We have previously shown that administration of progesterone during early pregnancy in
sheep enhances fetal weight and crown–rump length. The present study examined the effect
of this treatment on individual fetal organ weights and on placental growth and structure.
Embryos that had been exposed to either a normal or a high concentration of progesterone
on days 1–3 in initial recipient ewes were transferred at random to final recipient ewes that
had or had not been treated with progesterone on days 1–3. Embryos in an additional group …