Birth - Preterm

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Who Report[1]
Preterm birth[2]
Premature infant

Preterm delivery (PTD) is defined as birth before 37 completed weeks of gestation (GA). 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.[3] Very premature infants have associated clinical problems that may include: neonatal respiratory distress syndrome, bronchopulmonary dysplasia, cerebroventricular haemorrhage and a range of brain pathologies. Risk factors for mothers include a prior history of preterm birth, underweight, obesity, diabetes, high blood pressure, smoking, infection, age (either under 17 or over 40), genetics, multiple pregnancy (twins, triplets, and more) and pregnancies spaced too closely together. Human viability (50% chance of survival) is currently about GA 23 to 24 weeks in developed countries and is better in female than male infants.

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

Birth Links: Introduction | Lecture - Birth | Caesarean | Preterm | Birth Weight | Birth Statistics | Australian Birth Data | Developmental Origins of Health and Disease | Macrosomia | Neonatal Diagnosis | Apgar test | Guthrie test | Neonatal Development | Stillbirth and Perinatal Death | ICD-10 Perinatal Period | Category:Birth

Some Recent Findings

  • Comparison of cortical folding measures for evaluation of developing human brain[4] "We evaluated 22 measures of cortical folding, 20 derived from local curvature (curvature-based measures) and two based on other features (sulcal depth and gyrification index), for their capacity to distinguish between normal and aberrant cortical development (12 term-born control and 63 prematurely-born). ...Overall, though the curvature-based measures changed during this period of rapid cerebral development, they were not sensitive for detecting the differences in folding associated with brain injury and/or preterm birth. In contrast, gyrification index was effective in differentiating these groups."
  • Antenatal Corticosteroids for Reducing Adverse Maternal and Child Outcomes in Special Populations of Women at Risk of Imminent Preterm Birth: A Systematic Review and Meta-Analysis[5] "This study synthesizes available evidence on antenatal corticosteroids (ACS) use among special subgroups of women at risk of imminent preterm birth, including those (1) with pregestational and gestational diabetes mellitus, (2) undergoing elective caesarean section (CS) in late preterm (34 to<37 weeks), (3) with chorioamnionitis, and (4) with growth-restricted fetuses. ... Direct evidence on the effectiveness and safety of ACS is lacking for diabetic pregnant women at risk of preterm birth and those undergoing elective late-preterm CS, though this does not necessarily recommend against their use in diabetic women. While evidence remains inconclusive for women with growth-restricted preterm neonates, ACS appears to benefit preterm neonates delivered by women with chorioamnionitis. High-quality studies on maternal and long-term child outcomes in more diverse settings are needed to establish the balance of potential harms versus benefits in using ACS for these understudied subgroups."
  • Assisted reproductive technology and the risk of preterm birth among primiparas[6] "Among (USA) singleton births to primiparas, those conceived with ART had an increased risk for preterm birth, even when only the male partner had been diagnosed with infertility. The risk of preterm birth for ART-conceived infants whose mothers were diagnosed with infertility included the earliest deliveries. " Assisted Reproductive Technology
  • Outcomes of neonates with birth weight⩽500 g: a 20-year experience[7] "Ethical dilemmas continue regarding resuscitation versus comfort care in extremely preterm infants. Counseling parents and making decisions regarding the care of these neonates should be based on reliable, unbiased and representative data drawn from geographically defined populations. ...About a third of neonates admitted to NICU with ⩽500 g BW survived, with 33% of those surviving, demonstrating age-appropriate development at a 24-month follow-up visit."
  • Placental Transfusion Strategies in Very Preterm Neonates: A Systematic Review and Meta-analysis[8] "To investigate the effects of interventions promoting placental transfusion at delivery (delayed cord clamping or umbilical cord milking) compared with early cord clamping on outcomes among premature neonates of less than 32 weeks of gestation.A systematic search was conducted of PubMed, Embase, and databases (January 1965 to December 2013) for articles relating to placental transfusion strategies in very preterm neonates. ...Results of this meta-analysis suggest that enhanced placental transfusion (delayed umbilical cord clamping or umbilical cord milking) at birth provides better neonatal outcomes than does early cord clamping, most notably reductions in overall mortality, lower risk of intraventricular hemorrhage, and decreased blood transfusion incidence. The optimal umbilical cord clamping practice among neonates requiring immediate resuscitation remains uncertain."
