INTRODUCTION
Postpartum depression (PPD) is a psychiatric disorder, and one of the
main complications of pregnancy, affecting between 10% and 20% of
women in the year following delivery (1,2). PPD is a severe disease
associated with short-term complications such as suicide, and long-term
deleterious consequences, including depressive recurrence (2,3). It may
also have negative effects for the child, including disturbances of
early interactions (4).
Several types of PPD can be distinguished according to the onset of
symptoms, severity and evolution (5–8). Studies over the course of
several decades have consistently identified two distinct peaks of PPD:
one early in the postpartum period and another later (9–12). Early PPD
is usually defined as beginning in the first 6 weeks after delivery,
while late PPD develops between the second month and the end of the
first year postpartum (13–15).
PPD is a multifactorial disease. Some studies have reported
sociodemographic and psychiatric risk factors, including extreme ages,
primiparity or grand multiparity (more than 4 children), being single,
and personal or familial psychiatric history (1,16–19). The strongest
risk factor is a history of mood disorder (uni- or bipolar) (1,20,21).
Other psychiatric disorders, such as addictive, anxiety, or personality
disorders, are also considered to underlie vulnerability for PPD
(17,19,22). Stressful life events are also associated with higher rates
of PPD, whether they occur during childhood, adulthood or during
pregnancy (1,23). Obstetrical factors, such as unwanted pregnancy,
emergency cesarean section, or complications of pregnancy, are also
associated with PPD (17,24–26).
While sociodemographic factors, psychiatric history, and stressful
events have been individually described to be associated with postpartum
depression, their contribution to the specific and independent influence
on early or late PPD risk has not yet been characterized. Differences in
socio-demographic factors or depression history were found to contribute
to the onset timing of perinatal depression (pregnancy or postpartum),
establishing different trajectories of depression (9,27). However, to
the best of our knowledge, the distinction between early and late PPD
has not ever been studied. In addition, very few studies considering PPD
have a prospective design, making it extremely difficult to distinguish
factors associated with early PPD from those associated with late PPD.
While PPD is usually considered as a single disease irrespective of the
time of onset of symptoms, our hypothesis is that factors may differ
between early and late PPD. Indeed, the emotional and physical state of
the mother as well as the environment that she finds herself in change
between the first weeks postpartum and several months after birth (28).
Mother-infant bonding evolves during the first year postpartum and
changes the maternal emotional state; it seems important to determine
the differences between these two time periods. A better knowledge of
factors associated with early and late PPD is crucial to understanding
different physiopathological mechanisms, and to better target women at
risk.
We previously reported the prevalence of early and late PPD in a
prospective study involving 3310 women evaluated at three times in
postpartum, using face-to-face and telephonic interviews, as 8.3% and
12.9% respectively, resulting in one-year cumulative incidence of PPD
of 18.1% (29). The aim of the present study is (i) to identify risk
factors of early and late PPD among a wide range of variables including
sociodemographic characteristics, personal and family history of
psychiatric disorders, childhood trauma, and stressful life events
during pregnancy, (ii) to assess the contribution of each of these risk
factors to the development of early or late PPD.