Subject(s)
Esophageal Atresia/diagnosis , Prenatal Diagnosis , Ultrasonography , Female , Humans , Infant, Newborn , Male , PregnancyABSTRACT
Sonographic measurement of 150 pregnant and nonpregnant uteri indicate that the uterine cervix is about 2.5 cm in length in the nongravid and is seldom or never more than 6 cm in length during pregnancy. This information is used to better identify the level of the internal cervical os, especially in evaluating early placenta previa. If careful sonography is used to identify the lowest attachment of the placenta and the cervical tip, placenta previa could be excluded when the placenta is more than 6 cm from the cervical tip. This seems reliable in clinical practice and reduces the unreasonably high level of early placenta previa predictions and the attendant anxiety of mother and obstetrician.
Subject(s)
Cervix Uteri/anatomy & histology , Ultrasonography , Adolescent , Adult , Aged , False Positive Reactions , Female , Humans , Middle Aged , Placenta Previa/diagnosis , Pregnancy , Time FactorsSubject(s)
Hernia, Umbilical/diagnosis , Prenatal Diagnosis , Ultrasonography , Adult , Female , Humans , Infant, Newborn , PregnancyABSTRACT
Observations of random obstetrical cases out of a large-volume practice are presented to demonstrate the often overlooked effects of filling the urinary bladder for obstetrical sonography. The effects, predominantly evident in the second trimester, include: perssure effects on the lower uterine segment, displacement of the cervix and/or corpus of the uterus, rotation, flexion, version, and tilting of the uterus. These events may affect the perception of placenta location and fetal position. This is especially important in the diagnosis of placenta previa in the second trimester. Many instances of placental "migration" may be due to this phenomenon. Implications for amniocentesis are briefly discussed.
