Premature birth occurs when a baby is born before 37 weeks of pregnancy. The exact cause of premature birth is often unknown, but certain factors can increase the risk of it happening. Here are some of the most common causes and risk factors:

• Risk factors related to pregnancy: Pregnancy with twins, triplets, or other multiples; a span of less than six months between pregnancies; treatments to help you get pregnant, called assisted reproduction, including in vitro fertilization; more than one miscarriage or abortion; a previous premature birth.
• Health problems: Problems with the uterus, cervix, or placenta; some infections, mainly those of the amniotic fluid and lower genital tract; ongoing health problems such as high blood pressure and diabetes; injuries or trauma to the body.
• Lifestyle choices: Smoking cigarettes, taking illicit drugs, or drinking alcohol often or heavily while pregnant.
• Other factors: Chronic health conditions, such as diabetes or infections; drug or alcohol abuse; multiple pregnancies, such as twins or triplets; preeclampsia (high blood pressure during pregnancy); problems with the uterus or cervix; too little time (less than 18 months) between pregnancies; vaginal bleeding or infections during pregnancy; being Black; being under the age of 20 or over the age of 40; having a family or personal history of preterm births.

Its important to note that most premature births happen spontaneously (naturally) and doctors will not know why. However, certain factors can increase the risk of it happening.