to guarantee the right level of protection. The healthy immune system, on the one hand, recognizes and eliminates dangerous non-self pathogens and, on the other hand, protects the healthy self. However, there are circumstances where this fine balance is disrupted. In fact, in situations such as in pregnancy, the foreign fetal antigens challenge the maternal immune system and Treg cells will dominate Th17 cells to guarantee fetal survival. In other situations such as autoimmunity, where the Th17 responses are often overwhelming, the immune system shifts towards an inflammatory profile and attacks the healthy tissue from the self. Interestingly, autoimmune patients have meliorating symptoms during pregnancy. This connects with the antagonist role of Th17 and Treg cells, and their specific profiles during these two immune challenging situations. In this review, we put into perspective the Th17/Treg ratio during pregnancy and autoimmunity, as well as in pregnant women with autoimmune conditions. We further review existing systems biology approaches that study specific mechanisms of these immune cells using mathematical modelling and we point out possible future directions of investigation. Understanding what maintains or disrupts the balance between these two opponent yet reciprocal cells in healthy physiological settings, sheds light into the development of innovative pharmacological approaches to fight pregnancy loss and autoimmunity.

Unexplained recurrent pregnancy loss

Women with unexplained recurrent pregnancy loss (RPL) represent a highly heterogeneous group of patients. Past studies have investigated systemic endocrine and immunologic mechanisms as potential causes for pregnancy loss in unexplained RPL, while exciting new work has focused on spermatozoal, embryonic, and endometrial characteristics to explain the regulation of implantation and subsequent pregnancy loss. In the clinical and research context, stratification of women with unexplained RPL according to whether they have a high probability of pathologic status will help select women who are most appropriate for further investigation and potential future treatment.