Different kinds of birth control needles are used in different ways, usually said birth control needles are mainly progesterone injection, which needs to be injected intramuscularly in the buttocks, birth control needles actually also include HCG for injection, magnesium sulfate or ritodrine injection, etc. The following is a list of different pregnancy medications according to different pregnancy medications: 1. Commonly used in early pregnancy: progesterone injection, which is usually taken intramuscularly in the buttocks. Progesterone can supplement the insufficient secretion of progesterone caused by luteal insufficiency, and can prevent preterm abortion. Intramuscular gluteal injections are given away from the nerves and large blood vessels and have a lower risk of causing more bleeding and nerve damage. It should be noted that the most common adverse reaction to intramuscular injection is local skin allergy, which manifests as redness, swelling, itching, pain, hard nodules, liquefaction and necrosis of subcutaneous fat at the injection site. Progesterone belongs to the oil injection, its oil molecules particles surface tension, difficult to be dissolved, slow tissue absorption, easy to cause the accumulation of drug in the tissue, there can be hard nodules formed, it is recommended to do local hot compresses after injection to promote drug absorption; 2, common drugs in the middle and late pregnancy: commonly used magnesium sulfate injection, ritodrine injection, intravenous injection therapy is required. Premature labor after 28 weeks of gestation preferred magnesium sulfate intravenous drip, if the contractions are difficult to suppress, you can choose ritodrine injection. Among them, magnesium sulfate can make the smooth muscle of uterus relax, and at the same time have the function of protecting the fetal nervous system, so as to achieve the effect of fetal preservation, some people will have fever, nausea, vomiting, slowing down breathing after inputting magnesium sulfate, and long-term use of magnesium sulfate will cause fetal calcium deficiency. Therefore, it should be used under the guidance of a doctor, while maintaining emotional stability and avoiding excessive stress.