Placental Weight and Risk of Neonatal Death | Congenital Defects | JAMA Pediatrics | JAMA Network
[Skip to Navigation]
Sign In
Table 1.  Odds Ratios of Neonatal Death Among 868 617 Infants Without Congenital Malformations According to Gestational Age–Specific Quartiles of Placental Weight, Birth Weight, and Placental to Birth Weight Ratioa
Odds Ratios of Neonatal Death Among 868 617 Infants Without Congenital Malformations According to Gestational Age–Specific Quartiles of Placental Weight, Birth Weight, and Placental to Birth Weight Ratioa
Table 2.  Odds Ratios of Neonatal Death in 38 229 Infants With Congenital Malformations According to Gestational Age–Specific Quartiles of Placental Weight, Birth Weight, and Placental to Birth Weight Ratioa
Odds Ratios of Neonatal Death in 38 229 Infants With Congenital Malformations According to Gestational Age–Specific Quartiles of Placental Weight, Birth Weight, and Placental to Birth Weight Ratioa
Limit 200 characters
Limit 25 characters
Conflicts of Interest Disclosure

Identify all potential conflicts of interest that might be relevant to your comment.

Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued.

Err on the side of full disclosure.

If you have no conflicts of interest, check "No potential conflicts of interest" in the box below. The information will be posted with your response.

Not all submitted comments are published. Please see our commenting policy for details.

Limit 140 characters
Limit 3600 characters or approximately 600 words
    Research Letter
    December 2, 2019

    Placental Weight and Risk of Neonatal Death

    Author Affiliations
    • 1Department of Obstetrics and Gynecology, Akershus University Hospital, Lørenskog, Norway
    • 2Institute of Clinical Medicine, University of Oslo, Oslo, Norway
    • 3Department of Pediatric Research, Oslo University Hospital, University of Oslo, Oslo, Norway
    JAMA Pediatr. 2020;174(2):197-199. doi:10.1001/jamapediatrics.2019.4556

    The placenta is a determinant of fetal growth, and infants who are born small for gestational age have an increased risk of infant death.1,2 Such knowledge suggests that placental factors may be associated with infant death, particularly in deaths shortly after birth.

    Previously, low placental weight has been associated with increased risk of fetal death3 and with cerebral palsy in infants.4 By contrast, in preterm-born children, high placental weight and high placental weight relative to birth weight increased the risks.3,4 These previous findings suggest that placental weight may be associated with neonatal death and that associations may differ by gestational age at birth.

    Therefore, we studied the association of placental weight with the risk of neonatal death. We also studied whether placental weight relative to birth weight was associated with neonatal death.

    Methods

    We used data from the Medical Birth Registry of Norway during January 1999 to December 2015, including all singleton infants in Norway without congenital malformations (n = 868 617) and all singleton infants with congenital malformations (n = 38 229). The study was approved by the Norwegian Data Inspectorate. The use of data from the Medical Birth Registry of Norway is regulated by law and the study was recommended by its advisory committee.

    We grouped the distribution of placental weight (in grams) into quartiles within 2-week intervals of gestational age at birth. The associations of low (first quartile) and high (fourth quartile) placental weight with neonatal death were estimated as crude and adjusted odds ratios (aOR) with 95% confidence intervals. The second and third quartiles combined were used as the reference category. We made separate analyses among children born preterm (gestational weeks 29–36) and children born at term (gestational weeks 37-42) and we repeated the analyses using quartiles of placental weight relative to birth weight (placental weight/birth weight, in grams) as the exposure. Adjustments were made for offspring sex, parity (0 or ≥1), pregnancy after in vitro fertilization (yes/no), maternal age (years), maternal smoking (yes/no), preeclampsia (yes/no), and maternal diabetes (yes/no).

    Results
    Infants Without Congenital Malformations

    In total, 492 of 868 617 infants without congenital malformations (0.06%) died during the neonatal period. Among the preterm born infants, high (aOR, 2.31; 95% CI, 1.63-3.27) and low placental weight (aOR, 1.56; 95% CI, 1.05-2.32) increased the risk of neonatal death (Table 1). Also, high placental weight relative to birth weight increased the risk of neonatal death among preterm-born children (aOR, 1.94; 95% CI, 1.40-2.70). Among the infants born at term, placental weight was not associated with neonatal death.

