I did think so that can be happened .... at the same time, animal as well as human sexual drivers are probably the same and during the vaginal swap histology test all drivers are off so pseudo-pregnancy is less likely to be occurred...

Lastly ...You have to just calculate the phase of estrous cycle before you are going to do vaginal swap histology test..

Good luck

Yes.  Only use glass medicine droppers which are blunt

Dear, dr. Benalia Abdlelkrim. Good afternoon and I, hope you are fine.

About your question. And up on my modest experience. Yes, there is a risk, but you can reduce or completely avoidance these risks by initially synchronization of the estrous cycle, and by secondly (of important), use of specific stimulator preferably made of a glass bulb medicine probe (device) emerge with clean, non - toxic, and non - irritant of suitable lubricant oil. And, if want to avoided happening of pseudopregnancy during or when you try to take a vaginal swab. This can be done by decreased the repetition of taking vaginal swab for at least to (1-2 trial / day) in favorable with adequate gape of time (interval), between these of two consecutive trials.

Good luck.

Best wishes, 

NASEER ALUKHTAR

Dear Dr Benalia,

With my experience of collecting the vaginal sample and determining the stage of estrus cycle in the rats, the problem of pseudo-pregnancy is not encountered if appropriate procedure is followed. 

Since as a pre-requisite of many in-vivo reproductive experiments, female rats are subjected to daily collection of vaginal samples and staging them to ensure that the rats are cyclic. A non toxic, clean and blunt probe is gently inserted in vagina and 1 - 2 drops of saline is infused to irrigate the vagina and immediately sucked in the same probe and this sample is spread on a slide to make a smear. The smear is dried and subjected to staining to determine the stage of estrus cycle.

This procedure is simple and the animals gets used to it after a few exposures. Typically after a few trials (once a day for about 7 days) the animals get used  and do not struggle during the procedure. If the animal is stressed because of bad handling, it will not show a regular cycle because of stress but it does not get pseudo-pregnant.

For inducing pseudo-pregnancy, the females who are at estrus stage need to be copulated by sterile male who has undergone orchitectomy at least 4 weeks earlier.

So collecting vaginal swab does include mechanical stimulation by a probe, but the degree or intensity of stimulation is far below the level that is required to induce pseudo-pregnancy. Moreover, the rats gets used to the regular and routine vaginal manipulation for collection of samples and do not identify such stimulation to be similar or same as copulation.

Best wishes,

Sumitabha Ghosh

Dear colleagues, 

I thank you all for your answers which have really  added me to release this experiment 

Best regards