Amniotic fluid testosterone levels in midpregnancy

Amniotic fluid testosterone levels were measured on specimens obtained between 12 and 25 weeks' gestation from 58 male-fetus and 77 female-fetus pregnancies. For the male fetuses the mean +/- SE amniotic fluid testosterone level of 223 +/- 10 pg/ml was significantly higher (P less than 0.001) than the concentration found for the female fetuses (40 +/- 2 pg/ml). The ranges were 104-424 and 18-82 pg/ml, respectively, for the same fetuses. In the male fetuses the highest mean level was found during the 17th gestational week, but the mean level observed during any 1 week was not significantly differenf from any other week for both sexes. These data are consistent with the concept that amniotic fluid testosterone levels may be a rapid and effective method for establishing fetal sex in utero during midgestation.     

Amniotic fluid alpha-fetoprotein determination at the time of genetic amniocentesis: has it outlived its usefulness?

The purpose of this retrospective study was to evaluate the utility of routine measurement of amniotic fluid alpha-fetoprotein levels at the time of second trimester genetic amniocentesis (mean gestational age, 17.3 weeks +/- 2.5 weeks standard deviation; median, 16.8 weeks; range, 15 to 22 weeks). During the study period 7174 patients underwent second trimester genetic amniocentesis. Outcome data were available in all cases. In 79 (1.1%) cases the amniotic fluid alpha-fetoprotein level was > or = 2.0 multiples of the median. Thirty-three of the 79 (42%) patients had normal ultrasonograms, and in 31 of 33 (94%) the amniotic fluid alpha-fetoprotein level was between 2.0 and 3.0 multiples of the median. Forty-six of the 79 (58%) patients had abnormal ultrasonographic findings, and of these, 82% were neural tube defects, abdominal wall defects, or cystic hygromas. Acetylcholinesterase was positive in 37 cases, all of which had abnormal ultrasonographic findings. None of the fetuses with negative findings on sonographic screening had detectable abnormalities at birth. In this study, with over 7000 patients, amniotic fluid alpha-fetoprotein and acetylcholinesterase levels did not increase the detection of fetal abnormalities. On the basis of these results, routine measurement of amniotic fluid alpha-fetoprotein level at the time of routine genetic amniocentesis (15 to 22 weeks) does not appear justified.     

Amniotic fluid B12 and folate levels associated with neural tube defects

Abnormal marrow signal and marrow enhancement have not been described in association with benign avulsive cortical irregularity. We present the case of an 11-year-old gymnast with such findings that partially resolved over time. The marrow MR abnormalities are believed to represent an extension or spectrum of findings associated with avulsive cortical irregularity, and should not instantly suggest infection or malignancy, as has been previously indicated. Careful and close clinical and radiological follow-up is required to confirm its benign course.     

Progesterone levels in amniotic fluid and maternal plasma in prostaglandin F2alpha-induced midtrimester abortion

Progesterone concentrations in amniotic fluid and maternal plasma were determined in 11 midtrimester pregnant patients following the intraamniotic administration of prostaglandin F2alpha. Samples were obtained at 3-hour intervals until abortion or spontaneous rupture of membranes occurred or fetal heart tones disappeared. In amniotic fluid, the mean progesterone concentrations increased throughout the sampling period. The plasma progesterone levels declined by about one-third of basal values in the first 3 hours after prostaglandin administration. The paradoxic increase in amniotic fluid progesterone is probably secondary to alterations in uterine blood flow and intrauterine pressure.     

Amniotic fluid and fetal maturity

The lecithin/sphingomyelin ratio in amniotic fluid is a method of predicting fetal lung maturity. The L/H ratios in certain high risk pregnancies are poorly correlated with the shake test. The L/S ratios in drug addiction methadone pregnancies and diabetic pregnancies do not have a high degree of correlation with normal L/S ratios after 36 weeks of gestation and are often low.     

Amniotic fluid embolism: emergency management

A case of successful outcome is described in a patient with amniotic fluid embolism presenting to the accident and emergency department. Diagnostic features and guidelines for management are outlined.     

Biochemical markers of trisomy 21 and the pathophysiology of Down's syndrome pregnancies

Using biochemical and immunocytochemical methods, we have investigated endogenous levels of various markers in tissues obtained from 67 Down's syndrome pregnancies after therapeutic abortion in the second trimester and in corresponding tissues from unaffected abortuses. Alpha-fetoprotein (AFP), intact and free beta human chorionic gonadotrophin (hCG), pregnancy-specific beta-1 glycoprotein (SP-1), placental alkaline phosphatase (PALP), pregnancy-associated plasma protein A (PAPP-A), and gamma glutamyl transferase (GGT) were investigated in placental tissue; AFP and GGT in fetal liver; and GGT in fetal intestine. The results indicate that maternal serum levels of placental products reflect those found in the placenta: intact hCG, free beta hCG, and SP-1 levels were elevated in Down's syndrome pregnancies, while PAPP-A and PALP levels were little changed. This suggests that membrane passage of these markers is not affected but there is altered synthesis of hCG and SP-1. AFP levels were strikingly elevated in placental homogenates and unchanged in liver homogenates from Down's syndrome pregnancies, while the levels in maternal serum were reduced, pointing to a possible transport defect specific to AFP. GGT levels were high in placenta and liver from Down's syndrome pregnancies but low in fetal intestine.     