    Infants With Congenital Malformations

    In total, 467 of the 38 229 infants with congenital malformations (1.22%) died during the neonatal period. Among the preterm-born infants, the associations of placental weight with neonatal death displayed similar patterns as for infants without congenital malformation (Table 2). However, in term-born infants with congenital malformations, low placental weight increased the risk of neonatal death (aOR, 1.96; 95% CI, 1.48-2.60). Although the placental weight was low among the infants who died, birth weight was relatively lower. Thus, high placental weight relative to birth weight increased the risk of neonatal death in term-born infants with congenital malformations (aOR ,1.82; 95% CI, 1.37-2.41).

    Discussion

    We found that high placental weight increased the risk of neonatal death in preterm-born infants. This finding is novel and difficult to explain. It is possible that underlying adverse intrauterine conditions, such as fetoplacental hypoxemia, could induce biological responses that result in placental enlargement,5 and also increase the risk of preterm birth and neonatal death.

    Conclusions

    We found that preterm born infants with either high or low placental weight had an increased risk of neonatal death. In term-born infants, low placental weight was associated with an increase in the risk of neonatal death among infants with congenital malformations. These findings may help to identify infants at increased risk of neonatal death.

    Back to top
    Article Information

    Corresponding Author: Johanne Dypvik, MD, PhD, Department of Obstetrics and Gynecology, Akershus University Hospital, PO Box 1000, 1478 Lørenskog, Norway (johanne.dypvik@medisin.uio.no).

    Published Online: December 2, 2019. doi:10.1001/jamapediatrics.2019.4556

    Author Contributions: Drs Dypvik and Eskild had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

    Concept and design: Dypvik, Haavaldsen, Eskild.

    Acquisition, analysis, or interpretation of data: All authors.

    Drafting of the manuscript: Dypvik, Eskild.

    Critical revision of the manuscript for important intellectual content: All authors.

    Statistical analysis: Dypvik, Haavaldsen.

    Obtained funding: Eskild.

    Administrative, technical, or material support: Eskild.

    Supervision: Saugstad, Eskild.

    Conflict of Interest Disclosures: Drs Dypvik and Larsen reported grants from South-Eastern Norway Regional Health Authority during the conduct of the study. No other disclosures were reported.

    Funding/Support: The study received funding from grant 272901 from the South-Eastern Regional Health Authorities of Norway.

    Role of the Funder/Sponsor: The funding organization had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

    References
    1.
    Baer  RJ, Rogers  EE, Partridge  JC,  et al.  Population-based risks of mortality and preterm morbidity by gestational age and birth weight.  J Perinatol. 2016;36(11):1008-1013. doi:10.1038/jp.2016.118PubMedGoogle ScholarCrossref
    2.
    Altman  M, Edstedt Bonamy  AK, Wikström  AK, Cnattingius  S.  Cause-specific infant mortality in a population-based Swedish study of term and post-term births: the contribution of gestational age and birth weight.  BMJ Open. 2012;2(4):e001152. doi:10.1136/bmjopen-2012-001152PubMedGoogle Scholar
    3.
    Haavaldsen  C, Samuelsen  SO, Eskild  A.  Fetal death and placental weight/birth weight ratio: a population study.  Acta Obstet Gynecol Scand. 2013;92(5):583-590. doi:10.1111/aogs.12105PubMedGoogle ScholarCrossref
    4.
    Strand  KM, Andersen  GL, Haavaldsen  C, Vik  T, Eskild  A.  Association of placental weight with cerebral palsy: population-based cohort study in Norway.  BJOG. 2016;123(13):2131-2138. doi:10.1111/1471-0528.13827PubMedGoogle ScholarCrossref
    5.
    Eskild  A, Strøm-Roum  EM, Haavaldsen  C.  Does the biological response to fetal hypoxia involve angiogenesis, placental enlargement and preeclampsia?  Paediatr Perinat Epidemiol. 2016;30(3):305-309. doi:10.1111/ppe.12283PubMedGoogle ScholarCrossref
    ×