The Scandinavian Small-for-Gestational Age (SGA) pregnancy and birth cohort – A source to continual insight into fetal growth restriction and long term physical and neurodevelopmental health in mother and offspring

Abstract

Human in utero growth restriction (IUGR) is associated with an increased risk for perinatal mortality and morbidity among newborns and infants. To pursue this challenge, a Request For Proposals (RFP) was issued in 1983 by The U.S. Epidemiology and Biometry Research Program at the National Institute of Child Health and Human Development (NICHD). A consortium was set up at the universities and university hospitals in Trondheim, Bergen (Norway) and Uppsala (Sweden) and was funded by the NICHD to conduct the Scandinavian Successive Small-for-Gestational Age (SGA) Pregnancy and Birth Outcome Study. The study design included a comprehensive biobank with maternal and cord serum samples, placental tissue, and a multitude of data collected from interviews, questionnaires, and clinical examinations.The SGA cohort study involved 6,354 Caucasian pregnant women in the three study sites who expected their second or third child from 1986-88. The study women were screened in early second trimester and mothers who had an increased risk to deliver a smaller than expected newborn were followed in detail through the second half of pregnancy and at birth. Selected children were screened several times through their first and up to five years of age. Moreover, a highly selected subgroup in Trondheim has been followed at 14, 19, and 26 years' age.Almost thirty years later, we have searched the body of scientific publications that originated from this cohort study in an attempt to assess if and to what extent the main aims and objectives were achieved and to summarize the overall outcomes. The SGA cohort has resulted in close to 100 published papers in peer reviewed journals and some 40 graduate and undergraduate degrees. Risk factors of SGA, like maternal smoking, low prepregnancy weight and education attainment, and a previous SGA birth outcome were confirmed. Conversely, no totally new and unknown risk factors were identified. Serial ultrasound measures have enabled a distinction between SGA with restricted and normal intrauterine growth, and has further indicated that being born SGA is mainly a problem in combination with IUGR. Further, the consequences of IUGR are more pronounced at adolescence and young adulthood than at five years of age.An increased understanding of the pathogenesis of different categories of growth restriction is essential to recognize and diagnose IUGR properly, and to reduce the perinatal mortality and morbidity from SGA. Moreover, SGA is a significant predictor at follow-up of the child. An up to date biobank has ensured the quality of data and biological samples, and has been crucial for the outcome of the entire SGA study. It continues to be a valuable resource in future research.This is an open access article distributed under the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

On the use of the outcome variable “small for gestational age” when gestational age is a potential mediator: a maternal asthma perspective

“…As mentioned previously, the rationale for not exclusively using (L)BW in studies is now well understood. Although SGA is perceived as a more interpretable outcome than (L)BW since internally adjusted for GA, it remains that this variable is a mere statistical construct (e.g., [ 8 ]) and could also present some limitations.…”

Stunting, recovery from stunting and puberty development in the MINIMat cohort, Bangladesh

“…The reasons of the discrepancy between our findings and earlier evidence might be that the causes of intrauterine growth restriction and low birthweight are complex and vary between different contexts. High‐income settings, where most studies on SGA and puberty have been carried out, have a prevalence of SGA from 4% to 8% and smoking is the most prominent risk factor . In our setting, we had an almost tenfold higher prevalence of SGA, and smoking was extremely rare among women.…”

“…High-income settings, where most studies on SGA and puberty have been carried out, have a prevalence of SGA from 4% to 8% and smoking is the most prominent risk factor. 27 In our setting, we had an almost tenfold higher prevalence of SGA, and smoking was extremely rare among women. Another important factor that distinguishes the South Asian context is the relatively small maternal size, contributing to small size at birth.…”

Bør gravide avstå fra enhver bruk av nikotin?

“…Olsen fremhever at effekten på barnet langt fra er over etter at det har forlatt det intrauterine røykerommet. Siden midten av 1980-årene har jeg medvirket til en prospektiv studie med gravide der oppfølgingen av barna fortsatt pågår (7). Den opprinnelige hensikten var å studere faktorer som hemmer fosterveksten og fører til at barnet er lettere enn forventet ved fødselen (small for gestational age, SGA), dernest effekten av dette på kort og på lang sikt.…”

“…Den opprinnelige hensikten var å studere faktorer som hemmer fosterveksten og fører til at barnet er lettere enn forventet ved fødselen (small for gestational age, SGA), dernest effekten av dette på kort og på lang sikt. Et hovedfunn var at ingen enkeltfaktor kan måle seg med den negative effekten av tobakksrøyking på fødselsutfallet, uansett hvilke andre risikofaktorer som foreligger (7). Ett eksempel på at effekten av mors røyke-vaner ikke stanser ved fødselen, er at disse barna oftere enn andre er overvektige (8).…”