  • WHO World Prematurity Day 17 November 2012 "Preterm birth is the world's largest killer of newborn babies, causing more than one million deaths each year, yet 75% could be saved without expensive, high technology care."[1]
Some older articles 
  • Prepregnancy maternal body mass index and preterm delivery (PTD)[9] "The overall prevalence of PTD was 5.1%. Increased body mass index was associated with an increased risk of PTD; adjusted odds ratio (aOR) ranged from 1.11 (95% confidence interval [CI], 1.03-1.20) for preobesity to 2.00 (95% CI, 1.48-2.71) for grade-III obesity in the group that included all PTD subgroups. Grade-III obese women had an increased risk of both early and late PTD: aOR, 3.24 (95% CI, 1.71-6.14) and 1.81 (95% CI, 1.29-2.54), respectively. Prepregnancy maternal overweight increases the risk of both early and late PTD."
  • Babies born at 37-38 weeks lag academically eight years later [10] "Babies who are born “at term,” but early, lag in school achievement eight years later, concludes a study of 128 050 singleton pregnancies in New York by researchers from Columbia University. ...Analyses revealed that gestational age within the normal term range was significantly and positively related to reading and math scores in third grade, with achievement scores for children born at 37 and 38 weeks significantly lower than those for children born at 39, 40, or 41 weeks. This effect was independent of birth weight, as well as a number of other obstetric, social, and economic factors."
  • Preterm Birth and Psychiatric Disorders in Young Adult Life[11] "Preterm birth, intrauterine growth restriction, and delivery-related hypoxia have been associated with schizophrenia. It is unclear whether these associations pertain to other adult-onset psychiatric disorders and whether these perinatal events are independent. PARTICIPANTS All live-born individuals registered in the nationwide Swedish Medical Birth Register between 1973 and 1985 and living in Sweden at age 16 years by December 2002 (n = 1 301 522). CONCLUSIONS The vulnerability for hospitalization with a range of psychiatric diagnoses may increase with younger gestational age. Similar associations were not observed for nonoptimal fetal growth and low Apgar score."
  • WHO Report Born Too Soon: The Global Action Report on Preterm Birth The first-ever country-by-country estimate of premature births finds that 15 million babies a year are born preterm - more than one in 10 live births. The report on preterm birth provides the first-ever national, regional and global estimates of preterm birth. The report shows the extent to which preterm birth is on the rise in most countries, and is now the second leading cause of death globally for children under five, after pneumonia. Reports
  • Patterns and outcomes of preterm hospital admissions during pregnancy in NSW, 2001-2008[12] "Preterm hospital admission affects one in six women with singleton pregnancies. Methods that could improve assessment of labour status have a large potential to reduce the burden on maternity services. The increased morbidity for infants born after maternal transfer suggests women with high-risk pregnancies are being appropriately identified."
  • Singleton preterm birth: risk factors and association with assisted reproductive technology[13] The objectives of this study were to determine risk factors for early (less than 34 weeks gestation) and late (34-36 weeks gestation) preterm singleton birth, by assisted reproductive technology (ART) status. We linked data from Massachusetts birth records and ART records representing singleton live births from 1997 through 2004. ....Among non-ART births, increased risk for preterm birth was more strongly related to socioeconomic factors than among ART births. Medical conditions were associated with an increased risk for preterm birth regardless of women's ART status." Assisted Reproductive Technology
  • Preterm birth and reduced birthweight in first and second teenage pregnancies: a register-based cohort study[14] "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."
  • Overweight and obesity in mothers and risk of preterm birth and low birth weight infants[15] "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."
More recent papers 
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This table shows an automated computer PubMed search using the listed sub-heading term.

  • Therefore the list of references do not reflect any editorial selection of material based on content or relevance.
  • References appear in this list based upon the date of the actual page viewing.

References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.

