ABC of prediction
of OHSS in assisted reproduction
Ovarian
hyper stimulation syndrome
is one of the main iatrogenic
complications of controlled ovarian hyperstimulation in Assisted reproduction. It occurs after triggering ovulation with
exogenous human chorionic
gonadotropin and may be aggravated
by pregnancy . The incidence of moderate OHSS with assisted reproductive techniques is 0.1-3%
OHSS can have potentially
fetal consequences in 3/100000
stimulated women.
Some of the
factors that increase the risk of developing
OHSS are younger age low BMI
previous history of OHSS
history of exaggerated response to gonadotropins in intrauterine insemination cycles and presence of polycystic ovarian syndrome.
Pathophysiology
: Administration of hCG leads to an increase in various interleukins causing increased
capillary permeability resulting in fluid
shift from intravascular
to the extra vascular compartment . This leads to ascites occasionally pleural effusion and enlarged ovaries.
The rapid fluid shift also causes
hypovolemia and hemoconcentration
. The
haemoconcentration that
occurs is reflected in the rise of hematocrit level
Severity of OHSS
is classified according to the criteria suggested by Golan et al
Mild OHSS :
nausea vomiting ovarian size < 5 cm
Moderate
OHSS: abdominal distension
ascites along with
nausea and vomiting with
ovarian size more than 5 cm
Severe OHSS
: massive ascites haemoconcentration breathlessness Oliguria enlarged ovaries.
REVIEW OF LITERATURE
According to the royal college of
obstetricians and Gynae cologists OHSS
complicates almost 33% of cycles
of ovarian stimulation and
incidence of severe form varies
between 3 and 8 5 of IVF cycles.
OHSS adds
to the emotional and financial
burden of IVF and hence
we felt a need to search
for a simple marker which could help predict development
of OHSS and manage the
situation better avoiding
the associated morbidity
Risk factors
suggested for OHSS are PCOS
age multifollicular
response high estradiol on the day of HCG
and lean habitus.
A study on OHSS found
that the haemoconcentration established
by an increase of hematocrit of more than 35%
on the day of OPU was more
likely to result in OHSS when the haemocrit on the day
of OPU was more than 40% almost 60%
of the subjects developed OHSS.
When plotted on a receiver operator
characteristic curve the
haematocrit on the day of OPU had a 77.8% sensitivity for predicting OHSS but a poor
specificity .
Sensitivity of the haematocrit level on the day of ET in predicting OHSS was 85.2%
with the diagnostic accuracy
of 83.5% Due to the low prevalence of OHSS the
positive predictive value was 52.3% however
when th haematocrit on the day
of ET was less than 35%
the chances of developing OHSS
are small with a negative
predictive value of 81.8%
Predicting the occurrence of
OHSS therefore justifies the use of
hematocrit as a simple test.
Another predictor
of OHSS suggested by Verit et
al is the neutrophils lymphocyte ratio
which was found superior to platelet
lymphocyte ratio with a
sensitivity of 85% and specificity of 785
However it can be argued that
haemotocrit is a much simpler and
cheaper parameter to analyse compared to the above ratios.
Quantitative
3D Doppler angiography has also been studied as a predictor of OHSS There
was no demonstrable increased ovarian
blood flow between the women who developed OHSS
and those who did not thus
disproving the hypothesis.
AMH is a
more recent kid on the block Apart from being
considered a good predictor
of the ovarian response to controlled ovarian
hyperstimulation its role in predicting OHSS is also encouraging . In the study by Lee
et al AMH was found to be a better
predictor of OHSS than age and NMI
as well as marginally better
than the estradiol levels on the day of HCG.
Haematocrit is a simple inexpensive and fairly
accurate test for predicting the
development of OHSS in ART. There should
be a thorough assessment and a low threshold to defer embryo
transfers in women with a
hematocrit of more than 35% on the day
of ET or those showing
an increase 
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