Cervical Length Measurement
A parameter usually used in PRENATAL ULTRASONOGRAPHY to measure the length of the uterine neck (CERVIX UTERI). Cervical length or its shortening is used to identify and prevent early cervical opening and PRETERM BIRTH.
Cervix Uteri
The neck portion of the UTERUS between the lower isthmus and the VAGINA forming the cervical canal.
Obstetric Labor, Premature
Cervical Ripening
A change in the CERVIX UTERI with respect to its readiness to relax. The cervix normally becomes softer, more flexible, more distensible, and shorter in the final weeks of PREGNANCY. These cervical changes can also be chemically induced (LABOR, INDUCED).
Pregnancy Trimester, Second
The middle third of a human PREGNANCY, from the beginning of the 15th through the 28th completed week (99 to 196 days) of gestation.
Premature Birth
CHILDBIRTH before 37 weeks of PREGNANCY (259 days from the first day of the mother's last menstrual period, or 245 days after FERTILIZATION).
Pregnancy Trimester, Third
The last third of a human PREGNANCY, from the beginning of the 29th through the 42nd completed week (197 to 294 days) of gestation.
Ultrasonography, Prenatal
The visualization of tissues during pregnancy through recording of the echoes of ultrasonic waves directed into the body. The procedure may be applied with reference to the mother or the fetus and with reference to organs or the detection of maternal or fetal disease.
Gestational Age
The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization.
Pregnancy
Twins
Uterine Cervical Incompetence
Incompetent UTERINE CERVIX is usually diagnosed in the second trimester of PREGNANCY. It is characterized by passive painless cervical dilation in the absence of UTERINE CONTRACTION; BLEEDING; INFECTION; and sometimes with the amniotic sac (AMNIOTIC MEMBRANE) bulging through the partially dilated cervix. Left untreated, this condition may lead to premature pregnancy loss, such as HABITUAL ABORTION.
Cerclage, Cervical
The surgical closure of the incompetent cervix uteri with suture material.
Pregnancy, Prolonged
A term used to describe pregnancies that exceed the upper limit of a normal gestational period. In humans, a prolonged pregnancy is defined as one that extends beyond 42 weeks (294 days) after the first day of the last menstrual period (MENSTRUATION), or birth with gestational age of 41 weeks or more.
Axial Length, Eye
The distance between the anterior and posterior poles of the eye, measured either by ULTRASONOGRAPHY or by partial coherence interferometry.
Labor, Induced
Artificially induced UTERINE CONTRACTION. Generally, LABOR, OBSTETRIC is induced with the intent to cause delivery of the fetus and termination of pregnancy.
Labor Onset
The beginning of true OBSTETRIC LABOR which is characterized by the cyclic uterine contractions of increasing frequency, duration, and strength causing CERVICAL DILATATION to begin (LABOR STAGE, FIRST ).
Nasal Bone
Interferometry
Measurement of distances or movements by means of the phenomena caused by the interference of two rays of light (optical interferometry) or of sound (acoustic interferometry).
Gravidity
The number of pregnancies, complete or incomplete, experienced by a female. It is different from PARITY, which is the number of offspring borne. (From Stedman, 26th ed)
Pregnancy, High-Risk
Pregnancy in which the mother and/or FETUS are at greater than normal risk of MORBIDITY or MORTALITY. Causes include inadequate PRENATAL CARE, previous obstetrical history (ABORTION, SPONTANEOUS), pre-existing maternal disease, pregnancy-induced disease (GESTATIONAL HYPERTENSION), and MULTIPLE PREGNANCY, as well as advanced maternal age above 35.
Biometry
Crown-Rump Length
In utero measurement corresponding to the sitting height (crown to rump) of the fetus. Length is considered a more accurate criterion of the age of the fetus than is the weight. The average crown-rump length of the fetus at term is 36 cm. (From Williams Obstetrics, 18th ed, p91)
Tocolysis
Any drug treatment modality designed to inhibit UTERINE CONTRACTION. It is used in pregnant women to arrest PREMATURE LABOR.
Reproducibility of Results
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Abortion, Threatened
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.
Telomere Homeostasis
Maintenance of TELOMERE length. During DNA REPLICATION, chromosome ends loose some of their telomere sequence (TELOMERE SHORTENING.) Various cellular mechanism are involved in repairing, extending, and recapping the telomere ends.
Observer Variation
The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).
Telomere
Prospective Studies
Parity
The number of offspring a female has borne. It is contrasted with GRAVIDITY, which refers to the number of pregnancies, regardless of outcome.
Delivery, Obstetric
Predictive Value of Tests
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
Telomere Shortening
The loss of some TELOMERE sequence during DNA REPLICATION of the first several base pairs of a linear DNA molecule; or from DNA DAMAGE. Cells have various mechanisms to restore length (TELOMERE HOMEOSTASIS.) Telomere shortening is involved in the progression of CELL AGING.
Body Weights and Measures
Sensitivity and Specificity
Fetal Membranes, Premature Rupture
Hydroxyprogesterones
Pregnancy Outcome
Results of conception and ensuing pregnancy, including LIVE BIRTH; STILLBIRTH; SPONTANEOUS ABORTION; INDUCED ABORTION. The outcome may follow natural or artificial insemination or any of the various ASSISTED REPRODUCTIVE TECHNIQUES, such as EMBRYO TRANSFER or FERTILIZATION IN VITRO.
ROC Curve
Reference Values
Triplets
Polyhydramnios
A condition of abnormally high AMNIOTIC FLUID volume, such as greater than 2,000 ml in the LAST TRIMESTER and usually diagnosed by ultrasonographic criteria (AMNIOTIC FLUID INDEX). It is associated with maternal DIABETES MELLITUS; MULTIPLE PREGNANCY; CHROMOSOMAL DISORDERS; and congenital abnormalities.
Anterior Chamber
The space in the eye, filled with aqueous humor, bounded anteriorly by the cornea and a small portion of the sclera and posteriorly by a small portion of the ciliary body, the iris, and that part of the crystalline lens which presents through the pupil. (Cline et al., Dictionary of Visual Science, 4th ed, p109)
Anthropometry
Labor Stage, First
Period from the onset of true OBSTETRIC LABOR to the complete dilatation of the CERVIX UTERI.
Pessaries
Administration, Intravaginal
Amniocentesis
Percutaneous transabdominal puncture of the uterus during pregnancy to obtain amniotic fluid. It is commonly used for fetal karyotype determination in order to diagnose abnormal fetal conditions.