Perinatal Mental Health: Postnatal Depression and Puerperal Psychosis

Introduction

The perinatal period - pregnancy and the first year after birth - carries a substantially increased risk of both new and recurrent mental illness. Perinatal mental health problems affect up to one in five women, and their consequences extend beyond the mother to the infant's development and to the wider family.¹

This area matters disproportionately for two reasons. First, suicide is a leading cause of maternal death in the year after birth in the UK, and the MBRRACE-UK confidential enquiries repeatedly identify missed opportunities, fragmented care and failure to ask direct questions as contributing factors.² Second, puerperal psychosis is one of the few true psychiatric emergencies, with a rapid onset and a real risk of suicide and infanticide, and it is frequently missed because its early presentation can be mistaken for exhaustion or the baby blues.

The clinical task is largely one of discrimination: separating a normal, self-limiting adjustment from a depressive illness that will not resolve without treatment, and separating both from an emerging psychosis that needs assessment the same day.

Distinguishing the three conditions

Aetiology and risk factors

Perinatal mental illness arises from an interaction of abrupt hormonal change, sleep deprivation, psychological adjustment and social circumstances, superimposed on individual vulnerability.

• Hormonal - the precipitous fall in oestrogen and progesterone after delivery is the leading candidate mechanism, particularly for puerperal psychosis, alongside changes in the HPA axis and thyroid function
• Genetic vulnerability - especially strong for puerperal psychosis, which has a substantial familial component and close links with bipolar disorder
• Sleep deprivation - both a symptom and a powerful precipitant, particularly of mood elevation and psychosis
• Psychological - adjustment to a changed identity and role, unmet expectations of motherhood, birth trauma, and difficulty with feeding or bonding
• Social - lack of support, relationship difficulties, domestic abuse, financial strain, insecure housing, and recent migration or isolation

Risk factors

• Previous perinatal mental illness - the strongest single predictor
• Personal or family history of bipolar disorder or puerperal psychosis - a woman with bipolar disorder has roughly a 1 in 4 to 1 in 2 risk of a severe postpartum episode, which is why she needs a specialist preconception plan
• Previous depression or anxiety at any time
• Lack of social support, or being a single parent
• Domestic abuse - which frequently begins or escalates in pregnancy
• Unplanned pregnancy, or ambivalence about the pregnancy
• Traumatic delivery, emergency caesarean, or neonatal complications and NICU admission
• Stillbirth, previous pregnancy loss, or fertility treatment
• Substance misuse
• Discontinuation of psychotropic medication on discovering pregnancy - a common and avoidable precipitant of relapse

Clinical features

Postnatal depression

The criteria are the same as for any depressive episode, but the presentation has particular features worth knowing:

• Persistent low mood, anhedonia and fatigue - though fatigue must be interpreted against the baseline of caring for a newborn
• Guilt focused on motherhood - feeling like a bad mother, or that the baby would be better off with someone else
• Difficulty bonding with the baby, or feeling detached, indifferent or frightened of the infant
• Anxiety, often intense and focused on the baby's health and safety - anxiety is frequently more prominent than low mood in the postnatal period
• Intrusive thoughts of harm coming to the baby - very common, ego-dystonic, distressing, and usually obsessional rather than an indication of intent
• Sleep disturbance that persists even when the baby sleeps, which is a useful discriminator from simple exhaustion
• Hopelessness and suicidal ideation
• Reduced engagement with the baby, which is the mechanism by which maternal depression affects infant development

Puerperal psychosis

• Rapid onset, typically within days to two weeks of delivery, sometimes over hours
• Fluctuating, kaleidoscopic presentation - the picture can change markedly from hour to hour, which frequently leads to false reassurance when a patient is seen at a good moment
• Confusion and perplexity, often with disorientation
• Mood disturbance - elevated, depressed or mixed; the majority of cases are affective in nature and closely related to bipolar disorder
• Delusions, frequently involving the baby - that the baby is not hers, is defective, is possessed, or must be saved from some danger
• Hallucinations, which may include command hallucinations relating to the infant
• Marked behavioural disturbance - agitation, disinhibition, or conversely stupor and catatonia
• Insomnia, often with no felt need for sleep, which is an important early warning sign

