Macrosomia is when a newborn has excessive birth weight. Fetal macrosomia occurs in the second pregnancy of about one third of women. A newborn’s birth weight is influenced by the mother’s age, ethnicity and previous deliveries of a large infant. There is also large evidence suggesting that there is a strong link between excessive weight gain during pregnancy and increased birth weight.
Presently there are one billion adults in the world’s population who are overweight. When a woman’s has a high maternal BMI there is a high chance she will give birth to a larger infant. However, it has also been observed that the weight a woman gains during pregnancy is independently related to the weight of the newborn on delivery. Therefore the study wanted to put women on a carbohydrate controlled diet and see did the weight they did/did not gain affect the birth weight of the infant. Their main reason for studying this cause and effect is that increased birth weights are associated with increased health risks in later life for children. One of these health risks is childhood obesity.
A trial was carried out, measuring the incidence of macrosomia in women on a low glycemic index diet versus those who did not diet.
A low glycemic diet is carried out by eating foods that have a low glycemic index. All carbohydrates increase blood sugar levels, but their effect varies. Carbohydrate effects on blood sugar are categorized according to the glucose response they induce; their glycemic index. Low glycemic foods have a low glucose response, and high glycemic foods have a high glucose response. People on a low glycemic diet try to eat more carbohydrates that have a low glycemic index.
The results of this study found that a low glycemic index diet did have some health benefits for mother and newborn, however it did little to decrease the incidence of macrosomia.
The benefits of a low glycemic index diet were shown in the lower incidence of induced labor and primary postpartum hemorrhage in the women who followed the lower glycemic index diet. The diet also had a positive effect on maternal weight gain as well as maternal glucose tolerance.
The growing problem of obesity needs an intervention, or rather a combination of interventions. Although this particular diet was not shown to be sufficient in preventing macrosomia in newborns, it does have other benefits for women during pregnancy.