Declining incidence of ectopic pregnancy in a UK city health district between 1990 and 1999
Human Reproduction
Declining incidence of ectopic pregnancy in a UK city health district between 1990 and 1999
L.M.Irvine 1
M.E.Setchell 0
0 The Whittington Hospital , Highgate Hill, London N19 5NF , UK
1 Watford General Hospital , Vicarage Road, Watford, Herts WD18 0HB
3To whom correspondence should be addressed. BACKGROUND: On the basis of clinical impression that the number of cases of ectopic pregnancy seen in the City and Hackney Health District, London, was changing, a retrospective study of the years between 1990 and 1999 was carried out. METHODS: From the histopathology databases, cases of ectopic pregnancy and early pregnancy failure were identified. The number of deliveries at The Homerton Hospital was obtained from the Labour Ward register; the number of terminations of pregnancy and the number of fertile women was obtained from the Office for National Statistics, UK. RESULTS: There were 73 cases of ectopic pregnancy in 1990 rising to 96 in 1991 and then a fall to 52 cases in 1999. In terms of ectopic pregnancy per 100 deliveries, per all known pregnancies and per 1000 fertile women per year, there was a peak in 1991 and a fall to 1999. With regard to relative incidence per deliveries and per all known pregnancies, these falls were significant (P < 0.05). In 1991, there were 2.4 ectopic pregnancies per 100 deliveries, falling to 1.6 in 1999, a 33% fall. The reasons for this large decline are uncertain. CONCLUSIONS: There has been no change in patient population, diagnostic aids used or management protocols for patients with ectopic pregnancies.
ectopic pregnancy/relative incidence changes
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Ectopic pregnancy is defined as the implantation of a fertilized
ovum outside the cavity of the uterus. It is of considerable
medical importance since it is associated with an increased
risk of maternal death (Stationery Office, 1998), sterility and
problems in any subsequent pregnancies (Job-Spira et al.,
1996). Ectopic pregnancy is also one of the main reasons for
emergency admission to hospital, and investigations such as
ultrasound scans, pregnancy tests and diagnostic laparoscopy
have resource implications. Although no data are available
from the UK, it has been estimated that in the USA in the 1980s
the cost was about one billion dollars per year (Washington and
Katz, 1993). The problem with epidemiological studies of
extrauterine pregnancies is associated with its natural history
which may be observed, or pass unrecognized, because of
spontaneous resolution, and therefore not be observed. The
result is that any calculation can be distorted by artefacts such
as improved detection with the increasing use of laparoscopy,
transvaginal ultrasonography, highly sensitive urine pregnancy
test kits and quantitative serum human chorionic gonadotrophin
assays (Brennan, 1997; Ankum, 2000).
The choice of denominator used can also give rise to artefact.
The three commonly used denominators are the number of
births, the number of pregnancies and the number of women
of reproductive age (i.e. 1544 years). Births provide the most
accurate denominator as figures can usually be derived from
public records, but pregnancies may be more correct since
ectopics present at a time when the rates of miscarriage and
elective pregnancy terminations are substantial and possibly
should be included in any quoted figure. Since miscarriage is
not a registerable event, these figures may be difficult to
measure accurately. The earlier recognition of pregnancies
with the availability of over-the-counter urine pregnancy test
kits, and thus increased recognition of earlier pregnancy loss,
will influence such comparisons of incidence (Cuckle and
Murray, 1997). Figures based on the number of women of
reproductive age are influenced by the fertility rates and
contraceptive practices of the populations under scrutiny. In
England and Wales national data have been published. Using
official statistics on a routine 10% sample of hospital discharges
(Beral, 1975), the incidence per 1000 registered pregnancies,
excluding illegal abortions and miscarriages, increased
throughout the study period from 3.2 per 1000 pregnancies in
1966 to 4.3 in 1972. This corresponds to a rate of 2.8 and 3.7 per
10 000 women aged 1544 years. There have been numerous
publications on the increasing incidence of ectopic pregnancy
since the late 1970s. In the UK, a doubling over the period
from 1977 to 1986 has been reported (Dimitry and Morcos,
1990), and a similar increase has been reported in the Scottish
Highlands (Kok et al., 1989).
Many studies have tried to explain these rises, citing causes
such as improvements in diagnosis, but also the possible
association with the incidence of pelvic inflammatory disease
(Stray-Pedersen 1996; Low et al., 1999; Kamwindo et al.,
2000) or the change in maternal age distribution and the
increased incidence of ectopic pregnancy in older women
(Nyboe Andersen et al., 2000; Rajkhowa et al., 2000). There
are, however, fewer papers r (...truncated)