Introduction: The present study aims to investigate the effects of nicotine on foetal loss,
postnatal growth and corresponding levels of oestrogen and progesterone in pregnant rats.
Methods: Subcutaneous injection of nicotine tartrate (7.5 mg/kg/day) was administered to
groups of pregnant rats; with treatment scheduled from day 1 through day 5, day 5 through
day 9 or day 1 through day 9 of pregnancy. On day 10 of pregnancy, laparotomy was
performed to count the number of blastocyst implantation sites. During parturition, the
number of viable pups was recounted and statistically compared with the controls. One
group of rats which received nicotine from day 1 through day 9 of pregnancy was sacrificed
on day 16 of pregnancy, and circulating levels of oestrogen and progesterone were
measured. Upon delivery, the birth weight of the pups was measured, and their weights were
recorded until weaning. Results: There was a significant increase in foetal loss particularly in
rats which received nicotine from day 5 through day 9 and from day 1 through day 9 of
pregnancy. There was also significantly lower birth weight of pups in all groups; however,
this pattern did not continue until weaning. Plasma oestrogen level was significantly elevated
with a significant decrease in the plasma progesterone level. Conclusions: Nicotine
administration during pregnancy showed an increase in foetal loss with a corresponding
increase in oestrogen and decrease in progesterone levels. Although the birth weight of the
pups was low, there was catch-up growth in the pups.