The rate of ovarian and utero-placental blood flow through vessels of less than 25 mum diameter was examined with radioactive microspheres in 5 non-pregnant rats and 19 rats at Day 22 of pregnancy. Total blood flow to the reproductive organs was 0-559 ml/min in the non-pregnant animals and 13-2 ml/min in those near term, a 23-fold difference. The mean ovarian blood flow was high and increased from 0-202 ml/min to 0-845 ml/min. Myometrial and endometrial blood flow increased from 0-156 to 2-24 ml/min. The mean maternal placental blood flow at Day 22 of pregnancy was 0-76 ml/min or 121 ml.,min-1 .100 g-1. Litter size was negatively correlated with mean fetal weight but showed little relationship to mean placental weight or to mean maternal placental blood flow.

This study investigated the association between psychosocial stress and outcome of in-vitro fertilization and gamete intra-Fallopian transfer treatment. Ninety women, enrolled for treatment at a private infertility clinic, completed two self-administered psychometric tests (Bi-polar Profile of Mood States, POMS; and State-Trait Anxiety Inventory, STAI) and a questionnaire to ascertain demographic and lifestyle characteristics before the start of treatment. Approximately 12 months later an outcome measure was determined for each participant in terms of whether she was pregnant or not pregnant and the number of treatment cycles undertaken to achieve clinical pregnancy. The women's scores on the psychological tests were similar to published normative scores. On univariate analysis, history of a previous pregnancy was positively related to the probability of pregnancy and full-time employment, a more 'hostile' mood state and higher trait anxiety were associated with a lower cumulative pregnancy rate. A Cox multiple regression model found previous pregnancy history, trait anxiety, and the POMS agreeable-hostile and elated-depressed scales to be the most important lifestyle and stress variables predictive of pregnancy. The results emphasize the importance of psychosocial stress in treatment outcome but indicate that the relationships are complex. Further studies are required to validate whether these findings can be generalized to other populations.

The radioactive microsphere technique was used to determine the rate of blood flow through vessels of up to 15 mum diameter in the ovaries of 23 anaesthetized sheep in the 72 hr preceding ovulation. The validity of the microsphere technique was established in two preliminary studies. On Days 14, 15 and 16 of the cycle the rate of blood flow (ml.min-1 .100 g-1 tissue) was 1122, 708 and 116 to the CL; 157, 258 and 140 to the stroma; and 627, 742 and 1096 to the follicles, respectively. Blood flow to grossly atretic follicles did not differ significantly from that to non-atretic follicles of an equivalent size. Change in blood flow do not appear to initiate or control the activation, steriodogenic function or atresia of follicles.

The objective of this study was to compare average stress levels during the month of conception to those of previous infertile months. We postulated that stress level during the actual month of conception would be lower than that during previous non-conception cycles. Thirteen normal women from the general community, who were attempting pregnancy, kept daily records of coital activity and basal body temperature, and twice a month completed self-administered questionnaires and provided a 12 h overnight urine sample. On average, women reported significantly more favourable mood states on standard psychometric tests, during the month of conception than during the previous non-conception cycles. In addition, they felt significantly less 'hassled' during the month of conception. However, mean urinary hormone excretion of adrenaline, noradrenaline and cortisol did not significantly differ between conception and non-conception cycles and there was little relationship between the psychological measures of mood state and excretion of adrenaline and cortisol. There was no evidence of increased coital frequency during the month of conception when mood states were improved, suggesting that stress effects on libido were unlikely to account for the findings. The results support the conclusion that psychosocial stress influences fertility in females but as yet mechanisms remain unclear.

High doses of estrogens cause embryonic mortality, and fetal and placental growth retardation in rats. This study addresses the physiological relevance of such findings. Estradiol benzoate (EB), by s.c. injection, or estradiol-17beta (E2), delivered by a miniosmotic pump, raised maternal E2 concentrations from only slightly above control values to 5-fold. EB (1 microgram/day) over Days 6-13, 8-13, and 11-13, and continuous infusion of E2 (15 ng/h; Days 10-13) reduced fetal survival to 0%, 0%, 22%, and 75%, respectively. Single injections of EB showed that its lethal effect declined rapidly over Days 9 (44% survival) to 13 (90% survival). Embryos died within 48 h, but death was not due to luteal failure since progesterone levels were maintained and progesterone administered with EB did not reduce mortality. Administration of EB at 1 microgram/day (Days 14-21) or E2 at 40 ng/h (Days 13-16) retarded fetal and placental growth but did not affect survival. The rat embryo is highly sensitive to elevated maternal estradiol concentrations over much of gestation. The early lethal effect implies that endogenous E2 production is carefully regulated to maintain pregnancy; the latter growth-retarding effect suggests that E2 may have a role in the normal control of fetal growth.