Birth weight

Baby weighed as appropriate for gestational age.

Birth weight is the weight of a baby at birth. The average birth weight in babies of Europeans is 3.5 kilograms (7.7 lb); the range of normal weights is from 2.5 to 4.5 kilograms (5.5 to 9.9 lb). On average, babies of south Asian and Chinese people weigh about 3.26 kilograms (7.2 lb). The birth weight of a baby is important. Babies with a low birth weight are 100 times more likely to die compared to babies of a normal weight.

The rates of babies with low birth weight have changed. In 1970, 7.9% had a low birth weight. In 1980, this dropped to 6.8%. In 2006, it slightly increased to 8.3%, and the current level is at 8.2%, for the year 2016. The prevalence of low birth weight has trended slightly upward from 2012 to present day.

Studies have tried to link birth weight with other conditions that occur in later life, such as diabetes, obesity, tobacco smoking[verification needed], and intelligence. Low birth weight is associated neonatal infection and infant mortality.

Causes

Things that influence birth weight

Genetics

To some extent, birth weight is heritable. If the parents had a low birth weight, the babies may also have one. (This is the same for a high birth weight). The heritability of birth weight ranges from 25-40 %. There is a complex relationship between a babies genes and the maternal environment that the child is developing in. Foetal genes influence how the fetus grows in the womb, and the genes of the mother influence how the environment affects the growing fetus.

Health of the mother

The health of the mother during pregnancy can affect birth weight. If the mother is ill, or has a chronic condition during pregnancy, those factors can affect birth weight. Usually, this will lead to a lower bith weight. For example, celiac disease confers an odds ratio of low birth weight of approximately 1.8. Certain drugs, such as those used to treat high blood pressure or epilepsy can also have this effect. Other factors that affect birth weight are that if the mother is going to give birth to twins, which is called multiple births in English.

Another factor that affects birth weight is the age of the mother. Girls 15 or younger, or women over 35 have a higher risk of having a child with a low birth weight.

Stress

Stressful events have significant effects on birth weight. Mothers who are exposed to stressful events during their pregnancy have a higher risk of giving birth to babies with a low birth rate. This is especially true if the events happen during the first or the second trimester. Reserchers also found that stressful events that happen before conception (impregnation) can also have a negative effect on the pregnancy. The same is true for women exposed to situations of abuse.

Environment

The environment the woman lives in can also determine the weight of the baby. One of these factors is secondhand smoke

Environmental factors, including exposure of the mother to secondhand smoke can be a factor in determining the birth weight of child. In 2014, 13% of children exposed to smoke were born with low birth weight compared with 7.5% of those children born to nonsmokers. Children born to mothers who smoked or were exposed to secondhand smoke are more likely to develop health problems earlier in life such as neurodevelopmental delays. When mothers actively smoke during pregnancy, their child is at a higher risk of being born with a low birth weight. Smoking can also be a stress management tool used by expecting mothers. There is some support for lower socioeconomic status of the parents being a determinant of low birth weight, but there is conflicting evidence, as socioeconomic status is tied to many other factors.

Neonatal care

Most babies admitted to the intensive care unit are born before 37 weeks of pregnancy or have low birth weight which is less than 5.5 pounds. They could also have a medical condition that requires special care. In the United States nearly half a million babies are born preterm. Because of this, many of these babies also have low birth weights. There are four levels of care in the neonatal care units. Intensive Care, High Dependency Care, Low Dependency, and Transitional Care are the four levels:

Influence on the first few years of life

Poster from the Soviet Union encouraging mothers to weigh their babies every week. (1930)

Children born with an very low birth weight can have significant problems during the first few years of life. They may have trouble gaining weight, obtaining adequate nutrition, and supporting a strong immune system. They also have higher risks of dying, behavior problems, and mental deficiencies. Low birth weight babies are more likely to develop the following conditions after birth compared to normal birth weight babies:

