Does Sugar Intake Affect Fetal Weight Gain in the Third Trimester?

Nutrition before, during and after pregnancy impacts your baby's health.

It is essential for pregnant women to eat a balanced diet that supplies their developing fetus and changing body with the right nutritional support. Eating too many carbohydrates and sugary foods can cause health problems and lead to excessive weight gain in the baby.

Third Trimester

Pregnancy is divided into three main stages, or trimesters.

The third and last trimester is a critical time for growth, as the developing fetus will gain almost half its weight in this three-month period, and there is essential brain and lung formation.

The food you eat directly impacts the baby's weight, and proper, balanced nutrition is of primary importance for your health and that of your baby.

The American Pregnancy Association recommends gaining a pound per week during the seventh and eighth months of pregnancy. Your weight may stabilize or even decrease slightly in the ninth month. However, eating too many refined carbohydrates and sugary foods can negatively impact your baby's health and your own.

Gestational Diabetes

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In April 2002, "The Journal of Reproductive Medicine" published the results of research that studied the impact of gestational diabetes mellitus on pregnant women and the developing fetus. Excess sugar in the mother's blood due to consuming too many carbohydrates and sugary foods or because of uncontrolled type 2 or gestational diabetes can impact the growth of the fetus. Extra sugar or glucose in the blood crosses the placenta and enters the fetus, raising its blood sugar levels. This causes the baby to produce excessive amounts of the hormone insulin, which lowers blood glucose.

The high sugar intake and extra insulin cause the baby to grow too large, a condition called macrosomia. A large baby makes delivery more complicated and can increase the risk of health problems and injury for both the mother and the baby during the delivery.

Sugar Intake

Pregnant women who already have type 2 diabetes or who develop gestational diabetes during pregnancy must control their sugar intake and blood glucose levels to maintain a healthy pregnancy. According to, balanced sugar control can reduce the risks of a miscarriage, stillbirth and birth defects that affect the heart, brain and spine. High blood-sugar levels can also increase the chance of going into preterm labor and giving birth prematurely.

Even if the mother does not have diabetes, consuming too much sugar daily can increase the weight of the baby excessively and lead to serious complications for the mother, such as high blood pressure and preeclampsia, which is high blood pressure and too much protein in the urine after 20 weeks of pregnancy. The baby may also suffer from jaundice, which causes a temporary yellowing of the eyes and skin after birth.


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It is essential to eat a balanced diet and avoid foods that can be unhealthy throughout your pregnancy. Developing healthy eating habits before you become pregnant will help to improve your child's quality of life. Some foods and substances can cause direct harm to the vulnerable developing fetus and cause illness in the mother. The American Pregnancy Association recommends eliminating the risk of harmful bacterial infections, such as toxoplasmosis and salmonella, by eating only thoroughly cooked meat and avoiding suspect seafood, such as clams.

Pregnant women must also avoid cigarette smoke, alcohol consumption, drug use, and certain medications. Caffeine should be reduced or eliminated as well.