did you really not google it? 
(i went ahead and did it for you.)
low platelet count in pregnancy isn't all that uncommon. it's called gestational thrombocytopenia. while we are pregnant, we experience such a rise in blood volume that it's easy for the platelet count to fall as it gets diluted in the overall increase in blood volume. most of the time, if your platelet count is only moderately low, it doesn't pose a problem, but you'll need to keep monitoring it to make sure that it doesn't go too low. because platelets are responsible for blood clotting, having too few of them might make you at risk of excessive bleeding at birth. rapidly falling platelet counts paired with pregnancy- induced hypertension could be a sign of HELLP syndrome, but this is much less common. most of the time (~75%), low platelet counts are not a dangerous situation in pregnancy, but your doctor/MW will want to keep an eye on things.
everything i read said that unless your numbers are scary-low, there is no risk to your baby.
your platelet count is supposed to regulate back to normal a few weeks after delivery.
this is what one website recommended you could eat to help with your platelet levels:
beet root, tomatoes, dates, raisins, dried figs, soy, lentils, tofu, black strap molasses, prunes, beet greens, cashews, apricots, and peas. These foods help enhance the platelet count. Also, make sure your diet is absolutely free of refined foods – white flour, white sugar, processed foods – crisps, wafers, cookies, coffee, tea, and aerated beverages. They have a detrimental effect on the platelet level.
OF COURSE, i'm not recommending you substitute what i wrote for genuine medical/midwifery care. i just wanted to give you peace of mind before you could talk to the nurse again, that it's probably no big deal. The Google is a great tool, but i'm not suggesting it has all of the correct information all the time.
HUGS!
-hcm
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