Links: References | Discussion Page | Pubmed Most Recent | Journal Searches

Search term: Preterm Birth

Isabelle Goyer, Gabrielle Ferland, Ni Ruo, Caroline Morin, Marie-Sophie Brochet, Lucie Morin, Ema Ferreira Impact of Azithromycin on Pregnancy Prolongation in Women at Risk of Preterm Labor: A Time-to-Event Analysis. J Popul Ther Clin Pharmacol: 2016, 23(3);e183-e192 PubMed 27783473

Elena Lopez-Rodriguez, Gemma Gay-Jordi, Adele Mucci, Nico Lachmann, Anna Serrano-Mollar Lung surfactant metabolism: early in life, early in disease and target in cell therapy. Cell Tissue Res.: 2016; PubMed 27783217

Julio Jiménez, Jute Richter, Taro Nagatomo, Thomas Salaets, Rozenn Quarck, Allard Wagennar, Hongmei Wang, Jeroen Vanoirbeek, Jan Deprest, Jaan Toelen Progressive Vascular Functional and Structural Damage in a Bronchopulmonary Dysplasia Model in Preterm Rabbits Exposed to Hyperoxia. Int J Mol Sci: 2016, 17(10); PubMed 27783043

Ryan Pekson, Vladimir Poltoratsky, Samir Gorasiya, Sruthi Sundaram, Charles R Ashby, Ivana Vancurova, Sandra E Reznik N,N-Dimethylacetamide Significantly Attenuates LPS- and TNFα-Induced Proinflammatory Responses Via Inhibition of the Nuclear Factor Kappa B Pathway. Mol. Med.: 2016, 22; PubMed 27782292

Sunita Kulhari, Amit Rastogi, Ashish Kanaujia, Poulomi Biswas, Prabhat Kumar Singh Anesthetic management of premature conjoined twins posted for nonseparation emergency surgery. Paediatr Anaesth: 2016; PubMed 27781331

Premature Birth

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[16]

Gestational age and special educational prevalence.jpg

Improving Outcomes

Recent landmarks in improving extremely premature infant outcomes[17]

  • 1970s to early 1990s - continuous positive airway pressure, mechanical ventilation, and exogenous surfactant.
  • late 1990s - antenatal steroids during premature labor.
  • early 2000s - avoiding chronic postnatal administration of steroids to infants.

Growth Chart for Preterm Babies

Fetal-infant growth chart for preterm infants[18]
  • 1976 - the Babson and Benda "fetal-infant growth graph" for preterm infants was commonly used in neonatal intensive care.[19]
  • 1996 - the Beeby graph based upon New South Wales Midwives Data Collection (MDC) from 1990 to 1994 inclusive (n = 422139).[20]
  • 1999 - the National Institute of Child Health and Human Development Neonatal Research Network (NICHD) USA graph.[21]
  • 2003 - improved version of the Babson and Benda graph based upon literature review and intrauterine data.[18]

Australia Preterm Birth

Australian Indigenous birthweight graph 41.jpg

Data in this graph from AIHW 2014 Report, Birthweight of babies born to Indigenous mothers.[22]

Patterns and outcomes of preterm hospital admissions during pregnancy in NSW, 2001-2008[12]

NSW is the largest by population of all Australian states (7,238,819 or 32.4% 2010 estimate). The following information is from the abstract of the above paper published in March 2012.

  • Women who were admitted to hospital in weeks 20-36 of pregnancy (preterm) and gave birth to a liveborn singleton infant in New South Wales during 2001-2008. Numbers of preterm admissions of pregnant women who were discharged without giving birth, were transferred to higher care, or who gave birth.
  • 110 439 pregnancies (16.0%) involved at least one preterm admission. After their initial preterm admission:
    • 71.9% of women were discharged.
    • 6.3% were transferred.
    • 21.8% gave birth.
  • Median gestational age at admission was 33 weeks and median time to discharge, transfer or giving birth was 1 day.
  • Of the women who were admitted or were transferred with suspected preterm labour, only 29% and 38%, respectively, gave birth.
  • As gestational age increased, the proportion of women transferred decreased and the proportion giving birth increased.

USA Preterm Birth

Late preterm birth[23]"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."

USA Preterm Birth Rate

Preterm birth rates per 100 births in each specified gestational age category.

Total preterm Extremely preterm Early preterm Late preterm
less than 37 weeks’ gestation less than 28 weeks’ gestation less than 34 weeks’ gestation 34–36 weeks’ gestation
12.7 0.8 3.6 9.0

Data: USA Preterm birth rates national Vital Statistics System, United States, 2007.

