Until a few years ago, grandparents applauded the birth of big, fat babies because "They were beautiful", and in all family gatherings there is always the voice of a mother who had a son who weighed more than five kilos, as a feat worthy of mention. My sister weighed five and a half kilos at birth!
But the truth is that Excessive weight or height implies risks for the baby and is known as macrosomia (big body). But, Why does it occur? What risks does it imply?
When do you talk about a baby with macrosomia?
According to the report 'Newborn of high weight' of the Neonatal Unit of the Pediatric Service of the Hospital of Basurto (Bilbao), one usually speaks of macrosomia when it is estimated that the weight of the baby at birth will be greater than the 90th percentile or greater than four kilos of weight It is considered to be from 4.5 kilos of weight when complications increase significantly.
It is estimated that Five percent of babies are born above this 90th percentile, but not all are considered macrosomic, nor will everyone need special measures.
In Babies and more, a 6.3 kg baby was born naturally and without epidural But these researchers explain that "What is substantial in the definition of this concept is to differentiate newborns with an increased perinatal risk and susceptible to special care, from those probably normal infants and therefore with a similar risk to the rest of newborns."
The macrosomia is an estimate of weight and height made with an ultrasound taking into account three parameters (the diameter of the head, the perimeter of the abdomen and the length of the femur bone), and has an error range of between 300 and 550 grams, Therefore, it cannot be considered a totally accurate method for the diagnosis of macrosomia.
Therefore, the authors of the study explain that currently, in addition to birth weight (PN) and gestational age (EG), the weight index (PI) is proposed as a parameter that would define the two macrosomic subtypes: harmonic (no associated problems) and disharmonic (to watch).
If performed the relevant tests the existence of pathologies is ruled out, pregnancy and childbirth can be perfectly normal, even vaginally.
Risk factor's
Some predictive factors of macrosomia are:
Excessive growth of the fetus
Family diabetes
A placenta thickness greater than four centimeters.
Women over 30 years.
Male fetuses.
Big parents. It is one of the most normal and least worrisome factors for a high birth weight. In these cases, genetics is the fundamental factor.
In Babies and more, the world's largest baby in India was born with 6.8 kilos, the weight of a six-month-old baby However there are others Causes that can trigger excessive weight gain or height in the baby:
That the mother gained a lot of weight in pregnancy. If the baby's weight is not too high, it is usually not dangerous.
Maternal diabetes, whether the woman had it before pregnancy or if it is a gestational diabetes. It is one of the most common causes. The explanation is related to sugar metabolization. When the mother has a high blood sugar, the baby produces extra insulin, which can cause excessive growth or fat accumulation.
Associated complications
Traditionally it has been considered that macrosomic fetuses pose potential risks to the mother: greater possibility of perineal tear and greater risk of caesarean section. And also for the fetus (cardiomyopathy, congenital malformations) and the baby: increased risk of shoulder dystocia at birth.
But according to 'Childbirth is ours', "A very large baby is no reason in itself for an elective C-section or early induction of childbirth":
"Spontaneous termination of pregnancy should be favored and during labor, only intervene if there really is a true cephalo-pelvic disproportion."
Even a study published in the American Family Physician magazine indicates that "In the case of a previous caesarean section, the risk of rupture of the uterus with a macrosomic fetus is no greater than in the case of being pregnant with a smaller baby.
Even so, the disproportion of the pelvic fetus, operative deliveries with use of forceps or suction cup, caesarean section, postpartum hemorrhages and trauma in the birth canal lead to increased risk and subsequent problems in the vaginal wall. Today, the negative consequences are much less, but they do not disappear altogether.
Further, In vaginal births shoulder dystocia is more common than in normal weight babies. This occurs when a baby's head passes through the vagina during birth, but its shoulders get stuck inside the mother.
Too there may be higher percentages of neonatal asphyxiation, meconium aspiration and hospital admission after birth.
For these reasons, the possibility of having a C-section is considered as the appropriate alternative in most cases.
Definitely there are babies born with more than four kilos vaginally and without complications, and there are also cases of previous false positive, so professionals should be very aware of all the data before deciding on a scheduled caesarean section and explain to the mother the information they have with complete veracity.
If the mother had diabetes, the baby, at birth, may have problems with the regulation of her own blood glucose. And that will bring others complications to babies with macrosomia:
Jaundice
Persistent pulmonary hypertension
Hypoglycemia
Polycythemia
Breathing difficulties
Difficult diagnosis
Fetal macrosomia is difficult to detect and diagnose during pregnancy. Some signs and symptoms that can predict it:
Height of the large uterine fundus. During prenatal visits, the doctor can measure the height of the uterine fundus, the distance from the upper part of the uterus to the pubic bone. A height of the uterine fundus with a measure greater than expected could be a sign of fetal macrosomia.
Excess of amniotic fluid (polyhydramnios). Too much of the fluid that surrounds and protects the baby during pregnancy, it could be a sign that the baby is larger than average. The explanation? The amount of amniotic fluid reflects the baby's urine output, and a larger baby produces more urine.
In addition, calculating what the baby will weigh before birth is also very complicated, so The definitive diagnosis of fetal macrosomia is not made until after the baby is born and weighed.
If you have risk factors for fetal macrosomia, the Mayo Clinic warns that the doctor is likely to perform tests to monitor the health and development of the baby:
Ultrasound Towards the end of the third trimester, to take measurements of the baby's body parts, such as the head, abdomen and femur. "However, the accuracy of ultrasound to predict fetal macrosomia is unreliable.", according to this medical institution.
Prenatal analysis If the overgrowth of the baby is considered to be a consequence of a maternal disease, the doctor may recommend a prenatal analysis, starting at week 32 of pregnancy. Can be:
A resting test, which measures the baby's heart rate in response to their own movements.
A fetal biophysical profile, which combines a resting test with an ultrasound to control the baby's movement, muscle tone and breathing, and the volume of the amniotic fluid.
But, as this Clinic explains, it may not be that specific analyzes are performed, since macrosomia alone is not a reason to perform a prenatal analysis.
In addition, there is also no treatment that reduces its size. You can only try to avoid complications during childbirth and in the newborn.
Even so, the authors of the Basurto Hospital study report that the long-term effects of a very large baby should also be considered:
"Several studies link fetal macrosomia in children of a diabetic mother, obese and even in the normal population, with an increased risk of developing type 2 diabetes mellitus, obesity and metabolic syndrome in childhood or adulthood, which would perpetuate this cycle in the next generations. "
Therefore, according to their conclusions, "It is mandatory, especially in children who have been great for their gestational age and who develop obesity, exercise greater vigilance over their eating habits and lifestyle, to prevent future cardiovascular complications."
Photos | iStock
