Michael K, Ward B S, Moore W M
Eur J Obstet Gynecol Reprod Biol. 1983 Sep;16(1):53-62. doi: 10.1016/0028-2243(83)90220-4.
Placental weight and macroscopic surface area are closely correlated with fetal weight throughout the second half of gestation in the pig. The limiting effect of placental size on fetal weight becomes more obvious as gestation advances. Fetal weight/placental weight ratio increases as placental weight decreases. Within individual litters, lightweight placentas have up to 150% more macroscopic surface area per unit placental weight.
在猪的整个妊娠后半期，胎盘重量和宏观表面积与胎儿体重密切相关。随着妊娠进展，胎盘大小对胎儿体重的限制作用变得更加明显。随着胎盘重量的降低，胎儿体重与胎盘重量之比会增加。在同一窝仔猪中，较轻的胎盘每单位胎盘重量的宏观表面积比其他胎盘多150%。
