Neil S. Whitworth

Effect of body weight reduction on plasma androgens in obese, infertile women.

Although a variety of disorders are associated with polycystic ovarian disease (PCOD), obesity, hirsutism, and menstrual dysfunction are the most frequent manifestations. We investigated the possibility that obesity per se may give rise to androgen excess through alterations in estrogen metabolism and, consequently, through alterations in gonadotropin secretion. Eighteen obese, infertile women with PCOD were compared with 20 control women. Plasma androstenedione (A) was 252 +/- 18 ng/dl (mean +/- standard error of the mean [SEM]) in the obese women compared with 173 +/- 9 ng/dl in the controls (P less than 0.001); plasma testosterone (T) was 66 +/- 5.7 ng/dl, compared with 41 +/- 3 ng/dl (P less than 0.001). Thirteen of the obese women lost greater than 15% of their body weight by dietary restriction; ten of these women (77%) conceived spontaneously. In seven of the ten women who conceived, we remeasured plasma androgens following weight reduction but prior to conception. A decreased from 295 +/- 19 ng/dl to 179 +/- 5 ng/dl; T decreased from 75 +/- 8 ng/dl to 39 +/- 5 ng/dl (P less than 0.001). We conclude that obesity may play a role in the genesis of PCOD.

Measurement of amniotic fluid volume: Accuracy of ultrasonography techniques

OBJECTIVE Our purpose was to determine amniotic fluid volume by the dye-dilution technique and compare it with the amniotic fluid index, largest vertical pocket, and two-diameter pocket (defined as vertical x horizontal of the largest vertical pocket). STUDY DESIGN This prospective study involved 40 women undergoing amniocentesis in late pregnancy to detect fetal lung maturity or evidence of chorioamnionitis. The amniotic fluid volume was quantified ultrasonographically by means of the amniotic fluid index, largest vertical pocket, and two-diameter pocket. During amniocentesis the fluid volume was calculated by the dye-dilution technique of Charles and Jacoby. RESULTS Ultrasonographic measurements by amniotic fluid index, largest vertical pocket, and two-diameter pocket correctly predicted normal amniotic fluid and hydramnios (74%). A new measurement, two-diameter pocket, gave a significantly more accurate estimate of oligohydramnios than did amniotic fluid index (p < 0.002) or largest vertical pocket (p < 0.0003). CONCLUSION All three indices are moderately accurate in identifying normal amniotic fluid volume and hydramnios. Two-diameter pocket is the most accurate test to predict oligohydramnios.

Reproductive failure in women who practice weight control

Forty-seven women (29 with unexplained infertility and 18 with menstrual dysfunction) practiced weight control by caloric restriction in order to maintain a fashionable body habitus. All of these women were below ideal body weight (IBW) when compared with Metropolitan Life Insurance Company tables for height and weight. When 36 of these women followed a dietary regimen designed to increase their weight to predicted IBW, 19 of 26 infertile women (73%) conceived spontaneously; 9 of 10 women (90%) with secondary amenorrhea resumed menstruation. Eleven women (23%) would not accept their practice of weight control as the cause of reproductive failure and did not participate in the study. Differences in the serum gonadotropin luteinizing hormone:follicle-stimulating hormone (LH:FSH) ratio were found to be significantly related to differences in the percentage of IBW. The practice of weight control may be a cause of unexplained infertility and menstrual disorders in otherwise healthy women.

Antenatal testing among 1001 patients at high risk: the role of ultrasonographic estimate of amniotic fluid volume.

OBJECTIVE Our goal was to compare the accuracy of the amniotic fluid index and the 2-diameter pocket technique with respect to accuracy in predicting an adverse pregnancy outcome among patients at high risk undergoing antenatal testing. STUDY DESIGN All women with high-risk pregnancies and intact membranes who underwent antenatal testing during an 18-month period were prospectively enrolled. Ultrasonographic estimates of amniotic fluid volume were performed by means of the amniotic fluid index and the 2-diameter pocket technique. Relative risks with 95% confidence intervals and receiver operator characteristic curves were calculated for patients with an ultrasonographic estimate of oligohydramnios (amniotic fluid index of </=5 cm or 2-diameter pocket of </=15 cm2) versus normal fluid level (amniotic fluid index of >5 cm or 2-diameter pocket of >15 cm2). Outcome variables studied were intrapartum and neonatal complications. RESULTS Among 1001 patients the mean (+/-SD) amniotic fluid index was 10.5 +/- 5 cm and the mean (+/-SD) 2-diameter pocket was 18.7 +/- 13.6 cm2. Significantly more patients (46%) were considered to have oligohydramnios according to the 2-diameter pocket criteria than according to the amniotic fluid index (21%, P <.0001, relative risk 1.7, 95% confidence interval 1.5-1.8). No significant differences in the incidences of nonreactive nonstress test results, meconium-stained amniotic fluid, cesarean delivery for fetal distress, low Apgar scores, or infants with cord pH of <7.10 were observed between the oligohydramnios and normal amniotic fluid groups (P >.05) when assessed by relative risk with confidence interval and by receiver operator characteristic curves. CONCLUSIONS Current ultrasonographic measurements with the amniotic fluid index and the 2-diameter pocket technique are poor diagnostic tests to determine whether a patient is at high risk for an adverse perinatal outcome.

