Search

Obstetrician-gynecologists are frequently consulted by couples who are concerned about their fertility potential. During the initial fertility consultation, questions may arise concerning the potential impact of lifestyle choices on fertility. For the female partner, common exposures associated with a decrease in fertility are cigarette smoking, alcohol consumption of >4 drinks per week, and caffeine intake of >250 mg daily. For the female partner, a body mass index of >27 kg/m2 or <17 kg/m2 is associated with decreased fertility. On the basis of the evidence from epidemiologic studies, couples who are concerned about their fertility potential should stop the use of tobacco products. In addition, the female partner should limit alcohol consumption to no more than 4 drinks per week, decrease caffeine intake to no more than 250 mg daily, and adjust calorie intake and exercise levels to achieve a body mass index between 20 and 27 kg/m2.

The polycystic ovary syndrome is a common cause of anovulatory infertility. Women with severe insulin resistance are a unique subset of polycystic ovary syndrome. The syndrome of hyperandrogenism, insulin resistance, and acanthosis nigricans (HAIR-AN syndrome) is one presentation of the insulin-resistant subset of polycystic ovary syndrome. Insulin resistance and hyperandrogenism are caused by genetic and environmental factors. In women with anovulatory infertility caused by hyperandrogenism and insulin resistance, clomiphene citrate treatment often fails to result in pregnancy. For these women, weight loss and insulin sensitizers can be effective methods of inducing ovulation and pregnancy and may reduce the number of clomiphene-resistant women with polycystic ovary syndrome who are treated with gonadotropins, ovarian surgery, or in vitro fertilization-embryo transfer.

Objective: In an attempt to find more efficacious alternatives for the diagnosis of gestational diabetes mellitus, we evaluated whether (1) there is a glucose loading test value above which all glucose tolerance test results are positive, (2) omission of the third-hour plasma glucose measurement of the glucose tolerance test alters the sensitivity of the test, and (3) the presence of a fasting plasma glucose concentration >/=105 mg/dL suffices as a diagnostic standard after an abnormal glucose loading test result., Study Design: The charts of 512 patients who underwent 3-hour glucose tolerance tests at our institution between January 1995 and December 1996 were reviewed. Only subjects for whom the glucose loading test yielded plasma glucose levels >/=140 mg/dL were selected. The positive predictive value of a glucose loading test result >/=185 mg/dL was calculated. Results of glucose tolerance tests of subjects with elevated fasting plasma glucose concentrations were then evaluated to determine the positive predictive value for gestational diabetes mellitus of an elevated fasting plasma glucose concentration., Results: Among the subjects who underwent glucose tolerance tests, 22% (114/512) met positive test criteria for gestational diabetes mellitus. The positive predictive value for a glucose loading test result >/=185 mg/dL was 57% (25/44), whereas a glucose loading test result >199 mg/dL showed a positive predictive value of 69% (4/13). Omission of the third-hour glucose tolerance test value yielded a sensitivity of 87% (99/114). Among the 24 women with fasting plasma glucose concentrations >/=105 mg/dL, 96% had positive glucose tolerance test results. An elevated fasting plasma glucose concentration was highly associated with gestational diabetes mellitus necessitating insulin therapy (65%)., Conclusion: An elevated glucose loading test result was associated with but not highly predictive of gestational diabetes mellitus. Omission of the 3-hour glucose tolerance test measurement resulted in failure to diagnose 13% of gestational diabetes mellitus cases. A fasting plasma glucose concentration >/=105 mg/dL was highly predictive of an abnormal glucose tolerance test result among patients with an elevated glucose loading test value.

Uterine leiomyomas, benign tumors of myometrial origin, are the most common neoplasms of the uterus and occur in 20-30% of women over 30 years of age. Despite their high prevalence, little is known about the pathophysiology of these tumors. Recently, several studies have compared leiomyoma gene expression with that of normal myometrium. In general, the major differences in leiomyoma and myometrial gene expression are found for estrogen-regulated genes, which have elevated expression in myometrium during pregnancy. The tumors appear to maintain high sensitivity to estrogen during the estrogen-dominated follicular phase of the menstrual cycle, unlike normal myometrium. The abnormal gene expression of leiomyomas suggests that they are tumors of dysregulated differentiation and resemble the myometrium of pregnancy in several aspects.

