Spontaneous Preterm Birth: risk factors and long-term maternal health effects

In Chapter 2, we present the findings of the ALPHA-study, exploring the link between vaginal hygiene practices and SPTB. Our study revealed a significant association between the use of vaginal gels, both before and during pregnancy, and an increased risk of SPTB, particularly between 28+0 and 31+6 weeks of gestation. Chapter 3 examines sexual intercourse during pregnancy in relation to SPTB, comparing incidences between SPTB and term birth groups. While there was a comparable frequency of sexual intercourse during pregnancy between the groups, we observed a trend suggesting higher frequency might be associated with SPTB among primiparous women. However, due to small study groups, this association couldn't be significantly demonstrated. Besides exploring SPTB risk factors, this thesis delves into the long-term maternal health effects of SPTB. Chapter 4 presents findings from the PreCaris-study, a retrospective case-control study comparing cardiovascular risk between women with histories of SPTB and uncomplicated term births. Hypertension was more prevalent among women with SPTB, as was abdominal obesity, especially in extreme preterm births. Left ventricular diastolic dysfunction was investigated in Chapter 5. Women with a history of SPTB diagnosed with hypertension at follow-up showed early yet significant signs of impaired left ventricular diastolic function. Although not exceeding normal range in the general healthy population, these significant changes could indicate a subgroup of women at elevated risk of left ventricular diastolic dysfunction later in life. Acknowledging the heterogeneous nature of SPTB, Chapter 6 identifies a subgroup of women at risk for CVD using placental maternal vascular malperfusion (MVM) as a discriminator. Women with SPTB and placental MVM exhibited significantly higher cardiovascular risk. SPTB also impacts maternal psychosocial wellbeing, detailed in Chapter 7. While maternal depression, anxiety, and psychosocial distress incidences were comparable after SPTB and term birth, a notable percentage of women experiencing SPTB reported unmet needs for professional psychosocial support, correlated with higher anxiety and distress scores. In Chapter 8, we investigated whether stress-reducing interventions could lower the incidence of preterm birth in general low-risk obstetric populations. We conducted a systematic review and meta-analysis to investigate the association between stress-reducing interventions and pregnancy outcomes, indicating significant reduction of preterm birth and low birth weight with interventions such as yoga, despite low-quality study evidence. In Chapter 9 we recommend discouraging the use of vaginal gels as part of comprehensive efforts to reduce the incidence of SPTB. Secondly, healthcare professionals should communicate with women that overall sexual intercourse during pregnancy does not increase SPTB risk. Future research should focus on understanding the link between vaginal hygiene and SPTB, and explore the impact of sexual intercourse on SPTB risk in specific groups. Additionally, we recommend future research to focus on evaluating the effects of early cardiovascular screening among women after SPTB, along with investigating the potential advantages of including placental MVM as a criterion. Lastly, we recommend integrating psychosocial support into standard care for women after SPTB, and conducting a high-quality RCT to assess the effectiveness of stressreducing interventions in preventing preterm birth across various gestational ages.