Introduction 

After giving birth, it's common for individuals to experience symptoms like mood swings, crying spells, and difficulty sleeping. These feelings usually start within the first two days after childbirth and last about two weeks.

In some cases, a more severe and long-lasting depression can occur, which requires treatment. Several factors including emotional, social, genetic, and hormonal changes during and after pregnancy contribute to the development of this condition. 

What is postpartum depression (PPD)?

Postpartum depression is a type of depression that happens after having a baby - but in some cases, it can begin during the later stages of pregnancy. It can cause sufferers to experience feelings of sadness, anxiety, guilt, worthlessness, and fatigue that last for a prolonged period after giving birth. Postpartum depression can significantly affect a mother’s relationship with their baby, and should be managed by medications and counselling.¹

What is the role of hormones in postpartum depression?

Despite decades of research focusing on identifying the causes of postpartum depression, they are still not understood. Many studies have shown that rapid changes in the levels of reproductive hormones in the blood before and after giving birth can play a significant role in postpartum depression. During pregnancy, hormone levels vary greatly, and after childbirth, the levels of several hormones can drop rapidly.

This hormonal shift can cause feelings of sadness, anxiety, and exhaustion, which are all commonly associated with postpartum depression. While hormonal changes are a normal part of the postpartum period, for some individuals, these changes can lead to mood disturbances that require medical attention. However, many other factors, including genetic and social, are also involved in postpartum depression.

Types of postpartum depression

Postpartum blues (or baby blues)

Postpartum blues (often referred to as baby blues) is a common condition that affects between 50 to 75% of mothers after giving birth.² It usually begins within one to four days of giving birth. Common symptoms of baby blues include anxiety and frequent crying for no reason.

However, It is not a serious condition and can subside within two weeks without medication. If someone is experiencing baby blues, they should seek support from those around them or from their healthcare provider.

Postpartum depression

Postpartum depression is a significantly more serious condition. It affects 1 in 7 mothers after giving birth, with the risk increasing by 30% each pregnancy for those who have previously experienced postpartum depression.³

While those affected by baby blues usually recover quickly, postpartum depression tends to last longer and severely affects the mother’s ability to return to normal function. Symptoms can spontaneously or gradually appear within a week after childbirth and can range from mild to severe. They may last several months and even up to a year.

Mothers with postpartum depression experience mood swings, frequent bouts of crying, irritability, persistent fatigue, feelings of guilt, anxiety, and may be unable to care for their baby or themselves. Treatments such as psychotherapy or antidepressants have demonstrated significant efficacy in managing the condition. 

Postpartum psychosis

Postpartum psychosis is a severe type of postpartum depression that requires emergency medical attention. This condition is rare and only affects between 1 and 2 mothers per 1000.² Symptoms are severe and appear quickly after delivery, and may last for weeks to several months.

Individuals with postpartum psychosis may suffer from severe agitation, hallucinations, confusion, insomnia, paranoia, delusions, hyperactivity, rapid speech, and mania. Due to these severe symptoms, both the mother and baby are at an increased risk of harm, and immediate medical attention is required. Treatment usually includes hospitalisation, psychotherapy, and medication.

Symptoms of postpartum depression

• Persistent feelings of sadness, hopelessness, or emptiness
• Tearfulness and irritability
• Changes in appetite (either increased or decreased)
• Changes in sleep patterns (difficulty sleeping or sleeping excessively)
• Physical complaints such as headaches or stomachaches
• Loss of interest in activities once enjoyed
• Difficulty bonding with the baby
• Excessive worry or anxiety about the infant's well-being
• Feelings of guilt, worthlessness, or inadequacy as a parent

How do you know if you have postpartum blues or postpartum depression? 

While baby blues and postpartum depression share similar symptoms, they differ in duration and intensity. Baby blues typically last around 1 to 2 weeks and have milder symptoms, whereas postpartum depression can last for several weeks or months and have severe symptoms. Whether you experience baby blues or postpartum depression, you should be aware that it's not your fault and you should seek support from the people around you and your healthcare provider.

