Introduction:
Twinning rates were subject to many changes in the past few decades,
almost doubling between 1980 – 1985 and 2010 – 2015. This is mainly
due to increasing rates of assisted reproductive technology (ART) and
increasing maternal age, the latter being accompanied by a higher
likelihood for multiple pregnancies. In addition, a body mass index
(BMI) ≥30 kg/m2 is associated with a higher risk for
twin pregnancies. With the prevalence of obese people worldwide almost
tripling in the last three decades, it is no surprise that twinning
rates rise in the context with increasing overweight and obesity
incidences.
Although the relationship between maternal weight and the likelihood for
twins has been investigated, the risks of overweight and obesity on
fetomaternal outcomes have been subject to only few studies, especially
regarding the impact of the three obesity classes as defined by the WHO.
In singleton pregnancies, overweight and obesity lead to a 18 – 47%
higher risk for obstetric complications.
The incidence of overweight and obese women of child-bearing age in
Germany is at a distressing level. Thus, this study aims to examine the
impact of maternal weight and especially obesity on fetomaternal
complications and outcomes in twin pregnancies, hypothesizing that an
increasing BMI and an increasing obesity class lead to a higher
likelihood for adverse fetomaternal outcomes.