Labor Stage, First
Period from the onset of true OBSTETRIC LABOR to the complete dilatation of the CERVIX UTERI.
Labor Stage, Third
The final period of OBSTETRIC LABOR that is from the expulsion of the FETUS to the expulsion of the PLACENTA.
Labor Stage, Second
The period of OBSTETRIC LABOR that is from the complete dilatation of the CERVIX UTERI to the expulsion of the FETUS.
Labor, Obstetric
The repetitive uterine contraction during childbirth which is associated with the progressive dilation of the uterine cervix (CERVIX UTERI). Successful labor results in the expulsion of the FETUS and PLACENTA. Obstetric labor can be spontaneous or induced (LABOR, INDUCED).
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 ).
Labor Pain
Pain associated with OBSTETRIC LABOR in CHILDBIRTH. It is caused primarily by UTERINE CONTRACTION as well as pressure on the CERVIX; BLADDER; and the GASTROINTESTINAL TRACT. Labor pain mostly occurs in the ABDOMEN; the GROIN; and the BACK.
Obstetric Labor, Premature
Onset of OBSTETRIC LABOR before term (TERM BIRTH) but usually after the FETUS has become viable. In humans, it occurs sometime during the 29th through 38th week of PREGNANCY. TOCOLYSIS inhibits premature labor and can prevent the BIRTH of premature infants (INFANT, PREMATURE).
Obstetric Labor Complications
Trial of Labor
Allowing a woman to be in LABOR, OBSTETRIC long enough to determine if vaginal birth may be anticipated.
Pregnancy
Labor Presentation
Delivery, Obstetric
Delivery of the FETUS and PLACENTA under the care of an obstetrician or a health worker. Obstetric deliveries may involve physical, psychological, medical, or surgical interventions.
Oxytocics
Drugs that stimulate contraction of the myometrium. They are used to induce LABOR, OBSTETRIC at term, to prevent or control postpartum or postabortion hemorrhage, and to assess fetal status in high risk pregnancies. They may also be used alone or with other drugs to induce abortions (ABORTIFACIENTS). Oxytocics used clinically include the neurohypophyseal hormone OXYTOCIN and certain prostaglandins and ergot alkaloids. (From AMA Drug Evaluations, 1994, p1157)
Myometrium
The smooth muscle coat of the uterus, which forms the main mass of the organ.
Analgesia, Epidural
The relief of pain without loss of consciousness through the introduction of an analgesic agent into the epidural space of the vertebral canal. It is differentiated from ANESTHESIA, EPIDURAL which refers to the state of insensitivity to sensation.
Term Birth
CHILDBIRTH at the end of a normal duration of PREGNANCY, between 37 to 40 weeks of gestation or about 280 days from the first day of the mother's last menstrual period.
Tocolytic Agents
Drugs that prevent preterm labor and immature birth by suppressing uterine contractions (TOCOLYSIS). Agents used to delay premature uterine activity include magnesium sulfate, beta-mimetics, oxytocin antagonists, calcium channel inhibitors, and adrenergic beta-receptor agonists. The use of intravenous alcohol as a tocolytic is now obsolete.
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).
Amnion
The innermost membranous sac that surrounds and protects the developing embryo which is bathed in the AMNIOTIC FLUID. Amnion cells are secretory EPITHELIAL CELLS and contribute to the amniotic fluid.
Fetal Monitoring
Physiologic or biochemical monitoring of the fetus. It is usually done during LABOR, OBSTETRIC and may be performed in conjunction with the monitoring of uterine activity. It may also be performed prenatally as when the mother is undergoing surgery.
Extraembryonic Membranes
The thin layers of tissue that surround the developing embryo. There are four extra-embryonic membranes commonly found in VERTEBRATES, such as REPTILES; BIRDS; and MAMMALS. They are the YOLK SAC, the ALLANTOIS, the AMNION, and the CHORION. These membranes provide protection and means to transport nutrients and wastes.
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.
Chorioamnionitis
Fetal Membranes, Premature Rupture
Amniotic Fluid
A clear, yellowish liquid that envelopes the FETUS inside the sac of AMNION. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (AMNIOCENTESIS).
