A: Pregnancy symptoms are different for each woman. A woman's uterus will feel bigger during an exam in the first trimester and, in general, having twins can mean a higher incidence of morning sickness due to the increased levels of hormones. There can also be a higher incidence of first trimester bleeding because there is a high percentage of pregnant women miscarrying one twin early on. All women are recommended to receive a first trimester ultrasound, usually done at the first or second visit to the obstetrician, to look for twins or a higher number of multiples, a fetal heartbeat, and a fetal measurement to ensure accurate dating. At the ultrasound, your doctor will know for sure if you are having twins, and you won't need to worry about guessing anymore.