See also Preterm Birth: Causes, Consequences, and Prevention (2007).[24]

Links: USA Statistics

Singapore Preterm Birth

A Comparison of the Short-term Morbidity and Mortality Between Late Preterm and Term Newborns[25]

  • Late preterm babies are defined as those born between 34 to 36 completed weeks. There has been a recent increased awareness that this group of babies has a higher incidence of morbidity as compared to term babies. The aim of this study was to evaluate the short-term morbidities occurring in this group of babies managed in the neonatal unit at Singapore General Hospital (SGH). January 2005 to December 2008 a total of 6826 babies were admitted.
  • Ten percent (681 out of 6826) of babies were late preterm babies, making up 63% (681 out of 1081) of all preterm babies.
  • Late preterm babies had significantly greater need for resuscitation at birth.
  • increased risks of developing hyaline membrane disease (2.5% vs 0.1%)
  • transient tachypnoea of the newborn (TTN) (8.1% vs 1.7%)
  • pneumonia (7.0% vs 2.8%)
  • patent ductus arteriosus (PDA) (4.3% vs 1.1%)
  • hypotension (0.7% vs 0%)
  • apnoea (3.7% vs 0%)
  • gastrointestinal (GI) bleeding (1.5% vs 0.3%)
  • polycythaemia (2.2% vs 1.0%)
  • anaemia (3.4% vs 1.2%)
  • thrombocytopenia (3.2% vs 0.6%)
  • hypoglycaemia (6.6% vs 1.7%)
  • neonatal jaundice requiring phototherapy (41.1% vs 12.2%)
  • sepsis (1.7% vs 0.6%).

Ultrasound Short Cervix

Evaluation of the cervical morphology and biometry with transvaginal ultrasonography at 16-24 weeks of gestation is a useful tool to predict the risk of preterm birth in low- and high-risk singleton pregnancies. The following points are from a recent review on transvaginal sonography for both the prediction and management of spontaneous preterm labour.[26]

Cervical Length (CV)

  • > 30 mm - present cervical gland area have a 96-97% negative predictive value for preterm delivery at <37 weeks.
  • ≤25 mm - irrespective of other risk factors, use of progesterone.
  • ≤ 25 mm - asymptomatic cervical shortening with prior spontaneous preterm delivery, prophylactic cerclage procedure should be performed.

Fetal Fibronectin

A recent study has identified fetal fibronectin (fFN) levels as an indicator for spontaneous preterm birth in symptomatic women.[27] The sample is collected from the maternal vagina and test machines/kits that can measure this level.

Links: OMIM 135600


Who Report[28]

When given to mothers in preterm labour, dexamethosone, a steroid used to treat asthma, helps speed up the development of the baby’s lungs. At a cost of about US$1, two shots can stop premature babies from going into respiratory distress when they are born. This can prevent 400,000 deaths annually.

Kangaroo Mother Care

A neonatal care technique involving holding the infant skin-to-skin on the mother's chest, keeping the baby warm and facilitates breastfeeding.

Keeping preterm babies warm is especially important because their tiny bodies lose heat rapidly, making them highly vulnerable to illness, infection and death. This could prevent 450 000 deaths annually.[1]

Magnesium Sulfate

Epsom Salt (magnesium sulfate, magnesium sulphate) is an inorganic salt originally used to inhibit labor (labor-inhibiting), slowing or halting uterine contractions (tocolytic agent). Inhibitory mechanism not clear, but thought to; compete with calcium at the level of plasma membrane voltage-gated channels, hyperpolarize the plasma membrane, inhibit myosin light-chain kinase activity by competing with intracellular calcium.

While described as not effective for inhibiting labor, it has more recently been recommended for neuroprotection in very preterm birth.[29] (magnesium sulphate)

Respiratory Development

Preterm delivery and lung development.jpg

Preterm delivery and overview of related potential fetal and neonatal effects on lung development. [30]

Links: Respiratory Abnormalities

Neural Development

Prevalence of special educational need by gestation at delivery.[31]

A recent UK population-based study[31] "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."

