Small-for-Gestational Age Birth Confers Similar Educational Performance through Middle School.

OBJECTIVE: To estimate the association between small for gestational age (SGA) at birth and educational performance on standardized testing and disability prevalence in elementary and middle school. STUDY DESIGN: Through linked birth certificates and school records, surviving infants born at 23-41 weeks of gestation who entered Florida's public schools 1998-2009 were identified. Twenty-three SGA definitions (3rd-25th percentile) were derived. Outcomes were scores on Florida Comprehensive Assessment Test (FCAT) and students' disability classification in grades 3 through 8. A "sibling cohort" subsample included families with at least 2 siblings from the same mother in the study period. Multivariable models estimated independent relationships between SGA and outcomes. RESULTS: Birth certificates for 80.2% of singleton infants were matched to Florida public school records (N = 1 254 390). Unadjusted mean FCAT scores were 0.236 SD lower among <10th percentile SGA infants compared with non-SGA infants; this difference declined to -0.086 SD after adjusting for maternal and infant characteristics. When siblings discordant in SGA status were compared within individual families, the association declined to -0.056 SD. For SGA <10th percentile infants, the observed prevalence of school-age disability was 15.0%, 7.7%, and 6.3% for unadjusted, demographics-adjusted, and sibling analyses, respectively. No inflection or discontinuity was detected across SGA definitions from 3rd to 25th percentile in either outcome, and the associations were qualitatively similar. CONCLUSIONS: The associations between SGA birth and students' standardized test scores and well-being were quantitatively small but persisted through elementary and middle school. The observed deficits were largely mitigated by demographic and familial factors.

Evidence that prenatal testosterone transfer from male twins reduces the fertility and socioeconomic success of their female co-twins.

During sensitive periods in utero, gonadal steroids help organize biological sex differences in humans and other mammals. In litter-bearing species, chromosomal females passively exposed to prenatal testosterone from male littermates exhibit altered physical and behavioral traits as adults. The consequences of such effects are less well understood in humans, but recent near-doubling of twinning rates in many countries since 1980, secondary to advanced maternal age and increased reliance on in vitro fertilization, means that an increasing subset of females in many populations may be exposed to prenatal testosterone from their male co-twin. Here we use data on all births in Norway (n = 728,842, including 13,800 twins) between 1967 and 1978 to show that females exposed in utero to a male co-twin have a decreased probability of graduating from high school (15.2%), completing college (3.9%), and being married (11.7%), and have lower fertility (5.8%) and life-cycle earnings (8.6%). These relationships remain unchanged among the subsets of 583 and 239 females whose male co-twin died during the first postnatal year and first 28 days of life, respectively, supporting the interpretation that they are due primarily to prenatal exposure rather than to postnatal socialization effects of being raised with a male sibling. Our findings provide empirical evidence, using objectively measured nation-level data, that human females exposed prenatally to a male co-twin experience long-term changes in marriage, fertility, and human capital. These findings support the hypothesis of in utero testosterone transfer between twins, which is likely affecting a small but growing subset of females worldwide.

Socioeconomic status and genetic influences on cognitive development.

Accurate understanding of environmental moderation of genetic influences is vital to advancing the science of cognitive development as well as for designing interventions. One widely reported idea is increasing genetic influence on cognition for children raised in higher socioeconomic status (SES) families, including recent proposals that the pattern is a particularly US phenomenon. We used matched birth and school records from Florida siblings and twins born in 1994-2002 to provide the largest, most population-diverse consideration of this hypothesis to date. We found no evidence of SES moderation of genetic influence on test scores, suggesting that articulating gene-environment interactions for cognition is more complex and elusive than previously supposed.

Educational Performance of Children Born Prematurely.

Importance: Survivors of preterm birth often present with medical morbidities; however, variation in their long-term educational performance has not been well described. Objective: To estimate the association between gestational age and 4 outcomes in school-aged children: readiness to enter kindergarten, scores on standardized tests in elementary and middle school, gifted status, and low performance. Design, Setting, and Participants: In a retrospective cohort study, children born in Florida between 1992 and 2002 at 23 to 41 weeks' gestation who entered Florida's public schools between 1995 and 2012 were assessed for kindergarten readiness and tested in mathematics and reading in grades 3 through 8. Data analysis was performed from January 12, 2016, to March 1, 2017. Exposures: Gestational age at birth. Main Outcomes and Measures: Kindergarten readiness, scores on the Florida Comprehensive Achievement Test (FCAT), classified as gifted, and classified as low performance. Results: A total of 1 527 113 singleton infants with gestational ages of 23 to 41 weeks born between 1992 and 2002 were matched to Florida public school records. Of these, 1 301 497 children were included in the analysis; 641 479 (49.3%) were girls. A total of 301 (65.0%) Florida children born at 23 to 24 weeks' gestation were designated as ready to start kindergarten. When the FCAT test scores were adjusted for potentially confounding maternal and infant variables, children born at 23 to 24 weeks' gestation performed 0.66 SD (95% CI, -0.73 to -0.59) lower compared with those born at full term. A total of 123 554 (9.5%) of all Florida-born public school students were considered gifted, including 17 (1.8%) of those born at 23 to 24 weeks' gestation. In comparison, 75 458 (5.8%) of all Florida-born public school students were low performing; 310 (33.5%) of these children had been born at 23 to 24 weeks' gestation. Kindergarten readiness, FCAT scores, and gifted status were positively related to gestational age, whereas low performance was inversely related to gestational age. Conclusions and Relevance: Although gestational age has long been associated with poor educational performance, a sufficient proportion of children born near the limits of viability performed within expected school norms, warranting further investigation into how and why certain children are able to overcome the educational burdens that may follow preterm birth.

