Risk factors for spontaneous abortion among danish pregnancy planners
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Abstract
Spontaneous abortion (SAB) is the unexpected loss of a conceptus early in
pregnancy. Methodologic limitations such as left truncation bias, recall bias, and
misclassification have prevented investigators from identifying risk factors related to this adverse pregnancy outcome. The objective of this dissertation was to examine the
associations of body size, caffeine consumption, and history of oral contraceptive (OC)
use with SAB risk among a prospective cohort of pregnancy planners in Denmark.
In study 1, we examined SAB risk in relation to body size as measured by body
mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), height, and
location of typical weight gain. We found that overall obesity (defined as BMI230) was
associated with an increased risk of SAB, especially for pregnancy losses before 8
gestational weeks. Increasing WHR and increasing height were associated with a
decreased risk ofSAB. Underweight, WC, and location of weight gain were not
materially associated with SAB risk.
The second study evaluated risk of SAB in relation to consumption of caffeine
and caffeinated beverages before conception and during early pregnancy. We found that
women who consumed higher amounts of coffee per day before pregnancy had a slightly
higher risk of SAB. Overall, increased caffeine consumption during early pregnancy was
also associated with higher risk of SAB. Study 3 assessed the risk of SAB in relation to self-reported history of OC use, evaluated in terms of recency, duration, and formulation of the most recent pill. Recent and longer durations of OC use were independently associated with a decreased risk of SAB. When stratified by maternal age, younger women ( < 30 years) had an increased risk of SAB with longer duration but older women (~30 years) had a decreased risk of SAB.
Description
Thesis (Ph. D.)--Boston University