Objective: We tested the hypothesis that uterine leiomyomas are hypersensitive to estrogen as compared with autologous human myometrium., Methods: The estrogen-induced transcriptional responses of uterine leiomyoma and myometrial primary cultures were determined by transient expression assays. The relative levels of estrogen receptor (ER) in myometrial and leiomyoma tissues were determined by immunoblot., Results: Myometrial and leiomyoma primary cultures were transcriptionally responsive to the estrogen ethinyl estradiol (eE2). The partial agonist tamoxifen did not elicit a positive transcriptional response and antagonized estrogen-induced transcription in the cultured cells. The responses of hormone-treated leiomyoma cells averaged 4.5-fold higher than those in controls with no hormone (P = .0001). The myometrial cells from women in the follicular phase exhibited little if any transcriptional response to eE2, whereas myometrial cells from women in the luteal phase had a transcriptional response to eE2 averaging threefold higher than that in no-hormone controls (P = .0083). Differences in response between autologous myometrial and leiomyoma cultures were statistically significant by the two-tailed Wilcoxon paired nonparametric signed-rank test (n = 11; P = .0137). These differences were more pronounced in cultures from women in the follicular or early luteal phase. In addition, the levels of ER increased in follicular and early luteal phase myometrial tissues, which correlated well with the number of days from the last menstrual period (n = 8; r = 0.9046; P = .002). Estrogen-receptor levels in myometrial tissues decreased during the late luteal phase. Levels in leiomyoma tissues did not follow the same pattern as in the myometrium and were elevated in tissues taken from women in the follicular phase., Conclusions: Autologous leiomyoma cultures have a significantly higher response to estrogen than do matched myometrial cultures, especially if the cultures are derived from the follicular phase. The levels of ER in leiomyoma tissue from women in the follicular phase are significantly elevated.

Uterine leiomyomas are monoclonal tumors. However, the factors involved in their initiation and growth remain poorly understood. The neoplastic transformation of myometrium to leiomyoma likely involves somatic mutations of normal myometrium and the complex interactions of sex steroids and local growth factors. Traditionally, estrogen has been considered the major promoter of myoma growth. The purpose of this review is to highlight the biochemical, histologic, and clinical evidence that supports an equally important role for progesterone in the growth of uterine myomas. Biochemical studies suggest that progesterone, progestins, and the progesterone receptor modulate myoma mitotic activity. Several clinical trials demonstrate that progestins inhibit and/or reverse the ability of hypoestrogenism induced by a gonadotropin-releasing hormone agonist to shrink uterine myomas, suggesting a critical role for progesterone in growth of myomas. A new hypothesis to explain the pathogenesis of myomas is presented.

Objective: To determine whether acute alcohol ingestion raises estradiol (E2) and estrone (E1) levels in a randomized, controlled, crossover study on postmenopausal women using transdermal E2., Methods: Healthy, non-smoking postmenopausal women (n = 7) using no medications were enrolled. Transdermal E2, 0.15 mg, was applied 13 hours before the subjects ingested alcohol (1 mL/kg 95% ethanol) or isocaloric carbohydrate punch. Serum samples were obtained for 40 minutes before drink ingestion and 6 hours after drink ingestion and were assayed for E2 and E1., Results: Ethanol levels peaked 60 minutes after the start of ethanol-drink ingestion, at 25.4 mmol/L (117 mg/dL). Estradiol levels rose significantly above the mean baseline of 657 pmol/L (179 pg/mL) after ethanol-drink ingestion (P < or = .01), with a mean peak of 804 pmol/L (219 pg/mL) 35 minutes after the start of drink ingestion, and were significantly greater than the E2 levels that followed the carbohydrate drink (P < or = .0001). There were no significant changes in E2 or E1 levels after carbohydrate-drink ingestion., Conclusions: We conclude that ethanol ingestion may acutely raise circulating E2 concentrations in women using transdermal E2.

