Many healthy and fertile couples find that it takes them several months to conceive. Typically, a couple younger than 35 is advised to wait until after trying for a year before seeking a fertility evaluation. If there are unique concerns in your case, please discuss them with your physician.
It is common for women to immerse on the fourteenth night, and it is also common for such women to become pregnant. However, it does sometimes happen that a woman ovulates prior to immersion, and that affects fertility.
To address this concern, you should first make sure that you are getting to mikveh as early as halachically permitted. Sometimes, a woman misses her fertile window because she waits longer than halachically required before completing her seven clean days. The hefsek taharah, moch dachuk, and bedikot of the seven clean days do not need to be completely clear; many shades of brown are acceptable. Bedikot that are not clearly red should be brought to a halachic authority for evaluation.
If ensuring you are getting to mikveh as early as halachically permitted does not provide the solution, the next step is clarifying precisely when you are ovulating. You could use an ovulation predictor kit, readily available at pharmacies, for a few cycles and also explore other options for ovulation tracking (see more here).
If it seems you are consistently unable to immerse before ovulation, please read our article on the topic and then turn to your physician to discuss the best course of action for you.
Support during this process is available from Yoatzot Halacha Fertililty Counselors, who offer free consultations for women and couples experiencing fertility challenges. Click here to set up a meeting.
This response was updated on 22 November, 2020.