Factors That Determine the Health of a Baby Birth Weight

Large for Gestational Age (LGA)

The average newborn weight is about 7 pounds 8 ounces (3,400grams). The term macrosomia is used to describe a newborn with an excessive birth weight, which literally means "large body". The diagnosis of fetal macrosomia can be made only by measuring birth weight after delivery.

Fetal macrosomia has been defined in several different ways, including birth weight of 8 lb 13 oz to 9 lb 15 oz (4000-4500 g) or, greater than 90% for gestational age. High birth weight (HBW), babies weighing over about 9 pounds (4,080g) fall into the 90th percentile for weight and are known as large for gestational age (LGA) babies.

About 10 percent of all babies weigh more than 8 pounds, 13 ounces (4 kg). With about 1.5% of babies their birth weight was equal to, or was greater than 9 lb 15 oz (4500 g). Rarely do babies weigh over 10 pounds (4.6kg). Although most LGA babies are born at term (37-41 weeks of pregnancy), a few premature babies may be LGA.

How do they tell if baby is Large for Gestational Age (LGA)

When you visit your midwife or doctor for antenatal care, they may measure your abdomen on the outside. This measurement is taken from the upper edge of the pubic bone to the top of the uterus and is called the fundal height. The tape measurements (in centimetres) should equal the number of weeks that you are pregnant within 2 or 3 centimetres.

Based on that, you may be told, or see, on your antenatal records, that you are a little large for dates or (LGA) -- but this measurement can vary depending on your size and shape. Women expecting second or subsequent babies sometimes do tend to measure slightly large for dates in their first and second trimesters. This may be due to the fact that their muscles have been weakened by a previous pregnancy, although I haven't actually seen studies to support this idea.

Try not to be concerned if the fundal height is greater than dates, it may indicate twins, a large baby, mis-measuring, or even be because of fetal position. The most likely explanation is that everything is quite normal and that there is no need to worry. Doctors are more concerned when the fundal height is too small rather than too large, as this could indicate that the baby is not growing properly.

If there is an unexplained discrepancy between size and dates, your care provider could arrange an ultrasound to determine the cause of any discrepancy. An ultrasound can provide a more accurate idea of how big your baby really is, but this is not always accurate. There can be a difference of 10-15 per cent between the weight predicted by ultrasound and the actual weight of the baby at birth, especially if you are close to your due date.

During the ultrasound, several measurements are taken of the fetal body parts, fetus' head and limbs and these are compared with a growth chart to estimate fetal weight. This will only be, an estimation.

The two main reasons why a baby might be LGA:

• The first is an underlying medical problem. The most common medical cause of a LGA baby is the mother with gestational diabetes. When maternal blood sugar is high, more glucose is available to the fetus and glucose is the baby's favorite for growth, resulting in larger fetal weights. Babies of diabetic women are usually large at birth, but they behave clinically as if they are immature. These infants are not longer in average length but have increased fetal weight.

• The second reason for LGA babies is the mother's size and the family genetics. Mothers with heavy build are more likely to give birth to large babies. Excessive weight gain in pregnancy is a risk factor for macrosomia. The risk is greater for women with obesity than for women without obesity. Maternal weight prior to pregnancy can affect the weight of the fetus, a BMI greater than 30 is associated with larger infants at delivery.A father's heavy build may play a part in LGA babies, but there seems to be not much relation between father's weight and baby's weight.

Other determining factors include:

• Gestational age: Birth weight increases as gestational age increases. Prolonged pregnancies that go beyond 40 weeks increase incidence of macrosomia. Macrosomic infants account for about 10% of term deliveries and more than 6% of post-term deliveries.


• A history of macrosomia, can influence future pregnancies. Women who previously delivered a macrosomic fetus are 5-10 times more likely than women without such a history to deliver a baby considered large for gestational age (LGA) the next time they become pregnant.


• Multiparity (A woman who has given birth two or more times) and grand multiparity (4 or more) increase the risk of macrosomia. Parity has been reported to be associated with 4-5 ounces (100-150 grams) of weight gain at birth. Multiparity have 2 to 3 times the number of LGA infants vs. primaparas (First time mums).


• Fetal sex influences macrosomic potential. Male infants tend to weigh more than female infants at any gestational age. Recent studies have confirmed this association.


• The risk of macrosomia also varies with ethnicity. Even when controlled for diabetes, studies have demonstrated that Hispanic women have a higher risk of fetal macrosomia compared with white, African American, or Asian women.

Despite the identification and characterization of risk factors, no combination of these risk factors can predict macrosomia accurately enough to be used clinically. Much of the birth weight variation remains unexplained, and most macrosomic infants do not have identifiable risk factors.

Excessive maternal weight gain

• The third reason for LGA babies is the conditions inside the womb.

One of the luxuries of modern living is that it's easy to buy convenience foods that taste good - it's just too bad they're full of preservatives and other ingredients you should steer clear of during pregnancy.

The group at greatest risk were those who gained more than 40 pounds and had gestational diabetes. Nearly 30 percent of these women had heavy babies, compared with 13.5 percent of women with gestational diabetes who had normal weight gains during pregnancy.

Research findings suggest all women should avoid excessive weight gain during pregnancy. And women who are being treated for gestational diabetes should also strive to keep weight gain below 40 pounds.

Weight gain during pregnancy has been rising over the past two decades, and some researchers suspect this may be fueling an epidemic of childhood obesity.

Gain weight gradually in pregnancy

In general, you should aim to put on between 25 and 35 pounds if you began your pregnancy at a desirable weight. If you're underweight to begin with, you can gain a bit more (28-40 pounds); if you're overweight at the start, your goal should be to put on a little less (15-25 pounds).

If you're short (under 5 feet 2 inches), an adolescent, or are carrying more than one child, check with your doctor about how much weight you should gain.

When you put on weight may be as important as the total tally of pounds. You should gain the least weight during the first trimester (roughly 2 to 5 pounds total) and steadily increase, with the greatest number of pounds (roughly a pound a week) coming in the third trimester, when the baby is growing the most.

Women who eat well and gain the appropriate amount of weight are more likely to have healthy babies. So if you're eating fresh, wholesome foods and adding pounds, relax: You're supposed to be getting bigger. Pregnancy Weight Gain Calculator

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Some Large Babies - Pictures and information :-

Akbar, 19 pounds, 3 ounces (8.7 kg) - North Sumatra
Nadia, birth weight 17 pounds, 1 ounce (7.7 kg) - Siberia
Ademilton, weighed in at, 16 pounds, 11 ounces (7.6 kg) - Brazil
'Super Tonio' was born weighing 14 pounds, 8 ounces (6.6kg) - Mexico
Shaune - newborn at 14 pounds, 7 ounces (6.5 kg) - United Kingdom

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Week by Week Fetal Development ¦ Low Birth Weight Babies

Factors That Determine the Health of a Baby Birth Weight

Source: http://www.baby2see.com/baby_birth_weight.html

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