Objective: The purpose of this study was to test whether 17 beta-hydroxysteroid dehydrogenase might exist in a phosphorylated form., Study Design: Phosphorylation of 17 beta-hydroxysteroid dehydrogenase was evaluated in BeWo choriocarcinoma cells. The phosphorylation of 17 beta-hydroxysteroid dehydrogenase expressed in Escherichia coli as a glutathione transferase fusion protein was also studied., Results: Human BeWo choriocarcinoma cells were metabolically labeled with phosphorus 32 orthophosphate. Immunoprecipitates were prepared with rabbit anti-17 beta-hydroxysteroid dehydrogenase antiserum from the labeled cells and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A phosphorylated protein with a molecular size of 35 kd was obtained from anti-17 beta-hydroxysteroid dehydrogenase immunoprecipitates, which suggested that 17 beta-hydroxysteroid dehydrogenase was phosphorylated in BeWo cells. The predominant phosphoamino acid was phosphoserine. 17 beta-Hydroxysteroid dehydrogenase expressed in E. coli as a glutathione transferase fusion protein was a substrate of protein kinase A in vitro. Protein kinase A phosphorylated the recombinant 17 beta-hydroxysteroid dehydrogenase exclusively on serine. Incubation of BeWo cell lysates with bacterial alkaline phosphatase led to a decrease in the oxidative activity of 17 beta-hydroxysteroid dehydrogenase. Incubation of the alkaline phosphatase inhibitor levamisole with BeWo cell lysates resulted in a higher estradiol-to-estrone conversion rate, compared with cell lysates without any treatment., Conclusion: Our data suggest that 17 beta-hydroxysteroid dehydrogenase may exist in phosphorylated forms and that phosphorylation may regulate the activity of 17 beta-hydroxysteroid dehydrogenase in vivo.

Objectives: The expression of connexin-43 was examined in human leiomyomas and in autologous myometrium., Study Design: Indirect immunofluorescence was used to detect connexin-43 gap junctions in myometrial and leiomyoma tissues and in primary cultures. Immunoblot and Northern analyses were used to examine the levels of connexin-43 protein and cx43 messenger ribonucleic acid in primary cultures., Results: Connexin-43 gap junctions were detected in leiomyoma tissue from nonpregnant premenopausal women but not in autologous myometrial tissue. Connexin-43 gap junctions form spontaneously in primary cultures of myometrium and leiomyoma in the presence of 17 beta-estradiol. Fluorescent dye injection confirmed that the gap junctions were coupled in the primary cells. Connexin-43 protein and messenger ribonucleic acid levels generally were higher in leiomyoma cells compared with those of autologous myometrial cells. Steady-state levels of cx43 messenger ribonucleic acid decreased with addition of medroxyprogesterone acetate to the cultures., Conclusions: Differences in the levels of cx43 expression in leiomyoma and myometrial cells may reflect differences in responses to steroid hormones.

Objectives: We attempted to test the hypothesis that distinct forms of the 17-ketosteroid oxidoreductase exist in the human ovary and to compare its activity in stroma obtained from normally cycling women and from hyperandrogenic women., Study Design: Human ovarian granulosa-luteal cell and stromal 17-ketosteroid oxidoreductase were examined in cell incubations and subcellular homogenates., Results: In subcellular homogenates of granulosa-luteal cells 17-ketosteroid oxidoreductase activity was greater in the cytosol fraction than in the membrane fraction. In contrast, in homogenates of both ovarian stroma and Leydig cells its activity was greater in the membrane fraction than in the cytosol fraction. At the substrate concentrations used estrone was a better substrate than androstenedione for the granulosa-luteal cell 17-ketosteroid oxidoreductase. In contrast, androstenedione was a better substrate than estrone for that in ovarian stromal and Leydig cell membranes. In incubations of ovarian stroma from hyperandrogenic women, significantly more testosterone accumulated in the medium per milligram of tissue than in the medium of incubations of ovarian stroma from normally cycling women (142 +/- 48 vs 7.9 +/- 7.5 pg testosterone per milligram of tissue per 48 hours, mean +/- SD, p less than 0.05). The ratio of testosterone to androstenedione was significantly higher in the medium of incubations of ovarian stroma from hyperandrogenic women than in that from normally cycling women (0.61 vs 0.25, mean, p less than 0.05). The ratio of serum testosterone to androstenedione was significantly greater in hyperandrogenic women than in normally cycling control women (0.31 +/- 0.11 vs 0.20 +/- 0.03, mean +/- SD, p less than 0.05)., Conclusion: The localization (cytosol fraction) and substrate specificity (estrone) of the granulosa-luteal cell 17-ketosteroid oxidoreductase enzyme resembles that seen in human placenta. The localization (membrane fraction) and substrate specificity (androstenedione) of the ovarian stromal 17-ketosteroid oxidoreductase enzyme resembles that seen in Leydig cells. It may be one enzyme that exists in multiple forms or it may be two (or more) enzymes. In some hyperandrogenic women the ovarian stromal 17-ketosteroid oxidoreductase may be more active than in normally cycling women, contributing to an abnormally increased testosterone production rate.