Amniotic fluid index and single deepest pocket: weak indicators of abnormal amniotic volumes ☆

Objective To compare amniotic fluid index (AFI) with the single deepest pocket in the identification of actual abnormal amniotic fluid (AF) volumes. Methods One hundred seventy-nine women with singleton pregnancies at the University of Mississippi between March 1994 and June 1999 had ultrasound estimations of AF volume sequentially using the AFI and single deepest pocket techniques. Each woman subsequently had ultrasound-directed amniocentesis with dye-dilution and spectrophotometric calculation of actual AF volume. Results Actual AF volumes were low (under 5% by volume for gestational age) in 62 women, normal (5–95%) in 100 women, and high (more than 95%) in 17 women. An AFI up to 5 cm (sensitivity 10%, specificity 96%) and a single deepest pocket up to 2 cm (sensitivity 5%, specificity 98%) were similarly inadequate in identifying dye-determined low AF volumes. Likewise, AFI above 20 (sensitivity 29%, specificity 97%) and a single-deepest pocket above 8 cm (sensitivity 29%, specificity 94%) were poor in identifying dye-determined abnormally high volumes. Conclusion There was no difference between AFI and single deepest pocket techniques for identifying truly abnormal AF volumes. Both techniques were unreliable for identifying true AF volumes.

The accuracy of ultrasound evaluation of amniotic fluid volume in singleton pregnancies: the effect of operator experience and ultrasound interpretative technique.

The objective of this study was to evaluate the effect of operator experience and ultrasound interpretation technique on the accuracy of ultrasound estimates of amniotic fluid volume. Ultrasound evaluation was carried out by an obstetric resident, a nurse sonographer, a maternal‐fetal medicine fellow, and a maternal‐fetal medicine staff member to subjectively estimate (visual interpretation without sonographic measurements) amniotic fluid volume in 63 pregnancies. Amniotic fluid volume was also evaluated using ultrasound measurements based on the largest vertical pocket technique, the amniotic fluid index, and the two‐diameter pocket method. The accuracy of these ultrasound estimates was assessed by comparing the ultrasound results to actual amniotic fluid volume as determined by a dye‐dilution technique. For analysis, amniotic fluid volumes were classified as oligohydramnios, normal, or hydramnios using established volumetric criteria for singleton pregnancies. Subjective estimates ranged from 65% to 70% correct and did not differ by operator experience except for the more accurate diagnosis of hydramnios by the maternal‐fetal medicine staff. The three sonographic measurements were similar in overall accuracy (59–67%). The two‐diameter pocket method was, however, significantly more accurate in identifying oligohydramnios. It appears that neither operator experience nor sonographic technique greatly affects the accuracy of ultrasound estimates of amniotic fluid volume.

Comparative efficacy of two sonographic measurements for the detection of aberrations in the amniotic fluid volume and the effect of amniotic fluid volume on pregnancy outcome.

