What are ‘Normal’ blood test hormone levels in pregnancy?
The most common hormone looked for in pregnancy is human chorionic
gonadotropin (HCG), the “pregnancy hormone.”
This hormone can be found
in the urine as well as the blood, and is the basis of the home
pregnancy test. The level of HCG rises rapidly in normal pregnancy and
can be detected in either blood or urine as early as 8 or 9 days after
ovulation (before a missed period). Thereafter, it double every day and
a half to two days until about 60-70 days of pregnancy, at which time
it declines slowly. So the level in the blood can be used to see if the
pregnancy is "viable," that is, if it is progressing normally. If the
levels start to fall off earlier than 60 days, there is probably
something wrong and the pregnancy has a high risk of ending in
miscarriage (spontaneous abortion). Other hormones that are sometimes
measured in pregnancy are estriol and progesterone. Levels of these
hormones are correlated with the "viability" of early pregnancy.
However, there is no evidence that checking levels leads to any useful
ways of improving the chance of a good outcome (that is, live, healthy,
term baby), so there is really no reason to measure them as long as it
is known that the fetus (baby in the womb) is alive. This can be done
with ultrasound or by checking the HCG levels in the blood.
The test called the "triple screen," a screening test for babies with open
spine defects (hydrocephaly, spina bifida) and Down Syndrome, is an
optional blood test, done between 15-20 weeks. It checks for levels in
the mother’s blood of a protein called alpha-feto-protein, produced in
the baby’s spinal cord , and also amounts of HCG and estriol. This test
does NOT diagnose open spine defects or Down Syndrome; it only tells
you if you are at an increased risk over other women your age. If the
test says that you are, you then have to decide, with your midwife or
doctor, what other tests you might do to give you more information.
In conclusion, the most frequent and useful measurements of hormones in
pregnancy are HCG levels to see if you are pregnant and to make sure
that things are going well (only if there are signs that maybe they
aren’t, such as bleeding or cramping), and screening for spinal defects
and Down Syndrome, if you decide this is something you want to do.