9.3.1: Risks to the Newborn

Learning Objectives

1. Describe common medical complications of the newborn period.
2. Differentiate between preterm, small-for-date, and postmature infants.
3. Identify causes and risk factors for stillbirth and Sudden Infant Death Syndrome (SIDS).

Problems of the Newborn

Anoxia

Anoxia is a temporary lack of oxygen to the brain. Difficulty during delivery may lead to anoxia, which can result in brain damage or, in severe cases, death. Babies who suffer both low birth weight and anoxia are more likely to suffer learning disabilities later in life as well.

Low Birth Weight

A child is considered low birth weight if he or she weighs less than 5 pounds 8 ounces (2500 grams). About 8.2 percent of babies born in the United States are of low birth weight (Centers for Disease Control, 2015a). Sixty-seven percent of these babies are also preterm.

A low-birth-weight baby has difficulty maintaining adequate body temperature because it lacks the fat that would otherwise provide insulation. Such a baby is also at more risk for infection. Very low birth weight babies (2 pounds or less) have an increased risk of developing cerebral palsy. Many causes of low birth weight are preventable with proper prenatal care.

Preterm

A newborn might also have a low birth weight if it is born at less than 37 weeks gestation, which qualifies it as a preterm baby (CDC, 2015b). Early birth can be triggered by anything that disrupts the mother's system. For instance, vaginal infections can lead to premature birth because such infection causes the mother to release anti-inflammatory chemicals which, in turn, can trigger contractions. Smoking and the use of other teratogens can lead to preterm birth. A significant consequence of preterm birth includes respiratory distress syndrome, which is characterized by weak and irregular breathing (see the image below). Premature babies often cannot yet regulate their own body temperature or feed by nursing or bottle. They may struggle to regulate their heart rate effectively and may experience jaundice. They often require care in the Neonatal Intensive Care Unit (NICU) until they are as healthy as a full-term baby.

Figure \(\PageIndex{1}\): A premature baby on CPAP in the NICU. Photo by Jennifer Paris used with permission.

Small-for-Date Infants

Infants who have birth weights that are below expectation based on their gestational age are referred to as small-for-gestational-age. These infants may be full term or preterm (see image below), but still weigh less than 90% of all babies of the same gestational age. This is a very serious situation for newborns, as their growth has been adversely affected. Regev et al. (2003) found that small-for-date infants died at rates more than four times higher than other infants.

Figure \(\PageIndex{2}\): This baby was born at 32 weeks and only weighed 2 pounds and 15 ounces. Photo by Jennifer Paris used with permission.

Postmature

When babies are not born by 42 weeks gestation, or two weeks after their due date, they are considered overdue or postmature. There are some concerns about how long the placenta can function, and most doctors will consider induction for overdue babies.

Stillborn

When a fetus (unborn baby) dies while still inside the mother (after 20-24 weeks gestation) or dies during delivery (childbirth). It is said that the delivered baby is stillborn. The causes of many stillbirths are unknown, even when special tests are done to learn the cause. Possible causes include: nicotine, alcohol, or drugs taken by the mother during pregnancy, physical trauma, radiation poisoning, Rh disease, and umbilical cord problems. The number of stillbirths in the United States is about 1 in 115 births, which is about 26,000 a year, or one every 20 minutes. ²⁸

Sudden Infant Death Syndrome (SIDS)

Sudden Infant Death Syndrome (SIDS) is the unexpected and unexplained death of an otherwise healthy infant, typically occurring during sleep. While the exact cause of SIDS remains unclear, research has identified several risk factors related to newborn health that can contribute to its occurrence.

• Newborns with low birth weight (less than 5 pounds, 8 ounces) or who are born prematurely (before 37 weeks of gestation) face an increased risk of SIDS. These infants often have underdeveloped respiratory and cardiovascular systems, which can lead to difficulties in regulating breathing and heart rate during sleep (Horne et al., 2015).
• Additionally, premature and low-birth-weight infants may have immature brainstem development, which affects the ability to arouse from sleep and respond to low oxygen levels, a critical protective mechanism against life-threatening events during sleep (Kinney et al., 2009).
• Respiratory infections may impair breathing, especially during sleep, while undiagnosed metabolic disorders can interfere with energy production and other essential bodily functions, making an infant more vulnerable to sudden death (Moon, 2016).

References, Contributors and Attributions

^{28. Lifespan Development: A Psychological Perspective (pages 62-63) by Martha Lally and Suzanne Valentine-French is licensed under CC BY-NC-SA 3.0; Stillbirth by Wikipedia by Wikipedia is licensed under CC BY-SA 3.0}

Centers for Disease Control and Prevention. (2015a). Birthweight and gestational age. https://www.cdc.gov/nchs/fastats/birthweight.htm

Centers for Disease Control and Prevention. (2015b). Preterm birth. https://www.cdc.gov/features/prematurebirth/index.html

^{Horne, R. S., et al. (2015). Sudden infant death syndrome: Current perspectives. International Journal of Women's Health, 7, 735–745. https://doi.org/10.2147/IJWH.S66770}

^{Kinney, H. C., et al. (2009). The brainstem and serotonin in the sudden infant death syndrome. Annual Review of Pathology: Mechanisms of Disease, 4, 517–550. https://doi.org/10.1146/annurev.path....110807.092322}

^{Moon, R. Y. (2016). SIDS and other sleep-related infant deaths: Evidence base for 2016 updated recommendations for a safe infant sleeping environment. Pediatrics, 138(5), e20162938. https://doi.org/10.1542/peds.2016-2938}

Regev, R. H., Arnon, S., Litmanovitz, I., Bauer-Rusek, S., Boyko, V., & Lerner-Geva, L. (2003). Association between low birthweight and mortality among small-for-gestational-age infants. Israel Medical Association Journal, 5(7), 416–419. https://pubmed.ncbi.nlm.nih.gov/12870261/