Risk factors for postpartum depression

• A personal history of depression - mothers with a history of depression or other serious mood disorders are 30% more likely to develop postpartum depression
• A family history of depression³
• Depression or anxiety during pregnancy⁴
• Dysregulation in hormone levels
• Lack of social support
• Low socioeconomic status
• Marital or relationship conflict
• Pregnancy complications such as premature birth, difficult delivery, or loss of pregnancy 
• Delivering a baby with special needs or a baby that excessively cries
• Perceived body image (thinking poorly of appearance and lacking a sense of personal identity)⁵
• You're a single parent, or younger than 20 years old

The link between hormones and postpartum depression

The postpartum period is usually defined as the first six to eight weeks after giving birth, marked by hormonal shifts as the body adapts to the end of pregnancy. The postpartum period ends when the body returns to a pre-pregnancy state.⁶

Reproductive hormones 

Oestrogen and progesterone are the primary female reproductive hormones. These hormones reach peak levels throughout pregnancy to support foetal development and maintain the uterine lining. However, their levels decrease after childbirth, returning to pre-pregnancy concentrations or even lower.⁷

Oestrogen and progesterone influence several biological systems, including the activity of several neurotransmitters in the brain - particularly serotonin, dopamine, and gamma-aminobutyric acid (GABA). These neurotransmitters are crucial for mood regulation and have been directly linked with depression. This explains how hormonal instability in the postpartum period plays a major role in postpartum depression and other mood disorders.⁸

Studies have shown that reproductive hormones affect other systems that may contribute to postpartum depression, including: 

• Thyroid function⁹ 
• Lactogenic functions¹⁰ 
• The hypothalamic-pituitary-adrenal (HPA) axis¹¹ 
• The immune system¹²

Lactogenic function

Oxytocin, often called the love hormone for its role in social bonding and lactation, undergoes fluctuations during labour, delivery, and the immediate postpartum period. This is essential in facilitating uterine contractions, initiating breastfeeding, and enhancing maternal-infant attachment.¹³

The lactogenic hormones oxytocin and prolactin affect postpartum depression, as failed lactation and postpartum depression commonly happen together.¹⁴

Oestrogen and progesterone influence oxytocin expression in the brain regions associated with maternal behaviour and lactation.¹⁵ Oxytocin promotes feelings of nurturing when it is released during breastfeeding and skin-to-skin contact.

It regulates the synthesis and secretion of breast milk, modulates stress responses, and promotes relaxation. While decreased oxytocin levels during the third trimester are associated with increased depression during pregnancy and the immediate postpartum period,¹⁶ increased oxytocin secretion during breastfeeding is associated with reduced depression symptoms.¹⁷ This is why poor breastfeeding is associated with postpartum depression. 

Thyroid function 

Oestrogen increases levels of thyroid-binding globulin (TBG) and thus increases the blood's thyroxine (T4) levels. Depression accompanies thyroid dysfunction, which is often associated with pregnancy.^18,19 Therefore, thyroid dysfunction may contribute to postpartum depression.²⁰

Studies have shown that treatment with thyroid hormones accelerates and completes the treatment of depression. However, we need more studies to prove a clear relationship between thyroid dysfunction and the postpartum period.

Hypothalamic-pituitary-adrenal axis

During pregnancy, increased oestrogen can influence the intricate hormonal balance within the brain's hypothalamic-pituitary-adrenal axis (HPA). The levels of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and cortisol increase substantially during pregnancy and drop post-delivery. The HPA axis function returns to its normal state at around 12 weeks postpartum.²¹

This axis regulates mood and response to stress, and hypercortisolism is associated with depression.²² Also, the HPA axis is dysregulated by stress and trauma, which can be experienced in postpartum depression.^23,24

Women with postpartum depression exhibit higher baseline levels of cortisol, even without stress, and their stress response differs from women without depression.²⁵ Additionally, some studies indicate that elevated cortisol levels towards the end of pregnancy can be associated with postpartum depression.²⁶ However, we need further research to understand whether HPA axis dysregulation directly contributes to the onset of postpartum depression, or if it's a secondary effect.

Diagnosis 

Postpartum depression is diagnosed through a combination of screening tools like the Edinburgh Postnatal Depression Scale (EPDS), clinical assessment, and adherence to diagnostic criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).²⁷

Diagnosis involves evaluating symptom(s) and their duration and severity, and ruling out other conditions. Healthcare providers will assess those at risk by discussing their health history, and feelings after delivery. A physical exam and lab tests are also completed during postpartum visits. Individuals are advised to be open and honest to their healthcare providers so they can help determine if the individual’s feelings are normal or symptoms of postpartum depression.

