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Biomedical subjects

R Pittrof

Publications and source records attributed to R Pittrof.

At least 19 recordsLinked to original sources
PubMed2000

Vitamin A and causes of maternal mortality: association and biological plausibility.

OBJECTIVE: To review the association between major causes of maternal mortality and vitamin A, trying to determine if these associations are causal in nature, and to highlight possible biological pathways that may explain vitamin A effects. DESIGN: Literature review, observational studies and clinical trials. The strength of association was determined by applying Bradford Hill criteria of causality. RESULTS: In a vitamin A deficient population, vitamin A is essential for adequate treatment of anaemia. While vitamin A does not seem to be capable of preventing uterine atony, obstetric or surgical trauma, which are important causes of haemorrhage, it might be capable of preventing or decreasing coagulopathy. Possible effects on the placenta as regards implantation, site and size are not clear. As regards pregnancy-related infections, vitamin A supplementation can improve wound healing by decreasing fibrosis and increasing transforming growth factor-beta (TFG-beta). It can increase resistance to infection by increasing mucosal integrity, increasing surface immunoglobulin A (sIgA) and enhancing adequate neutrophil function. If infection occurs, vitamin A can act as an immune enhancer, increasing the adequacy of natural killer (NK) cells and increasing antibody production. beta-carotene in its provitamin form can act as an antioxidant by decreasing endothelial cell damage (the pathognomonic feature of pre-eclampsia) and promote the vasodilator effect of nitric oxide that might bring about a better outcome of toxaemia in pregnancy. It is unlikely that vitamin A or beta-carotene has an effect on obstructed labour. CONCLUSIONS: Plausible biomedical pathways can only be constructed for obstetric haemorrhage, anaemia in pregnancy, hypertension in pregnancy and pregnancy-related infections. A 40% reduction in the maternal mortality ratio, as observed in Nepal, is unlikely to be solely explained through the aforementioned pathways.

Anemia↗
PubMed1997

Observed versus expected obstetric complications: an assessment of coverage of obstetric care in developing countries.

The objective of this study was to evaluate access to obstetric care in a rural district in East Africa using easily collected and evaluated data and avoiding expensive field surveys, complicated study design or statistical methods. The number of observed obstetric complications occurring during 12 months in a rural East African district hospital (the only institution with surgical facilities and access to blood transfusion in the district) were compared to the number of expected complications the district should 'generate'. Of the expected > 10000 deliveries < 25% took place in the district hospital. The place of confinement for the other deliveries was not determined. As compared to the total number of expected conditions within the study district < 25% of the breech and < 45% twin deliveries took part in the district hospital and < 10% of pregnancies complicated by placental abruptions and < 5% of the pregnancies complicated by placenta praevia were managed in the district hospital. Comparing the number of serious pregnancy complications which were managed in the hospital to the total expected number for a particular region allows a simple assessment of the accessibility of obstetric care. This ratio might be more useful when evaluating obstetric care than traditional parameters as it stresses the importance of accessibility of care for the whole community.

Africa↗
PubMed1996

Assessment of uterine artery blood flow on the day of human chorionic gonadotropin administration by transvaginal color Doppler ultrasound in an in vitro fertilization program.

OBJECTIVE: To assess whether measurement of uterine artery blood flow impedance (the pulsatility index) as determined by transvaginal color Doppler ultrasound on the day of hCG administration in patients undergoing IVF can predict pregnancy and implantation rates. DESIGN: Prospective observational study of women undergoing IVF. SETTING: A tertiary referral center for assisted reproduction. PATIENTS: One hundred thirty-five patients undergoing 139 IVF cycles. INTERVENTION: Transvaginal color Doppler assessment of uterine artery pulsatility index on the day of administration of hCG. MAIN OUTCOME MEASURES: Mean pulsatility index of the left and right uterine arteries, pregnancy rate, and embryo implantation rate. RESULTS: The patients were grouped into pregnant and nonpregnant groups and according to whether the pulsatility index was low (1.00 to 1.99), medium (2.00 to 2.99), or high (> or = 3.00). The pregnancy rates were 13.8%, 34.7%, and 14.3% for the low, medium, and high pulsatility index groups, respectively, and were not significantly different. The implantation rates for the same groups were 10.7%, 16.3%, and 5.4%, respectively. The implantation rate for all the patients with pulsatility index < 3.00 (and especially 2.00 to 2.99) was significantly higher than the high pulsatility index group. CONCLUSIONS: The study suggests that the measurement of uterine artery pulsatility index on the day of hCG predicts subsequent implantation rates. It may allow the administration of hCG to be deferred until uterine artery pulsatility index falls to < 3.00, which may result in improved implantation rates.

