Abstract
We examine birth order differences in health of newborns and follow the children throughout childhood using high-quality administrative data on individuals born in Denmark between 1981 and 2010. Family fixed effects models show a positive and robust effect of birth order on health at birth; firstborn children are less healthy at birth. During earlier pregnancies, women are more likely to smoke, receive more prenatal care, and are more likely to suffer a medical pregnancy complication, suggesting worse maternal health. We further show that the health disadvantage of firstborns persists in the first years of life, disappears by age seven, and becomes a health advantage in adolescence. In contrast, later-born children are throughout childhood more likely to suffer an injury. The results on health in adolescence are consistent with previous evidence of a firstborn advantage in education and with the hypothesis that postnatal investments differ between first- and later-born children.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Notes
In line with this literature, we observe a negative effect of birth order on ninth grade GPA, see Appendix Table 7.
Missing information on health at birth results from (1) unrecorded data, which occasionally happens at the beginning of the data in 1981, (2) biological implausible values, and (3) non-existing information due to perinatal child death. When we look at the prenatal environment, we include information also for those children with missing birth outcomes to eliminate problems of selection.
Our results also hold for families with five to eight children.
We have fewer observations for birth order one due to a larger number of birth outcomes with missing information in the birth records, see footnote (5).
The 5-minute Apgar score is a diagnostic test measured 5 min after birth and based on five criteria: heart rate, respiratory effort, muscle tone, reflex irritability, and color. For each criteria zero, one, or two points are assigned with the resulting score ranging between zero and ten. The Apgar score has been found to be highly correlated with cognitive ability, health, and behavioral problems in later childhood (Almond et al. 2005). Considering the 1-minute Apgar score (measured 1 min after birth) instead of the 5-minute Apgar score provides very comparable results. However, as the data does not provide us with the 1-minute Apgar score after 1996, we focus on the 5-minute Apgar score only.
Using the first component of a principal component analysis of birth weight, low birth weight, high birth weight, prematurity, and Apgar score yields very similar results.
Unfortunately, we do not observe alcohol consumption during pregnancy and are therefore unable to analyze this aspect of maternal behavior.
Diagnoses are based on the International Statistical Classification of Diseases and Related Health Problems, 8th and 10th Revisions (ICD-8 and ICD-10). The reporting standard changed in 1994 from ICD-8 to the ICD-10 codes. However, we can still use information for all diagnoses in our sample, using the recoding of the old ICD-8 codes from Lykke et al. (2012) to merge with the ICD-10 codes.
Casey et al. (1997) report that between 1 and 3% of all pregnancies in the USA are diagnosed with gestational diabetes.
If women experiencing preeclampsia are counted, the figure for gestational hypertension would increase to 4%. Sibai (2003) notes a prevalence of gestational hypertension in the USA of 6 to 17% for nulliparous women and 2 to 4% for multiparous women. These numbers fit in line with the 4% given that we have 43% of nulliparous births and 57% of multiparous births in our sample.
We prefer the use of month of conception and year of conception over the use of month of birth and year of birth to compare children that have the same expected conditions in utero. This is in line with Persson and Rossin-Slater (2016), Almond and Mazumder (2011). However, our results do not change when we substitute month of conception and year of conception with month of birth and year of birth, respectively.
Except for the difference between birth order three and birth order four in column (4), the increase in the coefficients for each additional birth order is significant at the 1% level.
Additional measures for health at birth include the natural logarithm of birth weight and birth length, birth weight z-score, small for gestational age (SGA), large for gestational age (LGA), head circumference (available since 1997), and an indicator for being diagnosed for a condition relating to the perinatal period (available since 1994).
Perinatal death is defined as fetal deaths occurring with a stated or presumed gestation of 28 weeks or more or deaths occurring within the first 7 days of life. These children are grouped on the assumption that similar factors have caused the death (Barfield 2011). The definition is furthermore the official definition for perinatal death used by the National Center for Health Statistic and the World Health Organization. Notice that we have more observations for perinatal deaths than for our other health outcomes, as not all children dying in the perinatal period have information on these other outcomes.