Cortical structural abnormalities in very preterm children at 7years of age[32] "Comparison of 24 children born very preterm (VPT) to 24 healthy term-born children revealed reductions in total cortical gray matter volume, white matter volume, cortical surface area and gyrification index. Regional cortical shape abnormalities in VPT children included the following: shallower anterior superior temporal sulci, smaller relative surface area in the inferior sensori-motor cortex and posterior superior temporal cortex, larger relative surface area and a cingulate sulcus that was shorter or more interrupted in medial frontoparietal cortex. These findings indicate a complex pattern of regional vulnerabilities in brain development that may contribute to the diverse and long-lasting neurobehavioral consequences that can occur after very premature birth."

Links: Neural System Development

Sensory Development

Retinopathy of Prematurity

Retinopathy of prematurity in the right eye
Retinopathy of prematurity in the right eye. (Arrows show flat neovascularization)[33]

(ROP) A vascular proliferative disorder that affects the incompletely vascularized retina in premature neonates, birth weight 1250 grams or less and born before 31 weeks gestation GA are at highest risk. Classified as type 2 progressing to type 1, this is a primary cause of childhood blindness. Due to retinal immaturity, neovascularization occurs leading to retinal traction and retinal detachment, eventually affecting vision.

USA Statistics

  • 14,000-16,000 of low birthweight (<1.25 kg) infants are affected by some degree of ROP.
  • disease improves and leaves no permanent damage in milder cases of ROP.
    • 90% of all infants with ROP are in the milder category and do not need treatment.
  • About 1,100-1,500 infants annually develop ROP that is severe enough to require medical treatment.
    • About 400-600 infants each year in the US become legally blind from ROP.

(Data NIH - National Eye Institute)

Links: Vision Abnormalities | Birth - Preterm | Sensory - Vision Development | NIH - ROP | American Association for Pediatric Ophthalmology)

Maternal Obesity

The following text information is from a recent systematic review and meta-analyses of maternal obesity[15]

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

Bacterial Infection Fetal Membranes

  • Differing prevalence and diversity of bacterial species in fetal membranes from very preterm and term labor.[34]
"Intrauterine infection may play a role in preterm delivery due to spontaneous preterm labor (PTL) and preterm prolonged rupture of membranes (PPROM). Because bacteria previously associated with preterm delivery are often difficult to culture, a molecular biology approach was used to identify bacterial DNA in placenta and fetal membranes. ...A greater spread and diversity of bacterial species were found in tissues of women who had very preterm births. It is unclear to what extent the greater bacterial prevalence observed in all vaginal delivery groups reflects bacterial contamination or colonization of membranes during labor. Bacteria positive preterm tissues are associated with histological chorioamnionitis and a pronounced maternal immune paresis."


  • Screening to prevent spontaneous preterm birth.[2]
"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."

Inhaled Nitric Oxide Therapy

NIH Consensus Development Conference (2010) conclusions

  1. Taken as a whole, the available evidence does not support use of inhaled nitric oxide in early routine, early rescue, or later rescue regimens in the care of premature infants <34 weeks gestation who require respiratory support.
  2. There are rare clinical situations, including pulmonary hypertension or hypoplasia, that have been inadequately studied in which inhaled nitric oxide may have benefit in infants <34 weeks gestation. In such situations, clinicians should communicate with families regarding the current evidence on its risks and benefits as well as remaining uncertainties.
  3. Basic research and animal studies have contributed to important understandings of inhaled nitric oxide benefits on lung development and function in infants at high risk of bronchopulmonary dysplasia. These promising results have only partly been realized in clinical trials of inhaled nitric oxide treatment in premature infants. Future research should seek to understand this gap.
  4. Predefined subgroup and post hoc analyses of previous trials showing potential benefit of inhaled nitric oxide have generated hypotheses for future research for clinical trials. Prior strategies shown to be ineffective are discouraged unless new evidence emerges. The positive results of one multicenter trial, which was characterized by later timing, higher dose, and longer duration of treatment, require confirmation. Future trials should attempt to quantify the individual effects of each of these treatment-related variables (timing, dose, and duration), ideally by randomizing them separately.
  5. Based on assessment of currently available data, hospitals, clinicians, and the pharmaceutical industry should avoid marketing inhaled nitric oxide for premature infants <34 weeks gestation.

