Four different major clinical complications were identified in a retro
spective analysis of 2495 in-vitro fertilization (IVF) cycles resultin
g in oocyte retrieval, The severe form of ovarian hyperstimulation syn
drome (OHSS) occurred in 18 patients, giving a prevalence for this com
plication of 0.7%. Seven (39%) of these 18 patients had previously bee
n diagnosed as having polycystic ovaries, Eleven patients were admitte
d with moderate OHSS. Adnexal torsion was diagnosed in two patients, O
variectomy was considered necessary in both cases, Complications of th
e transvaginal procedure occurred in seven cases (0.3%): one patient h
ad an acute appendicitis with puncture holes in the appendix, six pati
ents were admitted shortly after oocyte retrieval with a pelvic inflam
matory disease, Of the 624 pregnancies obtained, 13 were ectopic, givi
ng an ectopic pregnancy rate of 2.1%, It is concluded that serious cli
nical complications of IVF treatment are rare, However, patients shoul
d be counselled for the occurrence of serious procedure-related compli
cations before entering an IVF programme.