The reason for this cut-off is that we observe births through December 31, 2010. This is a reasonable cut-off, as 91% of all women who were above 45 years in 2010 got their last child before the age of 38. This restriction decreases modestly age at birth by roughly half a year and decreases the interpregnancy interval by 1.5 months.
As the relationship in Table 4 column (6) is weaker than in column (2), these results indicate that some women quit smoking during pregnancy. Restricting the sample to women who smoked anytime in their first pregnancy, we continue to find that birth order has a negative effect on smoking at the end of pregnancy. We attempted to replicate the results from Black et al. (2016b) who study the probability to stop smoking conditional on smoking at the beginning of any pregnancy. To be able to estimate a family fixed effects model, this requires at least two observations within a family where the mother smoked at the beginning of the pregnancy (anytime during the pregnancy) and a variation in the probability to still smoke at the end. Even though this creates a very selected sample, we did not find that the order of the pregnancy (birth order) relates to the probability to stop smoking during pregnancy.
Because information on both prenatal smoking and prenatal care is available only for a subsample of all children, we test the robustness of our findings towards estimating the effect of birth order on child health at birth for the sample of children for which we have this information (common sample). Our results are robust to this exercise.
Due to the restriction of the hospital admission data, we do not observe the oldest cohorts when they are young. For example, the cohort born in 1981 will be observed from age 13 onwards.
We also exclude conditions related to pregnancy and childbirth as well as congenital malformations and conditions originating from the perinatal period to not confuse this analysis with the health at birth analysis. We include chapters I) Certain infections and parasitic diseases, II) Neoplasms, III) Diseases of the blood and blood-forming organs and certain diseases, IV) Endocrine, nutritional and metabolic diseases, V) Mental and behavioral disorders, VI) Diseases of the nervous system, VII) Diseases of the eye and adnexa, VIII) Diseases of the ear and mastoid process, IX) Diseases of the circulatory system, X) Diseases of the respiratory system, XI) Diseases of the digestive system, XII) Diseases of the skin and subcutaneous tissue, XIII) Diseases of the musculoskeletal system and connective tissue, and XIV) Diseases of the genitourinary system.
We find similar results when considering emergency room contacts instead of hospitalizations for injuries, underlining that the health disadvantage of later-borns stems from acute rather than chronic diseases.
Lundberg and Svaleryd (2017) group children into larger age groups and focus on inpatient contacts to the hospital only. While the authors also study health differences in early childhood, they do not find a robust firstborn advantage in hospitalizations before age six.
References
Almond D, Mazumder B (2011) Health capital and the prenatal environment: the effect of ramadan observance during pregnancy. Amer Econ J: Appl Econ 3 (4):56–85
Almond D, Chay KY, Lee DS (2005) The costs of low birth weight. Q J Econ 120(3):1031–1083
Argys LM, Rees DI, Averett SL, Witoonchart B (2006) Birth order and risky adolescent behavior. Econ Inq 44(2):215–233
Arrow KJ (1963) Uncertainty and the demand for medical care. Amer Econ Rev 53(5):941–973
Averett SL, Argys LM, Rees DI (2011) Older siblings and adolescent risky behavior: does parenting play a role? J Popul Econ 24(3):957–978
Barfield WD (2011) Standard terminology for fetal, infant, and perinatal deaths. Pediatrics 128(1): 177–181
Barker DJ (1995) The fetal origins of coronary heart disease. B Med J 311 (6998):171–174
Barker DJ, Martyn CN, Osmond C, Hales CN, Fall CH (1993a) Growth in utero and serum cholesterol concentrations in adult life. B Med J 307:1524–1527
