PRENATAL TREATMENT OF CONGENITAL ADRENAL HYPERPLASIA (CAH) DUE TO 21-HYDROXYLASE DEFICIENCY: EUROPEAN EXPERIENCE IN 223 PREGNANCIES AT RISK

Abstract

In the aim to prevent the in utero virilization of CAH affected females a prenatal treatment (Rx) has first been attempted by David and Forest in 1979; later these authors reported their first results and proposed a therapeutic protocol (J. Pediatr. 1984; 104: 799-803). Except for the experience of the French multicentric study in 42 pregnancies at risk (Endocr. Res.1989;15:277-301), prenatal Rx of CAH using therapeutic protocols quite similar to the above, and subsequently reported in the literature were concerned with a limited number of cases. Indeed, prenatal Rx of CAH is not frequently instituted. Nevertheless, a number of experiences have not been reported. This is why, we decided to collect a maximum of data from European Pediatricians. A questionnaire was constructed to enquire about the effects of prenatal Rx on the fetus on one hand (therapeutic protocols, prenatal diagnosis (Dg), results on the external genitalia of CAH female fetuses, effects if any on the development of the fetus or child) and on the mother on the other hand (follow-up, compliance and tolerance of Rx, course of pregnancy, short and long term effects or side-effects in the mothers). Informations were obtained in a total of 223 treated pregnancies: 75 cases from the French multicentric study (M.G. Forest, M.David), 58 German cases (collected by H.G. Dorr and W.G. Sippell in cooperation with the APE), and 27 Scandinavian cases coordinated by E.M. Ritzen. The questionnaire was also sent to the other European ESPE Members and to date data were collected on 63 additional cases. There was no prenatal Dg in 20 cases (not available or refused). Prenatal Dg was first made on HLA typing and/or steroid measurement in the amniotic fluid. An earlier prenatal Dg was subsequently made by HLA typing on chorion villus sampling (CVS). On the whole, steroid measurement was safe (if Rx interrupted) except in 2 cases and HLA serological typing helpful, but at least 8 false prenatal Dg were recorded. For the last 2-4 years, DNA studies are performed on CVS (HLA RFLP, C4-CYP21 genes) with increasing safety. Prenatal Rx was with dexamethasone (Dex) or Dex acetate (France in particular), usually at a dose of 0.5 mg, 2 to 3 times a day. The Dex dose was more rarely adapted to maternal body weight (20 μg/kg, as advocated by Forest et al (above ref). Among the 38 CAH treated females, 37 were born, with normal (9) or slightly virilized genitalia (17); none of them would need surgery. Prenatal Rx was not successful (stage III/IV) for apparently logical reasons (late start of Rx, insufficient Dex dose, early interruption, lack of compliance) in 9 CAH females but not explained in 2 others. There was a remarkable lack of side-effects in fetuses or children, except for a severe hydrocephalus in a male fetus (treated for 7 wks) and 2 deaths in utero near term while Rx was stopped for several months (both not attributed to Dex Rx by specialists), and an unexplained failure to thrive in a CAH girl treated until term. Maternal acceptance of Rx was said to be good to excellent. Maternal compliance was usually good (as judged by low maternal levels of cortisol, DHAS or estriol). Maternal side-effects were reported in some but not all mothers. In the mothers where Rx was stopped in mid-pregnancy (unaffected cases) there was often no complaint or that of an excessive weight gain (reasonably controlled by salt and caloric restriction in the French study), observed more often in the mothers given 1.5 mg of Dex, and always resuming after delivery. When treatment was continued until term (n = 53), more serious side-effects were observed in some mothers : marked weight gain (n=15), edema (n =3), increased blood pressure (n= 5). In addition, Rx tolerance was poor in 7 mothers (weight gain, edema, fatigue, feeling of exhaution, or hypertension, or gestational diabetes mellitus) leading twice to interrupting Rx despite prenatal Dg of a CAH female fetus. This is why a more detailed follow-up of the maternal well-being is undertaken. In conclusion, prenatal Rx of CAH appears effective, providing a good rationale in the Rx protocol. Observations made in a large number of pregnancies show that short term Rx (started at 4-7 wks, and stopped after a prenatal Dg based on DNA studies on CVS, at about 12 wks) is usually well tolerated. Tolerance of long term Rx seems to be a problem in some mothers. These findings lead us to propose that Dex Rx should be adapted to maternal size in all mothers (20 μg/kg), then Dex dose should or could eventually be decreased by 50% from mid-pregnancy to term in those mothers who bear a CAH female fetus.