References

  1. ↑ "Definitions". Georgia Department of Public Health. 4 December 2008. Archived from the original on April 2, 2012. Retrieved 16 January 2022. Birthweight: Infant's weight recorded at the time of birth
  2. ↑ "New birth weight curves tailored to baby's ethnicity | Toronto Star". thestar.com. 15 February 2012. Retrieved 2016-09-22.
  3. ↑ Janssen PA, Thiessen P, Klein MC, Whitfield MF, Macnab YC, Cullis-Kuhl SC (July 2007). "Standards for the measurement of birth weight, length and head circumference at term in neonates of European, Chinese and South Asian ancestry". Open Medicine. 1 (2): e74-88. PMC 2802014. PMID 20101298.
  4. 1 2 "Low and very low birthweight infants". Child Trends Databank. 2016. Archived from the original on 2020-04-14. Retrieved 2022-01-16.
  5. ↑ "FastStats". www.cdc.gov. 2018-08-08. Retrieved 2018-11-25.
  6. ↑ Martin JA, Hamilton BE, Osterman MJ, Driscoll AK, Drake P (January 2018). "Births: Final Data for 2016". National Vital Statistics Reports. 67 (1): 1–55. PMID 29775434.
  7. 1 2 "Low birthweight". Retrieved 2018-11-25.
  8. ↑ Mendez-Figueroa H, Truong VT, Pedroza C, Chauhan SP (June 2017). "Large for Gestational Age Infants and Adverse Outcomes among Uncomplicated Pregnancies at Term". American Journal of Perinatology. 34 (7): 655–662. doi:10.1055/s-0036-1597325. PMID 27926975. S2CID 4165673.
  9. ↑ Clausson B, Lichtenstein P, Cnattingius S (March 2000). "Genetic influence on birthweight and gestational length determined by studies in offspring of twins". BJOG. 107 (3): 375–81. doi:10.1111/j.1471-0528.2000.tb13234.x. PMID 10740335.
  10. ↑ Lunde A, Melve KK, Gjessing HK, Skjaerven R, Irgens LM (April 2007). "Genetic and environmental influences on birth weight, birth length, head circumference, and gestational age by use of population-based parent-offspring data". American Journal of Epidemiology. 165 (7): 734–41. doi:10.1093/aje/kwk107. PMID 17311798.
  11. ↑ Yaghootkar H, Freathy RM (May 2012). "Genetic origins of low birth weight". Current Opinion in Clinical Nutrition and Metabolic Care. 15 (3): 258–64. doi:10.1097/mco.0b013e328351f543. PMID 22406741. S2CID 3402464.
  12. ↑ Tersigni C, Castellani R, de Waure C, Fattorossi A, De Spirito M, Gasbarrini A, et al. (2014). "Celiac disease and reproductive disorders: meta-analysis of epidemiologic associations and potential pathogenic mechanisms". Human Reproduction Update. 20 (4): 582–93. doi:10.1093/humupd/dmu007. PMID 24619876.
  13. 1 2 "Low birthweight". Retrieved 2018-11-25.
  14. ↑ Hedegaard M, Henriksen TB, Secher NJ, Hatch MC, Sabroe S (July 1996). "Do stressful life events affect duration of gestation and risk of preterm delivery?". Epidemiology. 7 (4): 339–45. doi:10.1097/00001648-199607000-00001. JSTOR 3702049. PMID 8793357. S2CID 25514196.
  15. ↑ Zhu P, Tao F, Hao J, Sun Y, Jiang X (July 2010). "Prenatal life events stress: implications for preterm birth and infant birthweight". American Journal of Obstetrics and Gynecology. 203 (1): 34.e1–8. doi:10.1016/j.ajog.2010.02.023. PMID 20417475.
  16. ↑ Witt WP, Cheng ER, Wisk LE, Litzelman K, Chatterjee D, Mandell K, Wakeel F (February 2014). "Maternal stressful life events prior to conception and the impact on infant birth weight in the United States". American Journal of Public Health. 104 Suppl 1 (1): S81-9. doi:10.2105/AJPH.2013.301544. PMC 3975462. PMID 24354829.
  17. ↑ Khashan AS, McNamee R, Abel KM, Mortensen PB, Kenny LC, Pedersen MG, et al. (February 2009). "Rates of preterm birth following antenatal maternal exposure to severe life events: a population-based cohort study". Human Reproduction. 24 (2): 429–37. doi:10.1093/humrep/den418. PMID 19054778.
  18. ↑ Class QA, Khashan AS, Lichtenstein P, Långström N, D'Onofrio BM (July 2013). "Maternal stress and infant mortality: the importance of the preconception period". Psychological Science. 24 (7): 1309–16. doi:10.1177/0956797612468010. PMC 3713176. PMID 23653129.
  19. ↑ Murphy CC, Schei B, Myhr TL, Du Mont J (May 2001). "Abuse: a risk factor for low birth weight? A systematic review and meta-analysis". CMAJ. 164 (11): 1567–72. PMC 81110. PMID 11402794.
  20. ↑ Lee BE, Hong YC, Park H, Ha M, Kim JH, Chang N, et al. (May 2011). "Secondhand smoke exposure during pregnancy and infantile neurodevelopment". Environmental Research. 111 (4): 539–44. Bibcode:2011ER....111..539L. doi:10.1016/j.envres.2011.02.014. PMID 21397902.
  21. ↑ Pereira PP, Da Mata FA, Figueiredo AC, de Andrade KR, Pereira MG (May 2017). "Maternal Active Smoking During Pregnancy and Low Birth Weight in the Americas: A Systematic Review and Meta-analysis". Nicotine & Tobacco Research. 19 (5): 497–505. doi:10.1093/ntr/ntw228. PMID 28403455.
  22. ↑ Damron KR (May 2017). "Review of the Relationships Among Psychosocial Stress, Secondhand Smoke, and Perinatal Smoking". Journal of Obstetric, Gynecologic, and Neonatal Nursing. 46 (3): 325–333. doi:10.1016/j.jogn.2017.01.012. PMID 28390924. S2CID 4576511.
  23. 1 2 Mahumud RA, Sultana M, Sarker AR (January 2017). "Distribution and Determinants of Low Birth Weight in Developing Countries". Journal of Preventive Medicine and Public Health = Yebang Uihakhoe Chi. 50 (1): 18–28. doi:10.3961/jpmph.16.087. PMC 5327679. PMID 28173687.
  24. ↑ Parker JD, Schoendorf KC, Kiely JL (July 1994). "Associations between measures of socioeconomic status and low birth weight, small for gestational age, and premature delivery in the United States". Annals of Epidemiology. 4 (4): 271–8. doi:10.1016/1047-2797(94)90082-5. PMID 7921316.
  25. ↑ Martinson ML, Reichman NE (April 2016). "Socioeconomic Inequalities in Low Birth Weight in the United States, the United Kingdom, Canada, and Australia". American Journal of Public Health. 106 (4): 748–54. doi:10.2105/AJPH.2015.303007. PMC 4986052. PMID 26794171.
  26. ↑ "The Neonatal Intensive Care Unit". Stanford Children Health. Retrieved 2018-11-15.

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