The impact of bacterial and uterine factors on subfertility

Tweel, M.M. van (2024)

Doctoral Thesis

This thesis aimed to assess the impact of bacterial vaginosis (BV) and caesarean section scars on subfertility. In chapter 2 the relationship between (asymptomatic) bacterial vaginosis and pregnancy rates during intra uterine insemination or in vitro fertilization treatment (IVF) is investigated. The incidence of BV was 26%. This chapter reveals a higher incidence of miscarriages and a tendency to lower live birth rates among participants testing positive for BV. Chapter 3 showed that a simple pH-measurement could accurately predict if subfertile participants are BV positive. During fertility treatments, the vaginal microbiome of participants changes, as shown in chapter 4. Chapter 5 shows no difference in the time to pregnancy based on BV-status in participants at initial fertility assessment. However, participants with a lower chance to conceive tended to have a longer time to pregnancy if they were BV positive. Chapter 6 shows that participants with a previous caesarean delivery had significant lower live birth rates during IVF treatment compared to a previous vaginal delivery. The review of chapter 7 showed an adverse effect on live birth rates in persons with a caesarean scar niche. A potential relationship between abnormal microbiome (or BV) and a niche could not be accurately assessed.

• Microbiome
• Bacterial vaginosis
• Niche
• Caesarean section
• Subfertility
• IVF
• IUI
• Live birth
• Time to pregnancy

• All authors: Tweel, M.M. van
• Supervisor: Lith, J.M.M. van
• Co-supervisor: Boers, K.E.
• Committee: Kuijper, E.J.; Dekkers, O.M.; Goddijn, M.; Bloemenkamp, K.W.M.
• Qualification: Doctor (dr.)
• Awarding Institution: Leiden University Medical Center (LUMC), Leiden University
• Date: 2024-10-23
• ISBN (print): 9789465061825