Since about 31 percent of pregnancies won’t carry to term due to miscarriage, blighted ovum, ectopic pregnancy, etc., an ultrasound is the best way to determine if you have a viable pregnancy.

Early signs of pregnancy can include the following:

  • Missed Period or a Shorter or Lighter than Normal Period
  • Implantation Bleeding & Cramping
  • Swollen/Tender Breasts
  • Fatigue
  • Nausea or Vomiting
  • Lower Backache
  • Headaches
  • Frequent Urination
  • Food Cravings or Aversions
  • Darkening of the Nipples

Source: http://americanpregnancy.org/gettingpregnant/earlypregnancysymptoms.html