Title: AboutKidsHealth
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Content: Depending on the causes of the birth and how premature the baby is, it may also be an emergency. This section explores the causes of premature birth, the signs of premature birth, and strategies to delay premature birth. In many cases, premature birth cannot be avoided.</p>

<h2>Key points</h2> <ul><li>Some premature births can be caused by problems with the fetus, the mother or both.</li> <li>Certain events can stimulate the onset of premature labour including placental abruption, incompetent cervix, hormonal changes or infection.</li> <li>There are multiple risk factors for premature birth including having a previous premature birth, pregnancy with multiple babies, infection, drug or alcohol use, and age.</li> <li>While some risk factors cannot be changed, there are a few general ways to reduce the odds of having a premature birth.</li></ul>
<p>Premature birth can have many causes which include problems with the fetus, the mother, or both. However, about fifty percent of the time, the cause or causes of a premature birth are unknown. </p><p>When the cause is known, premature birth most frequently comes as a result of a premature rupture of the fetal membranes which initiates labour. </p><p>Certain events can stimulate the onset of premature labour. These include:</p><ul><li> <a href="/Article?contentid=354&language=English">placental abruption</a>, where the placenta separates from the uterus during pregnancy</li><li>incompetent cervix, where the cervix painlessly and gradually opens before the time it is supposed to </li><li>hormonal changes, which can cause stress in the unborn baby or mother </li><li>infection </li></ul> <figure class="asset-c-80"> <span class="asset-image-title">Placental abruption</span> <img src="https://assets.aboutkidshealth.ca/AKHAssets/Placental_abruption_MED_ILL_EN.png" alt="Fetus in a uterus with a normal placenta and fetus in a uterus with placental abruption" /> <figcaption class="asset-image-caption">The placenta is normally implanted into the wall of the uterus where there are many blood vessels that supply the baby with oxygen and nutrients. With placental abruption, the placenta becomes detached from the uterus, and bleeding may occur.</figcaption> </figure> <h2>Risk factors for premature labour</h2><p>There are a number of factors that can put a pregnant woman at higher risk for having a premature labour and delivery. If you had a previous premature labour, your chance of having another premature labour increases two and a half times. That rate jumps to 10 times if your previous premature labour occurred before the 28th week of pregnancy.