Normal nuchal thickness in the midtrimester indicates reduced risk of Down syndrome in pregnancies with abnormal triple-screen results

OBJECTIVE: Our purpose was to determine whether nuchal thickness measurement can identify the euploid fetuses in midtrimester pregnancies at increased risk for Down syndrome on the basis of maternal age and serum screening. STUDY DESIGN: Nuchal thickness was obtained prospectively in 651 consecutive fetuses at 14 to 21 weeks' gestation and at > or = 1:270 risk for Down syndrome on the basis of unconjugated estriol, alpha-fetoprotein, and human chorionic gonadotropin levels. The risk of Down syndrome with a normal nuchal thickness was determined. A receiver-operator characteristic curve was used to determine a serum-based risk threshold below which the risk for Down syndrome was low. The prevalence of Down syndrome in fetuses with both a normal nuchal thickness and a below-serum-risk threshold was compared with prevalence in either those above threshold risk or with an abnormal nuchal thickness. RESULTS: There were eight cases of trisomy 21 and one case each of 46,XX/47,XXX, 46,XY/47,XY, +7, and 46,XX, 11q-. The sensitivity of an abnormal nuchal thickness (> or = 6 mm) for detecting Down syndrome was four in eight (50%) (95%) confidence interval 15.3% to 84.6%). The risk of Down syndrome was significantly increased with an abnormal compared with a normal nuchal thickness, four in 13 (30.8%) versus four in 638 (0.6%), p < 0.0001. A risk threshold was defined at > or = 1:100 on the basis of the receiver-operator characteristic plot. Of 390 cases with a normal nuchal thickness and a serum risk estimate < 1:100, there were no cases of Down syndrome (0/390 vs 8/253, p = 0.002). CONCLUSION: Normal nuchal thickness significantly reduces the risk of Down syndrome and may help reduce the number of amniocenteses done for abnormal triple screen results.     

Changes in human amniotic fluid fibrinolytic inhibitor levels during pregnancy

The amniotic fluid (AF) when incubated with the patient's own plasma diminishes the lytic activity of the plasma. It is suggested that this inhibition is due to the presence of fibrinolytic inhibitors in the AF. The inhibitors rate increases as pregnancy advances. Evaluating these inhibitors in a group of 65 women before and after the 38th week of pregnancy, a higher rate of fibrinolytic inhibitors is found after the 38th week. The said differences are statistically significant. For the moment it does not seem that the increasing of the inhibitors in the last part of pregnancy might be used as a fetal maturity test.     

Amniotic fluid lipid profiles: a rapid gas chromatographic method

The lipid extract of amniotic fluid has been analysed for the important fatty acids derived mainly from the lecithin component of lung surfactant. Using gas-liquid chromatography and mass spectrometry, these fatty acids have been identified. A positive correlation between certain lipid profiles and lack of lung surfactant with its associated respiratory problems for the newborn infant has been demonstrated.     

Amniotic fluid embolism in trial of labor. A case report

Amniotic fluid embolism is a rare complication of pregnancy, which accounts for about 10% of all maternal deaths. A case of acute embolic episode occurred during labor in a 36-year-old patient with spontaneous rupture of membranes is described. Caesarean section was performed immediately, followed by hysterectomy; the baby survived but the mother died because of DIC and cardiorespiratory arrest.     

Recurrent pregnancies during oral contraception

The records of the Royal College of General Practitioners' Oral Contraception Study were examined for those women who had become pregnant while using combined oral contraceptive pills. Analysis reveals that these women are much more likely than average to have further failures if they resume taking the Pill (seven failures in 35 women-years, compared with one in 500 women-years for the whole study). This finding could occur through some factor in the patient's personality (patient failure) or through some factor in the patient's metabolism.     

The effect of oxytocics on the human cervix during midtrimester pregnancy

Observations of the effects of oxytocics on the human pregnant cervix have been made in vivo using a double open ended catheter technique. Prostaglandin E, prostaglandin F2alpha and oxytocin had similar but no specific effects upon the intracervical canal pressure; ergometrine caused contractions of the cervix. The significance of these findings is discussed in relation to cervical rupture and cervico-vaginal fistulae that have been reported following second trimester abortion induced with prostaglandins.     

Amniotic fluid lecithin/sphingomyelin ratio changes related to centrifugal force

Lecithin/sphingomyelin ratio (L/S ratio) in amniotic fluid has gained wide clinical acceptance as an index of fetal lung maturity. We determined L/S ratios of amniotic fluids centrifuged at various "g-forces." Our studies demonstrate that the L/S ratio value is highly dependent on the g-force used to prepare the fluid. We recommend standardization of the g-force, time, and temperature used in preparation of the amniotic fluid for L/S ratio determination.     

Amniotic fluid tests for fetal lung maturity (author's transl)

Amniotic fluid specimens of 30 pregnant women were examined for the evaluation of the fetal lung maturity. Three assays were used in parallel: the determination of the lecithin concentration, the estimation of the lecithin/sphingomyelin ratio and the shake test. The results were compared together and with the fetal outcome. The shake test has proved to be sufficient for the exclusion of an immature lung. To avoid failure from false-negative results of the shake test an additional determination of the lecithin/sphingomyelin ratio is recommended, whenever clinical dates give rise to expect a mature lung. The determination of the lecithin concentration has no advantage compared to the lecithin/sphingomyelin ratio. Pathology as candida infection or anecephaly falsifies.