Period Health 101: Phase 1 - Follicular Phase

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Period Health 101: Phase 1 - Follicular Phase

by Kristen DeAngelis, RD, LDN, RYT, CPT, 


In Period Health 101, we discussed the basics of why your period is so important to your health, along with what phases happen throughout the month. In this blog, we're discussing Phase 1, the Follicular Phase.







DAY 1 (of when your bleed starts) - until ovulation ~ day 14-18. 

Every cycle, by means of FSH (Follicle Stimulating Hormone), about 15-30 eggs start to mature to the ovaries (each egg is enclosed by a follicle). 

Follicles produce ESTROGEN, and estrogen is needed for ovulation to eventually occur (so if you aren’t getting a period or ovulating, you may not have adequate estrogen to reach the peak needed for ovulation to occur!)

The follicle race begins! The question is, what follicle will become the largest to dominate the pack?!  This “race” typically takes ~2 weeks to release the egg but can be longer or shorter depending on several factors like stress, training, caloric intake, or really any drastic shifts in your body or environment. 

*For those with ovarian cysts, these can happen when follicles continue to grow beyond normal size – (read follow-up post on ovarian cysts and PCOS)

*As I mentioned, estrogen is rising in this phase. And ESTROGEN is the primary factor that triggers luteinizing hormone (LH) to spike, which triggers ovulation. 




LH surges, triggered by estrogen buildup from the follicles, and the largest (most dominant) follicle at this point, gets released from one of your ovaries. 

SIDE NOTE: Did you know it takes 90-100 days for a follicle to fully mature and finally get to this peak of ovulation. If you were really stressed 2-3 months ago, it can totally affect your ovulation! Who knew?! 

LH is literally causing the egg to pass through the ovarian wall (for some this may result in slight pain or discomfort, known as Mittelschmerz), some may not feel this at all but just notice a change in digestion, slight bloating, or change in energy/mood. *If you are someone who notices major mood swings or feeling extremely emotional around ovulation, it may be an estrogen issue because estrogen is reaching a buildup at this time right before the egg is released. (I often recommend a combination of EstroFactors and Hormone Plus Complete to help improve a more balanced ratio of hormones and their detox pathways to help with major mood swings related to hormones!) 

*PSA: NOT all women ovulate on day 14 of their cycle! Our ovulatory day varies based on the individual (this is why you can’t just go by the prediction of an “app” that has no data other than when you bleed). Typically it’s anywhere between day 12-18. *If you are trying to regulate your cycle, or suffer from Hypothalamenic Amenorrhea, you may benefit from Vitex Chasteberry – I love Liposomal Chasteberry , seed cycling, and also working on stress, adrenal support, and supportive nutrition.  

After ovulation, the egg travels to the pelvic cavity and is swept up the fallopian tubes, where the egg stays alive for 24 hours (THIS IS THE TIME IF YOU WANT TO GET PREGNANT IT’s GO TIME.. if you are using natural contraceptive methods like Fertility Awareness Method, FAM (see post on this later!) and DO NOT WANT TO GET PREGNANT, this is the time to NOT engage in intercourse – you’re fertile mama!)

After 24 hours if the live egg is not met up with sperm, it will pretty much just disintegrate. 

*NOTE: If fertilization DOES occur… that means the sperm has made it’s way to the fallopian tubes and will then travel to the uterus to continue it’s development. 



Need help with amenorrhea or fertility issues? CLICK HERE for a free consultation with our team and request Kristen DeAngelis!


Kristen DeAngelis, RD, CYT, Registered Dietitian, Instagram kdwellness

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