Effect of vaginal pH on the efficacy of vaginal misoprostol for induction of midtrimester abortion.
OBJECTIVE
To evaluate the effect of vaginal pH on the efficacy of misoprostol for induction of midtrimester abortion.


METHODS
The study comprised 110 women, with a gestational age of 14-26 weeks, with a missed abortion as an indication for the induction of abortion. On admission, the vaginal pH was measured and two groups were generated: (A) those with pH<5 (n=63); and (B) those with pH >or= 5 (n=47). All of the women received intravaginal misoprostol tablets moistened with 3 mL of 5% acetic acid, 200 microg every 4 h for a maximum of 5 doses within 24 h. If the patient did not have adequate uterine contractions, the same regimen was repeated over the following 24 h and if no response was achieved, this was considered a failure of therapy.


RESULTS
All patients aborted within 48 h. A significant positive correlation between vaginal pH and the misoprostol application-abortion interval was found. The mean induction-abortion interval was significantly shorter in group A compared to group B (12.1 vs 23.6 h, P<0.001), with abortion rates at 24 h being 100% and 63.8%, respectively. Moreover, a significantly lower dose of misoprostol was used in group A with a lower incidence of fever and abdominal pain.


CONCLUSIONS
Vaginal pH influences the efficacy of misoprostol administered vaginally for the induction of midtrimester abortion. The presence of this relationship, despite premoistening misoprostol with an acidifying agent, suggests that the effect of vaginal pH might extend beyond affecting the pharmacokinetics of the drug.
Abd-El-Maeboud
Karim H I
KH
Ain Shams University Maternity Hospital, Cairo, Egypt. kabdelmaeboud@yahoo.com
Ghazy
Abbas A S
AA
Nadeem
Amr A-A
AA
Al-Sharaky
Amr
A
Khalil
Alaa-Eddin I
AE
D000020:Abortifacient Agents, Nonsteroidal / Q000008:administration & dosage*; D000028:Abortion, Induced; D000282:Administration, Intravaginal; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016595:Misoprostol / Q000008:administration & dosage*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D016896:Treatment Outcome; D014621:Vagina / Q000502:physiology*
D000020:Abortifacient Agents, Nonsteroidal; D016595:Misoprostol