"I can't see the connection,"
argued Vicky Baker, a 29-year-old mum of two in response
to past research suggesting that elective c-sections ward
off the postpartum blues. "In any case, opting for
c-sections isn't a good idea —
I wouldn't," she said as she nursed her one-month-old
daughter Kiana. Research published online February 25
in the British Medical Journal supports Vicky's
views and sends a clear message that we should abort
this notion. The study authors strongly suggest that
the risk of postnatal depression is certainly not a
valid reason to abandon vaginal birth.
"There is no reason for women with
a history of depression or those at high risk of depression
to be managed differently with regard to mode of delivery,"
concluded the authors, who were led by the University
of Bristol's Dr Roshni Patel. "Furthermore, even if
emergency cesarean section or assisted vaginal delivery
is required, women can be reassured that there is no
reason to believe that they are more likely to experience
postnatal depression."
The researchers base their conclusions
on data from the Avon longitudinal study of parents
and children, a cohort of over 14,000 women recruited
antenatally in 1990-92. All of the participants in the
study completed a depression questionnaire eight weeks
after delivery, which gave a score on the validated
Edinburgh postnatal depression scale. The women had
also been tested for signs of prenatal depression at
18 and 32 weeks.
CONFOUNDING
DATA
When elective c-section was compared to planned vaginal
delivery, the researchers' initial finding was that
c-section increased the risk of postnatal depression
by 30%. But once the data was adjusted for prenatal
factors associated with elective c-section, such as
maternal age, previous c-section, diabetes, gestational
age at delivery and non-cephalic presentation, as well
as for housing status, the relative risk fell to a completely
meaningless odds ratio of 1.06.
The team also compared patients
who underwent emergency cesareans to those who experienced
spontaneous vaginal delivery. In this case, both the
adjusted and the unadjusted data suggested that rates
of postnatal depression were identical in both groups.
Assisted vaginal delivery also showed no noticeable
effect on depression rates.
There have been previous studies
on mode of delivery and its effect on depression, some
of which also found no link, but none ever produced
such clear evidence as this study, which involved more
than five times as many patients as all previous research
combined.
Postnatal depression is taken more
seriously than 'normal' depression because it's known
to harm child development. Children of mothers diagnosed
with postnatal depression tend to have higher rates
of intellectual deficits at age four, behavioural problems
at age five and special educational needs at age 11.
But none of that means that postnatal
depression is a separate condition. The authors noted
that "the prevalence of depression in the postnatal
period is similar to background population rates of
depression and affects about 8-15% of women." Risk of
postnatal depression is also strongly associated with
prenatal depression, suggesting that postnatal depression
is in fact ordinary depression that simply happens to
occur around the time of pregnancy.
BMJ
published online Feb 25, 2005
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