Adult↗
PubMed1996

Transvaginal three-dimensional ultrasound: reproducibility of ovarian and endometrial volume measurements.

OBJECTIVE: To assess the reproducibility of ovarian and endometrial volume measurements obtained using transvaginal three-dimensional (3D) ultrasound (US). DESIGN: Prospective clinical study. SETTING: A tertiary referral center for assisted reproduction. PATIENTS: Forty women undergoing ovarian stimulation for IVF-ET using the long protocol of GnRH agonist. INTERVENTION: Three observers independently measured 20 stored ovarian scanned volumes and 20 endometrial volumes. Also, ovarian volume was calculated from three diameters obtained by two-dimensional (2D) US. MAIN OUTCOME MEASURE: Analysis of variance, the paired Student's t-test, and calculation of intraclass and interclass correlation coefficients were used for statistical analysis. RESULTS: Three-dimensional ovarian volume measurements were not significantly different from ovarian volume calculated from three diameters (7.98 versus 7.58 mL). The mean endometrial volume measurement was 3.56 mL. The intraobserver coefficient of variation for both ovarian and endometrial volume was 8%. The interobserver coefficient of variation was 9% for ovarian volume and 11% for endometrial volume. Intraclass and interclass correlation coefficients were 0.95 and 0.95 for ovarian volume and 0.90 and 0.82, respectively, for endometrial volume. CONCLUSION: Transvaginal 3D US produces highly reproducible ovarian and endometrial volume measurements.

Embryo Transfer↗
PubMed1996

Blood flow changes in the intraovarian arteries during the periovulatory period: relationship to the time of day.

Intraovarian blood flow was assessed by transvaginal color and pulsed Doppler ultrasound prospectively in six women during the periovulatory period. All patients had regular ovulatory menstrual cycles and a mid-luteal serum progesterone level consistent with spontaneous ovulation in the preceding cycle. Each patient underwent serial transvaginal ultrasound examination and Doppler assessment of blood flow in the ovarian stroma and in the wall of the dominant follicle or corpus luteum. When the mean follicular diameter was > 16 mm or day -2 from the estimated day of ovulation was reached, patients were scanned at 6-h intervals at 06.00, 12.00, 18.00 and 24.00 until follicular rupture, to investigate the presence of circadian rhythms. The pulsatility index (PI) and the maximum peak systolic blood flow velocity (Vmax) were calculated as Doppler indices of impedance to blood flow and velocity, respectively. A venous blood sample was taken at each visit for subsequent hormonal analysis. There was no significant circadian fluctuation in either mean follicular Vmax or mean follicular PI before or after the luteinizing hormone (LH) surge. Similarly, mean Vmax and mean PI in the non-dominant ovarian stroma did not show any significant fluctuation over the same periods. The mean PI in the dominant ovarian stroma showed daily fluctuations with the highest values occurring most commonly at 06.00 and the nadir in the afternoon and late evening. This fluctuation was the reverse of the circadian variation previously demonstrated in the uterine artery. However, in contrast to the uterine artery, comparison between the mean PI values in the dominant ovarian stroma at 06.00 and 18.00 only approached significance after the LH surge. The dominant ovarian stroma Vmax tended to rise during the day, although the differences between 06.00 and 18.00 were also not significant. Although there are fluctuations in Doppler blood flow indices in the dominant ovarian stroma, further studies are necessary to demonstrate whether this represents a significant circadian rhythm.

Adult↗
PubMed1996

Transvaginal three-dimensional ultrasound: accuracy of follicular volume measurements.

