First trimester (weeks 1–12)
- Oestrogen and progesterone: Rise rapidly to support implantation and early pregnancy; can cause fatigue, nausea, and heightened emotions.
- hCG (Human Chorionic Gonadotropin): Peaks early; helps maintain pregnancy and often contributes to pregnancy nausea and sickness.
- Mood impact: Many parents feel emotional swings, irritability, or anxiety as the body adjusts.
Second trimester (weeks 13–26)
- Oestrogen and progesterone: Continue to rise but stabilise slightly, often leading to more energy and fewer mood swings (“honeymoon trimester”).
- Relaxin: Increases to loosen joints and prepare the body for birth.
- Mood impact: Generally more stable; confidence may rise as morning sickness eases, though emotional changes are still normal.
Third trimester (weeks 27–40)
- Oestrogen and progesterone: Peak again to prepare the body for labour and lactation.
- Cortisol: Rises toward the end of pregnancy, increasing alertness but also anxiety or irritability.
- Mood impact: Fatigue, discomfort, and worry about birth can make mood swings more noticeable.
How hormones shift after birth
- Oestrogen and progesterone: Drop sharply, can trigger the “baby blues.”
- Oxytocin: Surges during birth and breastfeeding, helping parent and baby to bond, but also making emotions more intense.
- Cortisol: May remain elevated, contributing to stress or sleep disturbances.
- Mood impact: Emotional fluctuations are normal; prolonged sadness, anxiety, or hopelessness may indicate postpartum depression and should be addressed with support.
Once your baby is born, hormone levels drop quickly, especially oestrogen and progesterone.
This sudden shift can trigger the “baby blues”, tearfulness, irritability, or anxiety. For most people, these feelings are temporary, but they can be unsettling, especially when you’re adjusting to life with a newborn.
Common mood changes you might experience
The combination of physical changes, tiredness, and fluctuating hormones can make even small stressors feel huge.
It’s common to feel anxious, overwhelmed, or emotional in the third trimester and after birth. Recognising that your feelings are biologically influenced can make them easier to navigate.
Postpartum blues vs. Postpartum depression
Feeling down or tearful in the first two weeks after birth is common. But if low mood, anxiety, or hopelessness lasts more than two weeks, or interferes with daily life, it could be postpartum depression. This is not a sign of weakness, support and treatment can help.
Watch for persistent sadness, loss of interest in things you usually enjoy, difficulty bonding with your baby, or intense anxiety or panic attacks. These are signals to seek professional help.
Key hormones and their impact on mood
Oestrogen: The mood stabiliser
Rising oestrogen helps regulate serotonin, the “feel-good” neurotransmitter. When it drops during the postpartum period, it can contribute to low mood and irritability.
Progesterone: Calming or crashing?
Progesterone generally helps you feel relaxed, but rapid changes can leave you feeling unsettled or anxious.
Oxytocin: The bonding hormone
Oxytocin surges during birth and breastfeeding, strengthening bonding and calming stress. It also makes emotional responses feel more intense, so tears, or joy, might come more easily.
Cortisol: Stress and energy levels
Cortisol spikes during pregnancy and postpartum, helping your body respond to stress. Too much, too often, can heighten anxiety or tension.