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

Enteral Nutrition

Enteral nutrition (tube feeding) is often required for preterm or sick infants. Nutritient delivery as fluid into the gastrointestinal tract. Can be used to describe postnatal nutrition through milk as well as a clinical method for delivering nutrition to patients. The method usually involves either a nasogastric or nasoenteral feeding tube into the stomach. An alternative, generally in adults, is a surgical tube placed directly through the skin into the stomach or intestine (gastrostomy or jejunostomy).

Links: Sydney Local Health District Pamphlet - Enteral Nutrition for the Preterm Infant


  1. 1.0 1.1 1.2 Born Too Soon: The Global Action Report on Preterm Birth
  2. 2.0 2.1 H Honest, C A Forbes, K H Durée, G Norman, S B Duffy, A Tsourapas, T E Roberts, P M Barton, S M Jowett, C J Hyde, K S Khan Screening to prevent spontaneous preterm birth: systematic reviews of accuracy and effectiveness literature with economic modelling. Health Technol Assess: 2009, 13(43);1-627 PubMed 19796569
  3. NCHS Data Brief Number 39, May 2010
  4. Joshua S Shimony, Christopher D Smyser, Graham Wideman, Dimitrios Alexopoulos, Jason Hill, John Harwell, Donna Dierker, David C Van Essen, Terrie E Inder, Jeffrey J Neil Comparison of cortical folding measures for evaluation of developing human brain. Neuroimage: 2015; PubMed 26550941
  5. Rachel M Amiya, Linda B Mlunde, Erika Ota, Toshiyuki Swa, Olufemi T Oladapo, Rintaro Mori Antenatal Corticosteroids for Reducing Adverse Maternal and Child Outcomes in Special Populations of Women at Risk of Imminent Preterm Birth: A Systematic Review and Meta-Analysis. PLoS ONE: 2016, 11(2);e0147604 PubMed 26841022
  6. Galit Levi Dunietz, Claudia Holzman, Patricia McKane, Chenxi Li, Sheree L Boulet, David Todem, Dmitry M Kissin, Glenn Copeland, Dana Bernson, William M Sappenfield, Michael P Diamond Assisted reproductive technology and the risk of preterm birth among primiparas. Fertil. Steril.: 2015, 103(4);974-979.e1 PubMed 25707336
  7. K Upadhyay, M Pourcyrous, R Dhanireddy, A J Talati Outcomes of neonates with birth weight⩽500 g: a 20-year experience. J Perinatol: 2015; PubMed 25950920
  8. Carl H Backes, Brian K Rivera, Urbee Haque, Jeffrey A Bridge, Charles V Smith, David J R Hutchon, Judith S Mercer Placental transfusion strategies in very preterm neonates: a systematic review and meta-analysis. Obstet Gynecol: 2014, 124(1);47-56 PubMed 24901269
  9. Ali Khatibi, Anne-Lise Brantsaeter, Verena Sengpiel, Marian Kacerovsky, Per Magnus, Nils-Halvdan Morken, Ronny Myhre, Nina Gunnes, Bo Jacobsson Prepregnancy maternal body mass index and preterm delivery. Am. J. Obstet. Gynecol.: 2012, 207(3);212.e1-7 PubMed 22835494
  10. Kimberly G Noble, William P Fifer, Virginia A Rauh, Yoko Nomura, Howard F Andrews Academic achievement varies with gestational age among children born at term. Pediatrics: 2012, 130(2);e257-64 PubMed 22753563
  11. Chiara Nosarti, Abraham Reichenberg, Robin M Murray, Sven Cnattingius, Mats P Lambe, Li Yin, James MacCabe, Larry Rifkin, Christina M Hultman Preterm birth and psychiatric disorders in young adult life. Arch. Gen. Psychiatry: 2012, 69(6);E1-8 PubMed 22660967
  12. 12.0 12.1 Tim Badgery-Parker, Jane B Ford, Mary G Jenkins, Jonathan M Morris, Christine L Roberts Patterns and outcomes of preterm hospital admissions during pregnancy in NSW, 2001-2008. Med. J. Aust.: 2012, 196(4);261-5 PubMed 22409693 | Med J Aust
