The length of a term pregnancy should be around 40 weeks gestation. When a baby is born before 37 weeks gestation, they are considered premature. Around one in 10 babies, is born too early.
Babies born before they reach 37 weeks gestation are considered premature. It is estimated that one in 10 babies are born too early.
Prematurity can be broken down into: extremely preterm (25 weeks or less), very preterm (32 weeks or less), moderately preterm (32 to 34 weeks), and late preterm (34 to 36 weeks).
Numerous risk factors can cause preterm birth, like being pregnant with multiples, smoking/alcohol/drug use, high blood pressure, diabetes or other health conditions, stress, malnourishment, etc.
There are risk factors that increase the possibility of a baby being born prematurely, but sometimes, the cause of preterm birth is unknown.
When is a baby considered premature?
Any birth that occurs before 37 weeks gestation is considered a premature delivery. Premature babies, or preemies, can be classified into categories depending on what gestational age they are born at:
Extremely preterm: Born at 25 weeks gestation or younger.
Very preterm: Born at 32 weeks gestation or younger.
Moderately preterm: Born between 32 and 34 weeks gestation.
Late preterm: Born between 34 and 36 weeks gestation.
The birth of your baby is one of the most exciting and memorable moments in life. Parents hope for an uncomplicated pregnancy and for the baby to be born full-term and healthy, but this is not always the case. It is estimated that each year, approximately 15 million babies worldwide are born prematurely.
Experiencing a preterm birth can be a frightening and stressful event. The gestational age at which your baby is born and the situation surrounding the birth will determine the effects prematurity has on your baby. Every situation is different, so the effects of prematurity can vary widely.
How prematurity affects babies
A baby that is born at 23 weeks gestation will have a vast difference in complications compared to a baby born after 30 weeks gestation. Each week that a fetus remains in the womb allows for the further development of organs and body functions. The earlier a baby is born, the more underdeveloped its organs are.
Babies born prematurely will likely go into a Neonatal Intensive Care Unit (NICU). The staff in the NICU specializes in caring for preemies and sick newborns. The length of stay in the NICU will vary depending on the age of the baby and the situation.
Preterm babies are at a higher risk of bleeding in the brain, also called intraventricular hemorrhage (IVH). The vessels within the brain are fragile, and bleeding can occur more easily. The bleeding puts pressure on the brain and can cause damage to brain cells. Some babies may develop lasting neurological complications, like cerebral palsy. Babies born under 32 weeks gestation are at a greater risk of IVH.
Temperature instability is another common problem that premature babies experience. They should still be safe and warm within their mother’s womb but must adapt to the outside world too soon. Their skin is thinner, they have less body fat for insulation, and the part of the brain that regulates body temperature, the hypothalamus, is underdeveloped. Premature babies usually require a source of heat to maintain their body temperatures and may be placed in an isolette or bed warmer until they can be moved to an open crib.
Breathing problems are common among preemies. Their lungs are underdeveloped, and they can experience rapid breathing (tachypnea) and can have excess fluid in the lungs. Many premature babies require oxygen after birth, which can include:
- Low-flow nasal cannula.
- High-flow nasal cannula.
- Nasal CPAP (continuous positive airway pressure) mask.
Apnea of prematurity (AOP) can also occur. This is when a premature baby has episodes where they stop breathing for more than 20 seconds, which can cause the baby’s oxygen levels and heart rate to drop (bradycardia). There are several treatments available for AOP and bradycardia, and most preemies will outgrow these conditions.
Premature babies have difficulty feeding due to the immature muscles of the mouth and throat, the inability to coordinate sucking, swallowing, and breathing, and not having enough energy to properly breastfeed or bottle feed. Many preemies require total parenteral nutrition to be administered by an intravenous (IV) line and a gavage tube that is placed down the nose or mouth, ending in the stomach. Small amounts of milk can be fed by the gavage tube until the baby can tolerate full feedings.
Preemies have a more challenging time gaining weight, and as they get older, they may be smaller than other babies who were born closer to term. Parents of preterm babies may find that people assume their baby is younger than they are due to their smaller size, but many preemies eventually grow to be healthy-sized children.
Causes of premature births
There are risk factors that increase the likelihood of premature birth, but there are times when no definitive cause can be found for why a baby was born early. Some of the common risk factors include:
- Being pregnant with multiples: twins, triplets, etc.
- Pregnancy through in vitro fertilization.
- Congenital anomalies of the fetus.
- History of preterm birth, miscarriages, or abortions.
- Maternal high blood pressure or diabetes.
- Infection or problems with the cervix, uterus, or placenta.
- Stress, depression, or domestic violence.
- Being underweight or overweight.
- Smoking, alcohol, or drug use.
- Malnutrition and dehydration.
Tips to help prevent premature births
Premature births cannot always be prevented. There are certain situations and medical conditions of both fetus and mother that make premature delivery unavoidable.
Sometimes a baby is born prematurely without any known cause and at no fault of the mother. That said, here are tips to reduce risk factors for premature birth:
When you learn you are pregnant, make an appointment with an OB-GYN (obstetrician/gynecologist), so they can follow your health and the health of the fetus throughout the pregnancy.
Eat a healthy diet that consists of lean proteins, fruits, vegetables, and whole grains. Drink plenty of water and limit sodas, sugary drinks, and caffeine. Avoid processed foods as much as possible.
Take prenatal vitamins and exercise for 30 minutes a day, several times a week.
Do not smoke, drink alcohol, or use drugs during pregnancy.
Ask your OB-GYN which medications are safe to take during pregnancy and stop any unsafe medications.
Try to limit the stress in your life, talk to your doctor if you have depression, and seek help if you are in an abusive relationship.
Commonly asked questions
Expectant parents have many questions about the birth of their child. Here are some of the most frequently asked questions about premature babies:
Do all premature babies go into the NICU? No, some babies that are born late preterm and not struggling after delivery can go to the newborn nursery and then home with their parents.
Do premature babies look different from term babies? Preemies are often small and do not have much body fat, and they may have heads that are larger than their bodies. They may also have a layer of fine hair called lanugo that covers their thin skin.
Do all premature babies have lifelong health problems? No, some preemies grow to be healthy children/adults.
Can premature delivery be avoided? Limiting risk factors will reduce the chance of preterm birth, but many times it is unavoidable.
Premature babies are born before 37 weeks gestation, and many preemies will require specialized care in the NICU after they are born. There are multiple risk factors for premature birth, but sometimes there is no particular reason a baby is born early. Preemies are at higher risk of health problems; some are short term while others can be long-lasting effects.
- CDC. Preterm Birth.
- Annual Reviews. Prematurity: An Overview and Public Health Implications.