The use of assisted reproductive technologies has increased over the past decades. To date, 8 million children have been born worldwide following assisted reproductive technologies. In Switzerland, this refers to around 2-2.5% of newborn’s every year, this were 2’188 children in 2017.
The introduction of this thesis gives an overview of the reasons for increasing global infertility, and of the use of medically assisted reproduction. It also presents the treatment options available today, and the risks associated with them for mothers and offspring. It goes on to describe the methods and data used in the research projects conducted for this thesis.
In the following section, the four publications included in this thesis are presented. The first article on children within the Bern IVF Cohort compares the birthweights and birthweight percentiles of children born after natural cycle in vitro fertilisation, to those born after conventional in vitro fertilisation. This shows that the increased risk of small-for-gestational age infants being born may be associated with hyperstimulation of oocyte growth in conventional in vitro fertilisation, especially when high estradiol levels are reached on the day of ovulation induction.
The second article uses follow-up data on breastfeeding collected within the Bern IVF Cohort. Breastfeeding prevalence and duration is compared to data from the Swiss Infant Feeding Study, which served as a control population. The findings demonstrate that women after fertility treatment breastfeed their children as much and for as long as mothers in the control population. This suggests that fertility treatment does not affect the potential and ability to breastfeed in Switzerland.
The third article relates to the endometrium in natural cycle in vitro fertilisation, where the endometrium is not affected by hormonal stimulation. Data on endometrial thickness was collected from women during their first treatment cycle and the outcome measured, was successful pregnancy. It was shown that both very thin but also thick endometrium is associated with adverse pregnancy outcomes in natural cycle in vitro fertilisation.
The fourth article analyses data from a historical cohort of women under treatment due to repeated implantation failure and recurrent pregnancy loss from 2014-2018. The two conditions seem to be associated with chronic endometritis, and their discussion is controversial: so far, no agreement on a standardised diagnosis or treatment has been reached. The aim was to assess the effect of endometrial diagnostic biopsy on subsequent treatment in cases of chronic endometritis, which was introduced in 2016, compared to hysteroscopic assessment alone. This demonstrated that diagnostic endometrial biopsy and subsequent treatment of chronic endometritis shortens time-to-pregnancy and live birth
