Active ingredient: Pseudoephedrine

According to MotherToBaby, it is not known whether pseudoephedrine makes it harder to become pregnant because specific studies assessing its effect on female fertility are limited. The NHS, however, states that there is no evidence to suggest that pseudoephedrine affects fertility in women or men. (mothertobaby.org) There is no established clinical evidence that pseudoephedrine directly affects ovarian function or ovulation, including follicular development, ovulation timing, or luteal-phase duration. There is also no evidence that it alters menstrual cycle length. Pseudoephedrine is not known to directly alter basal body temperature or the progesterone-related post-ovulatory temperature rise. However, fever and systemic illness associated with the condition for which pseudoephedrine is taken may affect BBT independently of ovulation. Sleep disturbance may also make BBT measurements less consistent. Pseudoephedrine reduces nasal congestion and nasal secretions through sympathomimetic vasoconstriction. This effect is specific to the nasal mucosa, and there is no established clinical evidence that pseudoephedrine reduces cervical mucus or changes its fertility-related characteristics. Cervical mucus is primarily regulated by ovarian hormones, particularly estrogen, and changes in volume and physical properties around ovulation. Dry mouth and gastrointestinal symptoms such as nausea, vomiting or diarrhoea may occur with pseudoephedrine. If severe gastrointestinal symptoms cause true dehydration, hydration status could theoretically influence secretion volume or consistency. However, there is no evidence that pseudoephedrine causes clinically relevant changes in cervical mucus through this mechanism. Regarding pregnancy, MotherToBaby reports that most studies have not found an increased overall risk of birth defects with pseudoephedrine exposure, although some studies have suggested a small possible increase in specific defects. ACOG recommends avoiding pseudoephedrine during the first three months of pregnancy because of a possible small risk of abdominal wall birth defects. This recommendation concerns use during pregnancy and should not be interpreted as evidence of impaired fertility.