Understanding Your Baby’s Weight Gain during Your Pregnancy
Although your weight gain may follow a path all its own, your baby’s own bulking-up pattern is likely to progress slowly at first, and then pick up at about 32 weeks, only to slow again in the last weeks before birth.
At 14 to 15 weeks, for example, the baby puts on weight at about 0.18 ounce (5 grams) per day, and at 32 to 34 weeks, 1.06 to 1.23 ounces (30 to 35 grams) per day (that’s about half a pound or 0.23 kilograms each week).
After 36 weeks, the fetal growth rate slows to about a quarter of a pound per week, and by 41 to 42 weeks (you’re overdue at this point), minimal or no further fetal growth may occur.
In addition to your diet and weight gain, the following factors affect fetal growth:
Cigarette smoking: Smoking can reduce the birth weight by about half a pound (about 200 grams).
Diabetes: If the mother is diabetic, the baby can be too big or too small.
Genetic or family history: In other words, basketball players usually don’t have children who grow up to be professional jockeys!
Fetal infection: Some infections affect growth, although others don’t.
Illicit drug use: Drug abuse can slow fetal growth.
Mother’s medical history: Some medical problems, like hypertension or lupus, can affect fetal growth.
Multiple pregnancy: Twins and triplets are often smaller than single babies.
Placental function: Placental blood flow that’s below par can slow down the baby’s growth.
Your practitioner keeps an eye on your baby’s growth rate, most often by measuring fundal height and paying attention to your weight gain. If you put on too little or too much weight, if your fundal height measurements are abnormal, or if something in your history puts you at risk for growth problems, your doctor is likely to send you for an ultrasound exam to more accurately assess the situation.