Saliva oestriol, oestradiol, and progesterone concentrations were measured in 23 women who went into spontaneous preterm labour. The patients fell clinically and biochemically into two groups. The 13 who went into preterm labour with intact membranes had a saliva oestriol to progesterone ratio greater than one in every case and greater than the 95th centile for their length of gestation in 12 cases; by contrast, all those who went into spontaneous preterm labour after prolonged rupture of the membranes had an oestriol to progesterone ratio less than one and below the 50th centile for their period of gestation in the one to four days before delivery. Saliva oestradiol to progesterone ratios were randomly distributed throughout the normal range in both groups.It appears that preterm labour without prior prolonged rupture ofthe membranes is, like term labour, preceded by an increase in the saliva oestriol to progesterone ratio. It may therefore be possible to use this ratio to predict preterm labour. IntroductionPreterm delivery is a main cause of neonatal morbidity and mortality in Britain. The mechanisms underlying the onset of idiopathic preterm labour are poorly understood, and if the incidence of preterm labour is to be reduced we must increase our understanding of the events that lead up to it.

Saliva steroid levels reflect the unbound unconjugated (free, biologically active) plasma hormone levels. Saliva oestriol (E3), oestradiol (E2), oestrone (El) and progesterone levels were estimated by radioimmunoassay in saliva samples obtained twice a week from 18 weeks gestation until 38 days before delivery and then daily until the spontaneous onset of labour at term from 20 normal pregnant women. The overall percentage increases in the median concentrations of E3, E2, El and progesterone were 718, 370,80 and 214%, respectively, in the last 20 weeks and 149, 82, 24 and 41%, respectively, in the last 6 weeks of pregnancy. The median E3:progesterone ratio rose slowly from 0.65 at 20 weeks before delivery to 1.0 at 5 weeks before delivery and then rapidly to 1.65 one day before the spontaneous onset of labour. There was an increase in the E3:progesterone ratio from <1 to >1 before labour in every subject.

Self-administered subcutaneous human menopausal gonadotrophin is a safe and effective mode of therapy in increasing testicular size and inducing spermatogenesis in males with hypogonadotrophic hypogonadism.

When human chorionic gonadotrophin (hCG) is used to stimulate testosterone synthesis and release in males with hypogonadotrophic hypogonadism, it is administered two or three times weekly by intramuscular injection. We have compared the pharmacokinetics of a twice weekly standard dose of hCG (5000 U) given for the first week by intramuscular injection and in the second week by self-administered subcutaneous injection. The patients studied had Kallmann's syndrome, isolated idiopathic hypogonadotrophic hypogonadism or post-traumatic isolated hypogonadotrophic hypogonadism. Salivary testosterone was collected twice daily at 08.00 h and 20.00 h, and serum testosterone was collected after 0, 24 h, 72 h, 120 h and 168 h each week. The cumulated serum and salivary testosterone levels were comparable on both intramuscular and subcutaneous hCG. In normal males there is diurnal variation in testosterone, with peak serum levels in the morning falling to a nadir in the evening. The exact nature and controlling factors of this circadian rhythm have not been established. In four of the subjects, the twice weekly hCG injections, either subcutaneous or intramuscular, produced a regular testosterone diurnal rhythm. The other four patients had fluctuations in testosterone but with no strict diurnal pattern. This study provides evidence that the luteinizing hormone-like action of hCG is necessary to prime the circadian rhythm but only a single bolus of hCG is sufficient to induce the rhythm in the absence of endogenous gonadotrophin production. In conclusion, self-administered subcutaneous hCG is safe and produces comparable levels of serum and salivary testosterone to that administered by the intramuscular route. Moreover, it was very well accepted by the patients and was preferred to conventional treatments. Human hCG in some patients with hypogonadotrophic hypogonadism produces normal physiological changes in daily testosterone levels.