Effects of in-utero exposure to oral nifedipine and labetalol on some reproductive indices in hypertensive pregnant wistar rats

The study investigated the effects of in utero exposure to oral nifedipine and labetalol on some reproductive indices in hypertensive pregnant wistar rats. Thirty (30) pregnant female rats were randomly divided into six (6) groups of five (5) rats each and were treated as follows: Group 1: Normotensive pregnant control rats, Group 2: Normotensive pregnant rats + 51.1mg/kg b w of Nifedipine, Group 3: Normotensive pregnant rats + 2.5mg/kg b w of Labetalol, Group 4: Hypertensive pregnant control rats, Group 5: Hypertensive pregnant rats + 51.1mg/kg b w of Nifedipine and Group 6: Hypertensive pregnant rats + 2.5 mg/kg b w of Labetalol. Hypertension was induced in rats by using 8% sodium chloride added to their regular feeds for a period of eight weeks. The female rats were mated with fertile male rats in a ratio of 2:1. Treatment was given orally to animals once daily throughout gestation period in all groups till ten (10) days postpartum. At the end of treatment, reproductive indices were calculated and all animals from each group were sacrificed at postnatal day 10 and the uteri were excised and stained in few drops of 10% ammonium sulphide for ten (10) minutes to determine the implantation sites and post implantation losses. The results obtained revealed that the correlation of the implantation site with the litter size indicated that post implantation loss of 9% recorded from rats in the normotensive pregnant control group was significantly lower than the nifedipine (51.1mg/kg b w) and labetalol (2.5mg/kg b w) treated normotensive pregnant rats which had 25% and 45% post implantation losses respectively with labetalol (2.5mg/kg bw) treated normotensive pregnant group recording the highest post implantation loss. On the other hand, 11.1% of post implantation loss was also recorded from rats in the hypertensive pregnant control group which was significantly lower than the nifedipine (51.1mg/kg b w) and labetalol (2.5mg/kg b w) treated hypertensive pregnant animals which recorded 22.5% and 30.0% post implantation loss. It can be concluded that these anti-hypertensive drugs may be involved in large percentage of implantation losses especially in subject with pre-existing or chronic hypertension in pregnancy that may require the drugs throughout gestation.