Medicine to prevent uterine contractions

Because some women will experience false labor during pregnancy, even in the second trimester, which will make women feel abdominal pain and is not good for the growth and development of the fetus, so they need to take some drugs to prevent labor. These drugs can relieve the pain of patients and prevent false labor. What are the drugs to prevent labor?

What are the drugs that inhibit uterine contractions?

According to the mechanism of action, tocolytics can be divided into two categories: the first category: blocking or inhibiting the release of synthetic tocolytic substances, such as ethanol, prostaglandin synthase inhibitors, etc.; the second category: changing the reactivity of the uterine muscle to tocolytic substances, such as magnesium sulfate, β2-adrenergic receptor stimulants, antihypertensive drugs, etc. If they cannot prevent the progress of labor, they should be discontinued immediately. The commonly used drugs are as follows:

1. Indomethacin (Indomethacin): Prostaglandins stimulate uterine contraction and cause the cervix to soften and become receptive. Indomethacin can inhibit prostaglandin synthase and thus inhibit the synthesis of prostaglandins. The usual dose is 25 mg orally every 6 hours; or 50 mg rectal suppository once every 12 hours until uterine contractions stop.

2. Magnesium sulfate: Magnesium ions can compete with calcium ions to enter the sarcoplasmic reticulum and can directly act on muscle cells, reducing the potential difference of the muscle cell membrane without producing muscle contraction. The inhibitory effect is related to the dose. When the serum magnesium concentration is 2-4mmol/L (4-8mEq/L), it can completely inhibit the natural contraction of the uterine muscle and the uterine contraction caused by oxytocin.

3. β2-adrenergic receptor stimulants: β2-receptors are mainly found in uterine blood vessels, bronchi and diaphragm smooth muscles. The drug acts directly on the receptors on the smooth muscle cell membrane and after binding to the corresponding receptors, it activates adenylate cyclase and increases the cyclic adenosine monophosphate (cAMP) content in the smooth muscle cells, inhibits the release of calcium from the sarcoplasmic reticulum, reduces the calcium content in the cytoplasm, relaxes the uterine muscles and inhibits uterine contractions.

4. Calcium antagonists: The main function is to prevent calcium ions from entering the cell membrane, prevent the release of calcium from the intracellular muscle fiber membrane and increase the excretion of calcium from the smooth muscle, thereby reducing the calcium content in the cytoplasm and relaxing the uterine muscle. Among this type of drugs, the most effective is nifedipine (nifedipine) with a dose of 10 mg, taken orally 3 times a day. It works faster when taken sublingually and can reduce the amplitude of uterine contractions and muscle tension. However, it can cause peripheral vasodilation, slowing of atrioventricular conduction and subsequent reflex tachycardia, headache, hot flashes, and reduced uteroplacental blood flow.

What to do if you have frequent contractions

Uterine contractions usually begin about a month before delivery, and expectant mothers will feel that the frequency of uterine contractions is increasing. Generally, when calculating uterine contractions, if the number of contractions per hour is around 10, it is considered relatively frequent. You should go to the hospital in time and take some drugs to inhibit uterine contractions under the guidance of a doctor to prevent premature birth. If the contractions are not very frequent and there is no abdominal pain, just rest. It should be noted that you should not take any medication on your own to avoid harming the fetus. Moreover, taking medicine usually cannot relieve the symptoms. At this time, pregnant mothers should pay attention to rest, especially avoid stimulating the abdomen. If uterine contractions are accompanied by severe abdominal pain, such as pain that makes you restless and your work and life affected, you need to go to the hospital for treatment.