Barker DJ, Osmond C, Simmonds SJ, Wield GA (1993b) The relation of small head circumference and thinness at birth to death from cardiovascular disease in adult life. B Med J 306:422–426
Behrman JR (1988) Intrahousehold allocation of nutrients in rural india: are boys favored? Do parents exhibit inequality aversion? Oxford Econ Pap 40(1):32–54
Behrman JR, Rosenzweig MR (2004) Returns to birthweight. Rev Econ Stat 86(2):586–601
Behrman JR, Taubman P (1986) Birth order, schooling, and earnings. J Labor Econ 4(3, Part 2):121–150
Black SE, Devereux PJ, Salvanes KG (2011) Older and wiser? Birth order and IQ of young men. CESifo Econ Stud 57(1):103–120
Black SE, Devereux PJ, Salvanes KG (2016a) Does grief transfer across generations? Bereavements during pregnancy and child outcomes. Amer Econ J: Appl Econ 8(1):193–223
Black SE, Devereux PJ, Salvanes KG (2016b) Healthy (?), wealthy, and wise: birth order and adult health. Econ Human Biol 23:27–45
Buckles KS, Kolka S (2014) Prenatal investments, breastfeeding, and birth order. Soc Sci Med 118:66–70
Camilleri AP, Cremona V (1970) The effect of parity on birthweight. J Obstet Gynaecol B Commonw 77(2):145–147
Casey BM, Lucas MJ, McIntire DD, Leveno K (1997) Pregnancy outcomes in women with gestational diabetes compared with the general obstetric population. Obstet Gynecol 90(6):869–873
Chakraborty R, Das SR, Roy M, Mukherjee BN, Das SK (1975) The effect of parity on placental weight and birth weight: interaction with placental alkaline phosphatase polymorphism. Ann Human Biol 2(3):227–234
Cunha F, Heckman J (2007) The technology of skill formation. Amer Econ Rev 97(2):31–47
Currie J, Moretti E (2003) Mother’s education and the intergenerational transmission of human capital: evidence from college openings. Q J Econ 118 (4):1495–1532
Currie J, Walker R (2011) Traffic congestion and infant health: evidence from E-ZPass. Amer Econ J: Appl Econ 3:65–90
Dardanoni V, Wagstaff A (1990) Uncertainty and the demand for medical care. J Health Econ 9(1):23–38
Deaton A, Stone AA (2014) Evaluative and hedonic wellbeing among thosewith and without children at home. PNAS 111(4):1328–1333. doi:10.1073/pnas.1311600111
Del Bono E, Ermisch J, Francesconi M (2012) Intrafamily resource allocations: a dynamic structural model of birth weight. J Labor Econ 30(3):657–706
Deschênes O, Greenstone M, Guryan J (2009) Climate change and birth weight. Amer Econ Rev 99(2):211–217
Ejrnæs M, Pörtner C (2004) Birth order and the intrahousehold allocation of time and education. Rev Econ Stat 86(4):1008–1019
Evans WN, Lien DS (2005) The benefits of prenatal care: evidence from the PAT bus strike. J Econ 125(1-2):207–239
Figlio DN, Guryan J, Karbownik K, Roth J (2014) The effects of poor neonatal health on children’s cognitive development. Amer Econ Rev 104 (12):3921–3955
Fiscella K (1995) Does prenatal care improve birth outcomes? A critical review. Obstet Gynecol 85: 468–479
Gardner DS, Buttery PJ, Daniel Z, Symonds ME (2007) Factors affecting birth weight in sheep: maternal environment. Reproduction 133(1):297–307
Gluckman P, Hanson M (2004) The fetal matrix: evolution, development and disease. Cambridge University Press, Cambridge, UK
Hafner DE, Schuchter K, Metzenbauer M, Philipp K (2000) Uterine artery doppler perfusion in the first and second pregnancies. Ultrasound Obstet Gynecol 16 (7):625–629
Hinkle SN, Albert PS, Mendola P, Sjaarda LA, Yeung E, Boghossian NS, Laughon SK (2014) The association between parity and birthweight in a longitudinal consecutive pregnancy cohort. Paediatr Perinat Epidemiol 28(2):106–115
Hollis B, Prefumo F, Bhide A, Rao S, Thilaganathan B (2003) First-trimester uterine artery blood flow and birth weight. Ultrasound Obstet Gynecol 22(4):373–376
Hotz VJ, Pantano J (2015) Strategic parenting, birth order, and school performance. J Popul Econ 28(4):911–936
Johanson JM, Berger PJ (2003) BirthWeight as a predictor of calving ease and perinatal mortality in holstein cattle. J Dairy Sci 86(11):3745–3755