Long-term Cognitive and Health Outcomes of School-Aged Children Who Were Born Late-Term vs Full-Term.

IMPORTANCE: Late-term gestation (defined as the 41st week of pregnancy) is associated with increased risk of perinatal health complications. It is not known to what extent late-term gestation is associated with long-term cognitive and physical outcomes. Information about long-term outcomes may influence physician and patient decisions regarding optimal pregnancy length. OBJECTIVE: To compare the cognitive and physical outcomes of school-aged children who were born full term or late term. DESIGN, SETTING, AND PARTICIPANTS: We analyzed Florida birth certificates from 1994 to 2002 linked to Florida public school records from 1998 to 2013 and found 1 442 590 singleton births with 37 to 41 weeks' gestation in the Florida Bureau of Vital Statistics. Of these, 1 153 716 children (80.0%) were subsequently located in Florida public schools. Linear and logistic regression models were used to assess the association of gestational age with cognitive and physical outcomes at school age. Data analysis took place between April 2013 and January 2016. EXPOSURES: Late-term (born at 41 weeks) vs full-term (born at 39 or 40 weeks) gestation. MAIN OUTCOMES AND MEASURES: There were a number of measures used, including the average Florida Comprehensive Assessment Test mathematics and reading scores at ages 8 through 15 years; whether a child was classified as gifted, defined as a student with superior intellectual development and capable of high performance; poor cognitive outcome, defined as a child scoring in the fifth percentile of test takers or having a disability that exempted him or her from taking the Florida Comprehensive Assessment Test; and Exceptional Student Education placement owing to orthopedic, speech, or sensory impairment or being hospitalbound or homebound. RESULTS: Of 1 536 482 children born in Florida from singleton births from 1994 to 2002 with complete demographic information, 787 105 (51.2%) were male; 338 894 (22.1%) of mothers were black and 999 684 (65.1%) were married at time of birth, and the mean (SD) age for mothers at time of birth was 27.2 (6.2) years. Late-term infants had 0.7% of an SD (95% CI, 0.001-0.013; P = .02) higher average test scores in elementary and middle school, 2.8% (95% CI, 0.4-5.2; P = .02) higher probability of being gifted, and 3.1% (95% CI, 0.0-6.1; P = .05) reduced probability of poor cognitive outcomes compared with full-term infants. These cognitive benefits appeared strongest for children with disadvantaged family background characteristics. Late-term infants were also 2.1% (95% CI, -0.3 to 4.5; P = .08) more likely to be physically impaired. CONCLUSIONS AND RELEVANCE: There appears to be a tradeoff between cognitive and physical outcomes associated with late-term gestation. Children born late-term performed better on 3 measures of school-based cognitive functioning but worse on 1 measure of physical functioning relative to children born full term. Our findings provide longer-run information for expectant parents and physicians who are considering delivery at full term vs late term. These findings are most relevant to uncomplicated, low-risk pregnancies.

Maternal and infant factors associated with excess kindergarten costs.

OBJECTIVE: To estimate the excess educational costs at kindergarten from infant and maternal factors that are reported routinely at birth. METHODS: Birth and school records were analyzed for all children who were born in Florida between September 1, 1990, and August 31, 1991, and entered kindergarten from 1996 through 1999 (N = 120,554). Outcome measure was cost to state, derived from base allocation for students in regular classrooms plus multiplier weights for those who were assigned to 8 mutually exclusive special education categories or who repeated kindergarten. RESULTS: More than one quarter of the study cohort was found to be assigned to special education classes at kindergarten. Regression model estimates indicated that children who were born at <1000 g (n = 380) generated 71% higher costs in kindergarten than children who were born at >or=2500 g. Children who were born at 1000 to 1499 g (n = 839) generated 49% higher costs. Other birth conditions, independent of birth weight, were associated with higher kindergarten costs: family poverty (31%), congenital anomalies (29%), maternal education less than high school (20%), and no prenatal care (14%). Because of their prevalence, family poverty and low maternal education accounted for >75% of excess kindergarten costs. If 9% of infants who weighed between 1500 and 2499 g (n = 1027) could be delivered at 2500 g, then the state of Florida potentially could save 1 million dollars in kindergarten costs. Savings of a similar magnitude might be achieved if 3% of mothers who left school without a diploma (n = 1528) were to graduate. CONCLUSIONS: Any policy recommendation aimed at reducing education costs in kindergarten must take into consideration 3 factors: the prevalence of risk conditions whose amelioration is desired, the potential cost savings associated with reducing those conditions, and the costs of amelioration. Projecting these costs from information that is available at birth can assist school districts and state agencies in allocating resources.