Tocolytics are medications used to suppress premature labor (from the Greek tokos, childbirth, and lytic, capable of dissolving). They are given when delivery would result in premature birth. The therapy also buys time for the administration of betamethasone, a glucocorticoid drug which greatly accelerate fetal lung maturity, but takes one to two days to work. Premature birth is defined medically as a birth occurring earlier than 37 weeks. ... Childbirth (also called labour, birth, partus or parturition) is the culmination of a human pregnancy with the emergence of a newborn infant from its mothers uterus. ... Premature birth (also known as preterm birth) is defined medically as childbirth occurring earlier than 37 completed weeks of gestation. ... Betamethasone dipropionate is a corticosteroid with anti-inflammatory and immunosuppressive abilities, used especially where water retention is undesirable. ...

The suppression of contractions is often only partial and tocolytics can only be relied on to delay birth for several days at most. Depending on the tocolytic used the mother and fetus may require monitoring. In any case the risk of preterm labor justifies hospitalization. Where tocolytics are ineffective and the cervix continues to dilate, immediate cesarean delivery may be required if the baby is judged too fragile to traverse the birth canal. Schematic frontal view of female anatomy The cervix (from Latin neck) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. ... A caesarean section (cesarean section AE), or c-section, is a form of childbirth in which a surgical incision is made through a mothers abdomen (laparotomy) and uterus (hysterotomy) to deliver one or more babies. ...

Types of agents

Various types of agents are used, with varying success rates and side effects. Some medications are not specifically FDA approved for use in stopping uterine contractions in preterm labor, while others are used off label. Magnesium sulfate and nifedipine are the most commonly used tocolytic agents[1]. The United States Food and Drug Administration is the government agency responsible for regulating food, dietary supplements, drugs, cosmetics, medical devices, biologics and blood products in the United States. ... Off-label use is the practice of prescribing drugs for a purpose outside the scope of the drugs approved label, most often concerning the drugs indication. ... Magnesium sulfate or Magnesium sulfate heptahydrate or Epsom salt is a chemical compound containing magnesium, with the formula MgSO4·7H2O. Magnesium sulfate without water of crystalization MgSO4 is available as a far less common chemical and drying agent, but typically magnesium sulfate refers to the hydrate, and Epsom salt always... Nifedipine (brand name Adalat and Procardia) is a dihydropyridine calcium channel blocker. ...

Examples:

• MgSO₄
• ritodrine (Yutopar)
• fenoterol
• nifedipine (Procardia, Adalat)
• atosiban
• salbutamol
• indomethacin
• terbutaline (Brethine)

Ethyl alcohol was frequently prescribed as a tocolytic in the mid-20th century, but later double-blind studies^[2] found it was not effective. Magnesium sulfate or Magnesium sulfate heptahydrate or Epsom salt is a chemical compound containing magnesium, with the formula MgSO4·7H2O. Magnesium sulfate without water of crystalization MgSO4 is available as a far less common chemical and drying agent, but typically magnesium sulfate refers to the hydrate, and Epsom salt always... Ritodrine hydrochloride (Yutopar®) is a tocolytic drug, used to stop premature labor. ... Nifedipine (brand name Adalat and Procardia) is a dihydropyridine calcium channel blocker. ... Atosiban (Tractocile®) is an inhibitor of the hormone oxytocin, and is used in premature labor. ... Salbutamol (INN) or albuterol (USAN) is a short-acting β2-adrenergic receptor agonist used for the relief of bronchospasm in conditions such as asthma and COPD. Salbutamol sulfate is usually given by the inhaled route for direct effect on bronchial smooth muscle. ... Indomethacin (USAN) or indometacin (INN) is a non-steroidal anti-inflammatory drug commonly used to reduce fever, pain, stiffness, and swelling. ... The drug Terbutaline (trade names Brethine, Bricanyl, or Brethaire) is a β2-adrenergic receptor agonist, used as a fast-acting bronchodilator and off-label to delay premature labour as a tocolytic. ... Ethyl alcohol, also known as ethanol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ... Double-blind describes an especially stringent way of conducting an experiment, usually on living, conscious, human subjects. ...

Contraindications to Tocolysis

Several factors may contraindicate delaying birth with the use of tocolytic medications. ^[3]

• Fetus is older than 37 weeks gestation
• Fetus weighs more than 2500g or has IUGR
• Fetus is in acute distress or has passed (or has a fatal anomaly)
• Dilation is greater than 4 cm
• Chorioamnionitis or intrauterine infection is present
• Mother has severe PIH, eclampsia, active vaginal bleeding, a cardiac disease, or another condition which indicates that the pregnancy should not continue.

Intrauterine growth retardation or Intrauterine growth restriction (IUGR) refers to the condition during pregnancy where a fetus is considered to be too small for its gestational age (generally in the 10th percentile). ... In medicine (obstetrics), fetal distress is the presence of signs in a pregnant woman—before or during childbirth—that the fetus is not well or is becoming excessively fatigued. ... Dilation in physiological context may mean: pupil dilation (mydriasis) dilation of blood vessels (vasodilation) cervical dilation (or dilation of the cervix) in childbirth Dilation and curettage (surgical dilation) In mathematics: Dilation This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same... Chorioamnionitis is a inflammatory condition of pregnancy affecting the uterus. ... PIH can refer to: Permanent income hypothesis - an economic model Pocatello Regional Airport Pregnancy-induced hypertension ‹ The template below has been proposed for deletion. ... One of the main problems involving the female reproductive organs is vaginal bleeding. ... There are different forms of heart disease: Coronary heart disease, the end result of the accumulation of atheromatous plaques within the walls of the arteries that supply the myocardium Ischaemic heart disease, a disease characterized by reduced blood supply to the heart. ...

References

1. ↑  Castren O, Gummerus M, Saarikoski S. Treatment of imminent premature labour. Acta Obstet Gynecol Scand 1975;54:95–100. [4]

1. ↑ Wong, Perry, and Hockenberry. Maternal Child Nursing Care. Mosby 2002