OBJECTIVES: To evaluate the accuracy of three-dimensional (3-D) ultrasound (US) follicular volume measurements. DESIGN: Prospective clinical study. SETTING: A tertiary referral center for assisted reproduction. PATIENTS: Twenty-five patients undergoing ovarian stimulation for IVF-ET using the long protocol of GnRH agonist. INTERVENTION: Transvaginal two-dimensional (2-D) and 3-D ovarian scan performed immediately before US-directed follicle aspiration. MAIN OUTCOME MEASURES: The volume of follicular fluid aspirated was compared with the corresponding volume of the follicle measured by 3-D US and with the conventional 2-D US volume measurement calculated using the formula pi/6 (D1 x D2 x D3). Limits of agreement and 95% confidence intervals were calculated and systematic bias between the methods was analyzed. RESULTS: The limits of agreement between the volume of follicular aspirate and follicular volume determined by US were +0.96 to -0.43 mL for 3-D measurements and +3.47 to -2.42 mL for 2-D measurements. CONCLUSIONS: The true volume of ovarian follicles, within the clinically useful range for IVF-ET cycles, is measured more accurately by a 3-D US system than by 2-D US techniques.

Female↗
PubMed1995

Administration of progestogens to hasten pituitary desensitization after the use of gonadotropin-releasing hormone agonist in in vitro fertilization--a prospective randomized study.

OBJECTIVE: To assess the effect of administration of adjuvant IM progestogen to patients undergoing IVF who were not pituitary desensitized after 14 days of GnRH agonist (GnRH-a) administration. DESIGN: Prospective randomized study. SETTING: A tertiary referral center for assisted conception. PATIENTS: Forty-nine patients undergoing 51 IVF treatment cycles. INTERVENTION: Patients in whom the endometrial thickness was > 5 mm or who had an ovarian cyst > 15 mm after 14 days of GnRH-a administration were recruited if the serum E2 concentration was > 27.24 pg/mL (> 100 pmol/L). Patients in group 1 (n = 22) received a single IM injection of 100 mg P whereas patients in group 2 (n = 29) did not. Patients in both groups continued to receive SC GnRH-a 500 micrograms/d and had serum E2 levels measured every 3 days until the concentrations were < or = 100 pmol/L. MAIN OUTCOME MEASURES: The number of days of GnRH-a administration from recruitment until serum E2 concentration measured < or = 100 pmol/L, number of cycles with withdrawal bleeding, number of days from recruitment to withdrawal bleeding, total dose of hMG used, number of follicles > 14 mm, number of oocytes, number of embryos, and pregnancy rates per cycle commenced and per ET. RESULTS: There were no significant differences in all the above parameters except in the mean number of days from recruitment to onset of withdrawal bleeding, which were 5.33 +/- 0.7 (mean +/- SEM) and 8.62 +/- 1.26 days in groups 1 and 2, respectively. The pregnancy rate per ET was higher in group 1 (38.88%) when compared with group 2 (19.04%). However, this difference was not statistically significant. CONCLUSIONS: Adjuvant administration of a single IM injection of progestogen hastens the onset of withdrawal bleeding in patients who are not pituitary desensitized after 2 weeks of administration of SC GnRH-a. It does not appear to affect the length of time the serum E2 concentrations take to reach basal levels or to alter the ovarian responsiveness to exogenous gonadotropins.

Adult↗
PubMed1995

Endometrial thickness, morphology, vascular penetration and velocimetry in predicting implantation in an in vitro fertilization program.

A total of 96 women undergoing in vitro fertilization (IVF) treatment were studied on the day of human chorionic gonadotropin (hCG) administration by transvaginal ultrasonography with color and pulsed Doppler ultrasound. We assessed endometrial thickness, endometrial morphology, presence or absence of subendometrial or intraendometrial color flow, intraendometrial vascular penetration and subendometrial blood flow velocimetry on the day of hCG administration and related the results to pregnancy rates. The overall pregnancy rate was 32.3% (31/96) and there was no significant difference between the pregnant and non-pregnant groups with regard to endometrial thickness, subendometrial peak systolic blood flow velocity (Vmax) or subendometrial pulsatility index (PI). The pregnancy rates based on endometrial morphology were not significantly different, being 17.6% (3/17), 33.3% (2/6) and 35.6% (26/73) for types A (hyperechoic), B (isoechoic) and C (triple-line) endometria, respectively. In eight (8.3%) patients, subendometrial color flow and intraendometrial vascularization were not detected. This absence of blood flow was associated with failure of implantation (p < 0.05). The pregnancy rates related to the zones of vascular penetration into the subendometrial and endometrial regions were: 26.7% (4/15) for Zone 1 (subendometrial zone), 36.4% (16/44) for Zone 2 (outer hyperechogenic zone) and 37.9% (11/29) for Zone 3 (inner hypoechogenic zone), and were not significantly different. Of cycles with type A endometrium, 23.5% (4/17) had absent subendometrial color, which was greater than the frequency of absent color in the type C endometrium (4.1%, p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Description of circadian rhythm in uterine artery blood flow during the peri-ovulatory period.

