Premature birth, the delivery of an infant before the completion of 37 weeks of pregnancy, can be attributed to a variety of factors, including infections, chronic medical conditions, and multiple pregnancies. Socioeconomic factors may also play a role.
The World Health Organization (WHO) classifies preterm birth as moderately premature (32–37 weeks), very premature (28–31 weeks), and extremely premature (under 28 weeks).
Premature birth. Tragically, premature birth complications stand as a leading cause of mortality among children under five years of age. This article examines the causes of premature birth.
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What are the possible causes of premature birth?
Chronic health conditions
Despite ongoing research efforts by doctors and scientists, the exact causes of premature birth remain a mystery, with a multitude of complex factors potentially playing a role. These include:
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- Diabetes: Diabetes can increase the risk of premature birth by altering the function of crucial molecules in the body. Individuals with diabetes should maintain close collaboration with their healthcare providers to mitigate pregnancy complications.
- High blood pressure: Elevated maternal blood pressure can disrupt the flow of crucial nutrients and oxygen to the growing fetus, potentially prompting the need for early delivery.
- Heart disease: The physiological adaptations associated with pregnancy can increase the strain on the heart, and for individuals with underlying heart disease, these changes can exacerbate the risk of complications for both the mother and the developing fetus.
- Antiphospholipid syndrome (APS): People afflicted with Antiphospholipid Syndrome (APS) demonstrate an increased propensity for blood clot formation. Although the precise pathways through which APS contributes to premature birth remain to be fully elucidated, normal physiological adaptations associated with pregnancy may potentiate the risk of blood clot blockages in APS patients, potentially culminating in preterm delivery.
- Obesity: Obesity, characterized by an excessive accumulation of body fat or weight that can adversely impact health, can lead to chronic inflammation in pregnant women. This inflammation can impair placental function and hinder fetal growth, potentially triggering premature contractions and early labor.
Multiple pregnancies
Multiple pregnancies, characterized by the simultaneous development of more than one fetus, are associated with an increased risk of premature birth. A 2018 study revealed that half of all twin pregnancies culminate in premature delivery prior to 37 weeks of gestation, while 10% of individuals pregnant with twins experience delivery before 32 weeks of pregnancy.
The article states that researchers have proposed various potential causes for premature twin birth, which include:
- increased release of corticotrophin?releasing hormone, which may trigger premature birth
- increased levels of a protein called surfactant protein?A, which can stimulate an inflammatory response in the uterus that may begin labor
- stretching of the uterus, which can lead to premature birth
- a higher risk of complications, which may prompt a doctor to induce premature birth medically
Closely spaced pregnancies, characterized by a short interval between giving birth and becoming pregnant again, can also elevate the risk of premature birth. While the precise underlying mechanisms remain unclear, medical professionals recommend waiting at least 18 months between pregnancies to minimize this risk.
Pregnancy complications
Several pregnancy complications can precipitate premature birth. In the face of certain complications, medical professionals often opt to induce labor, thereby initiating premature delivery to mitigate risks for both the parent and the fetus.
Examples of complications include:
- Preeclampsia and eclampsia: High blood pressure in pregnancy can be life threatening. Severe cases may necessitate the induction of premature birth.
- Infections during pregnancy: Infections may affect the health of the parent and the fetus and can weaken the lining of the amniotic sac. Infections that premature birth include:
- sexually transmitted infections (STIs)
- urinary tract infections (UTIs)
- trichomoniasis
- bacterial vaginosis
- Fetal growth restriction (FGR): In FGR, a fetus is smaller than average and can develop various health complications. Fetuses with FGR are at higher risk of premature birth.
- Gestational diabetes: Gestational diabetes is a type of diabetes that may occur during pregnancy. It can cause various health complications in the parent and fetus.
- Placental abruption: In placental abruption, the placenta separates from the uterus lining too soon. This can cause premature birth and various health complications for the fetus and parent.
- Polyhydramnios: Polyhydramnios occurs when too much amniotic fluid surrounds the fetus, possibly causing early labor.
- Preterm prelabour rupture of membranes (PPROM): PPROM is when a person’s water breaks too soon before labor. If this happens, a doctor may need to induce early labor.
- Twin-to-twin transfusion syndrome: In pregnancies where twins share a placenta, there may be an imbalance of blood supply between the fetuses.
- Intrahepatic cholestasis of pregnancy (ICP): This liver disorder may cause bile to build up in the body. ICP may lead to premature birth and can cause stillbirth.
Drug or alcohol use
The consumption of alcohol and both legal and illegal drugs poses a grave risk to fetal health, as these substances effortlessly traverse the placenta and can induce severe and potentially life-threatening complications. This may lead to premature birth or necessitate early labor induction.
Uterine abnormalities
Certain abnormalities in the uterus or cervix may increase the risk of premature birth. These include:
- Having an unusually shaped uterus: If a pregnant person has an unusually shaped womb, such as a unicornuate uterus with one fallopian tube, they may be at increased risk of premature birth.
- Cervical insufficiency: A cervix may weaken and become unable to hold the fetus, which can result in premature birth.
- Placenta previa: With this condition, the placenta obstructs the cervix, which can lead to hemorrhage. Placenta previa can be life threatening for the parent and fetus and may require a doctor to induce a preterm birth.