Obstetrics (from the Latin obstare, "to stand by") is the medical specialty dealing with the care of all women's reproductive tracts and their children during pregnancy (prenatal period), childbirth and the postnatal period. Veterinary obstetrics is the same concept for veterinary medicine although theriogenology is more commonly used term that includes obstetrics, gynecology, and andrology. Almost all modern obstetricians are also gynecologists.

Prenatal care is important in screening for various complications of pregnancy. This includes routine office visits with physical exams and routine lab tests:

3D ultrasound of 3-inch (76 mm) fetus (about 14 weeks gestational age)

Fetus at 17 weeks

Fetus at 20 weeks

genetic screening for downs syndrome (trisomy 21) and trisomy 18 the national standard in the United States is rapidly evolving away from the AFP-Quad screen for downs syndrome- done typically in the second trimester at 16–18 weeks. The newer integrated screen (formerly called F.A.S.T.E.R for First And Second Trimester Early Results) can be done at 10 plus weeks to 13 plus weeks with an ultrasound of the fetal neck (thick skin is bad) and two chemicals (analytes) Papp-a and bhcg (pregnancy hormone level itself). It gives an accurate risk profile very early. There is a second blood screen at 15 to 20 weeks which refines the risk more accurately. The cost is higher than an "AFP-quad" screen due to the ultrasound and second blood test but it is quoted to have a 93% pick up rate as opposed to 88% for the standard AFP/QS. This is an evolving standard of care in the United States.