In women with recurrent pelvic pain caused by endometriosis, hormonal therapy with a gonadotropin-releasing hormone agonist is an effective alternative to surgical therapy. The basis for medical treatment of endometriosis is that endometriosis lesions are dependent on estradiol for continued growth. Further, end organ tissue varies in its sensitivity to estradiol. This forms the basis of the estrogen threshold hypothesis, that is, that a concentration of estradiol that will partially prevent bone loss may not stimulate endometrial growth. Thus there is a hierarchy of organ response to estradiol such that calcium metabolism is most sensitive followed by gonadotropin secretion, vaginal epithelial growth, lipid metabolism, and liver protein production. Similarly, breast cancer is most sensitive and endometriosis is least sensitive to estrogen. These differences may allow the design of regimens with a gonadotropin-releasing hormone agonist that maintain a therapeutic response and ameliorate potential adverse effects.

Gonadotropin-releasing hormone agonists induce a reversible hypogonadotropic hypogonadal environment. Leiomyomas are common, estrogen-sensitive, benign neoplasms that decrease in size by 40% to 50% during gonadotropin-releasing hormone agonist treatment. During gonadotropin-releasing hormone agonist therapy most women are amenorrheic. After discontinuation of gonadotropin-releasing hormone agonist treatment, uterine and myoma size increase and a return to pretreatment menstrual patterns often occurs. Concerns about the safety of long-term hypoestrogenism have made long-term gonadotropin-releasing hormone agonist administration an undesirable treatment strategy. This article focuses on the use of gonadotropin-releasing hormone agonists as preoperative therapy in selected women undergoing hysterectomy or myomectomy and the combination of a gonadotropin-releasing hormone agonist with estrogen-progestin "add-back" treatment as a potential long-term medical therapy for women with symptomatic leiomyomas. Finally, an estrogen threshold hypothesis to assess the effects of circulating estrogen concentrations on different tissues, is presented.

Gonadotropin-releasing hormone agonists are effective in the treatment of endometriosis and myomas, both of which are estrogen-dependent processes, but there is a high clinical recurrence rate after therapy is discontinued. Long-term continuous therapy (2 years or more) has a cumulative effect on bone loss and causes other uncomfortable or harmful side effects. Noninvasive assessments of disease response in patients with myomas have shown that bone changes might be prevented and other side effects of long-term therapy can be alleviated by adding back small amounts of estrogen or progestin. No comparable data are available for patients with endometriosis because the need for repeated laparoscopy has made long-term studies impractical. Nevertheless, a short-term study of patients with endometriosis showed that adding small amounts of progestin during treatment with a gonadotropin-releasing hormone agonist may help prevent bone changes.

The pharmacologic profiles of danazol and nafarelin differ considerably from each other. Danazol interacts with multiple classes of proteins, whereas the gonadotropin-releasing hormone agonist nafarelin interacts only with the pituitary gonadotropin-releasing hormone receptor. Differences in the molecular, endocrine, and clinical pharmacologic properties of these agents may provide clues to their varying effects in the management of women with endometriosis.

The true prevalence of endometriosis remains undetermined because diagnostic laparoscopy cannot be performed on large, random, population-based samples of women. However, available evidence suggests that the disease occurs in approximately 1% to 7% of women in the United States. The cause of endometriosis is though to be associated with mechanical factors (such as retrograde menstrual flow) or estrogen production. Recent research also has suggested that regular exercise may help to protect against the disease by decreasing the rate of estrogen production.

