Examples of causes of delayed onset of lactation and association with endocrine disturbances
| Cause | Effect on lactation | Associated endocrine abnormalities | References |
| Maternal factors/comorbidities | |||
| Pituitary insufficiency, for example, Sheehan’s syndrome | Absent or delayed onset | ↓ multiple pituitary hormones | 45 |
| Polycystic ovary syndrome | Delayed onset and/or lactation insufficiency due to lack of prenatal breast enlargement | ↑androgens, obesity-related endocrine abnormalities (see-below) | 46 47 |
| Obesity | Delayed onset | ↓ mammary responsiveness to prolactin | 50 51 |
| Primiparity | Delayed onset | Possible ↓ mammary responsiveness to pregnancy-related hormones | 48 49 |
| Labour and delivery factors | |||
| Medications, for example, epidural analgesia, i.v. oxytocin | Delayed onset | ↓oxytocin | 52 53 |
| Caesarean section | Delayed onset | ↓oxytocin, ↓prolactin | 32 54 |