Fetal macrosomia, or intrauterine hypertrophy of the fetus, consists in excessive weight gain of the fetus, inadequate to the gestational age. According to statistical data, it is a condition that occurs in up to 10 percent of pregnancies. Due to the recommended ultrasound examinations (at least three), a large weight of the fetus is recorded at the stage of pregnancy, and not only after delivery.
Fetal macrosomiaotherwiseintrauterine hypertrophy of the fetuscauses the newborn with macrosomia to have disturbed proportions: abdominal circumference is predominant over the head, the auricles are covered with and the skin remains slightly reddened, and observations are ongoing to identify risk factors for excess fetal weight. The vast majority of them result from the mother's he alth. Diseases that may modify fetal weight gain include:
- gestational diabetes
- hypertension
- maternal obesity
In addition, fetal macrosomia may be a consequence of multiple births, prior delivery of a child with a birth weight over 4500 g or, for example, of the mother's body structure or genetic disorders (Beckwith-Wiedemann syndrome). The observations show that male fetuses are much more likely to suffer from excessive weight gain.
Fetal macrosomia: pregnancy termination
Fetal macrosomia prompts for surgical termination of pregnancy by caesarean section. A physiological delivery with such a large estimated weight is less likely to be successful. Very often the labor is almost stopped. On the maternal side, the likelihood of damage to the birth canal, disruption of the pubic symphysis or secondary uterine paresis increases. In addition to heavy bleeding, postpartum infections are much more common. The biggest problem in labor is not so much the weight of the fetus, but the shoulder dystocia, which stops the progression of labor immediately after the head is delivered. It results from the lack of return of the baby's shoulders in the birth canal. Dystocia is associated with an injury to the brachial plexus or damage to the phrenic nerve.
Other macrosomic fetal consequences are:
- neurological complications in the form of encephalopathy, which may lead tomental retardation of a child, and in rare cases, death
- carbohydrate metabolism disorders in a newborn with a type of hypoglycaemia
- hypererythrocytemia, which is an excessive amount of red blood cells circulating in the body
- increased bilirubin in the bloodstream
- as long-term consequences: overweight / obesity, arterial hypertension, glucose fluctuations (impaired glucose tolerance, insulin resistance, i.e. tissue insensitivity versus insulin, type 2 diabetes)
Diagnostics and procedure for fetuses with macrosomia
Fetal macrosomia can be diagnosed in the fetal life by performing a standard ultrasound examination, then the measured bone dimensions are larger than the standard estimated for a given gestational age. Due to the developed imaging techniques of the fetus, hypertrophy is less often diagnosed only in the delivery room, when the baby is measured.
A pathological mass is one when the body mass is twice the weight predicted for a given gender and age.
Fetal macrosomia is on the list of relative contraindications for childbirth and force of nature, as well as forceps delivery, therefore the most common choice is the surgical termination of pregnancy, reducing the risk of complications for the child and mother.