Kantarevic J, Mechoulan S (2006) Birth order, educational attainment, and earnings: an investigation using the PSID. J Human Resour 41(4):755–777
Khong TY, Adema ED, Erwich JJHM (2003) On an anatomical basis for the increase in birthweight in second and subsequent born children. Placenta 24 (4):348–353
Kling JR, Liebman JB, Katz LF (2007) Experimental analysis of neighborhood effects. Econometrica 75(1):83–119
Kristensen P, Bjerkedal T (2007) Explaining the relation between birth order and intelligence. Science 316:2007
Lehmann JYK, Nuevo-Chiquero A, Vidal-Fernandez M (2017) The early origins of birth order differences in children’s outcomes and parental behavior. J Human Resour (forthcoming) 0816-8177. doi:10.3368/jhr.53.1.0816-8177
Lien DS, Evans WN (2005) Estimating the Impact of Large Cigarette Tax Hikes: the Case of Maternal Smoking and Infant Birth Weight. J Human Resour 40 (2):373–392
Lundberg E, Svaleryd H (2017) Birth order and child health. Uppsala University, Department of Economics. Working paper / Department of Economics, Uppsala University (Online) 2017:3, p 49. ISSN: 1653-6975
Lykke JA, Paidas MJ, Triche EW, Langhoff-Roos J (2012) Fetal growth and later maternal death, cardiovascular disease and diabetes. Acta Obstet Gynecol Scand 91(4):503–510
Magnus P, Bjerkedal T (1985) The association of parity and birth weight: testing the sensitization hypothesis. Early Human Dev 12:49–54
Pavan R (2015) On the production of skills and the birth order effect. J Human Resour (forthcoming). doi:10.3368/jhr.51.3.0913-5920R. http://jhr.uwpress.org/content/early/2015/11/20/jhr.51.3.0913-5920R.abstract
Persson P, Rossin-Slater M (2016) Family ruptures, stress, and the mental health of the next generation, nBERWorking Paper Series No. 22229
Plug E, Vijverberg W (2003) Schooling, family background, and adoption: is it nature or is it nurture? J Polit Econ 111(3):611–641
Price J (2008) Parent-child quality time: does birth order matter? J Human Resour 43(1):240–265
Prefumo F, Bhide A, Sairam S, Penna L, Hollis B, Thilaganathan B (2004) Effect of parity on second-trimester uterine artery doppler flow velocity and waveforms. Ultrasound Obstet Gynecol 23(1):46–49
Sibai BM (2003) Diagnosis and management of gestational hypertension and preeclampsia. Obstet Gynecol 102(1):181–192
Sonchak L (2014) Medicaid reimbursement, prenatal care and infant health. J Health Econ 44:10–24
Sønes T, Bakke T (1989) Uterine size, parity and umbilical cord length. Acta Obstet Gynecol Scand 68(5):439–441
Sulloway F (2007) Birth order and intelligence. Science 316(5832):1711–1712
Swamy G, Edwards S, Gelfand A, James S, Miranda ML (2012) Maternal age, birth order, and race: differential effects on birthweight. J Epidemiol Commun Health 66(2):136–142
Viscusi WK, Wa Magat, Huber J (1986) Informational regulation of consumer health risks: an empirical evaluation of hazard warnings. Rand J Econ 17(3):351–365
Warburton D, Naylor A (1971) The effect of parity on placental weight and birth weight: an immunological phenomenon? A report of the collaborative study of cerebral palsy. Amer J Human Genet 23(1):41–54
Woessner JF, Brewer TH (1963) Formation and breakdown of collagen and elastin in the human uterus during pregnancy and post-partum involution. Biochem J 89:75–82
Acknowledgements
We are thankful for helpful comments and suggestions from three anonymous referees, Stefan Bauernschuster, Sanni Nørgaard Breining, Michael Grimm, Timo Hener, Edward Samuel Jones, Jacob Alexander Lykke, Torben Heien Nielsen, Helmut Rainer, Heather Royer, members of the University of California Santa Barbara Human Capital Working Group, and participants at the Annual Meeting of the Society of Labor Economists 2016, the Royal Economic Society Conference 2016, the BGPE Research Workshop 2016, the Essen Health Conference 2015, the Bavarian Micro Day 2015, seminars at University of California, Santa Barbara; the University of Copenhagen; the Danish National Centre for Social Research; and the University of Passau.
