Siegelaar took part in the World Championships of 2003 in Milan winning the silver medal in the four. With the Dutch eights she qualified for the 2004 Summer Olympics in Athens and she and her team mates rowed to the bronze medal.[1] In 2007, she returned to the eights in which the Dutch only became seventh at the World Championships. Earlier that year they won the Rowing World Cup in Amsterdam and they finished third in both Luzern and Linz.[1]