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Prenatal diagnosis of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency by amniotic fluid (AF) steroid analysis is not possible in those cases in which prenatal dexamethasone (DEX) therapy is initiated to prevent virilization of female CAH fetuses because AF steroid levels are suppressed if DEX therapy is continued beyond amniocentesis (AC). In order to use AF steroids for prenatal diagnosis, it is necessary to discontinue DEX therapy for 5 days before AC. To study the effects of this interruption on AF steroid levels, we measured levels of aldosterone, corticosterone, 11-deoxycorticosterone, progesterone, 17-hydroxyprogesterone (170HP), 11-deoxycortisol, cortisol, and cortisone as well as androstenedione (delta 4-A) in AF samples (16-18 weeks) obtained from 25 pregnancies at risk for CAH treated with Dex (daily dosage: 1.0-1.5 mg). The prenatal diagnosis of 14 normal fetuses and 11 affected CAH fetuses was postnatally confirmed in all cases. Additionally, steroid levels were measured in AF samples (16-18 weeks) from 8 untreated CAH fetuses and in 19 AF samples (weeks 16-20) obtained in normal pregnancies. In 17/19 prenatally diagnosed CAH fetuses, the affected sibs had the salt wasting (SW)-form, in 2 cases the simple virilizing (SV)-form. All steroids were measured by RIA after extraction and Sephadex LH-20 chromatography. AF levels of aldosterone, corticosterone, deoxycorticosterone, progesterone, cortisol, cortisone, and 11-deoxycortisol were not different between CAH fetuses, prenatally DEX-treated normal fetuses and untreated controls. The 170HP-levels of the CAH-SW-fetuses (range: 19.9-59.8 mmol/L) were clearly above the normal range (3.74-11.6), but normal in the SV-fetuses (10.9, 11.5), whereas delta-4 A-levels (normal range: 0.87-5.13 mmol/L) were elevated both in the SW-(range: 6.53-37.6) and the SV-form (9.37,6.25) of CAH. 170HP and delta-4 A levels of prenatally DEX-treated pregnancies with normal fetuses were not different from levels found in normal pregnancies. Mean 170HP and delta-4 A AF steroid levels of prenatally DEX-treated CAH-pregnancies were slightly lower (NS) than levels of untreated CAH-pregnancies (170HP: 30.5 vs. 40.7; delta-4 A: 15.8 vs. 21.1). 170HP levels are elevated in the SW-form of CAH, but not in the SV-form. However, with the combination of 170HP and delta-4 A levels it is possible to diagnose prenatally both forms. There is no rebound phenomenon of AF steroid levels if DEX therapy is interrupted 5 days before amniocentesis.

The interrelations of steroid hormone levels in plasma and amniotic fluid from mothers and their undisturbed fetuses at early midgestation of human pregnancy have not been defined previously. We, therefore, studied 12 healthy mothers and their fetuses undergoing termination of pregnancy for social reasons at 16-20 weeks gestation. Fetal arterial and venous blood was obtained by direct vessel puncture through a fetoscope in the conscious sedated mothers immediately before termination of pregnancy. Simultaneously, maternal peripheral venous blood and amniotic fluid were collected. Aldosterone (Aldo), corticosterone (B), 11-deoxycorticosterone, progesterone (P), 17-hydroxyprogesterone (17OHP), 11-deoxycortisol, cortisol (F), and cortisone were simultaneously determined by specific RIA after extraction and chromatography. Positive fetal arterio-venous differences were found for F, B, and Aldo, whereas arteriovenous differences were negative for P and 17OHP. In amniotic fluid, six of the eight corticosteroids showed significantly lower levels during fetoscopy than during routine amniocentesis, as reported previously using the same analytical methods. The present study demonstrates that the undisturbed human fetus at 16-20 weeks gestation actively secretes the most important gluco- and mineralocorticoids, F, B, and Aldo, independent of the mother. P and 17OHP were shown to be primarily derived from placental production and supplied to the fetus as a source of F and Aldo biosynthesis. The fetoscopy procedure with premedication seemed to give rise to less stress to the fetus than routine amniocentesis without sedation. Fetoscopy is, therefore, an ideal method to study feto-maternal steroid interrelations in human pregnancy.