Screening and assessment

• Whooley questions at the booking appointment and at postnatal contacts - the two-item depression screen
• Edinburgh Postnatal Depression Scale (EPDS) - a 10-item validated tool. Higher scores indicate greater likelihood of depression; item 10 asks directly about thoughts of self-harm and any positive response requires immediate follow-up regardless of the total score.
• GAD-2 for anxiety, which is frequently the dominant symptom perinatally
• Direct risk assessment - thoughts of self-harm and suicide, and thoughts of harm to the baby, asked explicitly and non-judgementally
• Assess the mother-infant relationship - bonding, responsiveness, feeding, and whether the baby's needs are being met
• Physical assessment - TFTs (postpartum thyroiditis is a common and reversible mimic), FBC for anaemia, and consideration of infection, particularly in a confused or febrile woman
• Safeguarding assessment for the infant and any other children, and enquiry about domestic abuse conducted when the woman is alone

Management

Baby blues

Reassurance, explanation that it is common and self-limiting, practical support with rest and feeding, and health visitor follow-up. If symptoms persist beyond about two weeks, reassess for postnatal depression.

Postnatal depression

• Mild to moderate: facilitated self-help based on CBT principles, or psychological therapy such as CBT or interpersonal therapy, with practical and social support⁴
• Moderate to severe: an antidepressant, usually combined with psychological therapy, with prompt referral to the perinatal mental health team
• Consider the mother-infant relationship explicitly - video-feedback and parent-infant interventions can help where bonding is affected, and treating the depression alone may not fully repair it
• Practical support matters - sleep, help with feeding, and reducing isolation are not soft extras but part of treatment
• Referral to specialist perinatal mental health services for severe illness, complex medication decisions, previous severe mental illness, or significant risk

Puerperal psychosis

1. Treat as a psychiatric emergency - same-day assessment by the perinatal mental health team or crisis team; never a routine referral
2. Do not leave the mother alone with the baby until risk has been assessed by a specialist
3. Admission to a Mother and Baby Unit is the standard of care, allowing treatment without separating mother and infant. Admission under the Mental Health Act may be needed where insight is absent.
4. Exclude organic causes - infection and sepsis, eclampsia, thyroid disease, anaemia, electrolyte disturbance and, rarely, autoimmune encephalitis can all present with postpartum confusion and psychosis
5. Antipsychotics for psychotic symptoms, with lithium or another mood stabiliser where the presentation is affective; ECT is highly effective and is used where symptoms are severe, where there is catatonia or food refusal, or where a rapid response is needed
6. Plan for future pregnancies - the recurrence risk is high, and a documented preconception plan should be made

Prescribing in pregnancy and breastfeeding

Prescribing decisions must weigh the risks of medication against the substantial risks of untreated maternal mental illness, which include relapse, self-neglect, poor antenatal engagement, preterm birth, impaired bonding and suicide. Stopping medication abruptly on discovering pregnancy is a common and dangerous reflex and frequently precipitates relapse - decisions should be made deliberately, ideally before conception.³

Every prescribing decision should be documented with the reasoning, the alternatives considered, and evidence that the risks and benefits were discussed. Specialist perinatal psychiatry advice should be sought where the decision is not straightforward, and the UK Teratology Information Service can be consulted directly.

Complications

For the mother, untreated perinatal mental illness carries risks of chronic depression, recurrence in subsequent pregnancies, relationship breakdown, and suicide - which remains a leading cause of maternal death in the year after birth. Substance misuse and self-neglect may follow.

For the infant, maternal depression is associated with impaired bonding and reduced maternal responsiveness, which in turn is associated with insecure attachment, and with later emotional, behavioural and cognitive difficulties. These effects are substantially reduced by effective treatment, which is a strong argument for early intervention. Puerperal psychosis additionally carries a small but genuine risk of infanticide, almost always driven by delusional belief - typically altruistic delusions that the baby is suffering or in danger - which is why immediate specialist assessment is non-negotiable.

Red flags

Prognosis

Baby blues resolve spontaneously and completely. Postnatal depression responds well to treatment, with most women recovering fully, though it recurs in a significant minority of subsequent pregnancies and there is an increased lifetime risk of further depressive episodes - so relapse-prevention planning matters.

Puerperal psychosis, despite the alarm of its presentation, has a good prognosis for the acute episode, with most women recovering fully within weeks to months of appropriate treatment. However, the recurrence risk in a subsequent pregnancy is substantial - of the order of 1 in 2 to 1 in 4 - and a significant proportion of women go on to have episodes of bipolar illness outside the perinatal period. This makes preconception counselling, a documented perinatal care plan and early specialist involvement in any future pregnancy essential rather than optional.