Traditional<unk>  sonograms are done by placing a transducer on the abdomen of the pregnant woman. One variant, transvaginal sonography, is done with a probe placed in the woman's vagina. Transvaginal scans usually provide clearer pictures during early pregnancy and in obese women. Also used is Doppler sonography which detects the heartbeat of the fetus. Doppler sonography can be used to evaluate the pulsations in the fetal heart and bloods vessels for signs of abnormalities. 3D ultrasound Modern 3D ultrasound images provide greater detail for prenatal diagnosis than the older 2D ultrasound technology. While 3D is popular with parents desiring a prenatal photograph as a keepsake, both 2D and 3D are discouraged by the FDA for non-medical use, but there are no definitive studies linking ultrasound to any adverse medical effects. The following 3D ultrasound images were taken at different stages of pregnancy: Image:Fetal movements 3D Ultrasound Dr. Wolfgang Moroder.theora. 3D Ultrasound of fetal movements at 12 weeks Image:Ultrasound_image_of_a_fetus.75-mm fetus (about 14 weeks' gestational age) Image:Sucking his thumb and waving.Fetus at 17 weeks Image:3dultrasound 20 weeks.Fetus at 20 weeks
Obstetric ultrasonography
Fertility testing
Vaginal ultrasonography
Postcoital test
Gynecologic ultrasonography
Hysterosalpingography
Karyotype
Fetal echocardiography