Author information
Authors and Affiliations
Corresponding author
Additional information
Responsible editor: Erdal Tekin
Appendices
Appendix A: The nature hypothesis
The general understanding in the medical literature is that physiological changes during the first pregnancy, necessary for fetal development, do not fully return to their baseline value (before the first pregnancy). Higher order pregnancies profit from this incomplete reversal. These physiological changes encompass the uterine blood supply (Hafner et al. 2000; Hollis et al. 2003; Khong et al. 2003; Prefumo et al. 2004) and an enlargement of the uterus (Woessner and Brewer 1963; Sønes and Bakke 1989), both of which affect nutrient supply to the fetus (Gluckman and Hanson 2004). It has also been suggested that maternal sensitization to paternal antigens that occur at the first pregnancy affect birth weight of later-born children (Warburton and Naylor 1971; Chakraborty et al. 1975).
Animal studies perpetuate the findings from the medical literature. A positive effect of birth order on health at birth appears for cattle (Johanson and Berger 2003) as well as sheep (Gardner et al. 2007). Animal studies occur in a controlled environment, for example, with respect to nutrition, and therefore alleviate concerns about endogenous behavioral differences of the mother.
Appendix B
The effect of birth order on health at birth by maternal age at first birth. Notes: The figure plots the coefficients of the interaction term between birth order and maternal age at first birth in the family fixed effects model (model (1) where the three birth order dummies are interacted with five dummies for maternal age at first birth). The dependent variable is the health index (mean of zero and standard deviation of one) that is an equally weighted summary index of the following variables: birth weight, low birth weight, high birth weight, prematurity, and Apgar score. Age at first birth is divided into (1) < 22 years, (2) 22–25 years, (3) 26–29 years, (4) 30–33 years, (5) > 33 years. The regression includes family fixed effects, interactions between year of conception and month of conception dummies, and a dummy for gender of the child. The whiskers indicate the 95% confidence interval
The effect of birth order on health at birth by mother’s highest education. Notes: The figure plots the coefficients of the interaction term between birth order and education of the mother in the family fixed effects model (model (1) where the three birth order dummies are interacted with three dummies for mother’s highest education). The dependent variable is the health index (mean of zero and standard deviation of one) that is an equally weighted summary index of the following variables: birth weight, low birth weight, high birth weight, prematurity, and Apgar score. Education is divided into (1) < HS: no high school/education (< 12 years), (2) HS: high school and potentially some vocational training or two years of college, and (3) BA: Bachelor degree or more. The regression includes family fixed effects, interactions between year of conception and month of conception dummies, and a dummy for gender of the child. The whiskers indicate the 95% confidence interval
The effect of birth order on health at birth by gender of the child. Notes: The figure plots the coefficients of the interaction term between birth order and gender of the child (model (1) where the three birth order dummies are interacted with a dummy for boy and a dummy for girl). The dependent variable is the health index (mean of zero and standard deviation of one) that is an equally weighted summary index of the following variables: birth weight, low birth weight, high birth weight, prematurity, and Apgar score. The regression includes family fixed effects, interactions between year of conception and month of conception dummies, and a dummy for gender of the child. The whiskers indicate the 95% confidence interval
Rights and permissions
About this article
Cite this article
Brenøe, A., Molitor, R. Birth order and health of newborns. J Popul Econ 31, 363–395 (2018). https://doi.org/10.1007/s00148-017-0660-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00148-017-0660-1