It has been estimated that up to 50% of postpartum depression sufferers go undiagnosed because of conflict in privacy and fear of stigma or lack of support.¹ If you suspect you are experiencing postpartum depression, always remember that the earlier you seek support, the faster you will get better. There is nothing to be ashamed about, so do not hesitate to ask for support to protect yourself and your baby. 

Management and treatment

Treatment and recovery time varies depending on the severity of your depression and your individual needs. 

Baby blues 

The baby blues usually subsides within a few days to two weeks without medication. If you are experiencing baby blues, you should maintain a healthy diet and rest as much as possible, as exhaustion and sleep loss can increase feelings of sadness. You should also seek support from people around you and keep in touch with your healthcare provider, particularly if you are having issues breastfeeding or have any other health problems.

Postpartum depression

In addition to lifestyle changes and emotional and social support, postpartum depression requires medical intervention either through psychological counselling or medication.

Psychotherapy 

It is often helpful to discuss your feelings and concerns with a mental health professional. Examples of therapies used include:

• Cognitive-behavioural therapy (CBT)
• Interpersonal psychotherapy (IPT)

Antidepressants 

Healthcare providers may prescribe you an antidepressant to treat postpartum depression. Whilst traces of any antidepressants you take will end up in the breast milk, they have only a small risk of affecting the baby. It is up to your healthcare provider to weigh up the potential risks and benefits of antidepressant medications and monitor you throughout the course.

Common antidepressants for postpartum depression include sertraline, fluoxetine, duloxetine, amitriptyline, imipramine, and bupropion.

Antidepressants take at least three weeks to take effect. It is recommended you speak to a healthcare provider before coming off of your antidepressants, as they will help you gradually reduce your dosage to avoid relapse.

Anti-anxiety medications 

An anti-anxiety medicine may be recommended for a short time if you experience severe anxiety or insomnia.

Postpartum psychosis

Postpartum psychosis requires immediate treatment, and you may be admitted to a hospital for several days until you're stable. Treatment may require a combination of medications, such as antidepressants, antipsychotics, and benzodiazepines. If your symptoms do not respond to medication, electroconvulsive therapy (EST) may be recommended. 

Novel treatments based on the hormonal influence

Brexanolone (Zulresso) 

In 2019, the U.S. Food and Drug Administration (FDA) approved the first drug specifically for postpartum depression, called brexanolone. Brexanolone slows down hormonal changes after giving birth. It is given via intravenous infusion, and requires hospital admission and strict monitoring by a healthcare provider.

Zuranolone (Zurzuvae)

In 2023, the FDA approved Zuranolone, the first oral medication indicated to treat postpartum depression. Zuranolone has fewer side effects and does not require a stay in a hospital. It can be taken daily as a pill in the evening with a fatty meal.

Prevention strategies

While postpartum depression cannot be completely prevented, some strategies can reduce your likelihood of developing postpartum depression, such as: 

• Set realistic expectations and understand that there will be good and bad moments during pregnancy and the post-partum period
• Prioritise sleep or rest whenever possible, especially when your baby is asleep
• Find time for self-care, including enjoyable and relaxing activities
• Avoid isolation, stay connected with family and friends, ask for help, and communicate how others can support you
• Nurture your relationship with your partner
• Maintain regular exercise and balanced nutrition
• Attend prenatal classes to learn about potential challenges and coping tips
• Keep in touch with your healthcare provider to allow for early detection

Summary

Postpartum depression (PPD) is a type of depression affecting some individuals after childbirth. It is characterised by prolonged feelings of sadness, anxiety, and fatigue. It requires treatment through medication and counselling.

Hormonal shifts during and after pregnancy contribute to postpartum depression. The rapid drop of oestrogen and progesterone after delivery is directly implicated in this condition, as these hormones influence all the biological systems that can cause mood disorders.

However, many other factors contribute to postpartum depression, including genetic and social factors. Understanding the hormonal influences is essential for developing targeted interventions and prevention strategies for postpartum depression.