First get a urine
pregnancy test or serum
beta hcg for confirmation of pregnancy. If positive you need to get ultrasound pelvis done to see whether the pregnancy is intra uterine or extra uterine and also for confirmation of gestational age and to see if it is a singleton or multiple pregnancy. Blood tests like
complete blood count, blood group and Rh typing , random blood
sugar, screening for STI like syphilis, rubella, hepatitis B,
HIV must be done. Screening for genetic disorders must be done like NT scan (between 11-13weeks) and beta hcg and PAPP-A . These tests detect chromosomal abnormalities like Down's syndrome , neural tube defects etc. She needs to take vitamins like folic acid to prevent neural tube defects in the baby.