Original Article

Fetal Maturation and Intrauterine Survival in Asian American Women by Ethnicity

Authors: Deepa Dongarwar, MS, Sitratullah O. Maiyegun, MD, Korede K. Yusuf, MBBS, MPH, Dania E. Al Agili, DrPH, Hamisu M. Salihu, MD, PhD


Objectives: Although there are multiple ethnic subgroups of the Asian race, this population is usually treated as homogenous in public health research and practice. There is a dearth of information on fetal maturation and perinatal outcomes among Asian American women compared with their non-Hispanic (NH) White counterparts. This study aimed to determine whether fetal maturation, as captured by gestational age periods, influences the risk of stillbirth in Asian American fetuses, in general, as well as within different ethnic subgroups: Asian Indian, Korean, Chinese, Vietnamese, Japanese, and Filipino, using NH Whites as referent.

Methods: We included singleton births within 37 to 44 gestational weeks occurring in Asian American and NH White mothers from 2014 to 2017. Adjusted logistic regression models were used to quantify the association between mother’s race/ethnicity and risk of stillbirth by gestational age phenotypes: early-term, full-term, late-term, and postterm.

Results: Compared with NH Whites, Asian Americans had 35% (adjusted odds ratio 0.65, 95% confidence interval 0.53–0.76) and 28% (adjusted odds ratio 0.72, 95% confidence interval 0.59–0.85) lower risk of early-term and full-term stillbirths, respectively.

Conclusions: Our study suggests the existence of differential maturation of the fetoplacental unit as explanation for the decline in intrauterine survival advantage with advancing gestational age among Asian American subgroups.
Posted in: Obstetrics and Gynecology56 Pregnancy24

This content is limited to qualifying members.

Existing members, please login first.

If you have an existing account please login now to access this article or view your purchase options.

Purchase only this article ($15)

Create a free account, then purchase this article to download or access it online for 24 hours.

Purchase an SMJ online subscription ($75)

Create a free account, then purchase a subscription to get complete access to all articles for a full year.

Purchase a membership plan (fees vary)

Premium members can access all articles plus recieve many more benefits. View all membership plans and benefit packages.


1. The Center for American Progress. Who are Asian Americans? https://www.americanprogress.org/article/who-are-asian-americans/. Accessed February 28, 2022.
2. US Department of Health & Human Services, Office of Minority Health. Infant mortality and Asian Americans. https://minorityhealth.hhs.gov/omh/browse.aspx?lvl=4&lvlid=53. Accessed February 28, 2022.
3. Centers for Disease Control and Prevention. Stillbirth: data and statistics. https://www.cdc.gov/ncbddd/stillbirth/data.html. Accessed February 28, 2022.
4. Yim C, Wong L, Cabalag C, et al. Post-term surveillance and birth outcomes in South Asian-born compared with Australian-born women. J Perinatol 2017;37:139–143.
5. Drysdale H, Ranasinha S, Kendall A, et al. Ethnicity and the risk of late-pregnancy stillbirth. Med J Aust 2012;197:278–281.
6. Balchin I, Whittaker JC, Patel RR, et al. Racial variation in the association between gestational age and perinatal mortality: prospective study. BMJ 2007;334:833.
7. Heazell AEP, Siassakos D, Blencowe H, et al. Stillbirths: economic and psychosocial consequences. Lancet 2016;387:604–616.
8. National Vital Statistics System, Centers for Disease Control and Prevention. Birth data. https://www.cdc.gov/nchs/nvss/births.htm. Published July 10, 2020. Accessed February 28, 2022.
9. American College of Obstetricians and Gynecologists. Definition of term pregnancy. https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2013/11/definition-of-term-pregnancy. Accessed February 28, 2022.
10. Australian Institute of Health and Welfare. Birthweight. https://meteor.aihw.gov.au/content/327212. Accessed September 24, 2020.
11. Salihu HM, Dongarwar D, King LM, et al. Trends in the incidence of fetal macrosomia and its phenotypes in the United States, 1971–2017. Arch Gynecol Obstet 2019;301:415–426.
12. Salihu HM, Dongarwar D, King LM, et al. Phenotypes of fetal macrosomia and risk of stillbirth among term deliveries over the previous four decades. Birth 2020;47:202–210.
13. Alexander G, Himes J, Kaufman R, et al. A United States national reference for fetal growth. Obstet Gynecol 1996;87:163–168.
14. Joseph K. The fetuses-at-risk approach: clarification of semantic and conceptual misapprehension. BMC Pregnancy Childbirth 2008;8:11.
15. Joseph KS, Kramer MS. The fetuses-at-risk approach: survival analysis from a fetal perspective. Acta Obstet Gynecol Scand 2018;97:454–465.
16. Ravelli ACJ, Tromp M, Eskes M, et al. Ethnic differences in stillbirth and early neonatal mortality in the Netherlands. J Epidemiol Community Health 2011;65:696–701.
17. Willis E, McManus P, Magallanes N, et al. Conquering racial disparities in perinatal outcomes. Clin Perinatol 2014;41:847–875.
18. Ray JG, Jiang D, Sgro M, et al. Thresholds for small for gestational age among newborns of East Asian and South Asian ancestry. J Obstet Gynaecol Can 2009;31:322–330.
19. Henry OA, Guaran RL, Petterson CD, et al. Obstetric and birthweight differences between Vietnam-born and Australian-born women. Med J Aust 1992;156: 321–324.
20. Wang X, Guyer B, Paige DM. Differences in gestational age-specific birthweight among Chinese, Japanese and White Americans. Int J Epidemiol 1994;23:119–128.
21. Davies DP, Senior N, Cole G, et al. Size at birth of Asian and white Caucasian babies born in Leicester: implications for obstetric and paediatric practices. Early Hum Dev 1982;6:257–263.
22. Kierans WJ, Joseph KS, Luo ZC, et al. Does one size fit all? The case for ethnic-specific standards of fetal growth. BMC Pregnancy Childbirth 2008;8:1.
23. Mozooni M, Preen DB, Pennell CE. The influence of acculturation on the risk of stillbirth in migrant women residing in Western Australia. PLoS One 2020; 15:e0231106.evere obesity among children in the United States, 1999-2012. JAMA Pediatr 2014;168: 561–566.