Lisa, perhaps what this midwife you are talking about really needs is a
brief lesson in statistics.  She is seeing two events (tandem nursing and
the younger nursling "not getting enough colostrum") which seem to occur
together.  Additionally, you say, she has noticed a relationship between
nursing through a pregnancy and long labor to deliver the new nursling.  So,
she is seeing events which appear to be correlated.  However, unless she has
been collecting and analyzing data on these events, she could not tell us
the strength of the correlation between the events, nor even the direction
of the correlation (positive or negative).  Regardless, this midwife should
be told that a basic principle of statistics is that correlation does NOT
equate to causation.

Take the classic example of the correlation between height and weight.  Does
an increase in height cause a gain in weight?  Or is it the other way
around?  More likely (and I think this may be true in the case of tandem
nursing and the correlates the midwife is seeing), there is a third variable
which is influencing both factors, i.e., a healthy, ample supply of food to
a baby causes an increase in both height and weight.  Perhaps this midwife
might be willing to consider other factors which might be responsible for
what she is seeing in her patient population.  The reality is that there are
a multitude of factors which influence a woman's decision to tandem nurse.
Also, there are wide variations in the amount of colostrum produced in the
first days after birth as well as variations in the time it take for mature
milk to appear.  Finally, there are many factors which affect birthweight,
length of labor, etc.  To attribute so many "adverse events" to one fairly
uncommon practice (tandem nursing) is an oversimplification.

Sara Dodder Furr, MA, breastfeeding volunteer and advocate
(former health data analyst in a previous life)
in rainy Lincoln, Nebraska

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