Uterine artery blood flow was assessed by transvaginal colour and pulsed Doppler ultrasound prospectively in six women during the peri-ovulatory period. All patients had regular ovulatory menstrual cycles and a mid-luteal serum progesterone consistent with spontaneous ovulation in the preceding cycle. Each patient underwent serial transvaginal ultrasound examination and Doppler assessment of blood flow in the uterine arteries. When the mean follicular diameter was > 16 mm or day -2 from the estimated day of ovulation was reached, patients were scanned at 6 hourly intervals at 0600, 1200, 1800 and 2400 h until follicular rupture. The pulsatility index (PI) and time averaged maximum velocity (TAMX) were calculated as Doppler indices of impedance to blood flow and velocity respectively. A venous blood sample was taken at each visit for subsequent hormonal analysis. The mean uterine artery PI showed a marked daily fluctuation with a nadir occurring most commonly at 0600 h. A comparison between the mean PI values at 0600 and 1800 h showed significantly lower results at 0600 h in both dominant (P < 0.05) and nondominant (P < 0.02) uterine arteries. Furthermore, mean uterine artery TAMX showed daily fluctuations with peak values most commonly occurring at 0600 h with the nadir occurring during the afternoon and late evening. There was no temporal relationship between the fluctuations in PI and changes in luteinizing hormone, follicle stimulating hormone, oestradiol or progesterone concentrations. These observations suggest that there is a circadian rhythm in uterine artery blood flow during the peri-ovulatory period which appears to be independent from the hormonal changes.

Adult↗
PubMed1995

Ovarian stromal blood flow in women with polycystic ovaries--a possible new marker for diagnosis?

Blood flow changes in the ovarian stroma of women embarking on in-vitro fertilization treatment were assessed on day 2 or 3 of the menstrual cycle using colour and pulsed Doppler ultrasound. Women were divided into three groups: group 1, 63 women with regular, ovulatory menstrual cycles and normal ovaries on ultrasound scan; group 2, 13 women similar to group 1 but with polycystic ovaries (PCO) on ultrasound scan; and group 3, 12 women with biochemical evidence of previous anovulatory cycles and/or oligomenorrhoea and/or elevated serum luteinizing hormone concentrations (> 10 IU/l) in the early follicular phase together with PCO on ultrasound scan. A subjective assessment of the intensity and quantity of coloured areas in the ovarian stroma appeared to be greater in both groups 2 and 3 compared with group 1. Mean (SEM) ovarian stromal peak systolic blood flow velocity (Vmax) was 16.88 (1.79) and 16.89 (2.36) cm/s in groups 2 and 3 respectively. These velocities were significantly greater than the mean (SEM) ovarian stromal Vmax of group 1; 8.74 (0.68) cm/s (P < 0.001). Mean (SEM) ovarian stromal time averaged maximum velocity (TAMX) was 10.55 (0.91) and 10.89 (1.80) cm/s in groups 2 and 3 respectively, both significantly greater than mean ovarian stromal TAMX of group 1, (P < 0.001). There was no significant difference in pulsatility index (PI) between the three groups. There thus appears to be significantly greater ovarian stromal blood flow velocity in women with polycystic ovaries as detected by colour and pulsed Doppler ultrasound. Increased ovarian stromal blood velocity may be a new parameter to assist in the ultrasound diagnosis of PCO.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Transcervical endometrial cryoablation (ECA) for menorrhagia.

OBJECTIVE: To evaluate endometrial cryoablation (ECA) as a treatment for menorrhagia. METHOD: Prospective study of 67 women. ECA uses the Joule Thompson principle of expanding gases. The ECA probe has a channel to inject saline solution into the uterine cavity. The probe is introduced into the uterine cavity, which is distended with 5 ml saline solution. The device is activated for two freeze-thaw cycles. The saline solution forms an ice mold of the uterine cavity which can be observed by ultrasound scan. RESULTS: No surgical or long-term complications were observed. Two-thirds of patients followed up for > 3 months were completely satisfied. CONCLUSIONS: ECA is technically very easy, can be learned quickly, is free of complications and led to improvement of menstrual symptoms in 63% of patients followed up for 3-18 months. The device is virtually maintenance-free and requires only a small initial investment, while running costs are negligible.

Adult↗