  13. Naomi K Tepper, Sherry L Farr, Bruce B Cohen, Angela Nannini, Zi Zhang, John E Anderson, Denise J Jamieson, Maurizio Macaluso Singleton preterm birth: risk factors and association with assisted reproductive technology. Matern Child Health J: 2012, 16(4);807-13 PubMed 21516300
  14. Ali S Khashan, Philip N Baker, Louise C Kenny Preterm birth and reduced birthweight in first and second teenage pregnancies: a register-based cohort study. BMC Pregnancy Childbirth: 2010, 10;36 PubMed 20618921
  15. 15.0 15.1 Sarah D McDonald, Zhen Han, Sohail Mulla, Joseph Beyene, Knowledge Synthesis Group Overweight and obesity in mothers and risk of preterm birth and low birth weight infants: systematic review and meta-analyses. BMJ: 2010, 341;c3428 PubMed 20647282 | BMJ
  16. G C Curhan, W C Willett, E B Rimm, D Spiegelman, A L Ascherio, M J Stampfer Birth weight and adult hypertension, diabetes mellitus, and obesity in US men. Circulation: 1996, 94(12);3246-50 PubMed 8989136
  17. Hannah C Glass, Andrew T Costarino, Stephen A Stayer, Claire M Brett, Franklyn Cladis, Peter J Davis Outcomes for Extremely Premature Infants. Anesth. Analg.: 2015, 120(6);1337-1351 PubMed 25988638
  18. 18.0 18.1 Tanis R Fenton A new growth chart for preterm babies: Babson and Benda's chart updated with recent data and a new format. BMC Pediatr: 2003, 3;13 PubMed 14678563 | BMC Pediatr.
  19. S G Babson, G I Benda Growth graphs for the clinical assessment of infants of varying gestational age. J. Pediatr.: 1976, 89(5);814-20 PubMed 978333
  20. P J Beeby, T Bhutap, L K Taylor New South Wales population-based birthweight percentile charts. J Paediatr Child Health: 1996, 32(6);512-8 PubMed 9007782
  21. R A Ehrenkranz, N Younes, J A Lemons, A A Fanaroff, E F Donovan, L L Wright, V Katsikiotis, J E Tyson, W Oh, S Shankaran, C R Bauer, S B Korones, B J Stoll, D K Stevenson, L A Papile Longitudinal growth of hospitalized very low birth weight infants. Pediatrics: 1999, 104(2 Pt 1);280-9 PubMed 10429008
  22. AIHW 2014. Birthweight of babies born to Indigenous mothers. Cat. no. IHW 138. Canberra: AIHW. Viewed 5 August 2014
  23. Ryan W Loftin, Mounira Habli, Candice C Snyder, Clint M Cormier, David F Lewis, Emily A Defranco Late preterm birth. Rev Obstet Gynecol: 2010, 3(1);10-9 PubMed 20508778
  24. Institute of Medicine (US) Committee on Understanding Premature Birth and Assuring Healthy Outcomes; Behrman RE, Butler AS, editors. Preterm Birth: Causes, Consequences, and Prevention. Washington (DC): National Academies Press (US); 2007. Available from:
  25. Justin Ht Tan, Woei Bing Poon, Wee Bin Lian, Selina Ky Ho A Comparison of the Short-term Morbidity and Mortality Between Late Preterm and Term Newborns. Ann. Acad. Med. Singap.: 2014, 43(7);346-54 PubMed 25142470
  26. Resul Arisoy, Murat Yayla Transvaginal sonographic evaluation of the cervix in asymptomatic singleton pregnancy and management options in short cervix. J Pregnancy: 2012, 2012;201628 PubMed 22523687 | J Pregnancy
  27. Danielle S Abbott, Samara K Radford, Paul T Seed, Rachel M Tribe, Andrew H Shennan Evaluation of a quantitative fetal fibronectin test for spontaneous preterm birth in symptomatic women. Am. J. Obstet. Gynecol.: 2013, 208(2);122.e1-6 PubMed 23164760 | Am J Obstet Gynecol.
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Silvia Iacobelli, Elsa Kermorvant-Duchemin, Francesco Bonsante, Alexandre Lapillonne, Jean-Bernard Gouyon Chloride Balance in Preterm Infants during the First Week of Life. Int J Pediatr: 2012, 2012;931597 PubMed 22505945

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