The options for the medical management of endometriosis have been expanded by the introduction of the synthetic steroid, danazol. The results of large clinical studies suggest that danazol treatment produces significant improvement in the symptoms, signs, and laparoscopic findings of endometriosis. The original studies of the pharmacology of danazol concluded that danazol was a strong antigonadotrophin with mild androgenic effects and no other hormonal properties. Recent studies which emphasize the molecular pharmacology of danazol suggest that this steroid has direct effects on hypothalamic-pituitary function, multiple classes of steroid receptors, gonadal steroidogenesis, and endogenous steroid metabolism. These studies demonstrate that: (1) danazol prevents the midcycle surge of luteinizing hormone (LH) and follicle-stimulating hormone (FSH); (2) danazol does not significantly suppress basal LH or FSH in gonadally intact human beings; (3) in castrated animals danazol can prevent the compensatory increase in LH and FSH; (4) danazol binds to androgen, progesterone, and glucocorticoid receptors; (5) danazol does not bind to estrogen receptors; (6) danazol binds to sex hormone-binding globulin and corticosteroid-binding globulin; (7) danazol inhibits multiple enzymes of steroidogenesis; (8) danazol increases the metabolic clearance rate of progesterone; and (9) metabolites of danazol are hormonally active. Given the complex pharmacology of danazol it is inappropriate to continue to refer to danazol as a "selective antigonadotrophin."U

The evidence that supports the hypothesis that hyperinsulinemia causes ovarian hyperandrogenism was reviewed. The most dramatic clinical expression of the association between hyperinsulinemia and hyperandrogenism is the HAIR-AN syndrome. In the HAIR-AN syndrome, severe insulin resistance results in a compensatory hyperinsulinemia that stimulates ovarian androgen production. Acanthosis nigricans, a dermatologic manifestation of severe insulin resistance, is an epiphenomenon of the disease. Hyperandrogenic (HA) women can be divided into two major groups: insulin-resistant (HA-IR) and non-insulin-resistant (HA-nIR). HA-nIR women have markedly elevated LH, often have minimally elevated serum prolactin, and have polycystic ovaries. HA-IR women have minimally elevated LH, markedly elevated plasma insulin, and stromal hyperthecosis. Women with HA-nIR probably have a primary hypothalamic-pituitary abnormality as the cause of their hyperandrogenism. Women with HA-IR probably have a primary metabolic abnormality as the cause of their hyperandrogenism. The relationship between hyperinsulinemia and hyperandrogenism is one example of the complex interrelationships that exist between central metabolism and reproduction.

The effects of danazol on steroidogenesis in vitro in the 16-20 week old human fetal adrenal were examined by studying: 1) danazol binding to adrenal microsomal and mitochondrial cytochrome P-450, and 2) enzyme kinetics of danazol inhibition of the adrenal microsomal 21-hydroxylase and the mitochondrial 11 beta-hydroxylase. The addition of danazol to preparations of adrenal microsomes or mitochondria elicited a type I cytochrome P-450 binding spectrum. Danazol bound to microsomal cytochrome P-450 binding spectrum. Danazol bound to microsomal cytochrome P-450 with a high affinity apparent spectral dissociation constant (KS) of 1 microM and with a lower affinity K's of 10 microM. Danazol bound to mitochondrial cytochrome P-450 with a KS of 5 microM. In addition, danazol competitively inhibited the microsomal 21-hydroxylase (apparent enzymatic inhibition constant KI = 0.8 microM) and the mitochondrial 11 beta-hydroxylase (KI = 3 microM). These findings demonstrate that low concentrations of danazol directly inhibit steroidogenesis in the human fetal adrenal in vitro.

The HAIR-AN syndrome that consists of hyperandrogenism (HA), insulin resistance (IR), and acanthosis nigricans (AN) is an underdiagnosed endocrinopathy, because hyperandrogenic women are not commonly screened for insulin resistance or acanthosis nigricans. The distinct pathophysiologic features of the HAIR-AN syndrome are discussed in detail. In this syndrome, the primary pathophysiologic derangements are the insulin resistance and the hyperandrogenism. The acanthosis nigricans is an epiphenomenon of these primary processes. In patients with the HAIR-AN syndrome, the degree of severity of the insulin resistance is positively correlated with the degree of severity of the hyperandrogenism. In patients with adequate pancreatic beta-islet cell reserve, insulin resistance results in a long-term increase in circulating insulin levels. The hyperinsulinemia probably directly stimulates ovarian androgen production. In turn, hyperandrogenism itself produces insulin resistance. This positive feedback loop between insulin resistance and hyperandrogenism propagates the disease, and increases its severity over time. The relationship between insulin resistance and hyperandrogenism may explain the hyperandrogenemia seen in the following disease processes: obesity, acromegaly, lipoatrophic diabetes, leprechaunism, and Kahn types A and B insulin resistance.

