Maxwell W. Brinsmead

Postnatal disappearance of the pregnancy-associated reduced sensitivity of plasma cortisol to feedback inhibition.

We recently observed that the characteristic insensitivity of the pituitary-adrenal system in women to feedback inhibition during pregnancy persists for at least four days postnatally. We therefore examined women during the first five weeks after delivery to assess when the sensitivity of plasma cortisol to glucocorticoid inhibition returns to normal. Dexamethasone (DEXA, 1 mg) was ingested at 11 pm by normal healthy women, once between the 3rd and 27th postnatal days, and again on day 35. Blood plasma was collected at 4 pm on the following day for cortisol assay. Plasma cortisol levels (nmol/L, mean +/- sem [n]) after DEXA in the first two weeks (216 +/- 28, [47]) were higher (p less than 0.001) than in nonmedicated nonpregnant women (47.4 +/- 8.9 [12]) and were normal by the 35th day after delivery (41.7 +/- 4.8 [74]). A negative association was found between post-DEXA cortisol and time after delivery in the first 4 post-partum weeks (r = -0.46, p less than 0.001). The study confirms that insensitivity of plasma cortisol to feedback inhibition persists beyond normal pregnancy in a significant proportion of healthy women for two to three weeks, and is absent by the 5th postnatal week.

Male sex and pre-existing diabetes are independent risk factors for stillbirth

Aim:  To determine whether the risk of stillbirth is associated with male fetal sex, fetal growth and maternal factors in an Australian population.

Predictors of smoking in pregnancy and attitudes and knowledge of risks of pregnant smokers

This study examined the prevalence and predictors of smoking by pregnant women attending a public antenatal clinic. The prevalence of smoking in this population (n = 2577) was found to be 38.0% (95% CI 36.1-39.9%). A review of previous research investigating variables associated with smoking in pregnancy indicated that only three of 42 studies had used multivariate analysis. Using step-wise logistic regression analysis, five variables were found to be independent predictors of smoking in pregnancy: education (having 4 years or less high school), marital status (being unmarried), gravidity (being multigravida), age (being under 25 years) and language spoken at home (speaking English). The model correctly predicted 63.7% of cases. The knowledge and attitudes of pregnant smokers were also investigated using data from a sub-sample of consenting subjects. Three-quarters of the women claimed that they had reduced their smoking since discovering they were pregnant. However, their mean intake of 13.7 cigarettes daily remained at a hazardous level. Approximately half (51%) these smokers claimed to have tried to quit smoking in the current pregnancy. Most (61%) women said they believed smoking was definitely harmful to the unborn child. However, awareness and acceptance of specific risks were inadequate. Of the women in a current relationship, 72% said their partner was a regular smoker. Less than half (45%) the continuing smokers who had seen a doctor about their current pregnancy could recall being advised to stop smoking. There is a need for health care providers to adopt a more systematic and tailored approach to smoking cessation counselling. Efforts to convert quit attempts in pregnancy into sustained cessation represent a priority area of programme development and evaluation.

Prolonged follicle stimulation decreases pregnancy rates after in vitro fertilization

Ovarian stimulation with a GnRH-a and hMG for IVF treatment offers the potential to extend the period of follicle recruitment and growth free of the restriction imposed by a spontaneous midcycle LH surge. A randomized trial investigating the impact of extending follicle growth by 1 day resulted in a significantly reduced PR, despite an increase in the number of larger follicles (greater than or equal to 17 mm) at the time of hCG. The reason for a reduced PR was not related to the number of ova recovered or embryo quality. This suggests that follicular aging or the duration of estrogen rise may be important.

Post-partum psychoses and the dexamethasone suppression test

The hypothesis that post-partum psychoses are predominantly mixed affective disorders was tested by administering the dexamethasone suppression test (DST) to seven puerperal psychotics, six puerperal depressives and comparison groups of non-puerperal psychotic and depressed women. The hypothesis received support from the finding that two-third of the puerperal patients had positive DSTs versus one-third of similar non-puerperal patients. An 80% rate of positive DSTs in 19 normal women 5 days post-partum, however, suggested this was an invalid interpretation of this finding, particularly as the majority of these tests returned to normal when repeated several weeks later.

The way we teach medical students professional skills.

This article describes the progressive development of professional skills at the Faculty of Medicine, University of Newcastle, Australias newest medical school. These professional skills include information gathering (history taking and physical examination), information giving (patient information and education, case history write-up and case presentation) and management (counselling and monitoring) skills, as well as interpersonal, interactional and communication skills which are so important in the modern medical environment. The progressive development of these professional skills and their integration with basic, behavioural and clinical sciences in a problem-based curriculum is believed to be a rational approach to the development of an efficient, effective and caring doctor.

Urinary corticotropin-releasing hormone immunoreactivity is elevated during human pregnancy

Plasma corticotropin-releasing hormone immunoreactivity (CRH IR) rises with gestational age in women. In order to investigate the physiological changes of the hormone in pregnant womens urine, CRH IR was measured by radioimmunoassay in urine collected over a 24-hour period, a blood sample and a subsequent single collection of urine after the 24-hour collection (spot urine). Plasma CRH IR in pregnant subjects, 8682.8 +/- 2063.0 pg CRH IR/ml plasma (mean +/- SEM, n = 25), was significantly higher than that in the non-pregnant controls (7.2 +/- 1.6 pg/ml, n = 5; separate t = 4.21, p = 0.0003, d.f. = 24). Similarly, pregnant women had higher spot urine CRH IR - 54.6 +/- 15.5 pg/mumol creatinine (Cr) versus 5.0 +/- 0.5 pg/mumol Cr (separate t = 3.20, p = 0.0038, d.f. = 24.0) - and 24-hour urine CRH IR - 13.7 +/- 1.2 pg/mumol Cr compared with 7.7 +/- 0.8 pg/mumol Cr (separate t = 4.28, p = 0.003, d.f. = 24.4) than the non-pregnant cohort. The difference between urinary excretion of CRH IR as estimated by 24-hour urine (13.7 +/- 1.2 pg/mumol Cr) and spot urine (54.6 +/- 15.5 pg/mumol Cr) indicated that CRH IR in 24-hour urine may be degraded during storage. The weak associations between plasma and 24-hour urine CRH IR of pregnant women (correlation coefficient r = 0.34, p greater than 0.1), and total 24-hour urine and spot urine CRH IR (r = 0.25, p less than 0.1) further indicate CRH degradation. Plasma and spot urinary CRH IR, however, were strongly correlated (r = 0.80, p = 0.001). The total CRH IR excreted as estimated from the spot urine value (0.5 +/- 0.1 micrograms/day) compared with the total filtered load of CRH IR in the pregnant group (1306.9 +/- 324.6 micrograms/day) showed that 99.97% of the filtered CRH IR was reabsorbed or metabolized by the kidneys. Acidic gel chromatography of spot and 24-hour urine samples showed a CRH IR peak at CRH41 standard elution position (Kd = 0.5), indicating that the molecular form in urine is similar to the 41-residue standard. Pregnancy-induced hypertension correlated positively with plasma CRH IR (r = 0.62, p less than 0.001) and spot urine CRH IR (r = 0.46, p less than 0.01), and negatively with parity (r = -0.60, p less than 0.001). Plasma CRH IR and parity also negatively correlated (r = -0.41, p less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)