Am J Perinatol 2020; 37(01): 037-043
DOI: 10.1055/s-0039-1694775
SMFM 2019
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

The Association between Advanced Maternal Age and Diagnosis of Small for Gestational Age

Anna Palatnik
1   Department of Obstetrics and Gynecology, Medical College of Wisconsin, Milwaukee, Wisconsin
,
Sarah De Cicco
1   Department of Obstetrics and Gynecology, Medical College of Wisconsin, Milwaukee, Wisconsin
,
Liyun Zhang
2   Department of Pediatrics, Division of Quantitative Health Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
,
Pippa Simpson
2   Department of Pediatrics, Division of Quantitative Health Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
,
Judith Hibbard
1   Department of Obstetrics and Gynecology, Medical College of Wisconsin, Milwaukee, Wisconsin
,
Leonard E. Egede
3   Center for Advancing Population Science, Medical College of Wisconsin, Milwaukee, Wisconsin
› Institutsangaben

Funding This publication was supported by the National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health (NIH), through grant number UL1TR001436. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.
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Publikationsverlauf

05. Mai 2019

04. Juli 2019

Publikationsdatum:
20. August 2019 (online)

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Abstract

Objectives To identify whether advanced maternal age (AMA), defined as age ≥35 years old, is independently associated with small for gestational age (SGA).

Study Design This was a retrospective cohort of births from the National Vital Statistics System in the United States from 2009 to 2013. Women were categorized based on four age groups at the time of delivery: 20 to 29, 30 to 34, 35 to 39, and ≥40 years old. The primary outcome of SGA < 10th and SGA < 5th percentiles was compared between the four groups using both univariable and multivariable analyses to determine whether maternal age was associated with SGA independent of parity.

Results A total of 17,031,005 births were eligible for analysis, with 2,705,501 births to AMA women. In multivariable analyses, maternal age of 30 to 34, compared with 20 to 29, was associated with lower rates of SGA < 10th and <5th percentiles (adjusted odds ratio [aOR] = 0.95; 95% confidence interval [CI]: 0.95–0.96 and aOR = 0.97; 95% CI: 0.96–0.98, respectively). The AMA of 35 to 39, compared with 20 to 29, was associated with lower rates of SGA < 10th percentile and unchanged rates of SGA < 5th percentile (aOR = 0.97; 95% CI: 0.96–0.98 and aOR = 1; 95% CI: 0.99–1.01, respectively). In contrast, AMA of ≥40, compared with age 20 to 29, was associated with higher rates of both SGA < 10th and <5th percentiles (aOR = 1.06; 95% CI: 1.04–1.07 and aOR = 1.14; 95% CI: 1.12–1.16, respectively). A significant association was found between maternal age and parity toward the risk of SGA (p < 0.001). Nulliparous women ≥30 years old but not multiparous women had higher rates of SGA < 10th and SGA < 5th percentiles compared with nulliparous women in the age group of 20 to 29. In contrast, both nulliparous and multiparous women age ≥40 years old had an increased risk for SGA < 5th percentile compared with all women in the age group of 20 to 29.

Conclusion Nulliparous women aged 30 years and older have higher risk of SGA < 10th and SGA < 5th percentiles compared with nulliparous women age 20 to 29. In contrast, both nulliparous and multiparous women age 40 years and older have an increased risk of SGA < 5th percentile compared with all women in the age group of 20 to 29.

Condensation

The frequency of SGA was statistically significantly higher in nulliparous women ≥30 years old and in all women ≥40 years old, compared with women in the age group of 20 to 29.


Note

This study was presented in the poster format at the 39th annual meeting of the Society for Maternal-Fetal Medicine, Las Vegas, NV, February 11 to 16, 2019.