On 19/7/02 3:27 AM, "Automatic digest processor"
<[log in to unmask]> wrote:

> At what point in
> gestation, that if the pregnancy ends and delivery occurs, ie stillbirth,
> does lactation occur.

One study showed the initial secretion of lactose in urine (which reflects
the ability of the breast to synthesize milk components) occurs between  15
to 20 weeks gestation (with some as early as 10 weeks). Increase in lactose
excretion also correlates with an increase in blood prolactin at this time.
So this is termed the general time of Onset of lactogenesis I (obviously a
wide variation). Lactogenesis II onset is then triggered by delivery of the
placenta.
Arthur, P. et al. 1991. Lactose in Blood in non pregnant,  pregnant and
lactating women. J Pediatr Gastoent Nutrit. 13: 254-259.

Another study found rate of lactose excretion was significantly  higher by
22 weeks than before 12 weeks gestation. There was a further significant
increase  at 28 weeks.
There was however a large variation  with one women having no breast growth
during pregnancy and minimal lactose excretion, but then had a normal
increase near and after term.

Cox et al.1999. Breast growth and the urinary excretion of lactose during
human pregnancy and early lactation: endocrine relationships.
Exp Physiolog. 84: 421-434.

So the short answer is - can be as early as 10-15 weeks, although the
average seems to be 15-22 weeks.

Cathy Fetherston
Perth, Western Australia

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