1826 BRITISH MEDICAL JOURNAL VOLUME 287 17 DECEMBER 1983

its instability, its short duration of action, and its requirement
for carefully monitored infusion techniques.

For the present, then, we must accept that prostacyclin is
indeed powerful and useful in extracorporeal shunts. How
ironic that, despite its early claims to be a natural balancing
substance in the thrombotic equation, the usefulness of prosta-
cyclin has been most clearly proved in entirely man made
settings where blood meets an artificial surface. In the common
spontaneous vascular diseases we must recognise that not only
is prostacyclin not yet of proved value but that it is unlikely
to be so. The real hope here lies in the exploitation of this
novel compound to generate a stable, orally active prostacyclin
analogue which will have selective affinity for the platelet
receptors and will have minimal effects on the heart and blood
vessels. Like the inventor who answered his critics by saying
"But what is the use of a newborn baby?" we should be
prepared to say of epoprostenol "Wait till it grows up and has
children of its own-for what the world is waiting for is 'Son
of Prostacyclin.'

J R A MITCHELL
Foundation Professor of Medicine,
Nottingham University,
University Hospital,
Nottingham NG7 2UH

Kurzrok R, Lieb CC. Biochemical studies of human semen; action of
semen on the human uterus. Proc Soc Exp Biol Med 1930;28:268-72.

2 Bergstrom S. Chemistry of prostaglandin. Nordisk Medicin 1949;42:
1465-6.

3 Bergstrom S. Isolation, structure and action of the prostaglandins. In:
Bergstrom S, Samuelsson B, eds. Prostaglandins. Proceedings of the
2nd Nobel symposium. Stockholm: Almqvist and Wiksell, 1967:21-30.

4 Kloeze J. Influence of prostaglandins on platelet adhesiveness and platelet
aggregation. In: Bergstrom S, Samuelsson B, eds. Prostaglandins.
Proceedings of the 2nd Nobel symposium. Stockholm: Almqvist and
Wiksell, 1967:241-52.

5 Emmons PR, Hampton JR, Harrison MJG, Honour AJ, Mitchell JRA.
Effect of prostaglandin E1 on platelet behaviour in vitro and in vivo.
Br Med J 1967 ;ii :468-72.

6 Elkeles RS, Hampton JR, Harrison MJG, Mitchell JRA. Prostaglandin
El and human platelets. Lancet 1969 ;ii :111.

7 Vane JR. Inhibition of prostaglandin synthesis as a mechanism of action
for aspirin-like drugs. Nature New Biology 1971 ;231 :232-5.

8 Hamberg M, Svensson J, Samuelsson B. Thromboxanes a new group of
biologically active compounds derived from prostaglandin endoperoxides.
Proc Natl Acad Sci USA 1975;72:2994-8.

9 Moncada S, Gryglewski R, Bunting S, Vane JR. An enzyme isolated from
arteries transforms prostaglandin endoperoxides to an unstable substance
that inhibits platelet aggregation. Nature 1976;263:663-5.

10 Whittle BJR, Moncada S. Pharmacology of prostacyclin and thromboxanes.
Br Med Bull 1983;39:232-8.

1 Moncada S, Vane JR. Arachidonic acid metabolites and the interactions
between platelets and blood-vessel walls. N Engl J Med 1979;300:
1142-7.

12 Moncada S, Korbut R, Bunting S, Vane JR. Prostacyclin is a circulating
hormone. Nature 1978 ;273 :767-8.

13 Anonymous. The prototype. Lancet 1982;ii:424.
14 Lewis PJ, Dollery CT. Clinical pharmacology and potential of prostacyclin.

Br Med Bull 1983;39:281-4.
15 Sinzinger H, O'Grady J, Cromwell M, Hofer R. Epoprostenol (prostacyclin)

decreases platelet deposition on vascular prosthetic grafts. Lancet
1983 ;i: 1275-6.

16 Szczeklik A, Nizankowski R, Skawinski S, Szczeklik J, Gluszko P,
Gryglewski RJ. Successful treatment of advanced arteriosclerosis obli-
terans with prostacyclin. Lancet 1979;i:I 1 1 1-4.

17 Mitchell JRA. Clinical aspects of the arachidonic acid-thromboxane
pathway. Br Med Bull 1983;39:289-95.

1 Gryglewski RJ, Nowak S, Kostkatrabka E, et al. Treatment of ischemic
stroke with prostacyclin. Stroke 1983;14:197-202.

Legislation and teenage sex
To paraphrase Jane Austen, it is a truth universally acknow-
ledged that parliament should not make new laws when those
most closely affected advise that the proposed legislation is
unwise and unworkable. Earlier this month the BMA called a
press conference to leave the press and public in no doubt that
doctors do not want any change in the law governing the
prescription of oral contraceptives for girls under the age of 16.
No one doubts the good intentions of most of those who want
to prohibit doctors from prescribing the pill in these circum-
stances without the consent of the girl's parents; but the
campaigners have mostly been arguing from conviction rather
than experience. The attitude of doctors would have been very
different if the call for legislation had come from the families
directly affected-namely, those in which 14 and 15 year olds
have been prescribed the pill-or from doctors working with
teenagers. In practice the pressure has mostly come from
adults shocked by reports of promiscuous sexual behaviour
among adolescents but with little or no direct experience of the
realities.

Doctors in family planning clinics or in general practice who
are asked for advice on contraception by teenage girls have to
make a pragmatic assessment. Almost always these girls have
already formed a sexual relationship, often stable and overt.
Most have no wish to keep their mothers in the dark; of those
few who do ask for confidentiality, one third can be persuaded
at the first interview to tell their parents and another third
agree later.' The remaining third ofgirls must believe they have
very strong reasons for rejecting the doctor's advice-for
doctors do always make an attempt to bring the parent into the
picture.2 Who will gain from a law insisting that in these
circumstances the girl should be told that she may not be
supplied with a contraceptive ?
At the heart of the matter are the very different ways in

which people think of teenage sexuality. Should pregnancy be
seen as a punishment for illicit sex ? Is fear of pregnancy really
an important deterrent ? If sexually active teenagers are denied
access to medical contraception are they more likely to stop
having sex or to use some unreliable contraceptive technique
that requires no prescription ?
The BMA press conference spelt out the medical hazards of

early sexual experience and of pregnancy; doctors working
with schoolchildren are only too aware of the physical and
psychological problems that may sometimes be associated with
sexual activity in the early teens. But like it or not, doctors have
to work in the real world. Over the years we have worked out a
whole range of compromise solutions that seem to minimise
damage to our patients; intending legislators should be extra-
ordinarily certain that they have found a better answer.

Timmins N. All children's treatment threatened by pill challenge, doctors
say. The Times 1983 Dec 2:3 (cols 1-3).

2 British Medical Association. Minors and contraception. The handbook of
medical ethics. London: British Medical Association, 1981:18.

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