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.
Parity
Uterine Monitoring
Measurement or recording of contraction activity of the uterine muscle. It is used to determine progress of LABOR, OBSTETRIC and assess status of pregnancy. It is also used in conjunction with FETAL MONITORING to determine fetal response to stress of maternal uterine contractions.
Anesthesia, Obstetrical
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.
Cervix Uteri
The neck portion of the UTERUS between the lower isthmus and the VAGINA forming the cervical canal.
Vaginal Birth after Cesarean
Delivery of an infant through the vagina in a female who has had a prior cesarean section.
Apgar Score
A method, developed by Dr. Virginia Apgar, to evaluate a newborn's adjustment to extrauterine life. Five items - heart rate, respiratory effort, muscle tone, reflex irritability, and color - are evaluated 60 seconds after birth and again five minutes later on a scale from 0-2, 0 being the lowest, 2 being normal. The five numbers are added for the Apgar score. A score of 0-3 represents severe distress, 4-7 indicates moderate distress, and a score of 7-10 predicts an absence of difficulty in adjusting to extrauterine life.
Postpartum Hemorrhage
Excess blood loss from uterine bleeding associated with OBSTETRIC LABOR or CHILDBIRTH. It is defined as blood loss greater than 500 ml or of the amount that adversely affects the maternal physiology, such as BLOOD PRESSURE and HEMATOCRIT. Postpartum hemorrhage is divided into two categories, immediate (within first 24 hours after birth) or delayed (after 24 hours postpartum).
Tocolysis
Any drug treatment modality designed to inhibit UTERINE CONTRACTION. It is used in pregnant women to arrest PREMATURE LABOR.
Uterine Rupture
A complete separation or tear in the wall of the UTERUS with or without expulsion of the FETUS. It may be due to injuries, multiple pregnancies, large fetus, previous scarring, or obstruction.
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.
Natural Childbirth
Pregnancy Complications
Meperidine
Chorion
Pelvimetry
Measurement of the dimensions and capacity of the pelvis. It includes cephalopelvimetry (measurement of fetal head size in relation to maternal pelvic capacity), a prognostic guide to the management of LABOR, OBSTETRIC associated with disproportion.
Obstetric Nursing
Sufentanil
Placenta
A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (CHORIONIC VILLI) derived from TROPHOBLASTS and a maternal portion (DECIDUA) derived from the uterine ENDOMETRIUM. The placenta produces an array of steroid, protein and peptide hormones (PLACENTAL HORMONES).
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.
Uterus
The hollow thick-walled muscular organ in the female PELVIS. It consists of the fundus (the body) which is the site of EMBRYO IMPLANTATION and FETAL DEVELOPMENT. Beyond the isthmus at the perineal end of fundus, is CERVIX UTERI (the neck) opening into VAGINA. Beyond the isthmi at the upper abdominal end of fundus, are the FALLOPIAN TUBES.
Receptors, Oxytocin
Cell surface proteins that bind oxytocin with high affinity and trigger intracellular changes which influence the behavior of cells. Oxytocin receptors in the uterus and the mammary glands mediate the hormone's stimulation of contraction and milk ejection. The presence of oxytocin and oxytocin receptors in neurons of the brain probably reflects an additional role as a neurotransmitter.
Pregnancy Complications, Infectious
The co-occurrence of pregnancy and an INFECTION. The infection may precede or follow FERTILIZATION.
Hospitals, Maternity
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).
Fetal Distress
Uterine Inertia
Failure of the UTERUS to contract with normal strength, duration, and intervals during childbirth (LABOR, OBSTETRIC). It is also called uterine atony.
Perineum
The body region lying between the genital area and the ANUS on the surface of the trunk, and to the shallow compartment lying deep to this area that is inferior to the PELVIC DIAPHRAGM. The surface area is between the VULVA and the anus in the female, and between the SCROTUM and the anus in the male.
Episiotomy
Obstetrics
A medical-surgical specialty concerned with management and care of women during pregnancy, parturition, and the puerperium.
Cesarean Section, Repeat
Heart Rate, Fetal
Misoprostol
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.