Baby boys tend to be a little heavier than little girls, and their growth patterns are ever so slightly different. As a result they each have different centile charts. Visit the Royal College of Paediatrics and Child Health website to see some examples of baby weight charts.
Physical size and growth
Right from the start, boys tend to weigh more at birth and this trend continues as babies age, with girls measuring about a half pound less.
In general: Boys are usually a little heavier than girls. First babies are usually lighter than later siblings. Large parents generally have large babies.
Gender-specific body composition at birth has been reported, where the male infant has more fat mass and lean body mass than the female infant, especially in well-nourished mothers [31].
if the baby is a boy (baby boys tend to be larger than baby girls) having older siblings (the chance of fetal macrosomia increases with each pregnancy)
A father's genetic code influences the weight of a baby at birth, according to a new study led by the UCL Institute of Child Health (ICH).
We also know that the length of a baby is associated with its eventual height and weight. In other words, heavy babies tend to grow up fat and long babies tend to grow up tall.
It has been observed that women accumulate fat quicker than men and lose it far more slowly.
Biological differences between the sexes are apparent even from the early part of the pregnancy. The crown-rump length is larger in male fetuses compared to females in the first trimester. Placentae of male and female fetuses have different protein and gene expressions, especially in adverse conditions.
In her study, women who consumed the most calories had a 56 percent chance of having a boy. Those who ate the fewest calories had a 45 percent chance of giving birth to a boy. Either way, it's close to 50-50 odds.
What is considered a 'big baby'? Picking an absolute cut-off is tricky. Typically, we consider estimated weights of babies that weigh more than 4500 grams (10 lbs.) as larger than normal (or “macrosomic”).
The study determined that increased pregnancy weight was correlated with male babies.
At birth, boys tend to be longer than girls at any placental weight. Boy's placentas may therefore be more efficient than girls, but may have less reserve capacity. In the womb boys grow faster than girls and are therefore at greater risk of becoming undernourished.
The weight difference between newborn boys and girls is negligible. The baby bump method relies entirely on baby boys weighing more than baby girls. However, the average weight differential between a newborn boy and girl is less than 1⁄2 lb (0.23 kg).
Things that can lead to a lower birth weight include a mother with high blood pressure or heart problems; or one who used cigarettes, alcohol, or illegal drugs during the pregnancy. If the mother has diabetes or is obese, the baby may have a higher birth weight. Nutrition during pregnancy.
In mammals, once genetic sex has been determined and the fetus begins its development, the fetal environment, especially hormones, can result in significant modifications of the genetically based sex.
If the fetal heart rate is under 140 beats per minute (BPM), it's a boy. False. A baby girl's heart rate is usually faster than a boy's, but only after the onset of labor. There's no difference between fetal heart rates for boys and girls, but the rate does vary with the age of the fetus.
Sagittal sign: Each sex has a sagittal sign. It is obtained by looking at a profile view of the fetus (known as the midline sagittal plane). There is a nub at the end of the spine, called the caudal notch. If it is pointing downward at a 10-degree angle, then the fetus is a girl.
According to a 2014 CNN story on the subject, women average between 6 and 11 percent more body fat than men.
Fat weighs less per unit of volume than lean mass, and women have a higher percentage of natural body fat than men. So for a given height, men typically carry more lean mass and thus weigh more. Women also hold their body fat in different locations to men.
Women, compared to men, have higher percent body fat and deposit it in a different pattern, with relatively more adipose tissue in the hips and thighs. This 'female' fat distribution, independent of total body fat, confers protection against metabolic diseases, such as type 2 diabetes and atherosclerosis [1].
Study results published in The American Journal of Clinical Nutrition suggest that a mother's diet during pregnancy has a long-term impact on her child's weight gain trajectory.
Yep, giving birth to big babies can be hereditary. In general, babies tend to be in the same weight range as their parents. In other words, if you were nine pounds, eight ounces at birth, it's incredibly unlikely that you'll give birth to a five-and-a-half-pound peanut.
The average birth weight of a full-term female is 7 lb 2 oz , or 3.2 kg. The average weight of a baby born at 37–40 weeks ranges from 5 lb 8 oz to 8 lb 13 oz.