Incubation parameters for a radioderivative assay for estrogen 2-hydroxylase have been examined. The assay was found to be specific and sensitive if a chromatographically purified preparation of COMT was used. Estradiol was found to be a better substrate for the 2-hydroxylase than estrone or estriol. The liver had significantly higher estrogen 2-hydroxylase activity than any other tissue examined. The estrogen 2-hydroxylase was highly localized in the microsomal fraction in both the liver and the brain. The male rat was found to have significantly more estrogen 2-hydroxylase activity in the liver than the female rat. In addition, in the male rat liver, the estrogen 2-hydroxylase activity was reversibly inducible by testosterone and was not affected by phenobarbital. In the male and female rat brain the estrogen 2-hydroxylase activities were similar.

Hyperplasia of testicular Leydig cells and ovarian theca-lutein cells is a common histologic finding in infants of diabetic mothers. The functional correlates of this histologic finding were investigated by measurement of the beta-subunit of human chorionic gonadotropin, testosterone, dihydrotestosterone, androstenedione, estradiol, and estrone in the amniotic fluid compartment of gestations with male and female fetuses in diabetic mothers (N = 34) and control women (N = 34) at term. When compared with those of control subjects, gestations of diabetic mothers had significantly higher amniotic fluid concentrations of the beta-subunit of human chorionic gonadotropin. Gestations with either male or female fetuses in diabetic mothers had significantly higher amniotic fluid testosterone and dihydrotestosterone levels when compared with those of their respective gender controls. In gestations with male fetuses in diabetic mothers there was a significant positive correlation between the beta-subunit of human chorionic gonadotropin and testosterone. There was no significant difference in amniotic fluid androstenedione, estradiol, or estrone levels between the gestations of diabetic mothers and those of control women. These results suggest that the testicular Leydig cell and ovarian theca-lutein cell hyperplasia seen in infants of diabetic mothers is due, in part, to elevated levels of human chorionic gonadotropin and is associated with elevated testosterone and dihydrotestosterone concentrations in the amniotic fluid.

The potent gonadal steroids testosterone and estradiol are synthesized from the biologically weak precursors, androstenedione and estrone, by enzymatic reduction of the ketone group at carbon-17 of the steroid nucleus (17-ketosteroid reductase). To test the hypothesis that Leydig and granulosa cells may contain a distinct 17-ketosteroid reductase enzyme, the subcellular localization and the substrate specificity of the enzyme was examined in each cell type. In Leydig cells, the 17-ketosteroid reductase activity was concentrated in the microsomal fraction of the cell. In granulosa cells, the 17-ketosteroid reductase activity was concentrated in the cytosolic fraction of the cell. In Leydig cell microsomes, the apparent Michaelis-Menten constant for the conversion of androstenedione to testosterone was 0.41 mumol/L and for the conversion of estrone to estradiol it was 12 mumol/L. In granulosa cell cytosol, the apparent Michaelis-Menten constant for the conversion of estrone to estradiol was 1.1 mumol/L and for the conversion of androstenedione to testosterone it was 15 mumol/L. These results demonstrate that rat Leydig and granulosa cells each contain a 17-ketosteroid reductase enzyme with unique subcellular localization and substrate specificity.

Infants of diabetic mothers are known to have a greater incidence of respiratory distress syndrome than normal control infants. Fetal lung maturation is modulated by a large number of hormones. To further investigate a possible role of hormonal modulators of lung maturation in infants of diabetic mothers, fetal cord prolactin, estrone, estradiol, thyroxine, triiodothyronine, and triiodothyronine-resin uptake index levels were measured in infants of diabetic mothers (n = 40) and nondiabetic mothers (n = 40) at term. Infants of diabetic mothers had significantly lower mixed-cord serum prolactin levels (p less than 0.0005) than control infants. There was no significant difference in cord serum thyroxine, triiodothyronine-resin uptake index, triiodothyronine, estrone, or estradiol levels between the infants of diabetic mothers and the infants of control mothers. These findings raise the possibility that decreased fetal prolactin levels may be associated with, or contribute to, the delayed lung maturation reported with diabetic pregnancies.