The mean control level of 11-deoxycortisol as determined by radioimmunoassay in eighty-one human amniotic fluid samples was 1.20 +/- 0.07 ng/ml. Markedly elevated levels were found at term in amniotic fluid of two pregnancies with fetuses affected with 11 beta-hydroxylase deficiency, congenital adrenal hyperplasia (135.0 and 64.0 ng/ml respectively) as well as in the maternal serum of one of these cases (28.0 ng/ml). It is suggested that the determination of 11-deoxycortisol in amniotic fluid be a prenatal diagnostic test for 11 beta-hydroxylase deficiency congenital adrenal hyperplasia.

Amniotic fluid levels of 21-deoxycortisol (21-DOF) and 17-hydroxyprogesterone (17-OHP) were measured in 49 pregnancies, including 31 pregnancies at risk for CAH. The results were compared with those obtained by HLA typing and linkage analysis to a HLA DNA probe. The mean amniotic fluid levels in the control pregnancies were 0.28 nmol/L for 21-DOF and 4.1 nmol/L for 17-OHP. The levels were similar in early and midpregnancy for 21-DOF (0.29 vs. 0.27 nmol/L) and 17-OHP (3.4 vs. 4.2 nmol/L). The amniotic fluid 21-DOF level was 1.75 nmol/L in affected pregnancies, significantly higher than in the control pregnancies (mean, 0.28 nmol/L). The mean amniotic fluid 17-OHP level in the affected pregnancies (30.5 nmol/L) also was significantly higher than that in the control pregnancies (4.10 nmol/L). Simultaneous measurement of 21-DOF and 17-OHP levels in amniotic fluid from 10-18 weeks of gestation can be used for early diagnosis of congenital adrenal hyperplasia.

Corticosteroids (CS) are essential for fetal organ maturation; yet, knowledge of endogeneous CS and precursor levels throughout fetal life is limited. Therefore, unconjugated aldosterone (Aldo), corticosterone (B), 11-deoxycorticosterone (DOC), progesterone (P), 17 alpha-hydroxyprogesterone (17-OHP), 11-deoxycortisol (S), cortisol (F), and cortisone (E) were simultaneously determined by RIA after automated Sephadex LH-20 chromatography in 70 control samples of amniotic fluid (AF) obtained at all gestational ages between 14-42 weeks. Levels of the progestins P and 17-OHP slowly increased from means (+/- SE) of 14.7 +/- 2.8 and 1.63 +/- 0.21 ng/ml, respectively, in early gestation to maximum levels of 32.4 +/- 3.5 and 3.80 +/- 0.74 ng/ml at 36-38 weeks (P less than 0.005), then dropped significantly (P less than 0.01) to 19.2 +/- 2.2 and 1.58 +/- 0.22 ng/ml at term. All CS levels except E rose very markedly by 3- to 12-fold (P less than 0.0001) from the weeks 14-16 (DOC, 0.44 +/- 0.08; B, 1.49 +/- 0.23; Aldo, 0.043 +/- 0.012; S, 0.51 +/- 0.10; F, 5.96 +/- 0.93 ng/ml) until the 36-38th weeks (DOC, 3.50 +/- 0.66; B, 4.60 +/- 0.78; Aldo, 0.530 +/- 0.109; S, 6.00 +/- 0.75; F, 60.8 +/- 8.9 ng/ml). Term levels were significantly reduced (P less than 0.01) in the less active CS DOC (0.51 +/- 0.07 ng/ml), B (2.35 +/- 0.35 ng/ml), and S (1.14 +/- 0.14 ng/ml), whereas those of the biologically most potent CS Aldo and F declined less markedly (0.272 +/- 0.053 and 23.0 +/- 0.75 ng/ml, respectively, at 39-42 weeks). Levels of the inactive glucocorticoid E rose from 8.83 +/- 1.08 ng/ml at 14-16 weeks to 16.8 +/- 2.6 ng/ml at 31-35 weeks (P less than 0.01), then remained rather constant around 11.5 ng/ml until term. It is concluded that after the 25th week, large amounts of biologically active CS are available in AF which probably directly induce the final epithelial maturation of fetal lungs and intestinal tract.

Concentrations of unconjugated cortisol, 11-desoxycortisol, and 21-desoxycortisol were measured by radioimmunoassay in amniotic fluid throughout gestation. Cortisol levels rose from a median of 6.5 nanograms per milliliter prior to 20 weeks to 13.9 ng/ml at 28 to 37 weeks. Median levels of 11-desoxycortisol and 21-desoxycortisol were 2.6 ng/ml and 0.21 ng/ml, respectively, and did not change with advancing gestation. These normal values provide a basis for the application of assays of 11-desoxycortisol and 21-desoxycortisol in amniotic fluid in the prenatal diagnosis of congenital adrenal hyperplasia.