Objective: To determine in pregnant women with preterm labor the relative efficacy of the amniotic fluid index (AFI) and the two‐diameter pocket to detect abnormalities in amniotic fluid volume (AFV), and to relate these findings to pregnancy outcome. Methods: Fifty‐seven healthy women with preterm labor underwent amniocentesis in the third trimester to detect subclinical chorioamnionitis and assess fetal lung maturity. The AFV was estimated by the AFI and two‐diameter‐pocket methods, then confirmed by a dye (aminohippurate sodium)‐dilution technique. Each labor was evaluated for severe variable decelerations requiring amnioinfusion, fetal distress resulting in cesarean delivery, and a 5‐minute Apgar score below 7. Results: Using fluid volume confirmed by dye dilution, the AFI correctly diagnosed AFV as low (less than 500 mL) in only two of 23 (8.7%) patients, compared to 14 of 23 (61%) for the two‐diameter pocket (P < .001). Fetal distress requiring cesarean delivery occurred significantly more often in the hydramnios group (three of six) compared to those with normal AFV (one of 23) (P < .03), and approached significance in the oligohydramnios group (two of 21) (P = .056). There were no significant differences among the three patient groups regarding the need for amnioinfusion for severe variable decelerations or the occurrence of 5‐minute Apgar scores below 7. Conclusions: Compared to the AFI, the two‐diameter pocket is a superior sonographic measurement for the detection of oligohydramnios. In an otherwise low‐risk pregnancy with preterm labor, oligohydramnios is associated with no greater risk for an adverse outcome than is a normal AFV. (Obstet Gynecol 1994;83:959‐62)

Receiver-operator characteristic, efficiency analysis, and predictive value of serum progesterone concentration as a test for abnormal gestations

OBJECTIVE Our objective was to determine if a discriminatory progesterone concentration could be established that confidently predicted abnormal early gestations. STUDY DESIGN We analyzed differences in progesterone concentrations between normal (n = 40) and abnormal (n = 34) pregnancies during the first 49 days of gestation. The receiver-operator characteristic curve, test efficiency, and predictive value of serum progesterone to discriminate between an abnormal and normal first-trimester gestation were calculated for progesterone concentrations between 5 and 25 ng/ml. RESULTS Receiver-operator characteristic curve analysis indicated that the best discriminatory progesterone concentration was 10 ng/ml. Test efficiency was maximum between serum progesterone concentration of 9 to 14 ng/ml (80%). When progesterone was less than 10 ng/ml, the predictive value of the abnormal test result was greater than 90%. CONCLUSION Receiver-operator characteristic analysis, test efficiency, and the predictive value of an abnormal test result suggest that the best progesterone cut off point that predicts abnormal early pregnancies is 10 ng/ml.

LACTATION IN HUMANS

Postpartum milk secretion is a hormonally regulated process that reflects the highly coordinated actions of endocrine, neuroendocrine, and behavioral mechanisms. Structural development of the mammary gland during pregnancy is stimulated primarily by estrogen, progesterone, and prolactin (PRL), the secretion of which is controlled directly or indirectly by the fetoplacental unit. Following parturition, PRL also plays an important role in initiating and sustaining milk secretion and suppressing the resumption of cyclic hypothalamic-pituitary-ovarian function. Dynamic postpartum PRL secretion is in response to the neurogenic stimulus of suckling, which both acutely releases PRL and maintains the responsiveness of PRL regulatory pathways to subsequent nursing. The central control of PRL secretion at this time involves the integrated activities of inhibitory and stimulatory hypothalamic mechanisms. A major feature of lactation is the degree to which the entire process is controlled by the developing organism itself.

Ultrasound estimate of amniotic fluid volume : Color Doppler overdiagnosis of oligohydramnios

OBJECTIVE To determine if concurrent use of color Doppler affects ultrasound estimates of amniotic fluid (AF) volume. METHODS Study gravidas underwent ultrasound estimations of AF volume subjectively (visualization without measurements) and objectively (using amniotic fluid index [AFI]) and single‐deepest pocket techniques, without and with concurrent color Doppler. Amniocentesis with the dye‐dilution technique to measure actual AF volume was utilized for comparison. RESULTS Sixty‐seven women at a mean gestational age of 37.1 ± 2.5 weeks were entered into this investigation between June 1999 and March 2000. Dye‐determined AF volume was classified as low in 18 patients and as high in seven, with the remaining 42 within normal range. Using either ultrasound technique with color Doppler produced significantly lower estimates of AF volume (9.3 ± 4.9) compared to those without color ([11.6 ± 5], P < .001) for the AFI and (3.7 ± 1.5) with color compared to those without color ([4.5 ± 1.5], P < .003) for the single‐deepest pocket. Using AFI without color identified two of 67 (3%) of the pregnancies as having low fluid compared to 14 of 67 ([21%] P .002) using color. The increased classification of oligohydramnios with color did not accurately identify a greater number of dye‐determined low volumes; instead, the AFI with color mislabeled nine pregnancies with normal fluid as low. The diagnosis of dye‐determined low and high fluid volumes was not significantly different with or without color. CONCLUSION Concurrent use of color Doppler with AFI measurements leads to the overdiagnosis of oligohydramnios.