Previous research had found that infants born at 34 to 36 weeks’ gestation – classified as “late preterm” – have an increased risk of developmental delays and other mental and medical difficulties. A new study suggests even infants born at 37 or 38 weeks’ gestation – technically “at term” – are at risk.
The study, “Academic Achievement Varies With Gestational Age Among Children Born at Term,” in the August 2012 Pediatrics (published online July 2), analyzed data from 128,000 babies born between 37 and 41 weeks’ gestation in New York City.
Birth records were matched with public school records of standardized third-grade math and reading tests. Researchers found achievement scores for children born at 37 and 38 weeks were significantly lower than those of children born at 39, 40 or 41 weeks.
Compared to children born at 41 weeks, children born at 37 weeks have a 23 percent increased risk of having a moderate reading impairment; children born at 38 weeks have a 13 percent increased risk.
Math scores were also lower for children born at 37 or 38 weeks. The effect was independent of birth weight and other obstetric, social and economic factors. The infant brain grows rapidly in the last weeks of gestation, and may be more likely to be disrupted when children are born early, even within the commonly defined period of “term gestation”.
Study findings suggest this disruption may affect later academic achievement.
Given the trend for performing elective early deliveries for nonmedical reasons, study authors conclude that researchers, clinicians and parents should consider the link between weeks of gestation and school performance. The authors concluded:
“Earlier normal term birth may be a characteristic considered by researchers, clinicians, and parents to help identify children who may be at risk for poorer school performance.”
What is the difference between gestation and pregnancy? – gestation refers to how long it takes a fetus to develop inside the uterus, while pregnancy is the fact that the fetus is inside the mother to be. In other words, gestation refers to a period while pregnancy refers to a state. The gestation period for an elephant is 22 months, while for a human being it is 9 months.
Pregnancy refers to the fertilization and development of embryo(s) or fetus (fetuses) in a woman’s uterus. A pregnancy can consist of multiple gestations. In this case, pregnancy still refers to a state, while gestation refers to how many offspring there are inside the mother.
Experts say that the baby is usually born approximately 38 weeks after conception; after the fertilization of the egg by a sperm – this is about 40 weeks after the last normal menstrual period of a woman with a menstrual cycle length of four weeks.
In most countries, a pregnancy is divided into three “terms” or “trimesters”. During the first trimester (first three months) there is a much higher risk of miscarriage compared to the second and third. During the second trimester it is easier to monitor the pregnancy and diagnose the state of the mother and fetus. At the beginning of the third trimester, at month 7, the point of viability approaches – the point at which the fetus is able to survive outside the mother (sometimes with medical help).
Most of the weight gain in a pregnancy occurs in the third trimester – the fetus gains about 28g per day, and the mother’s belly transforms in shape as it drops because the fetus has turned to a downward position ready for childbirth.
A baby who is born with a gestational age of less than 37 weeks is “pre-term”. However, after the findings of this study, some experts may ask the authorities that lay down medical definitions to review the 37-week definition.
Kelly Fitzgerald