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    Babies Born at 31 Weeks: Everything You Might Need to Know

    Updated 27 August 2021 |
    Published 04 January 2020
    Fact Checked
    Reviewed by Olga Adereyko, MD, Primary Care Physician, General Practitioner, Medical Consultant
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    Pregnancy is an exciting time for many women, but it can also be filled with fears, especially for women with high-risk pregnancies. A baby born at 31 weeks has not had a chance to fully develop their lungs, immune system, sucking reflex, or enough body fat to maintain their body temperature. Thankfully, modern medicine can provide everything a baby born at 31 weeks needs to thrive. 

    Full term and early term

    Although a typical pregnancy lasts 40 weeks, a baby is considered full term after the 37th week of pregnancy. Babies born before 37 weeks are considered premature. 

    Premature babies often have medical problems that vary in complexity based on each case. The earlier a baby is born, the more severe the medical problems tend to be. Depending on the gestational week that the baby is born in, they may be: 

    • Late preterm — born between 34 and 36 weeks 
    • Moderately preterm — born between 32 and 34 weeks 
    • Very preterm — born at or before 32 weeks 
    • Extremely preterm — born at or before 25 weeks 

    Most premature births happen after 34 weeks of gestation, in the late preterm stage. Currently, the premature birth rate in the United States is approximately 11.5 percent.

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    Causes for preterm birth

    Preterm birth can happen for various reasons, and often the reason is unknown. It can happen spontaneously or because of medical intervention. Certain risk factors are known to increase a woman’s chance of giving birth prematurely: 

    • Having a medical condition such as diabetes, heart disease, kidney disease, or high blood pressure 
    • Poor nutrition before or during pregnancy 
    • Smoking
    • Using illegal drugs or drinking too much alcohol during pregnancy 
    • Having a previous premature birth
    • Being pregnant with multiples 
    • Having less than six months between pregnancies
    • Conceiving through in-vitro fertilization
    • Infection, such as lower genital tract or amniotic fluid infections
    • A weakened cervix opening early 
    • Problems with the uterus or placenta
    • Being underweight or overweight
    • Stress, including life events such as the death of a loved one
    • Multiple miscarriages or abortions
    • Physical injury

    Premature birth can happen to anyone, although for unknown reasons, black women are more likely to give birth prematurely than other women. In many cases, women who experience preterm labor have no known risk factors.

    Baby born at 31 weeks: appearance and possible complications

    Depending on the gestational age of your baby at birth, they may look different from a full-term baby.

    Babies born at 31 weeks are considered to be very preterm. Because they are not fully developed yet, their features may look different. 

    • Their skin may appear translucent.
    • Their head may be disproportionately larger than the rest of their body.
    • They may have sharper-looking features that are less rounded due to the lack of fat stores.
    • Fine hair called lanugo may cover their whole body.
    • Your baby may not be able to regulate their body temperature and may exhibit labored breathing.

    Short-term complications

    Not all premature babies experience health complications. Generally, the earlier a baby is born, the higher their risk of complications. 

    The first few months are the most critical for premature babies. During this time, your baby may experience: 

    • Breathing problems — Your baby may have difficulty breathing. Premature babies are at risk of developing a lung disorder called bronchopulmonary dysplasia and pauses in breathing called apnea.
    • Heart problems — Very premature babies can experience heart problems. The problem often resolves on its own, but if left untreated, it can lead to a heart murmur, heart failure, or other complications.  
    • Gastrointestinal problems — A premature baby’s immature gastrointestinal system is not designed to digest food yet. This can lead to potentially life-threatening complications once they start feeding. 
    • Brain problems — Preterm babies are at risk of brain bleeding (hemorrhaging). 
    • Temperature control problems — Premature babies often do not have enough body fat to maintain a healthy body temperature. Because of this, they are at risk of hypothermia, which can lead to breathing problems and low blood sugar levels. To counteract this, premature babies are often kept in incubators until they can maintain their body temperature on their own.
    • Jaundice and anemia — Premature babies are at risk of blood problems such as jaundice. Jaundice happens when there is extra bilirubin in the blood, which causes babies’ skin and the whites of their eyes to turn yellowish. Anemia can also develop when the body does not have enough red blood cells. 
    • Immune system problems — Premature babies have a high risk of infection because their immune systems are not fully developed yet. 
    • Metabolism problems — Some premature babies have hypoglycemia — a low level of blood sugar — because they have small stores of glucose.

    Long-term complications

    Premature babies have a higher risk of long-term complications than full-term babies. Problems that may occur in premature babies include: 

    • Overall developmental delays
    • Growth and movement problems
    • Language delays
    • Vision problems 
    • Hearing problems 
    • Dental problems 
    • Learning difficulties
    • Behavioral and psychological problems 
    • Social and emotional problems 
    • Chronic health issues

    For a baby born at 31 weeks, the survival rate is 90–95 percent.

    Treatment for a 31-week premature baby

    If you have a baby born at 31 weeks, they will be treated in the neonatal intensive care unit (NICU) with around-the-clock care that may include:  

    • An incubator — If your baby cannot maintain normal body temperature, an enclosed incubator will help keep them warm. 
    • Constant monitoring of vitals — Your baby’s heart rate, blood pressure, body temperature, and breathing will be monitored with sensors. 
    • Replenishing fluids — Your baby’s fluids and electrolytes will be monitored and replenished through an intravenous line when necessary. 
    • Breathing support — Your baby may need a ventilator to help them breathe. 
    • Feeding assistance — If your baby has difficulty swallowing, they may need a feeding tube through their nose and into their stomach.
    • Bilirubin lights — Your baby may be placed under a set of lights to help their body break down excess bilirubin. 
    • Blood transfusion — Your premature baby may need a blood transfusion to raise their blood volume.


    Depending on your baby’s condition, they may be given medication to help their heart, lungs, and circulatory system function properly. Sometimes, preterm babies are given diuretics — medication that increases urine output — to manage excess fluid. 

    If there is an infection or risk of infection, your baby will be given antibiotics. 

    In some cases, preterm babies may require surgery to treat a medical condition.

    When will you go home?

    After some time in the NICU, it can be a huge relief to finally get to go home with your baby. 

    When your baby can breathe on their own, maintains a stable body temperature, gains weight steadily, feeds properly, and is free from infection, they’re ready to go home. 

    Before you leave the hospital with your new baby, your health care team will walk you through everything necessary to care for your baby at home. Don’t hesitate to ask if you have any questions about your baby’s care.

    Wrapping up about babies born at 31 weeks

    Bringing a new life into the world can be challenging, especially when your baby is born preterm. Babies born at 31 weeks may have some health challenges, but they have a very good chance of living happy, healthy, and long lives. For now, take it one day at a time, and use the support of your family and friends to help you care for your baby as best as you can. 

    History of updates

    Current version (27 August 2021)

    Reviewed by Olga Adereyko, MD, Primary Care Physician, General Practitioner, Medical Consultant

    Published (04 January 2020)

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