Biomaterial Database

Abdominal ultrasound examination of the first-trimester fetus. 1988

J J Green, and J C Hobbins

Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06510.

The first-trimester fetus can now be comprehensively studied with ultrasound. Various biometric measurements correlate well with gestational age, such as crown-rump length (r2 = 0.938) and cranial apex to ear diameter (r2 = 0.983). On the other hand, yolk sac diameter (r2 = 0.129) and abdominal perimeter (r2 = 0.58) correlate poorly with gestational age. By 10 weeks' gestation, kidneys can be visualized in 60% of cases; 98% will be seen at 11 weeks; and 100% of cases will be visible by 12 weeks. The bladder appears later, and by 12 weeks' gestation this organ can be identified in 50% of cases. It is likely that renal agenesis can be diagnosed (or excluded) reliably in the first trimester. With improving technology, prenatal diagnosis of some fetal anomalies is now possible in the first trimester.

UI	MeSH Term	Description	Entries
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011261	Pregnancy Trimester, First	The beginning third of a human PREGNANCY, from the first day of the last normal menstrual period (MENSTRUATION) through the completion of 14 weeks (98 days) of gestation.	Early Placental Phase,Pregnancy, First Trimester,Trimester, First,Early Placental Phases,First Pregnancy Trimester,First Pregnancy Trimesters,First Trimester,First Trimester Pregnancies,First Trimester Pregnancy,First Trimesters,Phase, Early Placental,Phases, Early Placental,Placental Phase, Early,Placental Phases, Early,Pregnancies, First Trimester,Pregnancy Trimesters, First,Trimesters, First
D011296	Prenatal Diagnosis	Determination of the nature of a pathological condition or disease in the postimplantation EMBRYO; FETUS; or pregnant female before birth.	Diagnosis, Prenatal,Fetal Diagnosis,Fetal Imaging,Fetal Screening,Intrauterine Diagnosis,Antenatal Diagnosis,Antenatal Screening,Diagnosis, Antenatal,Diagnosis, Intrauterine,Prenatal Screening,Antenatal Diagnoses,Antenatal Screenings,Diagnosis, Fetal,Fetal Diagnoses,Fetal Imagings,Fetal Screenings,Imaging, Fetal,Intrauterine Diagnoses,Prenatal Diagnoses,Prenatal Screenings,Screening, Antenatal,Screening, Fetal,Screening, Prenatal
D004622	Embryo, Mammalian	The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.	Embryonic Structures, Mammalian,Mammalian Embryo,Mammalian Embryo Structures,Mammalian Embryonic Structures,Embryo Structure, Mammalian,Embryo Structures, Mammalian,Embryonic Structure, Mammalian,Embryos, Mammalian,Mammalian Embryo Structure,Mammalian Embryonic Structure,Mammalian Embryos,Structure, Mammalian Embryo,Structure, Mammalian Embryonic,Structures, Mammalian Embryo,Structures, Mammalian Embryonic
D005121	Extremities	The farthest or outermost projections of the body, such as the HAND and FOOT.	Limbs,Extremity,Limb
D005260	Female		Females
D005333	Fetus	The unborn young of a viviparous mammal, in the postembryonic period, after the major structures have been outlined. In humans, the unborn young from the end of the eighth week after CONCEPTION until BIRTH, as distinguished from the earlier EMBRYO, MAMMALIAN.	Fetal Structures,Fetal Tissue,Fetuses,Mummified Fetus,Retained Fetus,Fetal Structure,Fetal Tissues,Fetus, Mummified,Fetus, Retained,Structure, Fetal,Structures, Fetal,Tissue, Fetal,Tissues, Fetal
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000005	Abdomen	That portion of the body that lies between the THORAX and the PELVIS.	Abdomens
D012886	Skull	The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.	Calvaria,Cranium,Calvarium,Skulls