Birth - Preterm

Introduction

Preterm birth

In the USA the preterm birth rate declined in 2008 to 12.3 percent, from 12.8 percent in 2006. The preterm birth rates also declined from 2006 to 2008 for mothers of all age groups under age 40.

In the United States, more than 30,000 babies per year are born before the 28th week of pregnancy.

Some Recent Findings

Preterm birth and reduced birthweight in first and second teenage pregnancies: a register-based cohort study "The risk of preterm birth was increased in first and second time mothers aged 14-17 yrs compared to the reference group. Birthweight was reduced in the first and second time mothers aged 14-17 yrs compared to the reference group. There was some evidence of a protective effect against VSGA in 14-17 yr old first time mothers." The surprising composition of the salivary proteome of preterm human newborn PMID20943598 "Saliva is a body fluid of a unique composition devoted to protect the mouth cavity and the digestive tract. A quantitative label-free MS analysis showed protein levels altered in relation to the postconceptional age and suggested coordinate and hierarchical functions for these proteins during development. In summary, this study shows for the first time that analysis of these proteins in saliva of preterm newborns might represent a non-invasive way to obtain precious information of the molecular mechanisms of development of human fetal oral structures." Overweight and obesity in mothers and risk of preterm birth and low birth weight infants "Overweight and obese women have increased risks of preterm birth and induced preterm birth and, after accounting for publication bias, appeared to have increased risks of preterm birth overall. The beneficial effects of maternal overweight and obesity on low birth weight were greater in developing countries and disappeared after accounting for publication bias." Screening to prevent spontaneous preterm birth"For primary prevention, an effective, affordable and safe intervention applied to all mothers without preceding testing is likely to be the most cost-effective approach in asymptomatic women in early pregnancy. For secondary prevention among women at risk of preterm labour in later pregnancy, a management strategy based on the results of testing is likely to be more cost-effective." Late preterm birth"The American College of Obstetricians and Gynecologists suggests that preterm birth rates have also increased because of a dramatic rise in late preterm births, defined as births between 34 weeks and 36-6/7 weeks of gestation. Late preterm newborns are the fastest growing subset of neonates, accounting for approximately 74% of all preterm births and about 8% of total births."

Premature Birth

Premature infant

Year	< 34 weeks %	34-36 weeks %	total preterm %
1990	3.3	7.3	10.6
1995	3.3	7.7	11
2000	3.4	8.2	11.6
2005	3.6	9.1	12.7

Data from: Prevention of preterm birth: a renewed national priority Damus K. Curr Opin Obstet Gynecol. 2008 Dec;20(6):590-6 PMID: 18989136

Growth Chart for Preterm Babies

Fetal-infant growth chart for preterm infants

• 1976 - the Babson and Benda "fetal-infant growth graph" for preterm infants was commonly used in neonatal intensive care.
• 1996 - the Beeby graph based upon New South Wales Midwives Data Collection (MDC) from 1990 to 1994 inclusive (n = 422139).
• 1999 - the National Institute of Child Health and Human Development Neonatal Research Network (NICHD) USA graph.
• 2003 - improved version of the Babson and Benda graph based upon literature review and intrauterine data.

Neural Development

Prevalence of special educational need by gestation at delivery.

A recent UK population-based study "These findings show that gestational age at delivery strongly affects a child's subsequent risk of having an special educational need (SEN) in a dose-dependent manner across the whole range of gestational age. Furthermore, because early term delivery is much more common than preterm delivery, these findings show that early term delivery is responsible for more cases of SEN than preterm delivery."

Maternal Obesity

The following text information is from a recent systematic review and meta-analyses of maternal obesity

What is already known on this topic

• The effect of overweight or obesity in women on risk of preterm birth is debated in the literature
• Uncertainty is reflected in national guidelines, although it is widely believed that the risk of having an infant of low birth weight is decreased in overweight or obese women

What this study adds

• Overweight or obese women have increased risks of preterm birth before 32 weeks and induced preterm birth before 37 weeks, and, accounting for publication bias, preterm birth before 37 weeks overall
• The beneficial effects of overweight or obesity on low birth weight were greater in developing than developed countries and disappeared after accounting for publication bias
• Overweight and obese women should be counselled before pregnancy on their perinatal risks, and appropriate surveillance should be considered during pregnancy

Inhaled Nitric Oxide Therapy

Links: NIH Consensus Development Conference: Inhaled Nitric Oxide Therapy for Premature Infants October 27-29, 2010 | draft consensus statement

References

Search Pubmed

July 2010 "Preterm Birth" All (31665) Review (3598) Free Full Text (4781)

Search Pubmed: Preterm Birth

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Cite this page: Hill, M.A. (2024, April 27) Embryology Birth - Preterm. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Birth_-_Preterm

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G