Very large or very small placentas are both abnormal and warrant further investigation. I believe large placentas are often associated with diabetes. Anything that causes decreased perfusion (blood flow and oxygenation) to the placenta is going to affect its function, and may affect its size. If you have concerns about this, please seek information from a professional who knows more about placentas. Anemia can potentially cause problems with perfusion to the placenta. Hypertension causes microscopic damage to organs and vessels which may be one reason why gestational hypertension is associated with smaller placentas. (On the other hand, abnormal placentation is thought to potentially be a cause of hypertension and pre-eclampsia. It's a complicated topic.) edit: placentas should continue to grow throughout the pregnancy and keep apace with the fetus. If they don't, that suggests some alteration in perfusion.
The good news is that even with a placenta that isn't working as well as it should be, there are many things that can be done to protect mom and baby from ill effects, and good prenatal care includes all that.
DD1 6/2009 DD2 5/1/2013-5/5/2013 (HIE) DS 3/2014
Last edited by cyclamen; 03-30-2015 at 07:25 AM.