Plasma prolactin levels do not correlate with milk volume or rate of milk synthesis in mothers of term infants
There is definitely evidence to show increased milk production by mothers of prematurely born infants when they take domperidone, and this is standard practice. It is also reasonable to think that domperidone may help prepare the breasts when lactation is being induced in a non-puerperal parent.
Here, however, are the reasons why increasing plasma prolactin levels by taking domperidone is unlikely to increase the amount of milk produced by the mother of a term infant.
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Prolactin levels rise in a pulse after nipple stimulation and suckling, peaking about half an hour after the baby starts to suckle.
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Prolactin secretion varies with the circadian rhythm, resulting in serum levels being two or three times higher at night than during the day (including when not breastfeeding), peaking between two and six in the morning.
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But there is no good physiological rationale to the belief that night-time breastfeeds increase milk production because of the effect of night-time breastfeeds on prolactin levels. It is more likely that long periods overnight without milk removal are responsible for decreased milk production if a woman isn't breastfeeding during the night, due to raised intra-alveolar pressures.
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Baseline and peak levels are highly variable between women and do not correlate with a woman’s milk volumes or rate of milk synthesis.
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Frequent and flexible breastfeeds aren't likely to result in upregulation of milk secretion because of stimulation of prolactin and oxytocin. You can find out about the mechanisms more likely to underlie the upregulation of milk secretion here.
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Women with low breastmilk supply don’t usually have low prolactin levels.
| Time frame | Baseline prolactin levels ng/ml |
|---|---|
| Non-pregnant | 10 |
| Peak at birth | 200 |
| 10-90 days post-birth | 60-110 |
| 3-6 months post-birth | 50-100 |
| 6 months + post-birth | 30-40 |
Recommended resources
Does domperidone increase breast milk production? Dr Pamela Douglas, The Medical Republic 2022