Bitter taste in the mouth after taking antibiotics can occur in various circumstances, depending on the specific type of antibiotic, the individual's sensitivity to it, and the dosage. In general, this condition occurs when the antibiotic causes an alteration in the taste buds or taste perception in the mouth. The following factors may contribute to the development of a bitter taste in the mouth after taking antibiotics:

1. Drug concentration: The concentration of the antibiotic in the bloodstream and oral cavity can affect the bitterness. High concentrations of the antibiotic may trigger a more intense bitter taste due to the direct impact on the taste receptors.

2. Individual sensitivity: Each person may have a different degree of sensitivity to bitter tastes. If the individual is more sensitive to bitterness, the antibiotic may be more likely to induce a bitter taste.

3. Genetic factors: Certain genetic variations, such as variations in taste receptor genes, may impact how an individual perceives bitterness from the antibiotic.

4. Duration of treatment: The longer the duration of treatment, the higher the likelihood of developing a bitter taste in the mouth.

5. Interactions with food and beverages: The antibiotic may interact with certain foods or beverages, making the bitter taste more pronounced or even changing the taste perception altogether.

6. Dosage: Higher dosages of the antibiotic may increase the risk of developing a bitter taste in the mouth.

7. Other factors: Certain medical conditions, such as diabetes, may contribute to an altered taste perception, making an individual more susceptible to experiencing bitterness after taking an antibiotic.

There isn't a specific point in the birth process where bitter taste in the mouth after taking antibiotics becomes more or less common. However, it is important to note that pregnant women or those planning to conceive should consult with their healthcare provider before taking any antibiotics, as some antibiotics can be harmful to the developing fetus.

In conclusion, the bitterness associated with taking antibiotics can vary in severity and frequency based on factors such as individual sensitivity, genetic variation, duration of treatment, and drug concentration. The bitter taste may occur at any time during antibiotic treatment, but it is essential to inform your healthcare provider if you experience any discomfort or altered taste perception, as it may indicate a potential side effect or an issue that requires further investigation.