If you are looking specifically for CONS, here are EXCERPTS from some papers which are more cautionary about the risks of prenatal dex treatment. This is not meant to dissuade you, as I have had NO personal experience with this issue.....just sharing what I’ve come across, since you asked. Good luck with your decision making.
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 | Effects on the mother |
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Doses of dexamethasone have usually been large: 20 µg/kg/24 h (equivalent to 0.7mg/m2/24 h) in three divided doses has been recommended in the United States for reasons that are not entirely clear as the dose needed overnight to suppress adrenal function is 0.3 mg/m2 body surface area.10 Consequently rather frightening side effects (weight gain, oedema, hypertension, glucose intolerance, hirsutism, and striae among others) have been reported,11 which have been seen to a much lesser extent in the clinical practice at our centre where we have used 0.25 mg three times daily (about 0.5mg/m2/24 h). As maternal Cushing syndrome has a bad track record for the mother and the baby,12 we need to recognise the dangers of maternal complications at these sorts of doses.
Early amniocentesis (at 10-14 weeks of gestation) is slightly riskier in terms of miscarriage (3% less chance of successful pregnancy outcome) than amniocentesis performed at the conventional time (15-16 weeks), when the risk of miscarriage is about 1%. The overall risk of complications with either procedure is about 5%.13 Amniocentesis performed at the conventional time is not only slightly safer but is also more accurate for fetal karyotyping than chorionic villous sampling because amniotic fluid samples are altered about 10 times less often by inherent chromosomal mosaic problems than villous samples.
Chorionic villous sampling, which increases the risk of pregnancy loss compared with amniocentesis performed at the conventional time by 0.5-4%,13 comes into its own for the diagnosis of genetic disorders because it yields large amounts of DNA. Ideally the procedure should be performed at 10-12 weeks of gestation, and certainly not before 10 weeks because of the up to 2% risk of associated fetal limb defects.13
| | Effects on the fetus |
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The outcome of this treatment has generally been favourable in terms of improving genital ambiguity, but still about half of the affected treated females have needed surgical attention to their genitalia.14 This may partly be because dexamethasone has variable effects on fetal adrenal function.15 There must also be tissue response variability too because not all babies with classical congenital adrenal hyperplasia have ambiguous genitalia at birth.16 The timing of treatment is particularly relevant: a late onset or an inadequate dose of dexamethasone may prevent clitoral enlargement but may not prevent the formation of a urogenital sinus, which is a serious congenital abnormality with very adverse long term consequences.17
Babies in utero are generally protected against exposure to their own and their mother’s cortisol, and fetal concentrations of cortisol are much lower than those of their mothers through a number of mechanisms. It is precisely to override this protection that dexamethasone, which is a synthetic fluorinated steroid, is used
for example, for the treatment of fetuses at risk of hyaline membrane disease with steroids to induce lung maturation. It is also used to suppress adrenal androgen secretion in babies with congenital adrenal hyperplasia. We can expect that there will be side effects of such treatment. How serious are they, particularly for the seven of eight fetuses who are treated unnecessarily during the first trimester?
Treatment of rats with low doses of dexamethasone throughout pregnancy reduces birth weight and produces persistently elevated blood pressure when the rats reach adult life.18 This is probably mediated through changes in the renal vasculature. The studies of Barker et al19 show how dangerous this could be for humans.
There has been only one good study of the long term effects of antenatal treatment of congenital adrenal hyperplasia: it comes from Sweden and makes scary reading.20 Fetal and childhood growth were generally satisfactory but adverse events were reported in both children treated just in the first trimester and those treated for the whole of gestation. Of 19 unaffected children, one boy treated for seven weeks had agenesis of the corpus callosum and another had delayed psychomotor development. Failure to thrive was reported in three unaffected girls, and one further girl had unexplained mood swings, so there was something to remark in about one third of the group. In the group of six affected girls treated for the whole of gestation, three were considered to have adverse events, even though only one had serious long term consequences.
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Fetal complications and adverse events during childhood
Developmental milestones were normal for the majority of the prenatally treated children. However, some adverse events were observed among cases treated both short term and full term. One unaffected boy who was treated for 7 weeks was born with severe hydrocephalus and agenesis of the corpus callosum. Another unaffected boy was born large for gestational age, and at birth the obstetrician observed a broad neck and hypospadias with unilateral cryptorchidism. At 9 months of age this boy had developed baby-talk. Today, at 2 yr of age, his motor skills are undeveloped, his head circumference is unusually small, and he does not talk. The parents of this boy are first cousins.
Adverse events have also been noted in the case of three unaffected girls. At 2 weeks of age, one of these girls developed severe episodic vomiting that persisted for several months. Her serum concentrations of liver enzymes were elevated, and she developed liver steatosis. This girl was suspected of having a metabolic disease, but this was never confirmed. Today, at 3 yr of age, she is doing fine, and her growth is normal, as is her psychomotor development. Her problems during early life were suspected to be due to an adenovirus infection.
Another unaffected girl stopped gaining weight adequately after 6 months of age. At 20 months of age, her weight was 3 SD below the mean, and her height was 1.5 SD below the mean. She was admitted to the pediatric ward and investigated for celiac disease, which has not yet been confirmed.
Another unaffected girl treated during her entire fetal life had two episodes of pneumonia at 9 months of age. She recovered from these infections, but according to her mother this child developed extreme fluctuations in mood and aggressiveness and was therefore examined, by electroencephalogram and psychological development tests. The explanation for her behavior is still unknown.
In the group of CAH-affected girls treated during the entire fetal period, three cases have to be considered as involving adverse events. The full term treated girl with mild CAH, mentioned previously, was delivered by cesarean section during the 37th gestational week because of maternal preeclampsia. She was growth retarded at birth (-4 SD) but later recovered, and at 9 yr of age, she was doing very well with normal growth and psychomotor development.
Two affected sisters have had developmental problems. The older sister was born normal in size for gestational age, but gained weight poorly during the first year of life. At the age of 1 yr her weight and height were 5 SD below the mean. After 2 yr of age, she started to catch-up and at the age of 6 yr her height was only 1.5 SD below the mean.
Her younger sister was more virilized at birth due to poor maternal compliance. Labor was induced during the 38th gestational week because of decreased fetal growth and maternal hypertension. This girl was born growth retarded, and at 1 month of age she developed seizures. Soon after that, she developed severe vomiting and episodes of metabolic acidosis with hypoglycemia and was diagnosed as having a mitochondrial disease (complex I defect). Her psychomotor development is delayed, and today at 2.5 yr of age this girl has percutaneous gastrostomy. She communicates with her mother only through signs, but has normal hearing and motor functions. She still has occasional seizures, and her head circumference has dropped from 1 to 3 SD below the mean.
In the control groups one child with trisomy 21 was reported. No other chromosomal aberrations or abnormalities were observed
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