Some research suggests that Mucinex (or more specifically the active ingredient contained in Mucinex, guaifenesin) may help increase fertility by keeping the cervical mucus thin around the time of ovulation, which ensures sperm can travel freely through the cervix and also helps with sperm survival. An increase in fertility can help increase your chances of becoming pregnant.
Women with hostile mucus as the only cause of their infertility are the ones most likely to benefit from Mucinex (guaifenesin) treatment.
The research supporting its use for conception mostly comes from a 1982 study by Check et al, that investigated 40 couples who had had difficulty conceiving for at least a minimum of 10 months, and whose tests revealed hostile cervical mucus. Each woman received 200mg guaifenesin orally, three times daily from day 5 of her menstrual cycle until her basal temperature rise. 23 women showed a marked improvement in sperm motility and mucus quality while 7 showed slight improvement. 15 pregnancies occurred in the 23 couples showing a marked improvement with only 1 pregnancy occurring in those with a slight improvement. No pregnancies occurred in the 10 patients that showed no improvement. Of those women for whom hostile mucus was identified as the only factor contributing to their infertility, 8 became pregnant (80%), in an average of 2.4 months. No large randomized controlled trials (RCTs) have yet been conducted investigating the impact Mucinex has on fertility.
Mucinex (guaifenesin) is an expectorant that is usually used to thin mucus in the lungs and throat to make it easier to cough out when people have a wet, chesty cough. Using Mucinex to help with fertility is an off-label use (this means it has not been approved by the FDA).
What is the dosage of Mucinex (guaifenesin) used to increase fertility?
The dose used previously in the 1982 research was 200mg three times a day starting from day 5 of your period. Make sure you are taking a guaifenesin-only expectorant as some are available in combination products that may contain other ingredients such as dextromethorphan, that may potentially dry up cervical mucus.
However, several other factors also impact the likelihood of conception, such as sperm survival (an average of 3 to 5 days and a maximum of 7 days) and egg viability (24 hours) which means that cervical mucus only becomes a factor in the 5 to 7 days leading up to ovulation.
More recently, fertility experts have suggested guaifenesin only needs to be taken about 5 days before expected ovulation and continuing through ovulation day (six days in total for those with regular cycles). Those with irregular cycles should start 5 to 7 days before the earliest day ovulation might be expected. Some fertility specialists prescribe Mucinex (guaifenesin) with clomiphene because clomiphene can cause hostile mucus in 30% of women. If you are prescribed clomiphene (Clomid, Serophene) in a 5-day protocol, experts usually suggest waiting until the day after your last clomiphene pill before starting Mucinex.
Talk to your fertility specialist or doctor before you take Mucinex if you are having trouble conceiving, because it may not work or be suitable for you. In addition, it should only be taken while you are attempting to conceive and not once you are pregnant as Mucinex is considered pregnancy category C which means there are no controlled data in human pregnancies. One case series of 197 women reported an association between guaifenesin (Mucinex) exposure and an increased risk of inguinal hernias, although this was not supported by other studies.